Latin American Coral Reefs

Latin American Coral Reefs

EXPLANATORY TEXT OF COVER 1) Coral reef and lagoon at Achutupo, San Bl~is Islands, Caribbean of Panam~i (see chapter by Guzm~in, map: Fig. 1, eastern region). Photograph by Jorge Cort6s. 2) Chapeiros and reef structures of Itacolomis, Bahia, Brazil (see chapter by Le~o et al., map: Fig. 18" Coral reefs of the Cabr~ilia~orto Seguro area, eastem region). These reefs are located near Mount Pascual, the first point of Brazil seen by a European, Pedro /klvares Cabral in 1500. Photograph by Ruy Kenji P. Kikuchi.

3) Punta Islotes, Golfo Dulce, Costa Rica (eastern Pacific) (see chapter by Cort6s and Jim6nez, Pacific of Costa Rica, map: Fig. 8). Photograph by Jorge Cort6s. 4) Colpophilia breviserialis from Cahuita, Costa Rica (see chapter by Cort6s and Jim6nez, Caribbean of Costa Rica, map: Fig. 3). Photograph by Jorge Cort6s. Cover created by Percy Denyer.

l~atin American Coral Reefs

Edited by Jorge Cortds CIMAR Universidad de Costa Rica San Pedro, Costa Rica

2003

ELSEVIER Amsterdam-Boston-London-New York-Oxford-ParisSan Diego'San Francisco-Singapore-Sydney-Tokyo

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9 2003 Elsevier Science B.V. All rights reserved.

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Foreword The global decline in coral reefs during the last decades has provoked the most serious concerns about these remarkable ecosystems. If these declines were owing to a single worldwide cause, like influenza, plague and aids in humans, the focus of efforts to understand and remedy it would be clear. Instead, the causes of declines as well as the nature of reefs vary significantly from region to region and within regions. Thus the urgent need is to examine reefs and their declines regionally. This volume is one of the first of a new and much-needed series of compilations about reef regions of the oceans and their conditions. The collection offers comprehensive treatments of reefs of sixteen Latin American countries. For each, the Editor wisely established a standard format, which covers all the major aspects of reefs, the extent and nature of declines and their causes, and management efforts. The product is an in-depth characterization of the region's reefs, which will be of wide interest to reef scientists, managers and students. Coral Reefs of Latin America includes examples of an unusually wide range of oceanographic-tectonic settings. Caribbean reefs are interconnected by the Western Boundary Current (Gulf Stream System) such that the faunas and floras are the same over the entire regions. They have well-developed barrier, atoll and lagoonal reefs. They are frequently impacted by hurricanes, diseases and over-fishing and locally by runoff and sewage discharges. The southernmost reefs of the Western Atlantic off Brazil have an endemic coral fauna different from that of the Caribbean and some quite special morphologies; they are outside the influence of hurricanes, but subject to sediment stress in nearshore zones. Eastern Pacific reefs represent the global suboptimal endmember; they occur in the nearshore areas of a narrow shelf with extreme and often lethal temperature changes - upwelling and the elevated temperatures of E1 Nifio. The coral communities fringing remote Easter Island, which are bathed by subtropical sea conditions have a depauperate coral fauna; it is nevertheless surprisingly healthy, but has not produced significant relief over the surrounding sea floor. For anyone with a serious interest in coral reefs, this volume is an invaluable resource. For marine biologists, geologists and students it is on the one hand a welcome handbook. Each chapter provides summaries of previous research, through descriptions of subdivisions and even individual reefs. Included also are up-to-date information on declines and their presumed causes as well as management efforts. The tectonichydrographic explanation for the large-scale variability of Latin American reefs is a welcome framework, which may well apply to other reef regions. Moreover, the volume provides the necessary ingredients for other comparisons within and between the reefs of each country. University of Miami

Robert N. Ginsburg

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vii

CONTENTS Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

V

ix

INTRODUCTION Coral reefs of the Americas: An introduction to Latin American Coral Reefs J. Cort6s

BRAZIL Corals and coral reefs of Brazil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Z. M. A. N. Le~o, R. K. Kikuchi and V. Testa

CARIBBEAN The Cuban coral reefs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. M. Alcolado, R. Claro-Madruga, G. Men6ndez-Macias, P. Garcia-Parrado, B. Martinez-Daranas and M. Sosa

53

The coral reefs of the Dominican Republic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F. X. Geraldes

77

Puertorican reefs: research synthesis, present threats and management perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J.R. Garcia, J. Morelock, R. Castro, C. Goenaga and E. Hern~ndez-Delgado

111

The Atlantic coral reefs of M6xico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. Jord~n-Dahlgreen and R. E. Rodriguez-Martinez

131

Coral reefs of Guatemala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. C. Fonseca E. and A. Arrivillaga

15 9

The reefs of Belize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. Gibson and J. Carter

171

Nicaragua's coral reefs: status, health and management strategies ............ J. Ryan and Y. Zapata

203

Past, present and future of the coral reefs of the Caribbean coast of Costa Rica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. Cort6s and C. Jim6nez

223

Caribbean coral reefs of Panama: present status and future perspectives .... H. M. Guzm~n

241

The Caribbean coral reefs of Colombia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. Garz6n-Ferreira and J. M. Diaz

275

The corals and coral reefs of Venezuela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. Weil

303

viii EASTERN PACIFIC Coral reefs of the Pacific coast of M6xico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. Reyes-Bonilla

331

Corals and associated marine communities from E1 Salvador ...................... H. Reyes-Bonilla and J. E. Barraza

351

Corals and coral reefs of the Pacific of Costa Rica: history, research and status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. Cort6s and C. Jim6nez

361

Corals and coral reefs of the Pacific coast of Panama . . . . . . . . . . . . . . . . . . . . . . . . . . . J. L. Mat6

387

Corals and coral reefs of the Pacific coast of Colombia . . . . . . . . . . . . . . . . . . . . . . . . F. A. Zapata and B. Vargas-,iUagel

419

Coral communities and coral reefs of Ecuador . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. W. Glynn

449

Reef-building coral communities of Eastern Island (Rapa Nui), Chile ....... P. W. Glynn, G. M. Wellington, E. A. Wieters and S. A. Navarrete

473

Subject index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

495

ix

Acknowledgments The idea of this book originated at the 8th International Coral Reef Symposium in Panarn~ during the "Coral Reefs of Latin America Workshop" organized by Eric Jordan and myself. I thank the organizers of the 8th ICRS (Smithsonian Tropical Research Institute and the University of Panama) and specially H6ctor Guzm~n. Their generous support made it possible for a large number of Latin American reef scientists and students to attend the symposium and interact for the first time with colleagues from the region. During the workshop representatives from each country presented the state of knowledge of their coral reefs. The book on the coral reefs of Latin American took shape following the workshop and especially during the CARICOMP Site Directors Meetings. It was the possibility of these personal encounters that stimulated true transnational collaboration. For this, I thank funding organizations and all individuals who made possible this crucial initial phase. The goal of this book was to compile all the available information concerning the coral reefs in Latin America. Although in some countries there is a large amount of information about their reefs, it is in the form of reports, thesis or obscure journals and thus of limited circulation. Therefore, the best of that information has been included in this book in an effort of disseminating it to a wider sector of the scientific community. Whenever possible, local scientists working on coral reefs were asked to write about the history of reef research in their country, describe the reefs, point out natural and anthropogenic perturbations affecting those reefs, and outline management and conservation initiatives in relation to coral reefs in their area. I thank each and every one of the authors who submitted chapters for their effort and for making this book possible. I hope that this book stimulates more collaborative research, and increases the local and international awareness of the region's coral reefs. As pointed out in the Introduction to this book, there are three coral reef regions in the Americas: Brazil, Caribbean and eastern Pacific. Most, if not all the reef in each region, are found in Latin American countries. Fortunately, in the last decade or two the number of local scientists as well as the quantity and quality of the research has increased in most countries. From the chapters in this book we can learn about the types, size, species composition and conditions of the coral reefs in each country. And we can get a feel for the level of research in each country, which expands from a few isolated studies, to extensive, long-term research in many fields of reef ecology. Only one Latin American country with coral reefs, Honduras, is not presented in the book, which I regret; many people were contacted but a chapter was not produced. I greatly appreciate the excellent job done by reviewers of one or more chapters: R.B. Aronson, R.W. Buddemeier, G. Bustamante, A.G. Coates, A.I. Dittel, J. Geister, R.N. Ginsburg, P.W. Glynn, H.M. Guzrn~n, W.C. Jaap, B. Kjerfve, K. Koltes, J.H. Leal, C. Lotion, I.G. Macintyre, J. Ogden, K. Qualtrough, M. Reaka-Kudla, H. Reyes Bonilla, C.S. Rogers, K. Sullivan-Sealey, E. Villamizar, G.M. Wellington and J. Woodley. I thank Dr. Robert N. Ginsburg for accepting to write the Foreword to this book. I acknowledge the support of the Vicerrectoria de Investigaci6n, Universidad de Costa Rica, US-AID-CDR Project (TA MOU-97-C14-015), and M. Tupper. I thank Ms. Fenke Wallien of Elsevier Science, for her patience and support for this project. Finally, I salute my Mend and colleague Alberto Le6n who patiently and carefully did all the layout of the book up to the camera-ready version.

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Coral reefs of the Americas: An introduction to Latin American Coral Reefs Jorge Cortrs Centro de Investigaci6n en Ciencias del Mar y Limnologia(CIMAR), and Escuela de Biologia, Ciudad de la Investigaci6n, Universidad de Costa Rica, San Pedro, San Jos6 2060, Costa Rica

ABSTRACT: There are three main coral reef regions on the American continents: Brazilian, Caribbean and the eastern Pacific. Most coral reefs border Latin American countries, hence the title of this book. Corals and coral reef structures in these three areas vary largely in relation to plate tectonic activity and ocean circulation. Geologic separation of the Brazilian fauna from the Caribbean, due to Amazonian freshwater intrusion, dates from the end of the Cretaceous/early Tertiary, resulting in a highly endemic and relict coral fauna in the Brazilian region. The Caribbean and the eastern Pacific were separated by the Isthmus of south Central America about 3 million years ago. Due to the subsequent changes in amphiAmerican oceanographic conditions, the coral faunas of these two regions are dissimilar today. Although the faunas and reef structures are unique in each region, the natural and anthropogenic impacts affecting them are similar, resulting in marked reef degradation in most areas. Therefore, intercontinental collaboration between workers in North, South and Central America is necessary to study, protect and conserve the coral reefs of Latin America.

1. I N T R O D U C T I O N The American continents today contain three main reef areas: the Brazilian waters, the Caribbean and the eastern Pacific (Fig. 1). The reef area of Brazil extends from Atol das Rocas in the north, to the state of Bahia on the south, and from the mainland coast to Fernando de N o r o n h a offshore. The best-developed reefs are in the southern part o f the state of Bahia (Leao et al. chapter in this book). The Greater Caribbean or western tropical Atlantic, extends from Bermuda south to PanalTfi, and from Barbados in the Lesser Antilles to the coast of the Gulf of Mexico. The best r e e f development of this region is in the central Caribbean including Cuba, Jamaica and Belize (Goreau 1959; chapters on Caribbean reefs in this book). The eastern Pacific reefs extend from the Sea of Cortez south to Ecuador and oceanic Chile, and from Colombia west to Clipperton Island. The most extensive reefs are in Costa Rica, Panarn~, Colombia and on the oceanic islands of Cocos and Clipperton (Glynn et al. 1996; Cort6s 1997; chapters on Latin American Coral Reefs, Edited by Jorge Cortrs 9 2003 Elsevier Science B.V. All rights reserved.

1

jcr

EL MLVADOA’

,\&

NICARAGUA

‘

-,--

40.

.

COSTA R ICA PANAMA

-

Eastern Island

Fig. 1 . The American continent with its three main reef areas indicated.

Jorge Cortes

4

ECUAD

Coral reefs of the Americas: An introduction to the Latin American Coral Reefs

3

eastern Pacific reefs in this book). At Easter Island, the far southeastem Pacific outpost, incipient reef development has been observed recently (Glyrm et al. chapter in this book). All of the Brazilian, most of the eastern Pacific and a significant number of reef areas of the Americas are within Latin American jurisdiction, hence the focus of this book. Here, I will briefly describe the corals and coral reefs of the three regions noted above. Some possible explanations as to how each region acquired its present coral fauna will be considered. And finally, the common threats to corals and coral reefs of the Americas will be noted. It is necessary for the Latin American community to be well versed in the ecology of the regional coral reefs, since management of these important resources will require international collaboration in order to be effective. 2. BRAZILIAN There are two outstanding features of Brazilian reefs: their structure and coral composition. Reef structures called "chapeiros" are commonly observed on Brazilian reefs. They consist of several mushroom-shaped coral colonies fused above, some extending 20 m high and 50 m in diameter. Several chapeiros may fuse to form complex structures that the Brazilians call "reef banks". These reef banks are found along the southern range of Brazilian reefs, in the state of Bahia (Hetzel and Castro 1994). Calcareous algae predominate along the northern part of the Brazilian coast. Also unique to Brazilian reefs is their reef-building coral species composition. Close to one-half of the fifteen species are endemic and some are relics of the ancient coral fauna of the Tethys Sea. For example, Mussismilia hispida, an important reef builder in Brazil, is both an endemic and relict coral species. Recently have Brazilian scientists begun to study these reefs in detail and publish papers describing them (see chapter in this book by Leao et al.). 3. CARIBBEAN

The corals and coral reefs of the Caribbean are the most widely studied and best known of the three regions discussed herein (see Caribbean section in this book). A typical Caribbean reef has a shallow lagoon (few centimeters to 2 m deep), a reef crest where wave energy is dissipated (Geister 1977), a high diversity reef front and often a zone of spurs and grooves (Goreau 1959). The basements of many reefs occur to 35 m depth, but corals can be found as deep as 95 m (Fricke and Meischner 1985). A welldefined reef crest and lagoon are not present on either Brazilian or eastern Pacific reefs. 4. EASTERN PACIFIC Eastem Pacific reefs are relatively small, discontinuous and formed by only a few species of corals (see the eastern Pacific section in this book). Cort6s (1997) has referred to them as the minimum expression of a reef. There are two main types of reef structures and several minor geomorphologic variations. Reefs in M6xico, Panarn~, Colombia and in some areas in Costa Rica and Ecuador are built by species of Pocillopora. The branches of these corals grow interlocked, exhibiting virtually no submarine cementation

4

Jorge Cortes

or binding calcareous algae (Cortrs et al. 1994), which contribute to the stability of Brazilian and Caribbean reefs. Another major reef type in the eastern Pacific consists of the massive corals Porites lobata and Pavona clavus. The best expressions of this type are found at Cocos Island, Clipperton Island and the Gal~pagos Islands. Colonies may be enormous (several meters in diameter) and are sometimes not cemented to the substrate (Cortrs 1990). 5. DIFFERENCES AND POSSIBLE EXPLANATIONS Today, there are major differences among the three regions of the Americas with regard to coral reef structure and genetic/species composition of their reef-building corals (Table 1). The affinity between the Caribbean and Brazilian regions is high at the genetic, but less at the species level. The eastern Pacific and the Caribbean still have some genera in common, however, no species are shared between the eastern Pacific and either the Caribbean or Brazilian regions (Table 1). TABLE 1 Number of genera and species of reef-building corals in each region (Brazil, the Caribbean and the eastern Pacific) and those in common between region pairs. Sources: Brazil: Hetzel and Castro 1994, and chapter in this book by Le[io et al. Caribbean: Wells and Lang 1973, Budd 2000, and chapters in this book: Alcolado et al., Cortrs and Jimrnez, Fonseca and An'ivillaga, Garcia et al., Garzrn-Ferreira and Diaz, Geraldes, Gibson and Carter, Jord/mDahlgreen and Rodriguez-Martinez, Ryan and Zapata, Weil. Eastern Pacific: Glynn 1997, Glynn and Ault 2000, and chapters in this book: Cortrs and Jimrnez, Glynn, Glynn et al., Matr, Reyes-Bonilla, Zapata and Vargas-Angel. Region Brazil Caribbean E. Pacific Brazil - Caribbean Caribbean- E. Pacific E. Pacific- Brazil

Present Genera Species 10 21 8

In Common Genera Species

15 50+ 25 9 4 2

10 0 0

Differences in two oceanographic parameters may explain the obvious contrasts in coral species composition: plate tectonic events and ocean circulation. The position of the continents has changed over time, resulting in separation and isolation of the coral faunas. As a consequence, ocean current directional changes have remained the same or changed, thus creating new opportunities for speciation, which have resulted in the dissimilar coral faunas we now see in the Brazilian, Caribbean, and eastern Pacific regions. A circumtropical circulation existed during the Cretaceous, resulting in a relatively homogeneous coral fauna world-wide. With respect to the tropical American Seas, the first important fragmentation of the Tethys involved the separation of the proto-Mediterranean from the American continents. From this time onward, an entirely different coral fauna evolved in eastern American waters (Frost 1977; Budd 2000). At the end of

Coral reefs of the Americas: An introduction to the Latin American Coral Reefs

5

the Cretaceous (or early Tertiary), the Caribbean and Brazilian regions were separated as the South Atlantic Ocean widened. Around this time, the Andes were uplifted, changing the outflow of the Amazon River from the Pacific to the Atlantic Ocean, creating an enormous freshwater lens between the tropical Brazilian coast and the Caribbean. This freshwater lens presently remains an impassable barrier for corals. Also, in this region the Atlantic Equatorial current branches, moving north into the Caribbean and south to southern Brazil. Thus, ocean circulation also has enhanced the separation of these two regions, resulting in the unique Brazilian fauna. From 4 to 1 million years ago (mya), the evolution and divergence of the Caribbean coral fauna increased this dissimilarity (Budd et al. 1994). The presence of endemic Brazilian genera in the Caribbean fossil record, such as the relict M u s s i s m i l i a , fiu'ther provides evidence of the divergence of the Caribbean fauna (Budd et al. 1994). During this time of differentiation, the connection between the Caribbean and the eastern Pacific regions still persisted and coral faunas remained similar there. However, a tectonic event during the Pliocene epoch leads to the separation of the eastern Pacific and Atlantic American regions. The uplift of the Central American isthmus, some 3 mya (Coates et al. 1992), had fundamental oceanographic consequences as well as climatic and biological implications. The conditions for the generation of E1 Nifio events were created, resulting in warming disturbances in the eastern Pacific. Coastal upwelling also began, creating seasonal cool water centers as well (Cort6s 1997). Such thermal regimes are not conducive to coral growth and development. Additionally, sea level changes occurred during the Pleistocene (Cort6s 1986) initiating the extinction of reef-building corals in the eastern Pacific. Several workers suggest that shallow hard substrates were then colonized by corals that dispersed from the central Pacific, via eastward-moving ocean currents (Cort6s 1986; Glynn 1997; Glynn and Ault 2000). 6. NATURAL AND ANTHROPOGENIC IMPACTS The major coral reef regions of the Americas are distinct in structure and species composition, yet the environmental problems affecting these reefs are similar. Impacts from natural causes, such as coral bleaching (Glynn 1992; Glyrm and Colley 2001), have resulted in mass mortalities of corals in all three regions (see sections on Natural Disturbances in most chapters). Human impacts in marine environments have also taken their toll. Reef degradation in the American region is caused mainly by increased influx of terrigenous sediments (Rogers 1986; Cort6s 1990; Ginsburg 1994), primarily due to deforestation, uncontrolled coastal development and inappropriate agricultural practices (Cort6s and Risk 1985; Cort6s 1990). 7. CONCLUSIONS To prevent the further destruction of coral reefs world--~de, an accelerated program of education and training in reef science is necessary. Dissemination of information should occur within all user groups, from children to adults and at all custodial levels. More importantly, we must understand that coral reefs belong to all humankind and are not the property of any one nation. A cooperative, multinational program must be devel-

6

Jorge Cort~.s

oped in order to study, protect and rationally utilize these precious and fragile resources, these wonderful ecosystems we call coral reefs. ACKNOWLEDGMENTS This Introduction to the book Latin American Coral Reefs was enriched by the contributions of all the authors which I greatly appreciate. The critical reviews by several persons, and specially P. W. Glynn and S. Colley Theodosiou improved this chapter. REFERENCES Budd, A.F. 2000. Diversity and extinction in the Cenozoic history of Caribbean reefs. Coral Reefs 19: 25-35. Budd, A.F., T.A. Steaman & K.G. Johnson. 1994. Stratigraphic distribution of genera and species of Neogene to Recent Caribbean reef corals. J. Paleont. 68:951-977. Coates, A.G., J.B.C. Jackson, L.S. Collins, T.M. Cronin, H.J. DowseR, L.M. Bybell, P. Jung & J. Obando. 1992. Closure of the Isthmus of Panama: the near-shore marine records of Costa Rica and western Panama. Geol. Soc. Amer. Bull. 104: 814-828. Cort6s, J. 1986. Biogeografia de corales hermatipicos: el istmo centroamericano. Anal. Inst. Cienc. Mar Limnolog., U.N.A.M. 13: 297-304. Cort6s, J. 1990. The coral reefs of Golfo Dulce, Costa Rica: distribution and community structure. Atoll Res. Bull. 344: 1-37. Cort6s, J. 1997. Biology and geology of coral reefs of the eastern Pacific. Coral Reefs, 16(Suppl.): $39-$46. Cort6s, J. & M.J. Risk. 1985. A reef under siltation stress: Cahuita, Costa Rica. Bull. Mar. Sci. 36: 339-356. Cort6s, J., I. G. Macintyre & P. W. Glynn. 1994. Holocene growth history of an eastern Pacific fringing reef, Punta Islotes, Costa Rica. Coral Reefs 13: 65-73. Fricke, H. & D. Meischner. 1985. Depth limit of Bermudan scleractinian corals: a submersible survey. Mar. Biol. 88:175-187. Frost, S.H. 1977. Cenozoic reef systems of the Caribbean - Prospects for paleontologic synthesis. In: S.H. Frost, M.P. Weiss and J.B. Saunders (eds.), Reefs and Related Carbonates - Ecology and Sedimentology. AAPG Studies in Geology 4: 93-110. Geister, J. 1977. The influence of wave exposure on the ecological zonation of Caribbean coral reefs. Proc. 3rd Int. Coral reef Symp., Miami 1: 23-29. Ginsburg, R.N. (compiler). 1994. Proceedings of the Colloquium on Global Aspects of Coral Reefs: Health, Hazards and History, 1993. Rosenstiel School of Marine and Atmospheric Science, University of Miami: 240-246. Glynn, P.W. 1992. Coral reef bleaching: ecological perspectives. Coral Reefs 12:1-17. Glynn, P.W. 1997. Eastern Pacific reef coral biogeography and faunal flux: Durham's dilemma revisited. Proc. 8th Int. Coral Reef Symp., Panama 1: 371-378. Glynn, P.W. & J.S. Ault. 2000. A biogeographic analysis and review of the far eastern Pacific coral reef region. Coral Reefs 19: 1-23. Glynn, P.W. & S.B. Colley (eds.). 2001. A collection of studies on the effect of the 1997-98 E1 Nifio-Southern Oscillation event on corals and coral reefs in the eastern tropical Pacific. Bull. Mar. Sci. 69: 1-288.

Coral reefs of the Americas: An introduction to the Latin American Coral Reefs

Glynn, P.W., J.E.N. Veron & G.M. Wellington. 1996. Clipperton Atoll (eastem Pacific): oceanography, geomorphology, reef-building coral ecology and biogeography. Coral Reefs 15:71-99. Goreau, T.F. 1959. The ecology of Jamaican coral reefs, I. Species composition and zonation. Ecology 40: 67-90. Hetzel, B. & C.B. Castro. 1994. Corals of Southern Bahia. Editorial Nova Frontera, Rio de Janeiro, Brazil. 189 p. Rogers, C.S. 1986. Responses of coral reefs and reef organisms to sedimentation. Mar. Ecol. Prog. Ser. 62:185-202. Wells, J.W. & J.C. Lang. 1973. Systematic list of Jamaican shallow-water Scleractinia. Bull. Mar. Sci. 23: 55-58.

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Corals and coral reefs of Brazil Zelinda M. A. N. Leao a, Ruy K. P. Kikuchi a,b and Viviane Testa a a Laborat6rio de Estudos Costeiros, Centro de Pesquisa em Geofisica e Geologia, Universidade Federal da Bahia, Rua Caetano Moura 123,40210-340, Salvador, Bahia, Brazil b Departamento de Ci~ncias Exatas, Universidade Estadual de Feira de Santana, BR116 km 3 s/n, Campus Universit/trio, 44031-460, Feira de Santana, Bahia, Brazil ABSTRACT: The Brazilian coral reefs form structures significantly different from the well known coral reef models, because (i) they have a characteristic initial growth form of mushroom-shaped coral pinnacles called "chapeir6es", (ii) they are build by a very low diversity coral fauna, rich in endemic species, which are relic forms, remnant of an ancient coral fauna dating back in the Tertiary, (iii) incrusting coralline algae have an important role in the construction of the reef structure, and (iv) the nearshore bank reefs are surrounded and even filled with muddy siliciclastic sediments. The isolated reefs columns, the "chapeir6es", fuse together at their tops, forming large compound reef structures of varied sizes, with horizontal tops, and somewhat irregular shape. They can be completely exposed during low tides. These reef structures are distributed into three major sectors along the tropical coast of Brazil: the northern, the northeastern and the eastern coasts. There are different types of bank reefs, fringing reefs and an atoll. Corals, milleporids and coralline algae build the rigid flame of the reefs. The coral fauna, so far identified, comprises less than eighteen species, being some of them endemic to the Brazilian waters. Quaternary sea-level fluctuations affected the growth of the reefs in Brazil; transgressive and regressive seas marked different stages of reef development. The areas where the major coral reefs occur correspond to regions where nearby urban centres are experiencing accelerated growth and tourist development is increasing very fast. The major human impacts to the reef ecosystem are mostly associated with agricultural activities (sugarcane and timber), mineral and chemical industries and oil exploration. Increased sedimentation due to removal of the Atlantic rainforest and the disposal of industrial and urban effluents, are additional stresses to the coastal marine environment in Brazil. There are not many institutions concerned with preservation of the Brazilian coral reefs, and they are also fairly new.

1. I N T R O D U C T I O N Our k n o w l e d g e o f Brazilian coral reefs was limited c o m p a r e d to the Caribbean and the G u l f o f M e x i c o as prior to 1969, when the broadest description o f the Brazilian coral fauna b y the F r e n c h biologist Jacques Laborel was published (Laborel 1967; 1969a, 1969b), there were only reports about the corals o f Brazil b y visiting scientists (Spix and Martius 1828; Fitzroy 1832; Darwin 1851; Hartt 1868a, 1868b, 1869, 1870; Verrill 1868, 1901a, 1901b, 1912; Rathbun 1876, 1878a, 1878b, 1878c, 1879; Branner 1904; D e r b y 1907). These early works established the unusual characteristics o f the Brazilian reefs: their almost unique mushroom-like growth form (chapeirao) and the strong e n d e m i s m and low diversity o f the coral fauna. Latin American Coral Reefs, Edited by Jorge Cort6s 9 2003 Elsevier Science B.V. All rights reserved.

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Z.M.A.N. Le6o et al.

Interest in studies about the Brazilian reefs expanded in the last two decades, due to the increased number of researchers working in this field of investigation, and to the increased degradation of reef areas. Recent researches include more detailed surveys of the reef environment, and the elaboration of quantitative databases found in numerous articles, thesis, dissertations, as well as technical reports. They consist, mainly, of: a) mapping of reefs areas (Leao 1982, 1994a, 1996; Araujo 1984; Nolasco 1987; Dominguez et al. 1990; Coura 1994; Testa 1996, 1997; Maida and Ferreira 1997); b) providing data on various aspects of the reef communities - fauna and flora (Oliveira-Filho and Ugadim 1976; Oliveira-Filho 1977; Nunam 1979; Pemch 1979; Rios and Barcellos 1980a; Bel6m at al. 1982; Hetchel 1983; Young 1984, 1986, 1988; Castro 1989, 1990a, 1994; Leao 1986a; Pitombo et al. 1988; Cutrim 1990; Ma~al and Amaral 1990; Luz 1991; Amaral 1991, 1992, 1994, 1997; Pires and Pitombo 1992; Pires et al. 1992; Schlenz and Bel6m 1992; Rohlfs and Bel6m 1994; Samos and Correia 1994, 1995; Ferreira et al. 1995; Maida and Ferreira 1995; Marques and Castro 1995; Nogueira 1995; Pires 1995; Pinto-Paiva and Fonteles-Filho 1996; Amaral et al. 1997; Correia 1997; Echeverria et al. 1997; Figueiredo 1997; Migotto 1997; Pinto and Bel6m 1997; Pires and Castro 1997; Rosa and Moura 1997; Santa-Isabel et al. 1998a; Villaga and Pitombo 1998; Castro and Pires 1999); c) characterizing the reef subenvironments and related sedimentary facies (Le~o 1982; Nolasco and Leao 1986; Leao et al. 1988; Kikuchi 1994; Leao and Ginsburg 1997; Testa 1997; Testa et al. 1997; Testa and Bosence 1998, 1999); d) studying the modem and Quaternary reef structures (Leao 1983; Leao and Lima 1983; Araujo et al. 1984; Leao et al. 1985, 1997; Kikuchi and Leao 1997, 1998; LeSo and Kikuchi 1999), and e) informing about reef conservation, protection and management in Brazil (Joly et al. 1969; Castro and Secchin 1981, 1982; Leao 1986b, 1994b; Ma~al 1986; Secchin 1986, 1991; Bel6m et al. 1986; Gonchorosky et al. 1989; IBAMA/FUNATURA 1991; Coutinho et al. 1993; Leao et al. 1994; Amado-Filho et al. 1997; Telles 1998). This chapter will focus on three main aspects of the Brazilian reefs: 1) characterization of the coral fauna, its endemism and the adaptation of a low diversity fauna to a highly siliciclastic muddy environment; 2) the classification and distribution of the major Brazilian reef systems and the aspects that influenced their Quaternary evolution and, 3) reviewing the major natural and anthropogenic impacts, which are threatening the Brazilian coral reef ecosystems. 2. REGIONAL SETTING 2.1. The continental shelf sedimentary facies The continental shelf along the tropical coast of Brazil varies considerably in shape and width. Along most of its extension it is very narrow, with an average width of 50 km. In its southern portion, however, it widens, particularly in the Abrolhos area, where it extends circa 200 km, as a result of a volcanic intrusive activity, an accretion to the shelf that was responsible for the formation of the Abrolhos Bank. The shelf break is commonly at an average depth of 80 m. Carbonate sediments dominate the entire tropical Brazilian middle and outer shelves, from north to south. Bioclastic carbonate gravel and sands (free-living non-

Corals and coral reefs of Brazil

11

articulated coralline red algae - maErl - Halimeda, benthic Foraminifera and mollusk debris), are also an important constituent in the inner shelf in many areas (Coutinho 1980; Dominguez and Leao 1994; Testa 1997; Testa and Bosence 1998, 1999), and not only in the middle and outer shelves as it was previously thought. More commonly, the inner shelf constitutes a typical mixing zone of siliciclastic and carbonate sediments; the siliciclastic originate from fiver discharges, coastal erosion, and reworked relict deposits of former lower sea-level stands, and the carbonates have as sources the locally-produced grains by the growth and transport of calcareous organisms, such as red and green algae. In the vicinity of the Sao Francisco River mouth (10030 , S) (Fig. 1), the largest river on northeast Brazil, the carbonate sediment production is interrupted, probably due to water turbidity (Tiltenot et al. 1994). Also, the inner shelf of the south part of the eastern region, between the Jequitinhonha (15~ and Doce (19~ rivers (Fig. 1) is influenced by river discharges, and plumes of fine sediments are seen to advance some 50 km offshore. In these areas bioclasts occur only on the middle and the outer shelves, and the main carbonate sediments are mollusk shells, benthic Foraminifera tests, debris of calcareous algae, bryozoans, echinoids and, more rarely, coral gravel. Reefs occur along the entire carbonate province, and are distributed along four geographic regions: northern, northeastern, eastern and southern (Fig. 1). The northernmost part is the poorest area, if reef buildups are taken into consideration. This perceived scarcity of reefs, already referred to by Laborel (1969a), may be a result of the lack of extensive research in the area. The Nautical Charts of the Brazilian shelf indicate that reefs are indeed rarer on the northern part of the country continental shelf compared to its northeastern and eastern parts, where reefs are more frequent. Near shore patch and bank reefs occur commonly within siliciclastic sandy to muddy sediments, both in the northeast (Testa 1996) and in the east coasts (Leao 1982; Araujo 1984; Nolasco 1987; Leao and Ginsburg 1997). This is one of the reasons why it is said that the reef building corals in Brazil are resistant to high rates of sedimentation and/or water turbidity. Furthermore, Milliman and Barreto (1975) and Kikuchi and Leao (1998) have documented the occurrence of drowned reefs at the shelf break.

2.2. Physical environment 2.2.1. Winds. The general atmospheric circulation pattem along the northeast and east Brazilian coasts is controlled by two elements (Bigarella 1972): (i) air masses generated in the South Atlantic high pressure cell and (ii) advances of polar air masses. Since the South Atlantic is devoid of hurricanes, only the above cited two elements, associated with the Intertropical Convergence Zone, define climate in the tropical coast of the country. The Brazilian eastem and northeastem coasts are therefore dominated by the southeasterly and easterly trade winds in this part of the Atlantic. A divergence zone of trade winds occurs in the southem part of the pressure cell, and northeastem winds blow to the south of this zone. A seasonal variation of this cell produces a north-south oscillation of the divergence zone between 10~ and 20~ This zone moves northward during summer and southward during winter. As a result, easterly and southeasterly winds dominate the coast far north of 13~ year-round, with speeds ranging from 5.5 to 8.5 m s~ (US Navy 1978). South of 13~ the easterly and southeasterly winds blow during fall and winter (April to September), and the northeasterly winds prevail during spring and summer (September to February); in this area the wind speed rarely surpass

12

Z.M.A.N. Leao et al.

Fig. 1. Map showing the majorreef zones, and the reefs described in the text and illustrated in figures 13 to 19. 5.5 m s -1 ( U S Navy 1978). The Antarctic polar front moves northward across the South American continent, east of the Andes Mountains, as great anti-cyclones, and splits into two branches. The eastern branch moves along the coast towards the Equator and can reach as far as 10~ during winter but, rarely, reaches latitudes lower than 15~ in summer (Dominguez et al. 1992). The advance of this polar front also generates additional south-southeasterly winds, which reinforce the southeasterly winds generated by the anti-cyclone high-pressure cell. Gale-force winds (25 m S"1) have been measured with the advance of these polar fronts (Bandeira et al. 1975). 2.2.2. Rainfall. The climate in the northeast coast of Brazil is classified as semi-arid and in the east coast is tropical humid. Considering the distribution of annual rainfall (Nimer 1989), the northeast coast from 4~ to 6~ is characterized by an excess of four to five dry months, and from 6~ to 12~ the coastal segments with less than two dry months

Corals and coral reefs of Brazil

13

altemate with areas with four to five dry months. The east coast from 12~ to 20~ has less than two consecutive dry months. A month is considered dry when its precipitation value in mm is equal to or smaller than twice the monthly average temperature in degrees Celsius (Gaussen et al. 1953 in Nimer 1989). 2.2.3. Sea surface temperature (SST). The range of maximum SST is the most conservative parameter along the Brazilian coast, varying in the northeast coast from 30~ during summer and fall (February to May) to 28~ from the end of winter to the beginning of summer (August to December), and in the east coast from 30~ (February to May) to 27~ (July and August). The minimum temperature, however, shows a marked decrease from north to south. On the northeast coast, it decreases from 25~ during summer and fall, to 23~ during winter and spring; on the eastern coast, during winter, the minimum temperature can reach 21~ (U.S. Navy 1978). 2.2.4. Waves. The wave pattem is conditioned by variations in the trade winds, i.e. related to movements of the offshore high-pressure centers. The Brazilian coast is mainly dominated by sea waves (locally generated waves with periods lesser than 7s), and those with heights above 1 m account for more than 50% of the observations referred to in the U.S. Navy Marine Climatic Atlas (U.S. Navy 1978). This is the kind of waves that Larcombe et al. (1995) found to be more effective in increasing turbidity of water in their four months of measurements, near the city of Townsville, Australia. In the Brazilian north and northeast coasts, the waves moving from southeast dominate the year round, and the waves from the east are important from January to May (summer-fall) and from September to November (spring). The southernmost part of the northeast coast and the east coast, on the other hand, are dominated by wave moving from east during the whole year. Waves from northeast are only important from November to February (summer), and from southeast occur from March to August (winter). Thus, waves are an effective process in water circulation in the southern part of the northeast coast and in the east coast. The north coast and the northernmost part of the northeast coast are protected from the main wave train during all year, being affected only by a secondary train (waves from the east) from September to May. 2.2.5. Tides. The Brazilian continental shelf has semi-diurnal tides. Due to the large latitudinal extent of the shelf, three different areas are defined, according to the tidal range classification proposed by Hayes (1979): m_acrotidal in the north coast, upper mesotidal in the northeast coast and the northernmost part of the east coast, lower mesotidal in most of the east coast and microtidal in the entire south coast. The most conspicuous effect of the tidal component is observed in the north coast, where it enhances the northwestward flow of the Brazilian Current (the North Brazilian Current), and periodically produces an intensification of this drift. 2.2.6. Ocean currents. The Brazilian Current (BC) and the North Coastal Brazilian Current (NCBC) are the main surface currents on the Brazilian continental margin (Stramma 1991, Silveira et al. 1994). They originate from the South Equatorial Current at about 5 ~ to 6 ~ S and flow to the south (BC) with average velocities of 50 to 70 cm s"I, and to the north and northwest (NBC) attaining velocities of 30 cm s1. Data from the Atlas de Cartas Piloto (DHN 1993) show that between 10~ and 13~ during July and

14

Z.M.A.N. Le~o et al.

August (austral winter) a reverse flow to the north can occur. North of 5~ the North Coastal Brazilian Current becomes stronger as a result of combining with the South Equatorial Current. 3. CORAL FAUNA The Brazilian coral fauna (Scleractinia) has three distinctive characteristics: a) it is a very low diversity coral fauna (18 species) compared with that of Caribbean reefs; b) the major reef builders are endemic species from the Brazilian waters, and c) it is composed predominantly of massive forms. The first descriptions of the Brazilian corals are from those collected during Hartt's voyage to Brazil (Hartt 1868a, 1869, 1870), which were identified by Verrill (1868, 1901a, 1912). Later on, Laborel (1967, 1969a) compared Verrill's taxonomy with contemporary forms and Tertiary fossils and corroborated Verrill's remarks that the Brazilian ahermatypic corals were all related to Caribbean species, but among the reef framebuilders (hermatypic species), the endemism is rather strong. More recently, Bel6m et al. (1986) and Castro (1994) confirmed and expanded Laborel's list of the Brazilian corals. Eighteen species of stony corals (madreporarians), four of hydrocorals, four of antipatharians, and eleven of octocorals constitute the cnidarian fauna of Brazil so far identified.

3.1. Stony corals Six of the reef-building Brazilian corals are endemic (Fig. 2), and among these endemic species some have affinities with Caribbean coral forms and some are related to a Tertiary coral fauna. These archaic species are the most common forms in almost all modem Brazilian reefs. They are the three species of the genus Mussismilia: M. braziliensis, M. hispida and M. harttii and the species Favia leptophylla. This archaism is an inheritance from a large endemic common fauna that existed up to the late Miocene and early Pliocene and was then isolated from the Caribbean area (Frost 1977). Apart from ocean water circulation, the elevation of the Andes and the consequent reversal of flow of the Amazon river to the Atlantic Ocean, may have contributed to the isolation of these two coral provinces, the Caribbean and the Brazilian (Souza 1994). In Brazilian waters these archaic corals were preserved, during Pleistocene low stands of sea level, in a refugium provided by the seamounts off the coast (Le~o 1983). The other two species considered endemic from Brazil are Siderastrea stellata and Favia gravida, both related to the Caribbean coral fauna. Most of the frame-building corals from Brazil are massive. Encrusting forms are present along the edges of the reefs. All reefs lack the branching acroporids that are major corals of the reef crest and fore reef slope of Caribbean reefs. The species Mussismilia harttii, an endemic species very abundant in most of the reefs, has corallites in dichotomous groups with the calyces separated, but it does not make branches. According to data from Laborel (1969a), Bel6m et al. (1986), Castro (1994) and Testa (1997) the Brazilian hermatypic corals are distributed along the coast of Brazil in four major geographic regions: northem, northeastem, eastem and southem (Figs. 1 and 3). The northern marginal area occurs between the Amazon fiver mouth and the Cape Sao Roque (0030 , to 5~ the northeastern area extends from Cape Sao Roque to the mouth of the Sao Francisco river (5029 , to 10~ the eastern area comprises the entire

Corals and coral reefs of Brazil

15

Fig. 2. The Brazilian endemic corals and hydrocorals: a) Mussismilia braziliensis; b) Mussismilia hispida; c) Mussismilia harttii; d) Favia leptophylla; e) Siderastrea stellata; f) Favia gravida; g) Millepora braziliensis; h) Millepora nitida. coast of the state of Bahia, from the mouth of the Sgo Francisco river to the Doce fiver (10~ , to 19~ and the southem marginal area extends from the mouth of the Doce river to the coast of the Santa Catarina state (19o30 , to 27~ The major reef core area

16

Z.M.A.N. Le6o et al.

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Fig. 3. Distribution of the Brazilian corals and hydrocorals along the coast of Brazil. A - Northern region; B Northeastern region; C - Eastern region; D - Southern region. (Based on data from Laborel 1969; Bel6met al. 1982; Castro 1994; Testa 1997). comprises the northeastern and eastern regions. The two marginal regions (northem and southern) were called by Laborel (1969a), the north and the south regions of impoverishment in hermatypic corals. Among the Brazilian endemic species M. braziliensis and F. leptophylla are the corals that show the greatest geographical confinement, because they are described only along the coast of the state of Bahia (the eastern region). On the other hand, the species M. hispida has the largest spatial distribution, because it occurs from Rocas Atoll (northeastern region) to the coast of the Santa Catarina State (southern region). The species Siderastrea stellata and Favia gravida are the most common corals in shallow intertidal pools of the reef tops and are considered as very resistant to variations in temperature, salinity and water turbidity. Siderastrea stellata has a broad distribution along the Brazilian coast, as it is known from the reefs of the northern region to the coast of the state of Rio de Janeiro. Favia gravida is a common species on the reefs from the northeastern and eastern regions. The cosmopolitan species Porites astreoides, P. branneri, Agaricia agaricites, A. fragilis, Montastraea cavernosa and Madracis decactis are species found in both Brazilian and Caribbean reefs. In the Brazilian reefs, they have a secondary role in the construction of the reefs located on the northeastern and eastern regions. The species M. cavernosa varies its forms in relation to depth. The shallow forms are hemispheric and the ones found on the lateral walls of the reefs at depths greater than 5 m may be flattened and encrusting. The species Meandrina braziliensis has two morphological variations: a free-living form that inhabits sandy

Corals and coral reefs of Brazil

17

bottoms and a fixed form attached to the reef walls. It has a wide distribution along the Brazilian coast from the northem region to the southernmost portion of the eastern region. The small corals Scolymia welsii, Phyllangia americana, Astrangia braziliensis and A. rathbuni do not contribute much to the construction of the reef structures. A. rathbuni occurs in the southem region (from the state of Rio de Janeiro to the coast of the Santa Catarina State) at depths from few meters to 90 m, attached to skeletal fragments. The madreporarian corals of Brazil coexist with an active siliciclastic sedimentation. Fine-grained terrigenous sediment input to the shelf is deposited within reef channels. During winter storms, a large portion of this sediment is resuspended reaching the reef areas. The coexistence of corals in this highly terrigenous environment contrasts with most other coral reef environments described in the literature, which require clear waters with minimum runoff from land for growth. How the Brazilian species succeed in these water conditions is still a question. There are suggestions that corals with larger polyps are more resistant to environmental stress than species with smaller polyps: a) corals with large polyps have developed a more efficient mechanism for cleaning themselves of sediment (Stoddart 1969; Dodge et al. 1974; Logan 1988); b) brain-shaped corals that have larger and deeper corallites with large polyps are much more resistant to desiccation during long exposures than micropolypal forms (Fishelson 1973), and c) different species have different capabilities of clearing themselves of sediment or surviving lower light levels (Rogers 1990). Some of the major frame builders corals of the Brazilian reefs, particularly the archaic species Mussismilia braziliensis, M. hispida, M. harttii and Favia leptophylla, have large corallites. Also the species Siderastrea stellata, that is widely distributed along the entire Brazilian coast, have larger corallites than its Caribbean counterparts. Considering these facts, it seems that the prevalence of corals with larger polyps in the Brazilian reefs may be a response to the stressful conditions of our turbid waters. Only the most resistant and the best adapted corals are able to withstand those conditions. 3.2. I-lydroeorals Of the three species of millepores reported from the Brazilian reefs, two are considered as endemic. They exhibit two major growth forms: branching and encrusting. Delicate, finger-like branches are characteristic of low energy environments. Irregular, short, rounded branches are common on the edges of the reefs, with the thick, massive branches in zones of higher energy. Encrusting forms are seen on reef tops or encrusting the axes of gorgonians. The cosmopolitan species Millepora alcicornis predominates on the windward borders of the reefs, a reef region that corresponds to the Acropora palmata zone of the Caribbean reefs. It is found along the entire tropical Brazilian coast. The endemic species Millepora braziliensis (Fig. 2g) was first described by Verrill in 1868, and confirmed by Boshma (1961). More recently Amaral (1997), using biochemical studies, has proved it to be a valid species. In zones of high energy, the colonies of this hydrocoral are more massive, but in protected zones, their branches are flattened. Laborel (1969a) located the zone of Millepora braziliensis immediately below the zone of Millepora alcicornis. It is found on the reefs from the northeastern and eastern regions. The species Millepora nitida (Fig. 2h) is also considered endemic to Brazil and up to the present time is recorded only along the coast of the state of Bahia. The specimens described by Verrill (1968), Boschma (1961) and Laborel (1969a), show similarities

18

Z.M.A.N. Leao et al.

with the species Millepora exaesae, from the Indo-Pacific fauna. The branches are short and fork-like, and their ends are much flatter than in Millepora alcicornis. Besides the millepores, a small hydrocoral, Stylaster roseus, is found in the protected parts of the reefs from the northeastern and eastern regions. It forms small colonies, a few centimeters high, which have a thick base covered with small pointed branches. 3.3. Black corals According to Castro (1994) four species of corals from the group of the antipatharians are recorded from the Brazilian waters: three of the genus Antipathes and one from the genus Cirripathes. The former forms flat, fan-shaped colonies, or have branches arranged like brush bristles; the later, also known as wire coral, forms long branched colonies up to several meters long. They have been recorded only on the reefs along the coast of the state of Bahia (eastern region). Their occurrence is poorly known because black corals still have not been properly studied in Brazil. 3.4. Octocorals Before 1980, only three species of octocorals were described on the Brazilian reefs. All of them belong to the group of the gorgonians, and two of those were considered endemic to Brazil. The Brazilian blade sea fan Phyllogorgia dilatata is found in reefs from the northeastern region to the coast of the state of Rio de Janeiro; the large octocoral Plexaurella grandiflora, is commonly found in the shallow reef areas from the northeastern and eastern regions; and the species Muriceopsis sulphurea, whose colonies have a characteristic yellow color, is frequently found among concentrations of soft algae. In Brazil, M. sulphurea occurs from the northeastern region to the coast of the Rio de Janeiro State. The latest reviews of the Brazilian octocorals by Castro (1989, 1990a, b) revealed eight new species: Plexaurella regia, Muricea flamma, Neospongodes

atlantica, Lophogorgia punicea, Carijoa risei, Heterogorgia uatumani, Ellisella barbadensis and Ellisella elongata. Among these newly described species, two are recorded only on the reefs located along the coast of the state of Bahia (eastern region): Plexaurella regia and Muricea flamma. Two other species are also considered endemic to the Brazilian reefs: N. atlantica, found on soft bottoms at the base of the reefs, and L. punicea, found in the sidewalls of the reefs from south Bahia to the coast of the state of Santa Catarina. C. risei, H. uatumani, E. barbadensis and E. elongata are also recorded from the reefs in the North Atlantic Ocean. In Brazil, C. risei, can be seen occupying the shaded areas of the reefs (caves and ttmnels), H. uatumani occurs l~om the state of Bahia (eastern region) down to Santa Catarina State (southern region), and the large species of the genus Ellisella, E. barbadensis and E. elongata, are found along the entire coast of Brazil. 4. REEF TYPES The description of the Brazilian coral reefs distinguish two grand groups of r e e f s Nearshore and Oceanic reefs, and both types are strongly influenced by the underlying substrate, such as older reef, Precambrian bedrock, volcanic intrusion, beachrock, etc. 4.1. The nearshore reefs These reefs are found on the inner and middle continental shelves. Taking in account two descriptive characteristics of the reef morphology: a) the reefs distance from the coast,

Corals and coral reefs of Brazil

19

and b) the reefs dimension (particularly the proportion between length, width and height), as well as a third aspect that is the reefs relationship with the coastal evolution, two major subcategories of reefs are distinguished: the reefs attached to the coast, and the reefs detached from the coast. Each one of these subcategories can even be subdivided into various reef types (Fig. 4 A to I). 4.1.1. Reefs attached to the coast. These reefs are, at present, adjacent to the coastline, and most commonly partially covered by siliciclastic sands. They include flinging reefs and attached bank reefs (Fig. 4 A to D). Fringing reefs (Fig. 4 A and C). These reefs usually border the shore of islands up to several kilometers (Fig. 5), developing above the island substrate as a continuous fringe. This fifnge became narrower with the lowering of sea level that occurred in late Holocene time and, thus, diminished the reef distance from the shoreline, and partially buried the back-reef lagoon. The fore-reef depths can vary from 5 to 10 m where an incipient spurand-groove system can develop. A very shallow lagoon (1 to 2 m of depth) is common in the back-reef area where small reefs, coral knolls (sensu Ginsburg and Schroeder 1969), are seen. Channels, that allow the exchange of water between the back-reef and the outer reef zone, may occasionally interrupt the reef crest. Attached banks (Fig. 4 B and D). These reefs occur also adjacent to the beach but are of limited lateral extent (Fig. 6). Generally these bank-type of reefs do not exceed more than 5 km long. The entire reef fiat is in the intertidal zone and no lagoon is formed. Tidal pools are common, generally of a reduced extent, say 5 to 10 m of width, usually not exceeding 1 m in depth. The reef front depth varies from 5 to 10 m and reef walls are generally abrupt. We differentiate these attached banks from the above described fringing reefs by their smaller dimensions, the absence of the typical back-reef zone with a lagoon, and their development in relation with the coastal evolution. The bank reefs sit on submerged rock exposures, of diverse composition, and generally occur on the shelf bottom facing small promontories along the coastline (Fig. 6). These attached bank reefs were isolated from the shoreline when reef growth initiate as suggests the contour of the reef substrate drawn in Figure 4 B, opposed to what is seen with the fringing reefs (Fig. 4 A). With the sea level lowering and/or coastline progradation these discontinuous banks are found closer to the coastline and some may even be found, at present, with the leeward portion covered by sandy beaches.

4.1.2. Reefs detached from the coast. These consist of reef structures of variable dimensions, from few meters to tens of kilometers. They occur from 1 to tens of kilometers off the coastline, in various depths. They do not form a lagoon, and sediment transport occurs freely on the leeward side of these reefs. Detached reefs can be divided into various reef types: Coral knoll, Patch and Bank reefs, and Pinnacle (Fig. 4 E to I). Coral knoll (Fig. 4 E). It can attain maximum dimensions and heights of a few meters (sensu Ginsburg and Schroeder 1969), and is found at variable shallow waters (usually less than 5 m deep), where they may alternate with patch reefs.

Z.M.A.N. Le8o et aL

20

Patch reef (Fig. 4 F). It has lateral dimemions of tens of meters with widths and lengths larger than heights. The lateral walls may have abrupt relief, around 5 m high. They are sparsely distributed over wide areas of the Brazilian inner shelf, i.e., in water shallower than 10 m.

Origin of coral reefs, at present attached to the coast A. Cross-section of a fringing reef

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,, ,~ 0.3 ind rn2) in the Northeast (north of Camagfiey Province) and Southeast (Cayos Doce Leguas) of Cuba (M. Formoso per. com.). Now, local fishing quotas require a license from the Environmental Agency of the Ministry of Science, Technology and Environment (CITMA). Spiny lobster Panulirus argus is an important resource closely linked to coral reefs. This marine resource is considered to be the best regulated and the most sustainable in Cuba. Since 1978, catches have varied between 11000 and 13000 metric tons per year and were mainly based upon lobsters inhabiting the seagrass beds of the Cuban shelf, and not just upon those dwelling in the reefs, where an important reproductive potential remains. In the last years total catch varied between 9000 and 10000 metric tons due to some decrease in recruitment since 1989 (R. Cruz, in prep.). Baisre (2000) also documents this decline. Private lobster fishing is not allowed, but some poaching for the black market takes place. Variable catches of turtles on the order of 500 to 1300 tons per year were obtained from 1968 to 1992, with values higher than 1000 tons only before 1975. Since this year catches began to diminish down to 44 tons in 1997. The National Program for the Conservation of Turtles gradually diminished the legal harvesting of turtles since 1992, in accordance with the Convention for the International Trade of Endangered Species of Flora and Fauna. Measures included the prohibition of the private catching of turtles and the egg collection, as well as their transportation and consun~fion. Among other measures, the program establishes the protection of beaches where turtles nest. Since 1997, a total quota of 45 tons was established for two places (Nuevitas in the northeast of Cuba and Cocodrilo in the southwest). There is some poaching for local consumption through the black market. Research to test the hypothesis that Cuba has a resident hawksbill turtle (Eretmochelys imbricata) population is being conducted. Research on the artificial rearing of the hawksbill turtle, green t t ~ e and loggerhead has been carried out for the establishment of turtle farms. Financial constraints have limited the possibility of implementation of the two existing turtle farm programs of Cayos Doce Leguas and Cocodrilo (formerly Jacksonville). Some harvesting of the gorgonian Plexaura homomalla has taken place along two reefs at the southeast end of the Isle of Youth (southwest Cuba) to obtain prostaglandin. This collection was carried out in a sustainable way, by pnming 50% of the "mature" (>30 cm tall) colonies, with a subsequent "resting" of the harvested areas.

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Recently, craftsmen and some local state mini-enterprises for the manufacturing of jewelry, handicrafts, and imitation black coral have illegally collected several species of gorgonians (from some individual sellers). This has led to the devastation of gorgonian gardens in the shallow reef zones of Havana City and Varadero Beach (as far as we know). Commercial stocks of black coral (Anthiphates caribbeana) were discovered in 1960. From the 70's, they were collected in an unregulated manner. The official exploitation of black coral (mainly directed to Anthiphates caribbeana) began in the second half of the 80's. The harvesting of this resource was regulated in 1990, but continued in an ineffectively coordinated and poorly controlled fashion by a few state enterprises. Very recently, there has being a significant improvement in control, by using permanent harvest inspection on-board fishing boats. Illegal harvesting has taken place since the 70's, despite the fact that this activity is forbidden. As a consequence, adult black coral stocks have been depleted in some locations (at the shallower depth ranges of black coral) along the north of Pinar del Rio Province, in Matanzas Bay (northeast Cuba), Puerto de Sagua (north-central Cuba) and Cazones Gulf (east of the Gulf of Bataban6), amongst others. In 1998 an official estimate was that 1468.6 kg of black coral has been extracted at depths of 20-55 m by four enterprises. The regulated minimum size for black coral collected in Cuba is 1.20 m tall and 2.5 cm in diameter at the base. Due to the lack of knowledge on the abundance, biology, ecology and distribution of black coral, a research project partially supported by the UNDP has been conducted, in order to investigate black coral ecology and assess its populations.

4.4. Management prospective Since the 1970's more attention began to be paid to Cuban coral reefs research. However, real possibilities for a differentiated, comprehensive, holistic and legally supported reef management did not exist up to recent times. Rather, management was fragmentary and regulatory measures poorly enforced. A certain degree of protection and sustainability was then achieved through: 9 Some fishery regulations. 9 Existing legislation on the protection of natural resources, flora and fauna, on the prevention of pollution, on marine collecting, and on environmental impact assessment. In that legislation, the term coral reef was not expressed, but included within the genetic concept of fragile ecosystems. 9 Regulatory measures for tourism development in natural areas, required for the acquisition of environmental licenses. 9 Commitments with international treaties such as Agenda 21, MARPOL, SPAW, and CITES. To advance towards an Integrated Coastal Zone Management, a complex and difficult yet vital issue for coral reef conservation, is the current target of the Ministry of Science, Technology and Environment (CITMA). In 1994 a process of institutional improvement took place in which CITMA and its subordinate Environment Agency (AMA) were created. Since 1996 the legislation relevant to protection and rational use of fragile ecosystems improves year after year (Resolution 111/96 Rules about Biological Diversity, 1996; Resolution 168 Rule of Environmental Impact Assessment and for obtaining Environmental Licenses, 1996; Law 81 of Environment, 1997; National Environmental Strategy, 1997; the National Strategy for the Conservation and Sustainable Use of

The Cuban coral reefs

69

Biological Diversity, 1999 and others). CITMA, AMA and MIP are more aware of the urgent need for action for the conservation and sustainable use of coral reefs and they are formulating plans, regulations and a new legislation for the achievement of these goals. AMA and MIP are discussing specific regulations for coral reef use and protection. In 1996 the first explicit regulations for coral reefs appeared (Decree-law 164 Rules of Fishery, 1996; Resolution 33 on Black Coral, 1996; Joint Resolution MIP-MCTMA No. 1/97 of the Ministry of Fishery Industry and CITMA; and the draft bill of the Decree-Law of Biological Diversity). Among these regulations are the prohibition of collecting, anchoring, dredging, pouring sediments, pollutants and solid wastes, and using explosives in coral reefs and their vicinities. Fines are to be imposed for violations of those regulations according to the Decree-law of Contravention System on Environmental Issues, 1999. A recently approved Decree-law on Protected Areas (1999) paves the way to the urgent protection of several coral reefs in Cuba. The Ministry of Science, Technology and Environment is working to improve education and awareness on coral reef value and vulnerability. The UNDP/GEF SabanaCamagiiey Ecosystem Project on biodiversity protection of the Sabana-Camagiiey Archipelago, the Institute of Oceanology (Instituto de Oceanologia), the National Aquarimn, the Center of Environmental Information, Management and Education, the Coastal Ecosystem Research Center, the Marine Research Center, the National Center of Protected Areas, the National Enterprise for the Protection of Flora and Fauna, the ONG "Sibarimar" and the Cuban participants in the CARICOMP Project (Caribbean Coastal Marine Productivity) are working in that direction. Cuba has the necessary professional capability and the institutional capacity for the research and management of its coral reefs. However, the present economic difficulties seriously limit the fmancial resources available to implement and enforce such conservation actions. Although CITMA considers coral reefs in Cuba to be important, coral reef research is still fragmentary due to the lack of resources. The Project General Assessment of the Ecological Status of Cuban Coral Reefs and Monitoring of the Cuban Regional CARICOMP Station is being executed with many limitations. It is aimed at the assessment of the status of coral reefs throughout Cuba, and at identifying the natural and anthropogenic stressors involved, as well as giving relevant management recommendations to the Environmental Agency. It is also engaged with the monitoring of the coral reef station of the Cuban CARICOMP site in Cayo Coco (northern Cuba) and with the "Atlantic and Gulf Rapid Reef Assessment" initiative (AGRRA). 5. CORAL BLEACHING AND DISEASES Coral bleaching and diseases are treated as a separate section (apart from natural disturbances and anthropogenic impacts) because of uncertainty regarding the extent to which human activity may be directly or indirectly involved. The first mass coral bleaching event in Cuba was recorded in 1983 (N. Capetillo and C. Carrodeguas per. com.). Until 1994, coral bleaching was fragmentarily documented, with no reliable information about the extent of the events. In the late summer of 1995, widespread and intense coral bleaching was reported at many locations in the north of Cuba, from Cayo Jutia (Pinar del Rio Province) to Santa Lucia Beach (east of Camagtiey Province). This intense coral bleaching extended from very shallow reef (1 m) to 30 m

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deep. Affected corals were Montastraea annularis; Diploria strigosa," Agaricia agaricites; Porites astreoides; Acropora palmata; Millepora alcicornis; Palythoa caribbaea. Surprisingly, Siderastraea siderea were not bleached, at least in Cayo Guillermo. Recovery of many colonies was reported in January from Santa Lucia Beach reef. Some signs of recovery were also seen in October in a shallow reef at Cayo Guillermo. Before 1995, such intense coral bleaching and other diseases were recorded by the authors at the following times and locations: 9 North of Cayo Pared6n Grande (northern central Cuba) on October 12, 1989: affected corals were Acropora palmata (white band or predation?) at a reef crest, and Meandrina meandrites (coral bleaching) at 10-15 m depth. 9 Three miles west of the mouth of Cabafias Bay (northwest Cuba) on a reef crest (1.2 m depth) on September 29, 1990: Millepora alcicornis f. complanata was about 90% bleached. 9 Near Guardalavaca Beach, Banes (northeast Cuba), on a fore-reef about 15 rn in depth, on August 20, 1993): stands of Agaricia spp. had suffered bleaching (N. Capetillo per. corrL). Surveys conducted on one cruise in April-May 1994, along the north-central part of Cuba (Sabana-Camag4iey Archipelago), and another cruise in the first half of June 1995, along the southern coast of the Isle of Youth (southwest), did not reveal the occurrence of any massive coral bleaching events. During the first survey (in April-May, 1994) some partially bleached colonies of Montastraea annularis and M. cavernosa were observed on a reef at Cayo Coco (12-20 m deep), as well as some colonies of Acropora palmata with big white patches on the back reef in Cayo Guillermo (west of Cayo Coco). On the reef of Cayo Caimfin Grande (west of Cayo Guillermo), at 18-20 m deep, some colonies of Stephanochoenia intersepta and Dichocoenia stokesi were fully bleached, while a few M. annularis were partially bleached. On the reef of Cayo Fragoso (west of Cayo Caimfin), some partially bleached colonies of M. annularis were also detected at a depth of 5 m. On the second survey (June 1995), some Siderastraea exhibited dark spot disease at a depth of 30 m (D. lbarzfibal per. corn.), and some isolated Montastraea were completely bleached at about 20 m depth (J. P. Garcia-Arteaga per. com.). Periodic monitoring of the Cuban CARICOMP reef sites (twice a year since September 1993 to the early summer of 1995) at Cayo Coco (northern Cuba) has not revealed massive coral bleaching. In November 1995 coral bleaching was recorded at the site for many coral colonies. The most affected species, in decreasing order, were Mycetophyllia lamarckiana, Agaricia agaricites, Montastraea annularis, Colpophyllia natans and Diploria strigosa. An almost full recovery was reported at visited reefs. In the late summer of 1997, intense coral bleaching took place in the north of Cuba, but not in the south where several places were visited. It seemed to be the most intense coral bleaching event recorded in Cuba. We do not know the fate of the affected corals. Many colonies of Helioseris cucullata, which is considered a species resistant to bleaching, were bleached. Again, Siderastraea siderea did not suffer bleaching. Further coral bleaching also took place in the late summer of 1998. This was reported at Havana City reef, Cayo Coco (north-central Cuba), Cayo Largo (southeast of the Gulf of Bataban6, Dr. l)rsula Rehfeld per. com.), Cienfuegos (Dr. Jos6 Espinosa, per. com.), Trinidad (south of Cuba), and Santiago de Cuba (southeast of Cuba, down to 35 m depth in May, C6sar Garrido, per. com.). At Punta Franc6s (southwest of Gulf of Bataban6), no massive coral bleaching was observed in October (Jos6 R. Larralde per. com.), yet in the

The Cubancoralreefs

71

same month 30% of corals were bleached in the CARICOMP site reef of Cayo Coco (10 m depth). Many corals were not white, but paler, revealing that the event was just beginning. A cropora palmata populations were observed to have deteriorated to a large extend, presumably as a result of the joint action of "white band" disease, "coral bleaching" and/or predation (Coralliophilla snails) in several locations in the north and south of Cuba (Paraiso and Levisa keys in the northwest of Cuba; Coco, Sabinal, and Guajaba keys in the Sabana-Camagtiey Archipelago; Cayo San Felipe, Punta Francfs, and Cayo Cantiles in the southwest of Cuba; from Bajo de la Vela to Cayo Caguama at Jardines de la Reina Archipelago). In other locations visited in 1994 (e.g. Punta Francfs, Punta del Este, Cayo Matias, Cayo Campos and others, in the southwest of Cuba, and south of the provinces of Gramma, Santiago de Cuba and Guantfinamo) A. palmata stands were in good condition. Now they are predominantly dead. Acropora cervicornis mounds in front of Playa Siboney, at 15-20 m, (south of Santiago de Cuba) was said to still be healthy in 1997. Craig Quirolo from the NGO "Reef Relief' (per. com.) has observed and photographed the occurrence of "black band" disease and what he calls "white pox" in Punta Mafia la Gorda (northwestern end of Cuba) and in Coco and Guillermo keys (central-north Cuba) in 1997. In the north of Pinar del Rio (northwest of Cuba, between Bahia Honda Bay and Cayo Jutia) he reported the occurrence of "white band", "black band", "yellow band", "white pox" and "white plague" diseases, as well as "aspergillosis" in sea fans (Quirolo 1998). He also observed a frequent occurrence of the snail Coralliophila abbreviata on Acropora palmata. ACKNOWLEDGMENTS We are very grateful to Craig Quirolo (Reef Relief) for his valuable information on coral reef diseases in some Cuban reefs, and to Georgina Bustamante (The Nature Conservancy's Marine Conservation Center), Yair Lichtenztajn and Jorge Cortfs for reviewing the manuscript and for their invaluable advice. REFERENCES

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Herrera-Moreno, A. 1983. Efecto de residuales industriales sobre el patr6n estacional y las caracteristicas del meiobentos en Santa Cruz del Norte. Rep. Inv. Inst. Oceanol., Acad. Cien. Cuba 20: 1-35. Herrera-Moreno, A. 1991. Efectos de la contaminaci6n sobre la estructura ecol6gica de los arrecifes coralinos en el litoral habanero. Ph.D. dissert., Academia de Ciencias de Cuba. 110p. Herrera-Moreno, A. & P.M. Alcolado. 1983. Efecto de la contaminaci6n sobre las comunidades de gorgon~ceos al Oeste de la Bahia de La Habana. Cien. Biol. 10: 69-86. Herrera-Moreno, A. & P.M. Alcolado. 1985. Monitoreo de la contaminaci6n mediante el anfilisis de la estructura comunitaria de los gorgon~iceos. Contrib. Sin~. Cien. Mar y VII Jomada Cient. Inst. Oceanol. XX Aniversario, Ciudad de la Habana: 253-257. Herrera-Moreno, A. & P.M. Alcolado. 1986. Estructura ecol6gica de las comunidades de gorgon/lceos en el arrecife de Santa Cruz del Norte. Rep. Inv. Inst. Oceanol. 49" 1-27. Herrera-Moreno, A. & P.M. Alcolado. 1988. Estructura de las comunidades de gorgon/~ceos en el litoral de Mariel y su comparaci6n con el litoral habanero. Cien. Biol. 15: 55-69. Herrera-Moreno, A. & N. Martinez-Estalella. 1987. Efectos de la contaminaci6n sobre las comunidades de corales escleractineos al Oeste de la Bahia de la Habana. Rep. Inv. Inst. Oceanol. 62: 1-29. Herrera, A., P. Alcolado & P. Garcia-Parrado. 1997. Estructura ecol6gica de las comunidades de gorgon~ceos en el arrecife de barrera del Rinc6n de Guanabo. Avicennia 6/7: 73-85. Ibarz/lbal, D. 1993. Distribuci6n y abundancia de la macroinfauna bent6nica v/lgil en tres arrecifes de la plataforma suroccidental cubana. Avicennia 0: 84-111. Kiihlmann, D.H.H. 1970a. Die korallienriffe Kubas. 1. Genese und evolution. Int. Revue Hidrobiol. 55: 729-756. Ktihlmann, D.H.H. 1970b. Studien fiber physikalische un chemische factoren in kubanischen Riffgebieten. Acta Hydroph. 15: 105-152. Ktthlmann, D.H.H. 1971a. Die entstehung des west-indischen korallenriffgebietes. Wiss. Zeitschr. D. Humboldt-Univ. Berlin, Math.-Nat. R. 29: 675-695. Ktihlmann, D.H.H. 1971b. U-ber einige physicalische und chemische factoren in kubanischen korallenriffgebieten. Wiss. Zeitschr. D. Humboldt-Univ. Berlin, Math.Nat. R. 29:707-719. Kiihlmann, D.H.H. 197 lc. Untersuchungen zur Okologie und entstehung kubanischer banlrifle Kubas. Wiss. Zeitschr. D. Humboldt-Univ. Berlin, Math.-Nat. R. 29:721-775. Kiihlmann, D.H.H. 1971 d. Die korallienriffe Kubas. II. Zur Okologie der bankriffe und ihrer korallen. Int. Revue Hidrobiol. 56:145-199. KiJhlmann, D.H.H. 1974a. Die korallienriffe Kubas. III. Die rigelriff und korallenterasse, sweiverwandte erscheinungen des bankriffes. Int. Revue Hidrobiol. 59:305-325. Ktihlmann, D.H.H. 1974b. The coral reefs of Cuba. Proc. 2nd Int. Coral Reef Symp., Australia 2: 69-83. Lapointe, B.E., M.M. Littler & D.S. Littler. 1992. Modification of benthic community structure by natural eutrophication: the Belize barrier reef. Proc. 7th Int. Coral Reef Symp., Guam 1: 1323-334. Littler, M.M., D.S. Littler & P.R. Taylor. 1989. Evolutionary strategies in a tropical barrier reef system: functional groups of marine macroalgae. J. Phycol. 19: 229-237.

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Martinez-Estalella, N. 1986. Distribuci6n y zonaci6n de los corales cubanos (Scleractinea). Rep. Inv. Inst. Oceanol., Acad. Cien. Cuba 46: 1-24. Martinez-Estalella, N. & A. Herrera-Moreno. 1989. Estructura ecol6gica de las comunidades de corales escleractineos en el arrecife de barrera del Rinc6n de Guanabo. Rep. Inv. Inst. Oceanol., Acad. Cien. Cuba 9: 1-15. Martinez-Iglesias, J.C. & J E. Garcia-Raso. 1999. The Crustacean decapod community of three coral reefs from the southwestern Caribbean Sea of Cuba: Species composition, abundance and structure of the communities. Bull. Mar. Sci. 65: 539-557. Miravet, M.E., M. Lugioyo, S. Loza E. Perig6 & M. Montalvo. 1999. Indicadores microbiol6gicos del estado de salud de los arrecifes coralinos y fondos blandos de la plataforma suroeste de Cuba. Inf. parcial, Arch. Cien. Inst. Oceanol, 20 p. Mochek, A.D. & E. Vald6s-Mufioz. 1983. Acerca de la conducta de los peces de las comunidades costeras en la plataforma cubana. Cien. Biol. 9: 87-106. Ndfiez-Jim6nez, A. 1984a. Cuba: La naturaleza y el hombre. Vol. 2. Bojeo. Editorial Letras Cubanas, La Habana, Cuba. 702 p. N6fiez-Jim6nez, A. 1984b. Cuba Jardin Coralino. Catey, Ediciones Turisticas de Cuba, Instituto Nacional de Turismo de Cuba, La Habana. 44 p. Plante, R., P.M. Alcolado, J.C. Martinez-Iglesias & D. Ibarzabal. 1989. Redox potential in water and sediments of the Gulf of Bataban6, Cuba. Est. Coast. Shelf Sci. 28: 173-184. Quirolo,C. 1998. Reef Relief' s 1998 Cuba Expedition. Reef Relief(report): 1-47. Steneck, R.S. & M.N. Dethier. 1994. A functional group approach to the structure of algal-dominated communities. Oikos 69: 476-498. Su~rez, A.M. 1989. Ecologia del macrofitobentos de la plataforma de Cuba. Rev. Invest. Mar. 10:187-206. Trelles, J. A.M. Suhrez & L. Callado-Vides. 1997. Macroalgas del arrecife de la Herradura, Costa NO de La Habana. Revista de Investigaciones marinas 18(3): 191192. Vald6s-Mufioz, E. & O.H. Garrido. 1987. Distribuci6n de los peces en un arrecife costero del litoral habanero. Rep. Inv. Inst. Oceanol., Acad. Cien. Cuba 61: 1-22. Vaughan, T.W. 1919. Fossil corals from Central America, Cuba and Puerto Rico with accounts of the American Tertiary, Pleistocene and Recent coral reefs. Bull. U.S. Nat. Mus. 103: 189-524. Wells, S.M. 1988. Coral reefs of the world. Vol. 1: Atlantic and eastern Pacific. UNEP, Nairobi & IUCN, Gland. 373 p. Zlatarski, V. & N. Martinez-Estalella. 1980. Scleractinians of Cuba, with data on associated organisms. Bulgarian Academy of Sciences Press, Sofia (in Russian). 312 p. Zlatarski, V. & N. Martinez-Estalella. 1982. Scleractiniaires de Cuba. Acad6mie Bulgare des Sciences, Sofia. 290 p.

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The coral reefs of the Dominican Republic F r a n c i s c o X. G e r a l d e s Centro de Investigaciones de Biologia Marina, Universidad Aut6noma de Santo Domingo and Fundaci6n Dominicana Pro - Investigaci6n y Conservaci6n de los Recursos Marinos, P.O. Box 748, Santo Domingo, Dominican Republic

ABSTRACT: The Dominican Republic has a land area of 48,484 km 2, with a coastline of 1,389 km, of these 166 km or 11% are coral reefs. The continental shelf, averages 7.5 km wide and covers 8,130 km 2. There are two submerged offshore banks, two barrier reefs, as well as many fringing reefs. Dominicans in general recognize the importance of coral reefs as they provide safe ports, shelter and habitat for biodiversity, food and beaches. The first report of reefs in the Americas was from Hispaniola by C. Columbus in 1492, calling them "baxas" or "roqueiros". Other early naturalist worked with specimens from this island, and research continues until our days. The reef setting varies depending on the location and distance form the numerous river discharges. Dry areas and shallow platforms are favorable for reef growth at: Montecristi, Macao-Punta Cana, Parque Nacional del Este, Parque Nacional Jaragua, as well as the Silver Banks located some 170 km to the north of the island. The coral coverage varies from 40% to 9%, reflecting not only natural causes, but also anthropogenic impacts. There are reports of 64 coral species. The coastal marine habitats including the reefs of all the marine protected areas in the country have been studied, cataloged and mapped, the information produced have been important for their management and conservation. Some reefs are under threat by development of ports such is the case of Boca Chica, the most studied reef site in the island. Sedimentation along the coast has increased, and has become a threat to reef growth, occurring on 1/3 of the coastline, and now reaching reef sites such as Juan Dolio and Barahona. Coral bleaching has been found mainly on areas near urban development. The 1980's mass mortalities occurred as in the rest of the Caribbean. The reefs of the southern and eastern coasts of the Dominican Republic are usually exposed to hurricanes. The reef tracks near urban development are more impacted by habitat degradation due to physical damage and from nearby sources of pollution transported by currents. Non-adequate beach use in some tourists centers have caused reef degradation in the past, lessons learned have induced the tourism sector to become involved in reef conservation. The main problem reefs are facing is overfishing of several essential species such as Strombus sp., Panulirus sp., and fishes of the Serranidae, Lutjanidae, and Scaridae families. Several non-official institutions as well as the recent created Secretaria de Medio Ambiente y Recursos Naturales (Ministry of the Environment and Natural Resources) have programs for conservation of marine and coastal habitats, communities and species.

1. I N T R O D U C T I O N T h e c o r a l r e e f s o f the D o m i n i c a n R e p u b l i c are an i m p o r t a n t r e s o u r c e , a n d it is a c k n o w l e d g e d b y the citizens that t h e y p r o v i d e safe ports, shelter, a n d food. C o r a l reefs h a v e r e c e n t l y b e e n a s s o c i a t e d w i t h the t o u r i s m industry. W h i l e in the past, D o m i n i c a n s t o o k c o a s t a l a n d m a r i n e r e s o u r c e s for granted, a n d c o n s i d e r e d t h e m e v e r l a s t i n g , t h e r e is Latin American Coral Reefs, Edited by Jorge Cortrs 9 2003 Elsevier Science B.V. All rights reserved.

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today an awareness of their fragility, and of the fact that they need care and good management to ensure their health and function. At present, coastal and marine environments, as well as forest habitats, have national economic, political and aesthetic value. Nevertheless, overfishing, pollution and urban growth still pose very relevant and real threats to these ecosystems. In order to minimize these, the country has set aside four large coastal regions as marine protected areas: Parque Los Haitises, Parque Montecristi, Parque del Este and Parque Jaragua. The last three are located downstream of oceanic currents and receive minimal river influence. In all coral reefs, seagrasses, and mangroves constitute important habitat reserves. Other coastal features of the Dominican Republic include emerged reef terraces, shorelines of terrigenous origin, estuaries and sandy beaches. This chapter includes a description of the coral reefs of the Dominican Republic, as well as maps of the most important reef sites: two barrier reefs (Montecristi and MacaoBavaro-Punta Cana), and several fringing, hard base, high energy marine-coastal communities. Finally, a short review of the environmental hazards that coral reefs face in the Dominican Republic is presented.

1.1. Natural history The island of Hispaniola, situated at 17040 ' and 19~ and 68020 ' and 70~ is the second largest in the Caribbean (78,000 km2), and located in the north-central boundary of the Caribbean Sea. The deep Windward Passage (4,000 m) separates it from Cuba, to the north-northwest, and the Jamaica passage separates it from Jamaica, to the west-southwest (3,000 m). It is separated from Puerto Rico, to the east, by the shallow Mona Passage (350-400 m). Oceanic currents and winds are primarily governed by the easterly trade winds. Hispaniola is politically divided into two countries: Haiti to the west, and the Dominican Republic to the east (Fig. 1). The Dominican Republic has a land area of 48,484 km 2, with a coastline of 1,389 km. Of these, 376.7 km (or 27%) are mangroves, and 166 km (or 11%) are coral reefs. Emerged reef terraces and cliffs, are the main coastal features found along the coast, especially on the southeastern region of the island. The continental shelf has a mean width of 7.5 km, and covers an area of 8,130 km 2. There are two submerged offshore banks: La Navidad and La Plata, 70 and 150 km 2 respectively, located north of Cabo Saman~ (Fig. 1). 1.2. Geography The island topography is diverse, with three large valleys and four mountain chains. These have a directional trend northwest to southeast, with broad valleys in between. Two outstanding features of the Dominican Republic are: that it contains the deepest zone in the Caribbean (the Valle de NeybaJLago Enriquillo, at 48 m below sea level), and the highest peak (Pico Duarte/La Pelona, 3,087 m above sea level) (De la Fuente 1976). The island also has a very complex tectonic and geological history, being seismically active. 1.3. Climate and oceanography The climate of Hispaniola is considered to be tropical marine dry, with an annual average temperature ranging from 18 to 32~ at the lower elevations. There are regional variations in climate and rainfall, influenced by the predominant northeasterly trade winds,

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as well as cold fronts from the northwest, and sporadic hurricanes and summer storms from the southwest. Rainfall tends to decrease from east to west. The annual average rainfall is 980 mm, with May and November having the highest precipitation, and December to April having the lowest. The oceanic circulation patterns in coastal waters are dominated by the Northem Equatorial Current, which flows westward and divides itself into northem and southem branches at Mona Passage (Metcalf et aL 1977). Counter currents, usually associated with tides, are common near to the coast. Tides are semi-diumal, with mean spring tidal ranges of 90 and 30 cm on the northern and southem coasts respectively. 1.4. Culture, population, and development The people of the Dominican Republic form an agricultural and farming society, which is presently moving towards light industry and tourism. Historians indicate that deforestation and human intervention in the natural setting has occurred since the 15 th century. Severe environmental changes occurred during the early to middle 20 th century, when the sugarcane industry boomed and large areas of forest were cut down, increasing soil erosion and sedimentation, and hence ultimately affecting the nearby marine ecosystems.

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Another major impact to the environment has been the recent population rise, from 2.5 million in the 1960's to the present 8.5 million today. This rise has increased the degradation of watersheds, river systems, and marine and coastal habitats. 1.5. Coral reef research

The study of reefs in Hispaniola began in 1492, when Christopher Columbus described these submerged structures as "roqueiros", "baxas" and "restringas" (confinements) in his navigation log (Col6n 1492). Later, in 1525, Gonzalo Femfindez de Oviedo (in Chardon 1949) mentions these strange formations on his Sumario de la Natural Historia de las Indias. Several early naturalists, such as Carlos Plumier (1695 in Chardon 1949) and George L. Leclerc (1770 in Chardon 1949) made collections for the Muse6 de Historie Naturelle de Paris. In 1776, Luis Nicolson published his Essai sur l'Histoire Naturelle de St. Domingue (Chardon 1949), where he mentions madreporaria, corals, crustaceans, and other invertebrates. Also worth mentioning is the work of Moreau de Saint-M6ry during 1796 (Chardon 1949) and his Description Topographique et Politique de la Partie Espagnole de L'Ile de Saint Domingue. Later in the 19th century, more works followed such as those of William Gabb (1868, in Chardon 1949), who published "On the Topography and Geology of San Domingo". In the early 1900's, other scientists such as Vaughan (Vaughan 1900; Vaughan et al. 1921), Wells (1956), and William Hassler, who published "From Sea Base to Mountain Top at Santo Domingo" (1933, in Chardon 1949), collected and worked either on living and fossil reefs of the Dominican Republic. More recent studies, including those of Sir W. Halcrow and Partners's reports on the environmental impacts at Boca Chica (1976); Geister's (1980), and Schubert and Cowart's (1980) work on the paleontology of reef terraces on the south coast of the Dominican Republic; the studies of Galzin and Renaud-Mortand (1983) on pollution effects on coral reefs; and the work on the reef conditions after hurricanes (Barnwell 1983). Dominican contributors to reef studies include Bonnelly de Calventi (1974), who published a taxonomic coral list. Gonzfilez-Nufiez (1974) located reefs sites and lists species collected in "Operaci6n Madre Perla". In 1973, F. X. Geraldes began his research on coral reefs, publishing in the local newsletters of the Museo Nacional de Historia Natural, Centro de Investigaciones de Biologia Marina, and the Herbario de la Universidad de Santo Domingo. These early works included the first Dominican scientific reef study with descriptions of reef types, species, and locations, the results of which were later summarized and published (Geraldes 1976, 1978). Rathe (1981) produced the first systematic study of sponges in Dominican coral reefs. Geraldes (1982) also studied the effects of hurricanes on Dominican reefs. More recent studies include reef characterizations, ecological assessments, and species lists (Geraldes 1994a, 1996a, b, c; Vega 1994; Vega et al. 1994, 1997; Geraldes and Vega 1995a, b; Geraldes et al. 1997), as well as reef conservation efforts made by creating volunteer networks for reef monitoring (Cintr6n et al. 1994; Geraldes 1994b). 2. DESCRIPTION OF CORAL REEF AREAS Most coral reefs of the Dominican Republic are fringing reefs. There are also two barrier reefs, numerous patch reefs, and four large offshore banks; their distribution is associated with the coastal profile and depth of the ocean platform. In places like Macao

The coral reefs of the Dominican Republic

81

-Puma Cana and Momecristi, broad platform barrier reefs are found. Not so in Palenque, Saman~ Bay, and the Bahia Escocesa, where reefs are unable to establish due to the high turbidity caused by numerous river discharges. There are also unnatural conditions that are affecting the reefs such as increasing coastal development, pollution, untreated waste, water discharges, and beach erosion. This chapter describe the reefs found in the coasts of the Dominican Republic, starting with the offshore bank reefs (Silver Banks). The coastal reefs are described beginning at the northwestern shores bordering Haiti at Rio Masacre (Montecristi), and moving clockwise around the island to the southwestern border with Haiti at Rio Pedernales. 2.1. Offshore bank reefs: The Silver Banks, National Sanctuary of Whales The Silver Banks (Fig. 1), at 20~ 69~ l'W, and 140 km north of Puerto Plata in the Dominican Republic, have an area of 3,740 km 2. In the northern portion of this bank the barrier is composed of a series of patch reefs bound together near the surface. This area is shallower and shaped like a triangle. The reef extends for 30 km to the southeast; it is exposed at low tide: on its ocean side to a great depth, over a distance of less than 100 m. The coral patches are pillars of cemented coral skeletons ascending from the rubble and sandy base 15 to 25 m up the surface. The living coral species found here follow the zonation pattems described by Goreau (1959). A. palmata is found occupying the top portion of the reef down to the 6 m depth contour. Below that zone, most corals are typical of the lower palmata and buttress zones. The substrate of the Silver Banks is mainly sand and coral gravel. At the southern portion of the breaker zone, the mean depth is 40 m, and corals grow only where suitable substrate is present. The turbidity of the water tends to increase to the south and away from the reef crest. A reduction of coralline columns or pillars is obvious to the south of the reef crest. The mean coral cover in the Silver Bank is 40%. There is a low density of sponges (2%). Turf algae covers 51% of the sampled substrate. The rugosity of this reef is relatively high (1.3%) due to the magnitude of the coral columns or pillars, some of which reach the surface of the water. 2.2. Coastal reefs 2.2.1. Montecristi barrier reef (Fig. 2.). The Montecristi region in the northern coast of the Dominican Republic has the largest reef formation of the country with a length of 64.2 km, which grows on the nearshore areas of the Montecristi Shoals (1,181 km2). The coastline consists of a low mountain range of sedimentary (Miocene) origin. At the northwestern end is the landmark of E1 Morro (273 m) and the city of Montecristi, and 2 km to the west is the Yaque del Norte River estuary with its large mangrove forest. The climate and land ecology of the area is dry to very dry tropical forest, conditioned mainly by the lack of river runoff and the steady easterly winds (15 to 30 knots). The reef begins at E1 Morro and extends westward reaching Punta Rucia. Along the coast and protected by the barrier and lagoon, extensive nearshore seagrass beds and frondose growths of red mangroves (Rhizophora mangle) thrive. The reef system of Montecristi can be considered as a barrier reef in active expansion. High relief features and large living coral colonies with sizes exceeding 10 m in diameter are common. The deep reef

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The coralreefs of the DominicanRepublic

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has different characteristics depending on location and position relative to currents, waves, wind direction, and tidal channels. A representative portion of this setting is shown on Fig. 3, at Punta Mangle. Reef lagoon: The reef lagoon can be between 20 m and 2 km wide, and up to 20 m deep. In association with it there are sandy beaches, mangrove forests and terrigenous cliffs. In hard base areas (1 to 5 m deep), small coral patches (5 to 800 m 2) are found with Gorgonia spp. and Plexaura spp. as the dominant soft corals, associated with the M. annularis complex, Diploria spp., Manicina spp., A. cervicornis, Porites spp. and Millepora spp. The main feature in this lagoon is the dense to sparse seagrass beds of Thalassia and Syringodium on a sandy or sand-mud base. Other coral species found in the reef lagoons are: P. divaricata, M. areolata, S. siderea, S. radians and A. cervicornis. Reef flat and back reef: There is an extensive and diverse back reef followed by a reef fiat. In areas closer to tidal channels a more vigorous growth of corals occurs: Porites porites, Porites divaricata, the M. annularis complex, A. cervicornis, A. palmata and Millepora complanata are present with octocorals and sponges as well. Near to the reef crest a harder, more consolidated base is found, where calcareous algae Amphiroa spp. and Jania spp. are dominant. Thalassia and Syringodium grow in patches. Reef crest: Skeletal remains of poorly lithified Acroporids form the reef crest. Millepora is dominant although a few young A. palmata are also found. This change in dominance patterns could be attributed to the Acroporid disease, with Millepora substituting the previously dominant A. palmata and Porites spp. structures. In most of the reef area, the crest is narrow and crossed by tidal channels. Here, the waves from oceanic swells barely reach the reef. This may be due to the effect of the precedent shoal which reduces their force. The energy here is mainly represented by wind-generated waves with a short lifespan producing choppy seas, which conditions a low energy environment. On its ocean side the crest abruptly drops to 6 - 10 m in less than 30 m, allowing a clear view of its basal structure, which is composed of large skeletons of A. palmata, A. cervicornis, Porites spp. and Montastraea spp. Some of these skeletons have broken loose and lie at the base of the crest, serving as suitable substrates for future colonization, as well as refuge for other reef inhabitants. Outer reefs: In exposed areas, there is evidence of a lower Palmata zone consisting mostly of large, dead colonies of A. palmata. Seaward is a low relief spurs and grooves formation, with large colonies of the dominant Montastraea complex are also found. There are variations to this zonation pattern: when tidal channels divide the reef crest, there is usually a portion of the breaker zone, facing away from the predominant forces (wind and waves); this creates a very calm and protected portion on the reef. In this setting, the reef crest can sometimes abruptly drop into a sandy channel with seagrass, often down to 30 m deep. As this portion receives some of the ocean's energy, the coral growth can be found forming patches 10 to 5,000 m 2 in size. This set-up then continues either towards the shore where it connects to the backreef, or seaward, where it is followed by spurs and grooves or hard grounds. In the majority of the cases for Montecristi, the reef crest slopes towards a hard base (10 m deep), where octocorals are

84

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The coralreefs of the DominicanRepublic

85

dominant. The hard base ends in a wall, dropping to the 25 m contour where large coral colonies are found. The M. annularis complex, M. cavernosa, Diploria spp. and Agaricia spp. amongst others cover most of the bed, with a total coral cover exceeding 60%. In these places, the colonies form gigantic structures, some occupying up to 100 m E, formed by coral heads of multiple colonies forming a single structure. Among these, broad caves and deep crevices (14 m) are common. In the deepest portion (30 m), coral pinnacles are found. Live corals and other hermatypic organisms use the large boulders and debris that have precipitated down from shallower regions as substrate to grow vertically in a pillar-like fashion. When several of these pinnacles grow close together, they sometimes join to create a larger base. In most cases the dominant species is Montastraea, and it covers all previous growth. In other cases some of these are dominated by octocorals and coralline algae such as Halimeda goreaui, Halimeda discoidea and Dyctiota spp. The encrusting octocoral, Erythropodium caribaeorum, and the red calcareous algae Porolithium caribeaeum are also common features of the pillars at the Montecristi reefs. Another type of reef formation found here are deep reefs, which form buttress systems. These are characterized by large to very large dominating colonies of the M. annularis complex, as well as M. cavernosa, Siderastrea spp., D. strigosa, D. labyrinthiformis, D. stokesiL Madracis spp., M. meandrites, A. agaricites, A. cervicornis and the sponge Cliona langae. These buttress systems are usually found in association with the tidal channels located throughout the extension of the reef.

Offshore keys Punta Rucia keys. In the eastern end of the Montecristi Barrier Reef at Punta Rucia, there are 16 offshore coral keys. These are small (800 to 5,000 m2), submerged, mountlike features that rise from a sandy platform 45 to 100 m deep. They have an arch-like shape, with the convex side facing the incoming winds. There is a significant difference in coral growth pattern between the exposed and protected sides of these keys. On the protected side of the keys, at 15 m depth, there is sparse marine vegetation, with Syringodium and fleshy algae dominating; as this reaches the flat, a back reef may form. Here P. caribaeorum, and the corals P. astreoides, D. strigosa and M. annularis are found with small colonies. In these places the long-spined black sea urchin Diadema antillarum is common, hiding amongst the crevices of the healthy reef found here. Moving towards the reef crest, on its windward side and at 2 m deep, a breaker zone is evident; species diversity increases, as do organisms adapted to stronger waves and currents. On some of the keys the breaker zone occupies the entire key. The dominant species found here are: A. palmata, Millepora spp. the, M. annularis complex and D. strigosa. In some of the other keys in these high-energy areas, there are large areas of hard substrate without any coral growth; instead, large algae mats of Lobophora sp. and other algae cover most of the area. The frontal reefs usually end at approximately 12 m depth, sometimes followed by a sand plateau or by a forereef slope to deeper waters. Hermatypic corals dominate this reef slope. Numerous healthy colonies of the M. annularis complex, A. palmata, M. cavernosa, P. porites, A. agaricites, together with the sponges Cliona langae and Aplysina fistularis are found. Due to currents induced by heavy swells at the base of the exposed side (forereef slope), a detrital area is found.

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Here octocorals such as Plexaura homomalla, P. americana and P. flexuosa and the coral M. alcicornis become dominant species. Siete Hermanos keys. These keys are not part of the Montecristi barrier reef system. They are located 25 km west of El Morro, at the western and distal end of the Montecristi Shoals, on a ocean floor rise (5-30 m deep) and at the edge of the Manzanillo submarine canyon (>800 m deep). The keys occupy an area of 10 km 2, and vary in size between 3,000 to 40,000 m z. All are composed of sand and unconsolidated coral debris with arid vegetation, where nesting populations of Tula leucogaster (buN) are commonly found. Water turbidity and salinity show influences of the Yaque del Norte river estuarine system about 20 km upstream. The sea bed is sand-mud. Despite these conditions, the shallowness of these seven shoals offer enough light penetration for fringing reefs to form on the windward sides, as well as patches on the leeward sides of the keys. In shallow areas between the keys, there are numerous patch reefs. In some cases these are vaguely connected and form large structures, especially between Cayo Rata and Cayo Muerto. Coral reef formation is least at Cayo Tourur6, this being the most easterly key and thus closer to the estuary. Nevertheless, the river plumes can reach as far away as Cayo Arenas, located furthest to the west. It is considered that water quality, mainly its turbidity and salinity, have influenced this region to conform a unique reef formation. The coral structure on these keys is of a l~inging reef type down to 20 m, consisting of a sandy beach followed by a narrow reef flat 10 to 50 m wide. The species composition on the back reefs is similar to Punta Rucia back reefs. The breaker zone, however, presents differences between the keys. Most of them rise from a sand-mud base at 10 - 12 m. In keys facing surf and currents, the hard base substrate is bare and covered by cementing and boring sponges, and octocorals. In those keys where the currents and surf are not as strong, vertically growing species are found together with large to gigantic coral colonies. These grow sparingly, and are surrounded by finger-like corals such as Porites spp. Sometimes, gigantic round coral forms can be found which comprise most of an area, with very few if any other accompanying benthic species.

Biodiversity of the Montecristi barrier reef Recent studies done in Montecristi (Geraldes 1996a, b, c; Geraldes et al. 1997) have produced updated information about this area, a community and substrate map (1:40,000) of the coastal region, and the first biodiversity list for the region's marine and coastal habitats. The biodiversity sampled here includes 22 Classes, 285 Families, 525 Genera, and 742 species. The highest species richness is found in the hard base communities, which is related to substrate rugosity and complexity. Of these hard base community types, coral patches, high relief spur and grooves, and reef keys represent the refuges for biodiversity. 2.2.2. Luper6n reef, Luper6n Bay, Puerto Plata. Eastward of Montecristi, the coast is characterized by a diversity of habitats: a reef terrace extends from Punta Rucia to Luper6n, and the coast is then mainly of terrigenous origin until it reaches Puerto Plata. Luper6n Reef is a fringing reef located 250 m offshore. It grows over a narrow drowned reef terrace, which borders a shallow submarine canyon at the entrance of a bay (Bahia de Luper6n), where mangroves and a small town are found. The reef grows on a hard base, with low relief and high gorgonian cover up to 10 m deep. The reef slope ends at

The coral reefs of the DominicanRepublic

87

40 m depth near a submarine canyon. Coral cover is 12%, with algae dominating (67%). The growth is mainly of hard and smooth substrates, with very little reefrugosity (1.04%). 2.2.3. Playa Dorada reef, Puerto Plata (Fig. 4.) Patchy coral growth with low cover by live corals, dominated by encrusting turf and fleshy algae, are characteristics of a sedimentary coastal region of calcareous origin, which is washed by numerous torrential streams that form sedimentary plumes; rip currents are common here. Offshore (18 m deep) a hard basal community grows on top of a sandstone substrate. In areas where coastal features provide shelters, like Playa Dorada, the coast was originally fringed by healthy mangroves and marshes (now replaced by golf courses and hotels), which acted as sediment and nutrient barriers, and allowed the formation of patch reefs. These often formed small mounts and pillars, with rose vertically from a 15 m base to the surface. A small fringing reef of A. palmata and Porites sp. developed. These structures protected the coast and created a large stretch of beach, which is now intensely utilized by the tourism industry. At present, this reef is severely degraded due to environmental misuse by the resorts (over 5,000 rooms) and the golf course built here: all these infrastructures have exceeded their sanitary infrastructures capacity, thus streams and ground water pollution, together with nutrient runoff, have seriously affected the nearby reefs and coastal regions. There is little hope of recovery unless the activities that maintain this present level of pollutants are controlled. Studies shows that there is an 80% coral mortality, and that 92% of the basal and reef substrate is covered by algae, especially Gracilaria spp., Dyctiota spp., Turbinaria spp. and Codium spp. Eastward of Playa Dorada, the coastal features of the coast change to reef terraces followed by a narrow flinging reef that extends eastward for 3 km. The distance from shore to the reef crest reef varies from 10 to 200 m away, where the breakers begin; A. palmata skeleta are found here covered with algae. Millepora spp. now dominates this breaker system. In deeper water (15 - 25 m), irregular sandstone structures with many crevices and pillars, covered with scattered coral growth, rise up to 5 m high from the sandy beds. 2.2.4. Sosfia reef, Puerto Plata. SosOa reef is located in a small bay open at the northeast. The base is composed of beach rock. The calm waters and white sandy beaches off the coast make this a preferred tourist destination. High reef terraces encompassing a unique view surround the beach. Underwater, a patch reef surrounded by sand occupies approximately 30% of the center of the small bay. A prairie of octocorals with sparse growth of A. palmata, M. alcicornis, D. clivosa, and D. cylindrus begins at the 4-m contour. Deeper, at the 10 m contour, the diversity and cover by coral species increases, covering 28% of the substrate. Intense visitation by tourists has caused severe impacts on this site. Continuous visitation creates large sediment plumes. Algae cover is 43%, possibly due to some undetermined nutrient input. In terms of species diversity, the absence of large predatory fish species is noticeable. The sponges occupy 6.4%, and are mainly of the encrusting and burrowing types. 2.2.5. Reefs of the northern shore of the Samanfi Peninsula Reef Las Ballenas keys. This reef surrounds a carbonate outcrop in the coast of Las Terrenas, on the northern shore of the Samanfi peninsula. The base is a hard pavement

88

I

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Fig. 4. Playa Dorada - Punta Sosua, Puerto Plata.

I l

Hard Bottom Communities

5m

F.X. Geraldes

fi

20055'-

The coral reefs of the Dominican Republic

89

eroded relict reef, where sparse medium-sized coral colonies, mainly of Diploria spp. and Meandrina, establish themselves in crevices and grow. There are also octocorals, and a thick carpet of fleshy and turf alga covers this basic substrate. The species richness is not high, and comprises 11 species of algae, 9 sponges, 9 octocorals and 2 hard corals. E! Portillo reef. This reef is located on the northern shore of the Saman~i peninsula. The coastline is composed of high and steep carbonate mountain slopes and terraces. The climate is very humid. Since the 1940s, most of the coastal lands have been turned into coconut farms, deforesting the area in the process. The reefs here are fifnging, growing very close to shore in sparse patches with a tendency to close at the breaker and to form lagoonal environs. On these lagoons, and very close to the shore in shallow waters, the patches have coral remains of A. palmata, the M. annularis complex, Millepora spp., and Diploria spp. Most are fully covered by fleshy and turf algae; very few, if any, live corals are found on them (Geraldes and Vega 1995b). Further out to sea, approximately 9 km offshore, there are numerous shoals (15 m deep), that rise from the surrounding oceanic waters. These are carbonate terraces, eroded either by bioerosional processes or by exposure to weathering during past geological times. The species of corals found in these shoals are few and low in coverage (11.7%). More dominant is turf algae (44%), fleshy algae (20%), and encrusting sponges (18%) (Geraldes and Vega 1995b). The lack of large predators and the scarcity of large herbivores and sea urchins are affecting coral recruitment on these reefs, giving the opportunity for more active erosional processes to Occur.

Puerto Escondido. This site is the northermost shore in the east of the Saman~i peninsula. It is located very close to a terrigenous rocky shore with falling boulders, and to the edge of the narrow continental shelf. Corals here grow without any apparent anthropogenic influences. Runoff and springs in the past, which are now reduced, have created small, narrow, protected coves where corals flourish, and where A. palmata grows vigorously. In deeper waters, on a terrigenous base, a young fringing reef can be found with 25 coral species, 15 species of sponges, 11 species of octocorals and 18 species of algae (Geraldes and Vega 1995b). Cabo Cabr6n reef, Las Galeras. The reef near Cabo Cabr6n offers a spectacular wall dive. It is located at the tip of the Saman~ peninsula. The coastal region is formed by Tertiary rocks (marble), and is steep and high (400 m). The water depth right off the coast surpasses 150 m. In some areas where landslides have occurred, narrow terraces can be found formed by large boulders. In those places coral grows from the surface to 50 m deep in a 30 ~ incline. The coral forms are of the encrusting and massive type, and coral cover is approximately 40%. Tube sponges follow with a 28% coverage (Geraldes and Vega 1995b). Large fish are frequently found here. During winter, humpback whales are often encountered, here and in the Portillo and Terrenas reef sites. 2.2.6. Miehes reef. This region on the eastern coast of the Dominican Republic is very humid. Numerous rivers and streams loaded with sediments join the ocean near Miches. The Yuna river system discharges to the west in Saman~ bay, and together with the Los Haitises and the Sabana de la Mar watersheds, they form the largest estuarine system of the Caribbean islands. The waters in the entire region are generally murky due to the high loads of sediments, limiting coral growth. Near the town of Miches, at Punta Hicacos, a

90

F.X. Geraldes

68115,

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,.

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small fringing reef has developed. To the west there are small patch reefs. Extending towards the center of the bay to the north, there are offshore shoals, which are dangerous for navigation and where important 16 th century wrecks are found (Tolosa and Concepci6n). This coral region has not been documented. 2.2.7. Bfivaro- E! M a c a o - Punta Cana barrier reef system (Fig. 5). On the Eastern shores of the Dominican Republic, facing the Mona Passage, is the B~ivaro-E1 MacaoPunta Cana barrier reef system. This portion of the island has a configuration resembling a bold arrowhead. B~ivaro faces northeast into the Atlantic, E1 Macao is to the east (Mona Passage), and Punta Cana to the southeast (the Caribbean). The coastline is sandy, with mangroves, coastal lagoons, and swamps behind the coastal dune. These humids drain into the sea through numerous outlets or underground springs. The watershed is a coastal plain in the B~varo region. At E1 Macao and Punta Cana, reef terraces are usually found close to shore mainly at Cabo Engafio and near the airport. The reefs of E1 Macao, B~ivaro and Punta Cana extend for 70 km. There are marked structural differences between them. While E1 Macao and B~varo face northeasterly winds and high swells, Punta Cana faces southeasterly winds and waves. Thus E1 Macao and B~ivaro are high energy reef complexes with hard bases and eroded profiles, while Punta Cana has the characteristics of a low relief reef.

The coralreefs of the DominicanRepublic

91

El Macao (Arena Gorda) reef. This reef is located in the north central portion of the Mona Passage, close to Cabo Engafio, and has Atlantic reef characteristics. Its appearance is similar to the one described for Puerto Plata and E1 Portillo in Saman~t. The smooth and solid limestone rises from the sandy surroundings up to 10 m, forming a high relief reef. There are no spur and groove formations here: the rocky formations are more like reef relicts from the late Quaternary period. The substrate where the reef has established itself is covered with algae (23%, of which 1.3% are encrusting and boring algae). The basal reef rocks of this reef have become brittle through bio-erosional processes, forming sediments and sand and creating temporary sediment plumes that affect coral recruitment and growth. This explains the low coral coverage (5.5%), most of which consist of small colonies no larger than 20 cm in diameter. B~ivaro reef. The breaker zone at B~ivaro can be as far as 3.5 km from shore, creating a wide lagoon (2-5 m deep) with coral patches and an extensive seagrass bed, followed by a broad porous and shallow back reef that reaches gradually onto the reef fiat. Coral species commonly found in this area are P. porites, P. astreoides, S. radians, M. complanata, A. cervicornis, Diploria spp., C. natans and the M. annularis complex. A. palmata skeletons covered with algae in association with Millepora sp. dominate the windward side of the breaker zone, which is narrow and steep. At 4 m, there are large dead stands of A. palmata as well as large boulders of the M. annularis complex and Diploria sp. Reaching the 13 m depth there is an irregular and wide sand channel, ending on its seaside in a rise of 8 m, which continues to form a smooth sandstone shoal, mostly covered by turf algae; during stormy events, this area becomes the first breaker region on the reef complex. These shoals are uneven, with crevices 2-5 m deep. Between them, shallow sand pockets appear and interconnect with others. Towards the deeper regions and on the frontal face of this shoal, the 10 m contour is reached with a gentle slope. The reef base then flattens and low-relief spurs (1.5 rn high) with sand and rubble-filled grooves begin to extend for 800 m or more, to about the 18 m depth. The coral cover for this portion of the reef is 16%. Punta Cana Reef. This reef is located in the southern portion facing the Mona Passage, and begins on its northern side following the cornering of Cabo Engafio by deep seas. Here, isolated patch reefs may be found close to shore. The Punta Cana reef grows closer to shore, characteristic of the fringing reef type, and is oriented towards the southeast. This zone is frequently hit by hurricanes. The Punta Cana sandy beaches are interspersed with low coral cliffs, which tum into high escarpments towards the south where the reefs end and there are deep nearshore waters. The reef lagoon region is shallow with rubble and sparse seagrasses. Several freshwater springs discharge underwater, thus influencing the type of biological diversity found here. The breaker zone at 5 m is narrow and composed of large, compacted skeletons of A. palmata; algae cover is high and few live corals are present. Seaward of the breaker zone, there is a sand and rubble area, with large boulders comprising the base of this frontal structure. The spur and groove area is of low profile and highly eroded. The 50 rn contour line is very close, and there are some areas where it is possible to find features used as dive destinations. The Macao-B~ivaro-Punta Cana Barrier Reef is now facing large impacts and threats from a steadily growing tourism industry. In a 30 km stretch of coast, about 11,000 hotel rooms have been constructed. The intense use of some hotel front sites and dive destinations has inflicted obvious damage on the reefs. In those areas close to shore, coral cover-

92

F.X. Geraldes I

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age is less than 5%, and the seagrass beds as well as the lagoon patch reefs and backreefs are clearly degraded. There has been a rapid and unplanned development, without environmental impact assessments on the potential impacts of several activities, such as dredging and intense beach use creating sediment plumes, which mainly affect the backreefs, the reef flats, and the reef crests at Macao, B~ivaro and Cabeza de Toro. There are other impacts that have affected this reef, such as anchors, environmentally unconscious diving and snorkeling, and increased fishing pressure. The result of these actions has induced the algae growth, which has reached to 58% of substrate cover. Beside the sediment effect described above, there exists no control over the release of detergents and other water treatment chemicals that are usually associated with hotel operations. The evidence of a stressed system is clear, and there is an unusually noticeable presence of the black band disease, affecting several coral species.

The coral reefs of the Dominican Republic

93

2.2.8. Reefs of Parque Naeional del Este (PNE) (Fig. 6). The reefs of this protected area are basically low relief systems, found either as small, fringing, deep (20-30 m deep) patches, or as banks. Most of them are on the leeward side, protected by a land mass of Pleistocene and Recent reef terraces. Southeasterly trade winds are dominant. The reef on the leeward side can be divided into two distinct areas: that along the southern coast of Saona Island (influenced by oceanic currents,) and that along the western side of the Catuano Passage (more protected). The bases of the Saona reefs are consolidated hard bases and octocorals and sponges dominate the benthic communities. Hard corals are abundant only at the specific places where they concentrate, forming small, dispersed coral patches. Here the waves and currents are strong, and are in part responsible for sculpturing the reefs. The reefs west of Catuano mainly have sandy bases with patch reefs. Large amounts of sediment and biogenic sands are transported from the Catuano Passage and deposited along this coastline towards the west, with large seagrass meadows covering most of the nearshore areas. Corals mostly grow in patches from 12 to 30 rn deep. Further to the west, away from the influences of the Catuano Passage, coral patches increase in frequency and grow as deep-water fringing reefs, these being the most common reef structures of the southern coast of the Dominican Republic. Parque Nacional del Este (PNE) is the most studied marine site in the Dominican Republic (Vega 1994; Vega et al. 1994, 1997). Six categories of hard base substrate have been identified for this area: low relief spur and groove formations, reef flats, transitional reef communities, patch reefs, low relief rocky shoals, and rocky coasts. The basal substrate for these formations is consolidated carbonate reef, in addition to sediments and rubble.

Fringing Reefs Catalinita reef (Fig. 7.). This reef is located at the eastern end of a channel that separates the mainland f~om Saona Island. The base rises abruptly at the edge of the channel. In the deep portions, high relief spurs and grooves with large, rounded coral forms are common, while in shallower areas a hard base virtually without sand deposits, serves as a substrate for a large octocoral prairie. Following the 10 m contour depth, the base is covered by a wide frontal section of large skeletons ofA. palmata which project to the surface. In some areas where live colonies still exist, patches of Montastraea spp. and M. complanata form, mainly on the leeward side of the breaker zone and near Catalinita Island, which is a deposit of coral debris. Arreeife del Troneo (Catalinita reef). This is a leeward reef located to the north of Pasa Grande and south of Catalinita Island. Porites sp. is the dominant species at 0.5 m depth. At 3 m coral diversity increases. Algae (27 species) cover 50% of the area, sponges (16 species) occupy 5% of the area, octocoral (7 species) growth is sparse, and corals (14 species) cover 25% of the benthos. P. fureata is the dominant species. This setting forms a low frontal wall that ends in a narrow sand-gravel base, colonized by a dense seagrass bed of T. testudinum. Reef Crest, Catalinita Reef. Due to the act that this reef geographically faces the westbound currents, it is common to fred large amounts of solid waste from the heavy traffic of the Mona Passage and other offshore territories to the east. Dominating the top of the crest in 0.2 rn of water, is the short leaf type of Thalassia. There are also some live colonies of A. palmata, A. cervicornis, M. complanata, D. strigosa, M. areolata and S.

94

F.X. Geraldes !

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Fig. 7. Catalinitareef, ParqueNacional del Este.

radians. Below this, large, unconsolidated pieces of A. palmata lie like non-cemented tiles. At the 2 m deep, a patchy seagrass bed is established on top of coarse gravel (>25 cm diameter) substrate. In this zone, 8 species of algae cover 50% of the base. Sponges and octocorals are rare: There are 5 species of sponge and 3 species of octocoral. Hard corals are represented by 10 species, growing sparsely as small colonies. Adamanay Reef. This narrow fringing reef starts at E1 Faro to the West, and runs very close to shore along the village of Mano Juan, ending at Canto de la Playa in the central southern portion of Saona Island. The reef crest is separated by a shallow and narrow (30-50 m) sandy channel with seagrasses. Sporadic coral aggregations form the narrow reef fiat, which then continues into a Acropora-Montastraea zone; this is the basal structure of the breaker. In the seaward direction lies a hard carbonate platform, where gorgonians and coral grow in depths and configurations similar to other Saona Island sites. The Adamanay Reef protects the only human settlement in Saona Island, which dates back to the 1700s as a pirates' village, and is now a fishing settlement and a tourist destination.

The coralreefs of the DominicanRepublic

95

Low relief spur and groove communities

The low relief spur and groove communities are mainly found to the west of Mano Juan, in a somewhat protected region of PNE, and in the south of Saona Island. They are located between 0.5 - 3 km away from the coast at 15 to 30 m deep. Sponges are dominant, as are octocorals and algae. Coral colonies are medium-sized and scarce. M A M M A ' s reef. This reef begins 18 m in front of Punta E1 Faro. The reef system is a continuation of a patch reef near the coast, in 3 to 8 m of water, dominated by live A. palmata and the M. annularis complex. Going seaward from this patch reef, a broad sand channel occurs, ending where the spur and grooves begin, with an orientation facing East towards the incoming waves and winds. Coral cover is low (7.5%), octocorals are the dominant benthic forms (17% coverage), and algae occupy 25% of the base. Parque Naeional. This reef is located westward of the mainland, at 15 m depth. It has small, narrow spurs (6-9 m wide and a length up to 25 m), and the grooves are narrow (3-5 m wide) and filled with fine sediments. The basic orientation of this reef is east to west. The algae are dominant with 15 species, forming patches with Halimeda opuntia and H. tuna as the dominant species. Twenty-nine species of sponge have been documented, with ,4gelas, Xestospongia and Verongula constituting the most common genera. Octocorals are abundant with 10 species, Pseudopterogorgia acerosa and P. americana being the most common species. Twenty-five species of hard corals have been observed, with relatively low coverage. The most common species are medium sized colonies of D. labyrinthiformis, S. siderea and M. cavernosa. El Pefi6n (CARICOMP/site). E1 Pefi6n has a hard base, with sparse sand-clay sediments at 15 m. This eroded spur and groove formation gently slopes towards a 2 m cut reminiscent of ancient shores, and into a sand channel where seagrasses grow. The dominant benthic fauna are the octocorals, with 18% coverage and 16 species, Briareum, Eunicea and Pseudopterogorgia being the most common genera present. Sponge coverage is 11%, with a diverse sponge composition (36 species), Agelas, Verongula, and Xestospongia being the most common. The corals account for 8% of basal coverage with 26 species (the highest species count for the whole PNE). Algae cover is significant; 24%, with 15 species represented. This location has been chosen as the CARICOMP permanent reef monitoring station for the country. Arrecife de Rub6n. This reef lies on the 20 m contour line that extends from Mano Juan westward. The reef's loose substrate is formed by sand, clay, and rubble. The benthic biodiversity is dominated by algae, with 14 species covering 25% of the substrate. Sponge diversity is also high, with 34 species covering in some cases up to 50% of surveyed areas. The most common genera present are again ,4gelas, Verongula and Xestospongia. Coral coverage is low (5%), and only 18 species have been documented. El Toro. This reef is found in the southwestern shore of Saona Island, at the 20 m contour depth. The orientation and position of this site faces the incoming currents and seas from the southeast. A spur and groove system forms its basic design, ending abruptly in the cut of an old shore terrace at 26 m depth, where large gravel and reef debris accumulate from the bioerosional processes occurring in the living portion of the reef. Algae cover (50%) is dominant, followed by octocorals with 22 species. Corals (25 species) grow, but cover no more than 5% of the base.

96

F.X. Geraldes

Bayahibe Reef. This reef is located at the northwestern limit of Parque Nacional del Este, 800 m away from shore, on top of a submerged terrace 18 m deep. It has a welldef'med spur and groove system, with relief up to 2 m high. The reef orientation is eastwest, perpendicular to the shore. The coverage by corals is 34%, with 25 species; sponges 11% with 37 species; and algae 35%, with 16 species. Hard base carbonate reef flat communities This reef type is characterized by a hard base flat carbonate substrate. These reefs are low relief, and are associated with high energy seas and currents. They are most common in the eastern portion of the park facing the incoming surge and waves from the open seas. In terms of diversity, turf and brown algae, and/or a co-dominance of algae and corals dominate them. Pasa Grande (Catalinita Reef). Algae, with 36 species, dominate this hard base. The most conspicuous genera are Dictyota, Turbinaria, Stypopodium and Halimeda. Coral colonies grow sparsely forming large individuals. Octocorals are few in number, represented by Gorgonia ventalina, Pseudoplexaura poros and Plexaura flexuosa: all are species adapted to high-energy conditions. Seven sponge species are present, encrusting and boring forms (Chondrilla nucula and Cliona langae) dominating. The corals are more diverse with 12 species, the most common being A. palmata, D. clivosa, P.

astreoides and P. porites. Transitional reef communities E! Faro. To the northwest of the Adamanay reef crest, somewhat protected by an extension of the southern coast of Saona Island, a low relief-high energy occurs at 7 m depth, mostly colonized by: algae, corals, and octocorals. It may be considered a transitional reef with accumulations of sediments and rubble. There are 24 species of algae, with Halimeda, Dictyota and Amphiroa dominating, and a cover from 25 to 50%. There are 22 octocoral species, with Eunicea, Plexaura, Plexaurella and Pseudopterogorgia being the most abundant, and encompassing 25% of the basal coverage. Hard corals are present, with 23 species growing scattered along the fiat bottom, covering 5% of it. Patch reef communities These are located in protected waters in the western portion of the leeward side of the park, and inside the Catuano Passage, protected by the fringing reef and reef crest of Catalinita Island. Arrecife del Angel 1. This reef is located in shallow water (1.8-5.4 m), in the western entrance of the Catuano Passage, and is surrounded by a large seagrass bed. The structure is dome-shaped, with a diameter of 30 m, and is collapsed in its middle portion; hence the name that reminds one of a halo. In this middle portion Porites rubble accumulates. In its most exposed portion, large coral heads are found, with a tendency to link to the back reef by a rubble and deposition bed. Algae is the dominant form here with 50% coverage representing 21 species, the common ones being Halimeda opuntia, Caulerpa racemosa, Titanoderma sp., Stypopodium zonale, Amphiroa tribulus and Dictyota sp. Sponges here are scattered with a 5% coverage, but with 20 species present, of which Cliona langae and Iotrochota birotulata are the most obvious ones. Octocorals are very sparse, with 7 species found only in the periphery of the patch structure. Corals

The coralreefs of the DominicanRepublic

97

represent >5% coverage with 11 species present. P. porites, the M. annularis complex and M. cavernosa are the most common. Arrecife del Angel 2. Again in the Catuano Passage, at 5 rn depth, there is a patch reef with low relief, surrounded by a seagrass bed, sand, and gravel, with spotted and patchy coral colonies. Algae are dominant with 50% coverage and 15 species. Sponges have only 5% coverage with 18 species, with C. langae, Amphimedon compressa, I. birotulata and Aplysinafistularis being the most commonly seen species. Besides algae, the most dominant group is octocoral, with 13 species and large colonies (>50cm) of Eunicea, Plexaurella, Pseudoplexaurella and Pseudopterogorgia. Here coral cover is >5% of the substrate, with 15 species. There are moderate to large colonies (> 25 cm) of the M. annularis complex, M. cavernosa, D. labyrinthiformis and S. siderea. There are also acroporids present. Los Flamencos. This reef is located near E1 Faro reef, in the protected waters of the small cape which the coastline forms here. The reef is at 6 m depth and consists of a series of coral patches separated by sediments and rubble. The physical relief is medium to low in a hard substrate, where corals congregate to form outcrops of growth with large heads intercepted by the sand channels surrounding them. In some cases A. cervicornis is found, initiating the settling process and patch formation. Algae are represented by 21 species, dominated by Dyctiota sp. Octocoral fauna is common, with Eunicea, Plexaurella, Pseudoplexaurella, Pseudopterogorgia and Pterogorgia being the most commonly seen. Also common are the hard corals with 23 species. There are large (>2 m diam.) colonies of A. palmata serving as a basal structure for other species to settle on, such as A. tenuifolia and the rare M. squarrosa. Large numbers of Montastraea, Colpophyllia and Dendrogyra are also found in these coral patches. Hard base carbonate platform communities Arrecife de Los Cocos. At 4 m depth, in the western portion of the Catuano Channel, there is a tidal channel frequently washed by strong currents generated from tides and winds, which structures the benthic community. Due to the strong currents, the dominant biota found are algae and octocorals, and in a lesser quantity, sponges and corals. Algae cover is above 50%, with 29 species present, the most common being Hypnea cervicornis, Acanthophora spicifera, Jania rubens and Laurencia intrincata. Of these, H. cervir represents more than 25%. Halimeda opuntia, H. tuna, Coelothryx irregularis, Amphiroa brasiliana and Galaxaura oblongata are also common. It is notable that the red algae are dominant in this location. Sponges are sparse around this reef site, occupying 5% of the base with 28 species. It is interesting to note that some of them can reach sizes up to 1.2 m, and the most commonly found species here are Amphimedon compressa, Pandaros acanthifolium and Callyospongia vaginalis. Octocorals are the most conspicuous group on this reef, with some individuals reaching up to 2 m high. They are well represented by 23 species, the largest number of species found in the park nevertheless their basal attachment or foot only covers 5% of the base. The common species are: P. acerosa, E. clavigera and E. calyculata, representing 60% of the total. Corals cover 1% of the base, with small colonies ( 20 ~

> 20 ~

> 20 ~

Leeward slope

> 20 ~

> 20 ~

> 20 ~

> 20 ~

8.4 (2.9)

9.8 (1.3)

3.8 (2.2)

11.7 (7.9)

M

H

H

H

Unit size (km 2) ** Depth at base (m) **

Distance to shore (km) ** Terrestrial influence

CAMPECHE BANK

Emerged

Setting

Offshore

Reef type Reefs per system (n) * Unit size (km 2) **

Bank

Submerged

Ba-At

Offshore

Inshore

Bank

Bank

4

1

11

4

5.0 (2.5)

680

8

2

Depth at top (m) **

-

-

16 (10)

6 (5)

Depth at base (m) **

38 (7)

50

36 (9)

16 (8)

Windward slope

< 20 ~

< 20 ~

> 20 ~

< 20 ~

Leeward slope Distance to shore (km) ** Terrestrial influence

> 20 ~

> 20 ~

> 20 ~

> 20 ~

175 (21)

124

182 (16)

35 (11)

N

N

N

CARIBBEAN Setting

North

N

Central

South

Continental

Island

Submerged

Bar-Fr.

Fr. ***

Bank

Bar-Fr.

Bar-Fr.

Ba-At

60

50 +

-

110

100

-

Unit size (km 2) **

-

-

> 400

-

-

700

Depth at top (m) **

-

-

25

-

-

Depth at base (m) **

20-60

10-400

360

30-60

30-65

400 +

Windward slope

< 20 ~

< 20 ~

> 20 ~

< 20 ~

< 20 ~

> 20~

-

-

> 20 ~

-

-

> 20~

Reef type Reef tract length (km)

Leeward slope Distance to shore (krn) **

-

-

58

-

-

30

Terrestrial influence

N, L

N

N

L

N, L

N

Upwelling

L, M

?N

?L

?

?

9

136

Jordhn-Dahlgren & Rodriguez-Martinez

Fig. 2. Details of selected reefs in the Gulf of Mexico, Campeche Bank and Caribbean (see Fig. 1). Atoll-like bank reefs (Chinchorro and Alacranes), offshore bank reefs (Cayo Arenas and Cayo Arcas), offshore bankbarrier reefs (Trihngulos),and inshore reefs on the western Gulfcoast. All drawings are North-oriented.

All the offshore reefs rise from the shelf surface at depths of 30 to 40 m, and those of the northern sector may have developed, during a marine transgressive phase, from remnants of ancient sand dunes (Logan 1969). There are distinct morphological variations between leeward and windward sectors. An extensive and shallow reef flat is a common feature in most of leeward part of these reefs. Corallinaceae algae are quite abundant in these flats, and binding of coral skeletons in ample dead beds of Acropora cervicornis is evident. Some reefs have extensive spurs (Cayos Arenas, Tri~ngulos reefs), and deep moats on the fore reef zone (Cayos Areas, Tri~ngulos reefs). Main spur builder species are Acropora palmata (mostly dead at present) and Montastraea annularis in the deeper sections, although other species may play an important additional role (Table 3). Halimeda species abundance is scarce in these reefs, and in Cayos Arcas three separate surveys, from 1969 (Farrell et al. 1983) to 1997 (Jordan per. obs.) have failed to detect its presence. In contrast with the Caribbean shallow reef environment (-1 to-10 m) sandy areas are not colonized by seagrasses.

137

The Atlantic coral reefs of Mexico

TABLE 3 Characterization of reefs off the Atlantic coast of Mexico. Dom. (Dominant bio-constructor species or association): Aaga: Agaricia agaricites; Acer: Acropora cervicornis; Apal: A. palmata; AL: algal (corallines or fleshy); CA: coral-algal (crustose); CBA: branched coral-algal (unconsolidated); CG: Coral grounds, communities dominated by gorgonians, scattered corals (maybe abundant, but small) and sponges, that contribute in small measure to the reef relief; Cnat: Colpophyllia natans; Dcli: Diploria clivosa; Dstr: D. strigosa; Mann: Montastraea annularis; Mcav: M. cavernosa; Mfav: M. faveolata; MC: mixed corals; Mcom: Millepora complanata; Ssid: Siderastrea siderea; Past: Porites astreoides; Pfur: Porites furcata; OT: others. Cond. (bio-constructors condition): d: diseased; h: healthy; r: recovering (recovery of live tissue in standing colonies); x: dead (not-recently). Overg. (Overgrowth on dead bio-constructors): 1: consolidating (crustose algae); 2: stabilizing (zoanthids, Erythropodium caribbaeorum); 3: temporary non-consolidating (fleshy and filamentous algae). Sdom. (Sub-dominant bio-constructor species or association). Relief (Dominant reef features that provide relief to a given reef zone): b: Acropora belt; ch: coral heads; cms: complex multiple structures; icc: isolated coral colonies; lc: low-lying crests; n: no significant relief over substrata, as with coral grounds; o: open, porous matrix; pi: pinnacles; sg: spur and grooves. The relative importance of reef features is indicated as follows: +High; + Medium; - Low; 9not applicable. Reef Zone

Dom.

Cond.

Overg.

Sdom.

Relief

Mann

d, x

3, 1

Dstr

ch, pi

+

Lagoon/flat

Dcli

h, d

1, 3

pfur

pi

-

Reef crest

Apal

x

1, 2

CA

lc

-

Fore reef (shallow)

Apal

x

3

Dcli

n

-

Fore reef (deep)

Mcav

h

Ssid

o

+

Leeward

Mann

h

Cnat

ch, pi

+

Lagoon/fiat

Dcli

h

CBA

n, o

SW GULF REEFS Isla Lobos Leeward

9 Tuxpan 9 1, 2, 3

9

Reef crest

Apal

x

CA

b

+

Fore reef (shallow)

Dstr

h

9

Mfav

o, pi

•

Fore reef (deep)

Mfav

h

9

Ssid

o

+

Leeward

Acer

x

Mcav

ch, pi

+

Lagoon/fiat

Dcli

h

Past

n, ch

-

Reef crest

Apal

x

1,3

CA

B

+

Fore reef (shallow)

Apal

x

1,3

Mann

ch, lc

+

Fore reef (deep)

Cnat

h

9

Mfav

pi, ch

+

Leeward

MC

h

Mcav

pi, ch

+

Lagoon/flat

Apal

x

1

Mann

cms

+

Reef fiat

Acer

x

2, 1

AL

n, ch

-

Reef crest

Apal

x

1, 2

CA

n

-

Fore reef (shallow)

CG

h

9

Dstr

ice

+

Fore reef (deeper)

Mcav

h

9

Ssid

ch

•

Veracruz and Ant6n Lizardo 3

CAMPECHE BANK REEFS Banks 9

138

Jo rd6n-Dah lgren & R odriguez-Martinez

Table 3 cont.

Reef zone

Dom.

Cond.

Leeward

Mann

h

Lagoon/fiat

Mann

h

Reef flat

Dcli

h, d

Reef crest

Apal

x

Fore reef (shallow)

CG

h

Fore reef (deeper)

Mfav

h

Overg.

Sdom.

Atoll-Bank (Alacranes) 9 Mcav 9 1, 2

9

Relief pi, ch

OT

cms

CBA

n, ch

AL

lc

Dcli

icc

Ssid

CARIBBEAN REEFS Continental Leeward

9

9

.

Lagoon/channel

Mfav

h

9

MC

ch

-

Back reef/fiat

Mfav

h

9

Apal

ch

•

Mcom

lc

+

Mcav

icc-sg

+

MC

icc-sg

+

ch,pi

+

Apal

x, r

Fore reef (shallow)

CG, Mfav

h

Fore reef (deeper)

CG, Mfav

h

Reef crest

3 9

Island (Cozumel) Leeward

MC

h

OT

Fore reef (shallow)

CG, Mfav

h

Mcav

icc-sg

+

Fore reef (deeper)

CG, MC

h

OT

icc-sg

+

+

Lagoon/channel Back reef/flat Reef crest

Chinchorro Bank Leeward

MC

h

Lagoon/channel

Mfav

h

Back reef/flat

Mfav

h

9

OT

oh, pi

MC

cms

+

9

Apal

ch, lc

+

CA

h

9

Mcom

lc

+

Fore reef (shallow)

Apal

h

9

Aaga

sg

+

Fore reef (deeper)

CG

h

9

MC

ice, ch

+

Reef crest

Alacranes in the northern Campeche bank (Fig. 1) is an exceptionally large bank-reef (Komicker et al. 1959; Bonet 1967) with an atoll shape that covers an area greater than 650 km z (Fig. 2). In contrast with all other Campeche bank reefs, it has a deep lagoon (~ -20 m, Fig. 3) which is segmented by a complex network of inner reefs (Bonet 1967). A core boring recovered 33.5 rn of Acropora cervicornis facies on this reef, which indicates one of the fastest rates of Holocene reef accretion yet recorded: 14 m per 1000 year (Macintyre et al. 1977).

139

The Atlantic coral reefs of Mexico

Caribbean

G u l f of M~xico SW

NE

w

E

10m [ I

i

I

5 km

j

Alacranes W

'

5km Chinchorro

E

w

Cayos Arcas

E

Puerto Morelos W

E

lOre [ I

,

i

2km

Veracruz

I

0.1km

|

Majahual

Fig. 3. Profiles of selected reefs in the Gulf of Mexico and Caribbean (see Figs. 1 and 2). Puerto Morelos reef profile corresponds to the northern Caribbean sector and Majahual reef profile to the southern Caribbean sector. Profiles are drawn approximatelyat mid reef section. 3.1.3. C a r i b b e a n reefs. Fringing-like reefs border most of the continental and insular shores of the Mexican Caribbean (Jordfin-Dahlgren 1993a)(Fig. 1; Table 2). However, strictly fringing reefs (growing directly from shore) are found infrequently. Commonly a wide (typically hundreds of meters, range from hundreds to thousands of meters), shallow (typically-3 to -4 m, range -1 to -8 m) lagoon separates the reefs from the shoreline (Fig. 4). Thus perhaps these reefs are more aptly referred to as extended fringing reefs, as these Caribbean reefs do not form a classical barrier reef (James and Ginsburg 1979)

140

Jordrn-Dahlgren & Rodriguez-Martinez

(m the Caribbean region only the southem Belizean barrier reef may qualify as such); nor do they correspond to the bank-barrier reef concept of Davies (1928). The lagoon floor is usually sandy, harboring extensive beds of the marine phanerogam Thalassia testudinum, and sporadically coral knolls. We have arbitrarily divided the Caribbean margin into northern, central and southem sectors (Figs. 3 and 5). Northern sector. The dominant reef types are extended fringing reefs (Jord~inDahlgren 1988; Jord~n-Dahlgren 1993a, b) (Figs. 3, 4 and 5). There is a relatively high coral cover on the crest and rear reef zones, while the fore reef zone is mostly of low relief, gentle slope and is colonized by coral grounds (hard grounds colonized by multispecies assemblages with many small scleracfinian colonies, abundant sponges and hydroids, and where gorgonians may be highly conspicuous; Table 3) (Jord~n-Dahlgren et al. 1981; Jord~n-Dahlgren 1993a). Therefore, modem reef accretion has been minimal and features of ancient structures, more likely of late Pleistocene origin (Ward et al. 1985), determine present reef morphology. Commonly these reefs have an Acropora palmata cover on the shallow fore reef, reef crest and protected environments, while Montastraea annularis dominates the rear reef zone. In the coastal margin, leeward of Cozumel Island, reefs are mostly absent and instead, the near shore zone is sand floored. This condition may result from a "wave shadow" effect, induced by the windward setting of the island in relation to the mainland coast (Burke 1982). However, even in these mostly reef-less area, isolated but well-developed local reefs may appear, as in the Ahmaal area. On the windward side of Cozumel Island there are no extended fringing reefs, as in the continental margin. Here the island windward slope tends to descend gradually from the shore and thus coral grounds predominate. In a couple of sites along this margin there is a strong change in bottom relief, and here large scleractinian colonies generate a distinct reef wall, lacking spur and grooves (Jord~in-Dahlgren 1989). Also, on the NE of the island, highly porous but strong coralline-algae microatolls, up to five meters high, form a shallow arc against the shore (Ward et al. 1985). The most highly developed reefs of Cozumel island are found along the edge of the SW insular shelf (Fenner 1988; Muckelbauer 1990), topping an almost 400 m high underwater cliff. These reefs are on the lee of the island, but the very clear waters of the north-flowing Yucatan current (a branch of the Gulf Stream) continuously wash them, a fact that allows for a very diverse and abundant coral community to depths in excess of 50 m. Together the physiography of the area and the rich biotic assemblages make a very spectacular reef setting. Central sector. Reef morphology in this sector follows the same trends observed in the northern sector (Figs. 3 and 5) as these reefs arise also from a submerged crest that may correspond to an ancient shoreline (Jord~in-Dahlgren 1988; Jord~n-Dahlgren et al. 1994). The main characteristic of this area is a chain of shallow A. palmata reefs that border the two large shallow bays in the Sian Ka'an Biosphere Reserve area, which tend to be better developed than on the northern sector (Jord~in-Dahlgren 1993a; Jord~mDahlgren et al. 1994). Although the shelf widens in this area and the fore reef has a low angle slope, there is a high bottom relief of the bottom at several sites. This relief arises from varied features, from series of consolidated shallow crests or risen platforms poorly coral-colonized, to extensive dendritic projections of A. palmata into the shallow fore reef (Jord~in-Dahlgren 1988). Commonly, stands of A. palmata skeletons in growing position are found, indicating a high, although patchy mortality of this species in the area, by 1994 (Jord~n-Dahlgren et al. 1994).

The Atlantic coral reefs of Mexico

141

Fig. 4. Morphology of a typical extended fringing reef in the northern Caribbean sector. The relativelywide reef lagoon allows active water circulation thus generating an adequate environment for coral growth on the back-reef zone.

Southern sector. The extension of the continental shelf is reduced and reefs are better developed than in the northern sectors (Jord~n-Dahlgren 1988). Continental reefs are mostly extended fringing reefs with similar lagoon characteristics to the reefs in the north (Fig. 5), but the fore reef typically shows a higher bottom relief. Not uncommonly, spur and groove morphology dominate the fore reef both at shallow (1-12 m) and deeper depths (10-40 m) (Jord~m-Dahlgren 1993a). Shallow spurs have a variable height from

142

Jord{m-Dahlgren&Rodriguez-Martinez

3 to 7 m, rounded side walls separated by irregular groves 3 to 6 m wide. Deeper water spurs are commonly very long and thin, 5 to 12 m high, with steep and non-porous walls, separated by narrow channels 1 to 6 m wide. Below forty meters usually isolated coral patches in a mostly bare rocky pavement dominate (Jordfin-Dahlgren 1988). In some sites there is no spur morphology, but impressive and extensive sets of shallow water (5-10 m) Montastraea annularis and Colpophyllia natans pinnacles, topped with A. palmata. On the reef crest A. palmata usually dominates, but in several instances Millepora complanata also colonize the breaker zone. The major reef formation of the southem sector is Chinchorro bank (Figs. 1, 2, 3), the largest atoll-like reef found in the Caribbean region (Jord~in and Martin 1987) (Table 3). The windward fore-reef of Chinchorro consists of a complex set of 2 to 3 series of spur and grooves f r o m - 2 to -18 m (Jord~in and Martin 1987), not unlike the shallow depth spurs previously described. Below the spur sets, a relatively gentle slope is colonized by coral grounds, and below -40 m by isolated coral patches. The windward reef crest is almost continuous and the breaker zone tends to be colonized by coralline algae (Jord~in and Martin 1987), in contrast with the Millepora-Acropora assemblage that dominates northern reefs crest. A chain of small banks and islets make-up the leeward margin, which descends to a narrow terrace (300-700 m wide, depth 12-30 m), beyond which an almost vertical cliff descends to depths in excess of 400 m, as off Cozumel island (Jord~in and Martin 1987) (Fig. 3). Chinchorro's lagoon is relatively shallow increasing from a couple of meters in the northern area, down to -8 to -10 m in the south, where a

Fig. 5. Reefs of the Caribbean coast of Mexico. Shallowreefs indicated by the dark bands, deeper reefs and coral groundsby light graybands. Referto figure 1 for relative geographicalposition of the three sectors.

The Atlantic coralreefs of Mexico

143

network of shallow reefs is found. Chinchorro is likely related to Belizean atolls whose development was strongly influenced by subsidence (Jordfin and Martin 1987).

3.2. Coral communities Coral reefs in the Caribbean and Gulf of Mexico have a similar coral biota to reefs farther south due to their downstream position in the major circulation patterns of the Caribbean (L6pez and Polanco 1991). Nevertheless, there is a reduction in the number of common scleractinian coral species from the Caribbean to the reefs of the SW Gulf (Fig. 6; Table 3). Coral species richness however, does not seem to decrease drastically as it does with gorgonians (Jordfin-Dahlgren 1992). 3.2.1. Reef crest (breaker zone). All reef crests are dominated by Acropora palmata. However, there is a decrease in subdominant components such as coralline algae and Millepora complanata toward the Gulf and an increase in zoanthids, mainly Palythoa caribaeorum and Zoanthus sociatus, both of which can be extremely abundant locally (Fig. 7). 3.2.2. Protected reef areas. Other common corals such as Diploria clivosa, Porites astreoides and Siderastrea siderea tend to be more abundant in the protected areas of the back reef and shallow lagoons of the Gulf reefs, than in similar environments in Caribbean reefs. Where the protected areas are deeper than a few meters, composition is similar in all the Mexican Atlantic reef area with large coral heads and pinnacles of Montastraea annularis and M. faveolata, usually topped by A. palmata.

Fig. 6. Live coral cover and number of common species in shallow reef areas (rear reef to fore reef ~ -10m) of differentreefs in the Atlantic margin of Mexico.Acroporapalmatastands composedmostlyby dead skeletons in growing position in the Gulf of Mexico reefs. M. annularis refers to the Montastraea annularis species complex. AL: Ant6n Lizardo.

144

Jord6n-Dahlgren &Rodriguez-Martinez

Fig. 7. Dominant biota in the reef crest on selected reefs along the Atlantic margin of Mexico. AL: Ant6n Lizardo. 3.2.3. Exposed reef areas. The shallow windward margin is usually fringed by a well developed belt of A. palmata although by the early 1990's most acroporid colonies in the SW Gulf reefs were dead (Jord/m-Dahlgren and Rodriguez-Martinez 1998). A similar condition was observed in Tri/mgulos and Cayos Arcas reefs by 1997, and Cayos Arenas in 1999 (per. obs.), whereas in Alacranes the species was scarce by 1992. The windward fore reef, between 5 m and 20 m, in most of northern and central Caribbean reefs as well as in the Campeche Bank reefs have coral grounds (Table 3) (Cochrane 1972). In the SW Gulf reefs in contrast, massive scleractinians such as M. annularis, D. strigosa and D. clivosa, predominate in this environment. In the Gulf reefs the deep fore reef, and in many cases the leeward reefs, have massive heads of the M. annularis complex, D. strigosa, P. porites and Colpophyllia natans, and coral cover can be close to 100%. In many instances the highest species richness is found at mid-depths close to the reef edges on the leeward margins. In some of the SW Gulf and Campeche Bank reefs extensive and thick beds of A. cervicornis predominate on the leeward and shallow areas but nowadays they are mostly dead. In the southern Caribbean reefs well colonized terraces and complex spur and groove systems contrast strongly with the northern Caribbean reefs. Also, there is a large coral cover on shallow spurs, mainly of Agaricia agaricites f carinata, and A. palmata on the upper parts. While coral cover is mostly restricted to the upper parts of the deeper spurs, basically by a rich assemblage of species dominated by Montastraea species, and where sponges and fleshy algae are also an important component. 4. NATURAL CONDITIONS AND STRESSES

4.1. Physical Environment The main oceanographic influence on the Atlantic reefs of Mexico comes from the Caribbean current system, as one of its branches is northwardly deflected by the Yucatfin peninsula into the Yucatfin channel, where all other Caribbean currents merge into the Gulf Stream. From here, Caribbean waters enter the Gulf of Mexico by two main paths:

The Atlantic coral reefs of Mexico

145

a) a shelf flow, over the Campeche Bank down to Trifingulos reefs, and periodically down to Cayos Arcas reef (Fig. 1), before turning Westward into the central Gulf basin as suggested by drift observations (Rezak et al. 1985); and b) by way of the loop-current (Cochrane 1972), as very large gyres of Caribbean waters detach from the main current and drift westward, eventually reaching the eastern shores of the Gulf of Mexico. For most of the year west-directed trade winds prevail. From September to April, polar continental air masses flow into the Gulf of Mexico and the Caribbean generating strong south to southwest-directed winds with speeds up to 120 km/h, although common speeds are half of that (Tulmell 1988). The main effect of these "nortes" is to reduce atmospheric and seawater temperatures, and increase turbidity, wave energy and ocean surf. They majority affect the southwest Gulf reefs, where sudden temperature drops of as much as 7~ have been recorded. The winter "nortes" also reach the Mexican Caribbean reefs, causing rapid drops in surface water temperatures of about 3~ (F. Ruiz per. com.). However this change does not seem to stress the coral community as evidenced by the healthy presence of the temperature-sensitive A. palmata. 4.1.1. Terrestrial runoff. Land influence upon reefs is restricted to the nearshore reefs of the SW Gulf. Which are affected by the discharge of large rivers during the rainy season. Although coral communities have being able to resist this freshwater input (Freeland-Lockwood 1971) (Fig. 1, Table 4), the lower coral and gorgonian diversity on these reefs may result from the combined effect of terrestrial runoff and winter storms, as well as from a relatively low oceanic circulation (Jordfin-Dahlgren 1993a). Such a situation has existed since at least the 16th century when the Spaniards introduced extensive farming and deforestation. The progressive expansion of agriculture has dramatically increased soil erosion of the extensive coastal plain, and mountain slopes, TABLE 4 Occurrence and relative intensity of natural perturbations (some may be indirectly enhanced by anthropogenic activities) on the coral reefs of the Atlantic coast of Mexico. H = high; M = medium; L = low; N = nil; X = unknown.

Southwestern Gulf

Campeche-Yucatfin

Caribbean

Climatological Storms

H

H

H

Strong storms

M-H

H

H

Cold spells

L-M

X

N

Water warming

X

X

L

Biological Diadema die-off Acropora mortality

H

H

H

H

H

M

Coral diseases

X

L

L

Algal overgrowth

M

M

L

Fish mortality

X

X

L

Bleaching

X

L?

L

146

Jorddn-Dahlgren & Rodriguez-Martinez

which constitute the watersheds of these large rivers. Nowadays, the threats to these reefs may come from sedimentation and additional anthropogenic effects, as discussed below. In the Caribbean sector, the karstic nature of the land and the lack of soils cause rapid rainwater percolation down to the water table, and no surface rivers are formed (Ward et al. 1985). Fresh water circulation is therefore underground and there is a net flux from land to ocean, therefore underwater springs may occur in reef areas. However, the water from these springs does not carry sediments, and it is not likely able to affect the coral community in this context. 4.1.2. Tropical storms and hurricanes. Hurricanes and tropical storms more likely affect all reefs in the Mexican Atlantic, but with different intensity and frequency. The hurricane season extends from June to November, peaking between August and September. Between 1886 and 2000, 162 storms (112 tropical storms and 50 hurricanes) have passed through the reef regions. Fifteen of these storms crossed all three reef regions (SW Gulf, Campeche Bank and Caribbean), twenty-three passed through the Campeche Bank and the Caribbean, and the remaining ones affected only one region (Fig. 8). The Campeche Bank and the Caribbean reefs are affected more often and by more severe hurricanes than those in the SW Gulf (Fig. 8). The highest hurricane frequency occurs in the Campeche Bank, because there is two storm sources: the ones coming from

Fig. 8. Number of tropical storms (white bars) and hurricanes (categories 1-2 in gray; categories 3-5 in black) between 1886-2000 that passed close to the three regions that include coral reefs in the Atlantic margin of Mexico (tracks between 17.5~ and 22.5~ latitude and 85~ and 98~ longitude). Hurricane categorybased on the SAFFIR-SIMPSON scale. Source: National Hurricane Center; NOAA and Colorado State University/Tropical Prediction Center.

The Atlantic coral reefs of Mexico

147

the Caribbean, and those generated in the Gulf itself. For the 111 years of available data the return period of major hurricanes (categories 3-5 in the SAFFIR-SIMPSON scale) was 37 years on the SW Gulf of Mexico, 18.5 years in the Caribbean, and 12.3 years in the Campeche Bank. In spite of this high storm frequency, the effect on reefs and on coral communities has only been documented for the northem Caribbean sector (Hurricane Gilbert in 1988: Jord/m-Dahlgren and Rodriguez-Martinez 1998). Observations of the effect of Hurricane Roxanne in 1996 on Cayos Arcas and Trifingulos reefs are in preparation to be published.

4.2. Biological Perturbations The effects of biological perturbations in the coral community, if somewhat discrete and of short duration are difficult to properly assess unless there is a permanent facility at a reef site. In Mexico, the only such facilities are in the northern Caribbean sector at Puerto Morelos, and thus more is known about this area. The occurrence, intensity, and after effects of biological perturbations in other reef regions of Mexico are largely unknown, but it is likely that widespread events such as the mortality of Diadema (Lessios et al. 1984), have impacted all reefs of the region (Table 4). 4.2.1. Diadema die off. During 1982, Diadema antillarum, a very abundant sea urchin on the northern Caribbean reefs was wiped out possibly by a water-borne pathogen (Lessios et aL 1984) (Table 4). However, the effect of this widespread mortality did not result in massive algal overgrowths in the Mexican Atlantic. This was probably because the herbivore fish population was not as depleted to the extent it was, in Jamaica, for example (Hughes 1994). Presently, there is a slow recovery of this formerly abundant species in the Mexican Caribbean as well as in the Campeche Bank (per. obs.), and in the SW Gulf reefs (G. Horta per. corn.) 4.2.2. Acropora mortality. Massive mortalities of Acropora palmata and A. cervicornis occurred during the 1970s in the SW Gulf reefs killing practically all the colonies (Jordhn-Dahlgren 1993a) (Table 4). As the mortality seemeded to have occurred gradually during several consecutive years (Jord~n-Dahlgren 1993a), and skeletons of the dead colonies remain intact and in growth position, the more likely killing agent could have been white band disease (Antonius 1981; Gladfelter 1982). The sudden mortality of acroporids due to cold spells during winter storms (Tunnell 1988) has been recorded, and that may have been an additional source of lethal stress. Cover of A. cervicornis in the shallow waters at Enmedio Reef decreased from up to 100% in 1971 to less than 5% in 19871991 (Tunnell 1992). Recovery is now proceeding slowly (Jordfin and Martin 1987). In the Campeche Bank at Cayos Arcas, and at Trifingulos reefs (Fig. 1), a similar situation was observed in 1997, and in Cayos Arenas in 1999. Most, if not all, colonies of A. palmata were dead, and most skeletons remained in the growth position; the effect was evident in both exposed and protected areas. Also, dead thickets of A. cervicornis, both intact and heavily disturbed (presumably by storms), were observed, from a few meters down to 25 m. Recolonization of A. palmata is occurring on reefs of the Campeche Bank and at Alacranes reef where many small colonies are growing on stumps of former large colonies, on the windward reef margin but not on the inner patch reefs (per. obs.). We have recently observed (1999) an ample number of live A. palmata

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colonies in many places at Cayos Arenas (unpublished results) suggesting an initial phase of recovery for this species. In the northern Caribbean reefs, A. palmata stands seem to have been less affected by the mortality events, and although white band disease had always been present, it has only affected isolated colonies. In this sector, physical destruction by hurricane Gilbert in 1988 was the main cause of massive acroporid mortalities (Jord/m-Dahlgren and Rodriguez-Martinez 1998). However, although A. cervicornis cover (Jord~n-Dahlgren et al. 1981) was scarce by 1979, a marked decrease has been observed in the last fifteen years (per. obs.), to the extent that the species is now rare. In the central and southern Caribbean sectors, large areas of living A. palmata reefs alternate with large areas where the species has been killed. Because skeletons remain in growth position, it seems more likely that the cause of mortality is biological, rather than physical-such as that derived from storm effects. 4.2.3. Coral diseases. Little is known of the extent of coral diseases in the Mexican Atlantic reefs (Table 4), although we have observed black band (Secretaria del Medio Ambiente, Recursos Naturales y Pesca 1996) and white band (Gladfelter 1982) in all reef areas. What appears to be white band (Richardson et al. 1998) on Dichochoenia stokesii has been observed on colonies off Cozumel. However, we have not seen a widespread epidemic of any of these coral diseases, nor of diseases of gorgonians (Nagelkerken et al. 1997). Changes in coral coloration are observed routinely, but rarely on more than a few colonies of a given reef in the northern Caribbean sector; if these correspond to some disease stage, or are something else, is unknown. 4.2.4. Algal overgrowth. Algae' overgrowing corals and the surrounding reef substrates, resulting in the death of corals and/or inhibiting the settlement of new coral larvae, seems to be restricted to a few sites, which are heavily influenced by human activities (Table 4). Reefs off Veracruz in the SW Gulf (Fig. 1) lying close to the shore, constitute one example. Point algal-overgrowth events are seen in places of heavy human influence. One such point is found in the Cayos Arcas reef (Campeche Bank), in a restricted area where supply and maintenance ships for the oil take shelter. In the Caribbean sector the most dramatic example is that of the small Garraf6n reef in Isla Mujeres, where in the past people were allowed to walk and stand over the reef. No other extensive algal overgrowths are seen in this sector. Periodically, after hurricanes and strong storms, when mechanical damage is severe and plenty of new substrate becomes available, fleshy algae like Padina spp. and Lobophora spp., take hold for a few months, and dominate the hard grounds. However this gradually decline to reduced, pre-storm abundances (per. obs). 4.2.5. Fish mortality. In 1980, extensive mortality was observed in the northern sector of the Mexican Caribbean. This event mainly involved herbivorous fish, and seems to have been widespread throughout the Caribbean at this time (Landsberg 1981). The cause of death was not determined, although plankton tows at the same time showed large and unusual numbers of copepods, suggesting a previous phytoplankton bloom. Since then, no other massive mortality of the kind has been observed (Table 4).

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4.2.6. Bleaching. Bleaching of corals in the northern sector of the Mexican Caribbean was observed in 1995, 1997 and 1998, but not before. The major bleaching events of 1982-83 and 1989-90, observed in other Caribbean regions (Glynn 1991) did not extend to this area, and apparently were not witnessed in the rest of the Mexican Caribbean as far as Belize. During the 1990s bleaching of corals, gorgonians and sponges occurred, most pronounced on species of the Montastraea annularis complex, Millepora complanata and Agaricia tennuifolia. Although the bleaching was extensive, it did not seem to cause extensive coral mortality and recovery proceeded rapidly (per. obs.). It is not known if there were bleaching events in the Campeche Bank and SW Gulf reefs, although isolated pale colonies were observed on several occasions (Table 4). 5. ANTHROPOGENIC IMPACTS Anthropogenic impacts on coral reefs in the Mexican Atlantic are here grouped into two major types: fisheries, and those associated with coastal developments. In the past, the SW Gulf reefs have been the most exploited, followed by the Campeche Bank reefs It is only quite recently, from the 1980s onward, that anthropogenic pressure on the Caribbean reefs has been building up to now significant levels. 5.1. Fisheries As in most other countries, fishing has been the primary use of coral reefs in the Mexican Atlantic (Table 5). There is no proper documentation of reef fisheries, as fishery information is normally based on catch landings, not on the specific location of the catches. As the fishing is carried out on the inner shelf, near reefs and in the reefs themselves as well as on the open shelf, it is not possible to know whether the catch is coming from reefs or not. Also, since most of the fishing is done in small boats, much of this catch may go unrecorded. Mexico's commercial fishing fleet consisted of 76,974 vessels in 1996, 95.7% of which were small boats (Secretaria del Medio Ambiente, Recursos Naturales y Pesca 1996).

5.1.1. SW G u l l The SW Gulf reefs are close to the shore and to near large urban centers, with the exception of the Isla Lobos reefs. In Veracruz, the largest city on the coast of the Mexican Gulf, the nearby reefs had been the object of commercial, recreational and self-sustainable fishing activities for several hundred years. The main fishing produce include octopus, snail, grouper, snapper, grunts, sharks and lobster (Secretaria del Medio Ambiente, Recursos Naturales y Pesca 1996). Some areas of seagrass beds on the shallow lagoon of the Veracruz reefs have been destroyed by clam fishing (Ch~vez and Tunnell 1993). Use of these reefs is now regulated, but enforcement seems to be difficult, mostly by lack of resources. In the other SW Gulf reefs of Tuxpan and Isla Lobos, fishing still goes on very much unchecked, and the situation seems to be similar to that known from the Veracruz reefs. 5.1.2. Campeche Bank. Fishermen from many settlements bordering the Southem Gulf of Mexico, from Veracruz to Yucat~in, exploit the Campeche Bank reefs. Fishermen will travel up to 300 km of open ocean, in 24 feet-long open boats with outboard motors and

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TABLE 5 Human use of coral reefs and its effects. H = high; M = medium; L = low; N = nil; X = not known. Issues

SW Gulf of Mexico

Campeche Bank

Caribbean

Over fishing

H

H

H

Destructive fishing methods

N

N

N

Collection of specimens

H

X

L

Coral mining (in past times)

H

N

N

Channel dredging

H

N

L

Ship grounding

H

M

M

Anchor damage

M

L

M

Eutrophication

H

N

X

Chemical pollution

H

L

X

Oil spilling

M

M

N

Agricultural runoff

H

N

N

Discharge of sewage effluents

H

N

L

Coastal strip development

H

N

H

Deforestation

H

N

L

Unrestricted tourism

M

L

M

a small ice-chest, to fish in the reefs area. Common fishing procedures are line, long-line and net fishing in and around the reefs. In the last 10 years spear and hook fishing with homemade hookas had have a very severe impact on the lobster populations in the shallow reefs. Although not technically sophisticated, the main practice is to actually comb the reef with small boats that are able to cross all over it. The day's catch is concentrated in larger vessels which carry ice-chambers and which also serve as moving platforms. The owners of small boats will usually trade fish with the crew of the larger vessels for ice or gas. 5.1.3. C a r i b b e a n . In the Caribbean reefs, the fishing effort has been intensive over the last twenty years. But is mostly directed to high quality species like spiny lobster (Panulirus argus and P. guttatus), conch (Strombus gigas), and of several species o f groupers and snappers. The Caribbean coast of Mexico was formerly an isolated and completely undeveloped area, with the exception of Cozumel and the Mujeres islands. The expansion o f the resort area of Cancfn has opened this territory to the pressures of m o d e m development. Nowadays, most commercial fin-fisheries have suffered a reduction in mean fish size and catches. An ongoing shift from fishing to guiding tourists to reefs coincides with harvesting smaller fishes of a wide array of species to fill the demand of local restaurants. Spiny lobster fishery subsists with some oscillations (Bri6nes and Lozano 1994), but conch (S. gigas) fishery is practically depleted along the mainland coast, although commercial fishing continues on Chinchorro Bank.

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5.2. Coastal developments Urban, tourism, industrial and port developments in or nearby coastal and reef zones occur in all three reef regions, although with quite different magnitudes (Table 5). 5.2.1. SW Gulf. The large city of Veracruz exerts the heaviest anthropogenic impacts on any reefs in Mexico, which results from its large size and proximity to the reefs. In addition to intense fishery, these reefs receive the outflow of major fiver systems carrying agricultural and industrial wastes both from the urban discharges of the city and port of Veracruz as well as from the wide area around it. The Anton Lizardo reefs, a few kilometers southeast of Veracruz, fare better, as they are not so close to the city, but they still suffer some riverine influence. Direct impacts are mainly those caused by ship grounding, and, by recreational divers and snorkelers which are becoming common in certain popular reefs (Chfivez and Tunnell 1993). Only one reef, Isla de Sacrificios, has been closed to recreational activities by government authorities (since 1982). Although a widespread mortality of acroporids might have affected these reefs (Jordfin-Dahlgren 1993a), they are surprisingly in a much better condition that may be suspected from all these anthropogenic influences. The reefs of Tuxpan are supposed to be affected only occasionally by contaminated river discharges, and recently, by recreational diving and snorkeling which is a great success. The Isla Lobos reefs are farther from urban settlements, but on Isla Lobos island there is an oil pumping station, and spills are known to occur. Although is not known whether these have affected the reefs. 5.2.2. Campeche Bank. It seems unlikely that the reefs of the Campeche Bank, lying far from shore, suffer any effects from coastal urban developments, nor they are currently affected by massive tourist activities. Nevertheless, a large deep-water oil terminal has been operating in the neighborhood of the Cayos Arcas reef since 1982. This terminal is able to fill up three very large tankers simultaneously in less than 48 hours and the waiting line of ships is clearly visible on the horizon (per. obs.), and the closest filling buoy is about 1.4 km WSW from the reef, in a downstream position. However, the maintenance and supply ships anchor in the open lagoon of Cayos Arcas (Fig. 2) where they have caused localized impact on the coral community below the anchoring buoys, because of the practice of dumping solid waste overboard, and possibly organic wastes as well. No other extensive, negative effects of this oil facility on the health of these reefs are documented. But chronic spills exist in the area (Gladfelter 1982) (per. obs.), and more likely the oil-tankers pump out oil-contaminated water ballast, prior to being filled. 5.2.3. Caribbean. The Mexican Caribbean is bordered by Quintana Roo state, the least populated one in the country, and an estimated annual growth rate of 6.48% between 1990 and 1995 (Instituto Nacional de Estadistica, Geografia e Informfitica 1997). This coast has become a very successful resort area and is nowadays the main destination of tourists within Mexico, with almost 4 million visitors in 1997. Because the coast was formerly undeveloped, there is a tremendous boom of resorts of all kinds to service the increasing tourist demand. Because coastal development in the area is quite recent, reef health is still good (per. obs.), but the proximity of reefs to shore and the accelerated expansion of the urban and tourism infrastructure in the coastal strip, is cause for concern.

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Aside from the threats to reefs by coastal landscape modification, which affect both the natural drainage system and shore sediment dynamics, pollution and direct physical impacts appear of paramount importance. As the mainland terrain is karstic, with little or no soil and most of the reefs are fringing the shore, urban and resort untreated discharges are the major threats, because all discharges eventually seep into the underground water system which flows from land to sea. There are no general sewage treatment systems. The only proper treatment of discharge waters is in the large resorts, while towns and small settlements have no sewage treatment. There is no effort to remove excess nutrients (as by plant uptake), beyond a few very small-scale experiments. All the impacts associated with recreational activities on coral reefs, from boating to swimmers and divers, occur in the northern reef sector. In some instances, impacts are serious enough to cause rapid reef degradation as observed locally at Garraf6n reef off Isla Mujeres and at Punta Nizuc in Cancfin. On the other hand, in Cozumel where the reefs setting is more conducive to protection and there is more ecological awareness in the users population, the National Park regulations approach adequate protection levels. Large development projects have up to now been concentrated around Cancfin. However, modem coastal development is rapidly expanding toward the south, and the government plans are to build up a huge, high density, tourist resort complex all along the Caribbean coastal strip, extending down to the Belizean border. This tourist complex will be only partially interrupted by the existing Sian Ka'an biosphere reserve area, where only low-density developments are allowed. It is hoped that proper regulations and opportune enforcement may lessen these threats, especially when the status of National Park is being granted to many reef areas, but there is still a long way to go in this respect. 6. CORAL R E E F P R O T E C T I O N Reef refuges, and marine protected regions, were established by decree for certain regions many years ago, but no formal regulation or enforcement was devised for them. Recently, after a slowly emerging national public concern and international pressures, the federal government has implemented activities to better protect natural resources of the country. For coral reefs, protection has been focused on the creation of specific protected marine areas. The current law governing protected areas is the General Law for Ecological Equilibrium and Environmental Protection, last modified in 1996. This law regulates natural protected areas, defines criteria for the use of flora and fauna, and includes guidelines for environmental impact assessment. It transfers responsibilities to state agencies and municipalities, although marine affairs are still of federal concern. There is no question that these actions are a major improvement over past government and social attitudes, and there is reasonable expectation that the protection efforts will expand. What remains to be seen is whether these actions to protect the reefs are implemented rapidly enough to buffer the effects of ever-expanding massive coastal development. In practice, lack of proper management programs, and of government funds for independent administration and surveillance hinder the proper implementation of these actions. In addition, difficult social conditions in the country, together with the poor

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quality of law enforcement, constantly challenge the strict adherence to the existing protection laws, many of which also need constant revisions as experience on the complexity of regulation accumulates. This situation is further complicated by low ecological public awareness, and as Mexican society is primarily land-based, the contact with the sea environment has been minor. A major flaw of the protection programs is lack of support for widespread educational programs at all levels (Rodriguez-Martinez and Ortiz 1999). In addition quality scientific research is not well supported, nor monitoring programs in the proper scale. 6.1. Marine protected areas reef in Mexico

Coral reefs are protected either as biosphere reserves or national parks. The second category is usually reserved for coastal and tourist development areas. Nine protected natural areas that include coral reefs exist in the Atlantic margin of Mexico, two of them are biosphere reserves and seven are national parks (Fig. 9). 6.1.2. S W Gulf of Mexico Parque Nacional Sistema Arrecifal Veracruzano. Created in 1992, this park includes

all the coral reefs in the Veracruz Reef System. It has been estimated that 1,000 divers per month visit the park between May and September and less than 200 per month the rest of the year (G. Horta per. com.). The management program is under review, but surveillance is generally insufficient. Only one reef, Isla de Sacrificios (Fig. 2), has been closed since 1982 to recreational activities by local government authorities, apparently with good results. Scientific knowledge of these reefs is limited. The main threats are: chemical pollution, oil spills (local), over-fishing, channel dredging, coastal development, and recreational impacts.

Fig. 9. Marine protected areas that include coral reefs on the Atlantic margin of Mexico. Barrier/fringing reefs along the Caribbean coastline are not evident at this scale, see figure 3. * Reefs incorporated to the protected area in 1998 are not considered in the managementprogram.

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6.1.3. Campeche Bank Parque Nacional Arrecife Alacranes. Created in 1994, but because it is relatively far from land tourism demand is still small, although ecotourism is being planned for the area with the building of dormitories on one of the islands. A management program is being developed. Although one of the more studied reefs in M6xico, scientific knowledge of this reef is still limited. The main threats are presently over-fishing, and in the near future the effects of tourism. 6.1.4. Caribbean There are seven marine protected areas in the Caribbean, four National Parks and two Biosphere Reserves (Fig. 9): Parque Nacional Costa Occidental de Isla Mujeres, Punta Canctin y Punta Nizuc. Reefs between Isla Mujeres and Cancfin were declared a Flora and Fauna Reserve in 1973, and became a National Park in 1996. Almost 2,500 tourists visit these reefs every day (Direcci6n del Parque Nacional per. com.). Serious conflicts exist among owners of marinas and fishermen. The management program was published in 1998, although scientific knowledge of these reefs is scarce. The main threats are effects of tourism, eutrophication, and pollution from untreated sewage. Parque Nacional Arrecife de Puerto Morelos. The park was created in 1998 by request of the local community. Perhaps the best known reefs in M6xico are included in this park as two marine laboratories have operated in this area since the 1970's. Scientific knowledge of these reefs can still be improved. Tourism use is low with less than 300 people per month, and fishing is allowed in the area. The coral reefs are in good condition, although undergoing recovery from damage caused by hurricane Gilbert in 1988. The management program was published in 2000. The main threats are effects of fishing on reefs, tourism, risk of increased nutrients due to the input of raw sewage. Parque Nacional Arrecifes de CozumeL SE Cozumel reefs were declared as a Refuge for the Protection of Flora and Fauna in 1980. In 1996 the area was declared a National Park, after great popular concern regarding the construction of a pier within the limits of the refuge area. Although this is one of the most visited diving sites in the world, with almost 1500 divers per day (E. Carvajal per. com.), it also has a series of ways to achieve effective reef protection. The management program was published in 1998. Scientific knowledge of these reefs is limited. The main threats are damage by careless divers, shore development, and potentially pollution from untreated sewage. Reserva de la Biosfera Banco Chinchorro. Created in 1996, it has been estimated that fewer than 100 divers visit the reef each month (A. Aguilar per. com.). Scientific knowledge of this reef is limited and the management program is being developed. The main threats are over-fishing and tourist development. Reserva de la Biosfera de Sian Ka'an. Originally a land-coastal reserve created in 1986, an additional area of coral reefs was included in 1998 (Fig. 9). Over 42,000 tourists visited the Reserve in 2000 and it is estimated than 40% of them make use of the reefs (Direcci6n de la Reserva de la Biosfera Sian Ka'an per. com.). There are approximately 120 authorized boats, most of them offering their services for sport fishing in the lagoons and bays and for the observation of the wildlife around the reserve. It has been estimated that 60% of these boats operate on the reefs. The only management program is for the decree of 1986; but the area added in 1998 is managed

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under the same criteria. Scientific knowledge of these reefs is limited. The main threats are over-fishing of commercial species (lobster, queen conch, and fish), tourist development and expanded private housing on the coast of the reserve. Parque Nacional Isla Contoy. Not a reef reserve per se, Isla Contoy was declared a Natural Reserve and Fauna Refuge in 1961, because is a nesting ground for many avian species. In 1998 it was declared a National Park, including the marine portion around it, where some reefs are found. In 2001 the average number of visitors was 1,000 per month and it is estimated than 10% make use of the reefs (Direcci6n del Parque Nacional Isla Contoy per. com.). Scientific knowledge of the few reefs is limited and the main threats are over-fishing and pollution. Parque Nacional Arvecifes de Xcalak. The park was created in 2000 by request of the local community. A management program is under development. Tourism use is low, with less than 100 visitors per month to the reefs. Main treats include over-fishing, shore development and tourist-related activities. ACKNOWLEDGMENTS

Many thanks to R. Ginsburg for a careful review of this work, and also to H. Reyes, A. Banaszak, and two anonymous reviewers for their helpful comments to this manuscript. Also we wish to thank all our colleagues who kindly share with us their knowledge of coral reefs in Mexico, particularly J.P. Carricart, G. Horta-Puga, E. Carvajal, A. Arellano and A. Aguilar. REFERENCES

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Jordan, E. 1988. Arrecifes profundos en la Isla de Cozumel, M6xico. Anal. Inst. Cienc. Mar Limnol., UNAM. 15:195-208. Jordan-Dahlgren, E. 1988. Arrecifes coralinos del Caribe Mexicano: Su potencial de uso. Informe final del convenio PCCBBNA-021928 CONACyT- UNAM, M6xico. 192 p. Jord~in-Dahlgren, E. 1989. Efecto de la morfologia del sustrato en el desarrollo de la comunidad coralina. Anal. Inst. Cienc. Mar Limnol., UNAM. 16:105-118. Jordan-Dahlgren, E. 1992. Recolonization patterns of Acropora palmata in a marginal environment. Bull. Mar. Sci. 51: 104-117. Jord~n-Dahlgren, E. 1993a. E1 ecosistema arrecifal coralino del Atlantico Mexicano. Rev. Soc. Mex. Hist. Nat. 44: 157-175. Jord~n-Dahlgren, E. 1993b. Atlas de los Arrecifes Coralinos del Caribe Mexicano. In." E1 sistema continental, Vol. 1. ICMyL-UNAM/CIQRO, M6xico, DF. 110 p. Jordan, E. & E. Martin. 1987. Chinchorro: Morphology and composition of a Caribbean atoll. Atoll Res. Bull. 310: 1-33. Jordan-Dahlgren, E. & R.E. Rodriguez-Martinez. 1998. Post-hurricane initial recovery of Acropora palmata in two reefs of the Yucatan Peninsula, Mexico. Bull. Mar. Sci. 63: 213-228. Jordan-Dahlgren, E., M. Merino, O. Moreno & E. Martin. 1981. Community structure of coral reefs in the Mexican Caribbean. Proc. 4th Int. Coral Reef Symp., Manila 2: 303-308. Jordan-Dahlgren, E., E. Martinez-Chavez, M. Sanchez-Segura & A. Gonzalez de la Parra. 1994. The Sian Ka'an Biosphere Reserve Coral Reef System, Yucatan Peninsula, Mexico. Atoll Res. Bull. 423: 1-19. Komicker, L.S., F. Bonet, R. Cann & C.M. Hoskin. 1959. Alacran Reef, Campeche Bank, Mexico. Inst. Mar. Sci. Publ., Univ. Texas. 6: 1-22. Landsberg, J.H. 1981. Unusual mass fish mortalities in the Caribbean and Gulf of Mexico. Dis. Aquat. Org. 22: 83-100. Lessios, H.A., J.D. Cubit, D.R. Robertson, M.J. Shulman, M.R. Parker, S.D. Garrity & S.C. Levings. 1984. Mass mortality of Diadema antillarum on the Caribbean coast of Panama. Coral Reefs 3:173-182. Logan, B.W. 1969. Coral reefs and banks, Yucatan shelf, Mexico. Amer. Assoc. Petrol. Geol. Mem. 11: 129-198. L6pez, L. & O.J. Polanco. 1991. La fauna de la ofrenda H del templo mayor: 199-163. In: O.J. Polanco (ed.), La fauna en el templo mayor. Inst. Nac. Antrop. Hist., Mexico. Macintyre, I.G., R.B. Burke & R. Stuckenrath. 1977. Thickest recorded Holocene reef section, Isla P6rez core hole, Alacran Reef, Mexico. Geology 5" 749-754. Moore, D.R. 1958. Notes on Blanquilla Reef. Inst. Mar. Sci. Publ., Univ. Texas 5: 151155. Morelock, J. & J. Koening. 1967. Terrigenous sedimentation in a shallow water coral reef environment. J. Sedim. Petrol. 37: 1001-1005. Muckelbauer, G. 1990. The shelf of Cozumel, Mexico: Topography and organisms. FACIES 23: 185-240. Nagelkerken, I., K. Buchan, G.W. Smith, K. Bonair, P. Bush, J. Garz6n-Ferreira, L. Botero, P. Gayle, C. Heberer, C. Petrovich, L. Pors & P. Yoshioka. 1997. Widespread disease in Caribbean sea fans: I. Spreading and general characteristics. Proc. 8th Int. Coral Reef Symp., Panama 1: 679-682.

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Rezak, R., T.J. Bright & D.W. McGrail 1985. Reefs and Banks of the Northwestem Gulf of Mexico. John Wiley & Sons, U.S.A. 259 p. Richardson, L.L., W.M. Goldberg, K.G. Kuta, R.B. Aronson, G.W. Smith, K.B. Ritchie, J.C. Halas, J.S. Feingold & S.L. Miller. 1998. Florida's mystery coral-killer identified. Nature 392: 557-558. Rigby, J.K. & W.G. MacIntyre. 1966. The Isla de Lobos and associated reefs, Veracruz, Mexico. Brigham Young Univ. Geol. Stud. 13: 3-46. Roberts, C.M. 1997. Connectivity and management of Caribbean coral reefs. Science 278: 1454-1457. Rodriguez-Martinez, R.E. & L.M. Ortiz. 1999. Coral reef education in schools of Quintana Roo, Mexico. Ocean Coast. Manag. 42: 1061-1068. Secretaria del Medio Ambiente, Recursos Naturales y Pesca. 1996. Anuario estadistico de pesca, M6xico. www.semamap.gob.mx/sspesca/annario96.htm Spaw, R.H. 1978. Late Pleistocene carbonate bank deposition; Cozumel Island, Quintana Roo, Mexico. Gulf Coast Assoc. Geol. Soc. Trans. 28: 601-619. Tunnell, J.W., Jr. 1988. Regional comparison of Southwestem Gulf of Mexico to Caribbean Sea coral reefs. Proc. 6th Int. Coral Reef Symp., Australia 3: 303-308. Tunnell, J.W., Jr. 1992. Natural versus human impacts to Southem Gulf of Mexico coral reef resources. Proc. 7th Int. Coral Reef Symp., Guam 1: 300-306. Villalobos, A.F. 1971. Estudios ecol6gicos en un arrecife coralino en Veracruz, M6xico" 531-545. In." Symp. Investig. Res. Carib. Sea Adjac. Reg., Willemstad, Curaqao. Ward, W.C., A.E. Weidie & W. Back. 1985. Geology and Hydrogeology of the Yucatan and Quatemary Geology of Northeastern Yucatan Peninsula. New Orleans Geol. Soc. 160 p.

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Coral reefs of Guatemala Ana C. Fonseca E. 1 and Alejandro Arrivillaga 2 1Centro de Investigaci6n en Ciencias del Mar y Limnologia (CIMAR), Universidad de Costa Rica. San Pedro, San Jos6 2060, Costa Rica 2johnson Controls World Services. USGS National Wetlands Research Center, 700 Cajundome Blvd. Lafayette, Louisiana 70506, USA

ABSTRACT: Coral reef research in Guatemala has a very short history. Hard-bottom biotopes are sparse along both Guatemala's coasts; however, there is no evidence of coral reefs presence on its Pacific coast. Reef development exists on the Caribbean coast, mainly around Punta de Manabique, and most reefs are protected by the Refugio de Vida Silvestre de Punta de Manabique (Punta de Manabique Wildlife Refuge). This is the sole marine park in Guatemala. Coral reefs at Punta de Manabique consist of a series of continental carbonated banks. Currently they are highly deteriorated, live coral cover is low (8.75%) and non-coralline macroalgae cover is high (65%). There are 29 species of scleractinian corals. The main impact to coral reefs at Punta de Manabique is terrestrial sedimentation coming from deforested lands, mainly from the Motagua river basin. High sediment loads are causing coral death and algae overgrowth. Apparently, current herbivorous populations are not able to control the macroalgae. Coral composition is atypical to most Caribbean reefs, which are dominated by Montastraea annularis: Guatemalan reefs are dominated by macroalgae and coral species resistant to sediments, such as Siderastrea siderea. In addition, natural events such as hurricanes, temperature increases and the massive mortality of Diadema in 1983, may have contributed to the deterioration of Guatemalan reefs. Coral reefs at Punta de Manabique constitute one of the most important resources of the coastal-marine territory of Guatemala. The economic activity in Punta de Manabique is focused on artisanal fisheries around these reefs and developing tourism. Promotion of environmental education and research, reinforcement of fishing and tourism regulations, and an adequate management plan for the Refuge and the regional fiver basins are recommended.

1. I N T R O D U C T I O N

Guatemala is located in the northern part of Central America and has borders with Mexico to the north and west, and Belize, Honduras, and E1 Salvador to the east (Fig. 1). Its territory occupies 108,780 km 2. The total littoral length is 405 km (Foer and Olsen 1992). The largest coastal zone is located on the Pacific side (255 km), in the southern portion of the country, and it consists of black volcanic sand beaches. Several small-tomedium sized rivers discharge on this side of the country and there are a series of coastal lagoons and mangrove forests. The Caribbean coast of Guatemala extends for 150 km and is located on the Gulf of Honduras; despite its small size, it supports important commercial and artisanal fisheries. Latin American Coral Reefs, Edited by Jorge Cortrs 9 2003 Elsevier Science B.V. All rights reserved.

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Fig. 2. Location of known reefs and hard bottom biotopes on the Atlantic coast of Guatemala.

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Punta de Manabique occupies a large section of this coast which is generally low with forested areas overlooking the coast, dissected with rivers. Most sea beds bottoms at the rivers mouths and bays consist of silty sands (PROARCA 1996). Three main rivers discharge their water into the Caribbean: Sarstoon, Motagua and Dulce (Fig. 1). The primary freshwater influence in the region is from Rio Motagua located on the eastern side of Punta de Manabique (Gulf of Honduras). An artificial channel, Canal de los Ingleses, connects Graciosa Bay to the eastern shore of Punta de Manabique (Y~fiez-Arancibia et al. 1999).

1.1. Reef research history Coral-reef research in Guatemala is scarce and recent. Coral reefs of the Caribbean coast have been incidentally mentioned in studies conducted with other objectives in mind. One of the earliest written reports was that of Bortone et al. (1988), who studied fish communities in an artificial reef established in 1982 in the Amatique Bay, about 15 km NW of Puerto Barrios (Fig. 1). Similarly, the presence of reef formations was indicated by Cazali (1988) in her study of bivalves and Prado (1990) in her study of gastropods. Near-shore coral reef and hard-bottom biotopes are sparse along both Guatemala's coasts, but there is reef development on the Caribbean coast of Guatemala, mainly around Punta de Manabique (Fonseca 2000) and on Heredia Shoal, 15 km west of Punta Moreno (Cazali 1988). Hard bottoms and coralline algae are present at Punta Cocoly, Punta Herreria and La Guaira, and on the littoral from Punta Herreria to Tapon Creek (Cazali 1988). Other rocky and reef beds are present near the Sarstoon River mouth and at Palo Blanco Shoal. Other reef formations know to local fishermen are Chatarra, Hamilton and Satuye (Fig. 2). There is no evidence of the existence of coral reefs on the Pacific coast maybe only isolated corals on the few hard bottoms (Cort6s and Hatziolos 1998; Kramer et al. 2000). Fonseca (2000) made a rapid reef assessment on those Caribbean carbonated banks known by fishermen around Punta de Manabique in order to describe reef structure and the composition of benthic organisms. The Point Intercept Transects Method was used to determine the relative substrate cover; using a 10 m long linear transect and recording what was located at each point every 50 cm. Chain transects were used to calculate the spatial relief (Rogers et al. 1994). A collection of corals, other invertebrates, algae and seagrass samples were deposited at the Natural History Museum of the University of Guatemala. There were no previous descriptions or evaluations of these reefs. The results of this report (Fonseca 2000) are published in this chapter. Further research must be undertaken to determine the history of formation, extension, and diversity of these reefs. Other coastal ecosystems have been studied, including mud flats (Salaverria and Rosales 1993) and seagrass beds (Arrivillaga and Baltz 1999; Y~ifiez-Arancibia et al. 1999; Arrivillaga 2000). Specifically, seagrass beds of La Graciosa Bay in Punta de Manabique have been the object of recent extensive studies (Arrivillaga 2000). In addition, the utilization of seagrass meadows by fishes and decapod crustaceans has been described for exposed (beach) and protected (bay) estuaries near the mouth and inside of La Graciosa Bay (Arrivillaga and Baltz 1999; Arrivillaga 2000). 1.2. Description of Punta de Manabique shoreline Punta de Manabique is located southwest of the Gulf of Honduras on the northeast side of Amatique Bay (Fig. 1). This peninsula is 23 km long, and is separated from the

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continent at its base by the Canal de los Ingleses. The coast of Punta de Manabique consists of a series of sandy bars and peat swamps. Sandy bars are old carbonated banks, and the swampy sections between these banks have been filled with sand and organic matter. Rain forest is the dominant vegetation (Centro de Estudios Conservacionistas 1995). The northeastern section of Punta de Manabique, facing the Gulf of Honduras, has on the windward side narrow, free gray sandy beaches exposed to high surges for most of the year. There is a large accumulation of thinks, branches, Sargassum, Thalassia, Syringodium. and garbage. These materials mainly come from the mouth of the Motagua river transported by the northwest current. The southwest section facing Amatique Bay, consists of leeward narrow, and f'me gray sandy beaches with low surge. On the southeast, Punta de Manabique has sandy beaches, with good nesting sites for the marine turtles Dermochelys coriaceae, Eretmochelys imbricata, Caretta caretta and Chelonia mydas. Graciosa Bay is a shallow coastal lagoon located on the east side of Amatique Bay. Graciosa Bay is surrounded by red mangrove forests although large sections of these mangroves were destroyed by Hurricane Mitch in 1998. It also has extensive seagrass meadows of Thalassia testudinum, Syringodium filiforme and Halodule beaudettei (Arrivillaga 2000). At La Graciosa and Amatique bays, the manatee Trichechus manatus, an endangered species worldwide, is frequently observed (Centro de Estudios Conservacionistas 1995; Fonseca 2000). 2. CORAL REEFS OF PUNTA DE MANABIQUE

2.1. Reef descriptions The reefs at Punta de Manabique are low carbonated banks (Fig. 3), with moderate coral richness, low coral cover, high noncoralline algae cover (Fig. 4), and small coral colonies (diameter and height < 1 m). A list of species found in these reefs, 29 corals, 44 other invertebrates, 24 algae and 4 seagrasses is given in Tables 1, 2 and 3. Visibility is low (7 m) and the mean temperature is 29~ A general description of four of the main banks (Graciosa, Manglar, Guinea, and Cabo Tres Puntas banks) (Fig. 2) is presented below. Graciosa bank is located 3 km west from La Graciosa Bay mouth (Fig. 1). It is 6 to 8 m deep, with an area of 25 x 50 m, and a low complexity index (i=1.37 • 0.2; Fig. 3). Mean live coral cover is 10.1 + 4.6%, and algae cover is 73.7 + 7.6% (Fig. 4). Mean density of corals is 4.0 • 1.0 colonies m -2 (Fig. 5) and 8 species were found. The most common coral species were Siderastrea siderea, Porites astreoides and Montastraea cavernosa. Suspended sediment concentrations are high and coral colonies are covered by layers of mucous. The sediment seen at this bank may come from the Canal de los Ingleses. Manglar bank is located southwest of Ptmta de Manabique and 1.5 km of shore (Fig. 2). It is 14 to 17 m deep, has an area of 25 x 25 m, and has a low complexity index (i=1.25 + 0.1; Fig. 3). Mean live coral cover is 13.6 + 6.4%, and algae cover is 33.4 + 4.3% (Fig. 4). Mean coral density is 4.0 + 1.4 colonies m "2 (Fig. 5), and 8 species were found. The most common coral species were Siderastrea siderea, Siderastrea radians, Porites astreoides, Montastraea cavernosa, Madracis decactis, Stephanocoenia micheliniL Agaricia tenuifolia, Meandrina meandrites and Helioseris cucullata. Guinea bank is composed of many reef patches of low relief (i=l .2 + 0.0; Fig. 3), with a mean depth of 24 m and located northeast of Guinea creek in San Francisco del Mar (Fig. 2). Mean live coral cover is 1.5 + 2.1%, and algae cover is 81.8 + 8.6% (Fig. 4). Mean

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1.35

i 1.25

1.15

1.1

Graciosa

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Fig. 3. Complexity index (i) by site, Punta de Manabique, Guatemala.

80

[] Graciosa bank

70

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, !

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Fig. 4. Substrate cover by site, Punta de Manabique, Guatemala.

•'E1.5 "5 u

1

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Fig. 5. Coral colonies density by site, Punta de Manabique, Guatemala.

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TABLE 1 Stony corals (Class Hydrozoa and Anthozoa) found in reefs around Punta de Manabique.

Millepora complanata Porites astreoides Porites porites forma divaricata Siderastrea siderea Siderastrea radians Leptoseris cucullata Agaricia tenuifolia Agaricia agaricites Agaricia grahamae Oculina difusa

Montastraea annularis Montastraea franksi Montastraea faveolata Montastraea cavernosa Solenastrea hyades Diploria strigosa Meandrina meandrites Manicina areolata Colpophyllia natans Mycetophyllia ferox

Mycetophyllia aliciae Mycetophyllia danaana Scolymia cubensis Mussa angulosa Eusmilia fastigiata Madracis decactis Madracis mirabilis Stephanocoenia michelinii Phyllangia americana

TABLE 2 Other marine invertebrates of Punta de Manabique (*Included in CITES list). Phylum Porifera Class Demospongiae Callyspongia plicifera Callyspongia vaginalis Cibrochalina vasculum Verongula gigantea Xetospongia muta Niphates erecta Niphates digitalis Amphimedon compressa Cinachyra sp. Cliona delitrix Phylum Cnidaria Class Hydrozoa Order Hydroida Dentitheca dentritica Order Stylasterina Stylaster roseus * Class Anthozoa Subclass Octocorallia Order Gorgonacea Erythropodium caribaeorum Pseudoplexaura sp. Eunicea sp. Plexaurella sp. Muricea gpendula? Pseudopterogorgia sp. Pterogorgia guadalupensis Gorgonia ventalina Order Alcyonacea Carijoa riisei Subclass Hexacorallia Order Antipatharia Cirrhipathes (Stichopathes) leutkeni Order Zoanthidea Palythoa caribaeorum Order Actinaria Condylactis gigantea Bartholomea annulata

Phylum Ctenophora Class Tentaculata Mnemiopsis mccradyi Phylum Annelida Class Polychaeta Bispira brunnea Bispira variegata Phylum Molusca Class Gastropoda Strombus raninus Cassis madagascariensis Class Bivalvia Spondylus americanus Pinna carnea Phylum Arthropoda Class Crustacea Order Decapoda Periclimenes pedersoni Stenorhynchus seticornis Phylum Ectoprocta Class Gymnolaemata Order Cheilostomata Trematooecia aviculifera Phylum Echinodermata Class Asteroidea Oreaster reticulatus Class Holothuroidea Actinopygia agassizii Eostichopus amesoni Holothuria mexicana Class Echinoidea Lytechinus variegatus Diadema antillarum Echinometra virides Eucidaris tribuloides Phylum Chordata Class Ascidiacea Ascidia sydneiensis

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TABLE 3

Marine algae and seagrasses of Punta de Manabique. MARINE ALGAE

Phylum Phaeophyta Sargassum fluitans Sargassum sp. Dictyota ciliolata Dictyota sp. Lobophora variegata Turbinaria turbinata Phylum Chlorophyta Halimeda incrassata Halimeda discoidea Penicillus pyriformis Penicillus dumetosus Caulerpa sertularoides Caulerpa racemosa Caulerpa mexicana Codium isthmocladum Ventricaria ventricosa

Valonia utricularis Udotea sp. Acetabularia sp. Phylum Rhodophyta Galaxaura sp. Jania adherens Amphiroa tribulus Porolithon pachydermum Peyssonnelia sp. Phylum Cyanophyta Schizotrix sp. SEAGRASSES

Class Angiosperma Thalassia testudinum Syringodium filiforme Halodule beaudettei Halophila baillonis

density of corals is 0.5 a: 0.7 colonies m "2 (Fig. 5), and 9 species were found. The most common coral species were Siderastrea siderea, S. radians, Porites astreoides, Montastraea cavernosa, Madracis decactis, Stephanocoenia michelinii and Leptoseris cucullata. Several vase sponges (Niphates digitalis and Callyspongia plicifera) have been found in this site. Northeast of Cabo Tres Puntas ("Three Point Cape"), between the second and the third points, 1 to 5 km from the coast, a number of patch reefs can be found, which are well known to fishermen (Fig. 2). The bottom is sandy except for the nearest section to the first point where there is a large accumulation of mud, apparently coming from the Motagua River and other small effluents such as the San Francisco and Canal de los Ingleses. At 9 to 12 m depths, there are dense octocoral gardens (11.1 octocorals m2). From 12 to 18 m deep, there are several reef patches of low relief (i=1.19 + 0.2; Fig. 3), of around 15 x 15 m, which are separated from 50 to 100 m. There are many fleshy macroalgae attached to the substrate over the reef patches and floating over the surrounding sandy plains. Some algae reach heights of up to 1 m. Mean live coral cover is 9.1 + 3.0%, and algae cover is 55.6 + 21.5% (Fig. 4). Mean density of corals is 2.0 + 1.0 colonies rn"2 (Fig. 5), and 8 species were found. The most common coral species were Montastraea faveolata, 34. franksi, Siderastrea siderea, Stephanocoenia micheliniL Agaricia agaricites, Agaricia tenuifolia, Porites astreoides and Eusmilia fastigiata. Offshore from the sandy bank where these reef patches are located, there is a deep channel parallel to the shoreline and is used by large ships. Behind this channel, 12 km offshore, there is another sandy bank with reef patches that have never been evaluated. The substrate is mostly covered by non-coralline macroalgae, especially on Guinea and Graciosa banks (Fig. 3). Macroalgae on these banks are known to be harmful to corals. The most common species are: Caulerpa sp. and Dictyota sp., Lobophora variegata, Ventricaria ventricosa, Valonia utricularis, Codium isthmocladium, Sargassum sp. and the blue-green algae Schizotrix sp. Frequently encountered coral species on these banks

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are Siderastrea radians, S. siderea, Madracis decactis, Montastraea cavernosa, Stephanocoenia michelini and Porites astreoides. This is not the typical coral composition of most Caribbean reefs, which are usually dominated by Montastraea annularis (CARICOMP Data Base 1999). Particularly, Siderastrea siderea, Siderastrea radians and Porites astreoides are known to be very resistant to sediments and are relatively abundant in sites with a high sedimentation (Cortrs and Risk 1985). The density of coral colonies is higher on the southwestern banks of Punta de Manabique (La Graciosa and Manglar) than on the northeastern banks (Guinea and Cabo Tres Puntas) (Fig. 5). The sea urchin Diadema has not been found (Fonseca 2000). 2.2. Present condition

Reef banks within Punta de Manabique show fleshy macroalgae typical of sandy plains where herbivory is low. Apparently, the herbivorous are not able to control macroalgae abundance as on other Caribbean reefs (Hay 1984). The Manglar bank could be considered the area in best condition, as it shows the highest levels of live coral and sponge cover (Fig. 4). However, the Cabo Tres Puntas bank has the largest reef area and coral richness (Fonseca 2000). Reefs in Guatemala have degraded mainly as the result of siltation stress. Since information on these reefs is scarce, it is hard to determine changes that have occurred over time. However, live coral cover is similar to what is found on other reefs on the Central American Caribbean coast that are also affected by terrestrial sediments (e.g. 13% in Cahuita, Costa Rica) and Belize (10-16%) (CARICOMP Data Base 1999). In addition, as on other Caribbean reefs, algae cover is greater than coral cover (CARICOMP Data Base 1999). 3. NATURAL DISTURBANCES Some natural events that have affected the entire Caribbean region could have contributed to the deterioration of Guatemalan reefs. Several hurricanes that affected the Guatemalan coast (e.g. hurricanes between 1945 and 1949, Hurricane Fifi in 1972, and Hurricane Mitch in 1998) could have caused some reef destruction. Local fishermen and diving instructors have observed several bleaching events in 1983 and 1998, possibly due to temperature increases, and the Diadema massive mortality (1983) that resulted in widespread non-coralline algae overgrowth (Hughes et al. 1987). There was also an earthquake on February 4, 1976 that extended east and west from the Motagua fault (Young et al. 1989). The effects of this event on the coral reefs of Punta de Manabique were not quantified, but reefs could have been affected by sediment increase and substrate fracture, as observed in Costa Rica (Cortrs et al. 1992). 4. ANTHROPOGENIC IMPACTS It could be inferred from high-water turbidity that the biggest problem at Punta de Manabique is the chronic influx of terrestrial sediments coming from upstream rivers. This is a major long-term threat for reefs at Puma de Manabique and for continental reefs elsewhere (Wilkinson 1992). Sediments are transported by the main current that flows northwest, causing corals death and algae overgrowth. On the northeastem section

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of Puma de Manabique, the influence of the Motagua river, and other small effluents, which flow over deforested and eroded watersheds is evident. Amatique Bay also receives terrestrial sediments from the Dulce, Machacas and Sarstoon rivers and Canal de los Ingleses (Centro de Estudios Conservacionistas 1995). Human population is relatively low (850 inhabitants) on Punta de Manabique. A narrow coastal band has been used mostly for small house construction, subsistence agriculture, and cattle ranching. Artisanal fishing is the main economic activity, primarily along the eastern section of Amatique Bay and the Gulf of Honduras (Echeverria de Le6n 1994). Fishermen like to fish and dive over coralline banks where fishes, lobsters (Panulirus spp.) and snails (Strombus spp.) are concentrated. Some of the common fishing techniques (e.g. netting) are not recommended since they are neither size nor species selective. Capture levels of commercially important species from Puma de Manabique are unknown. Moreover, inhabitants from Puma de Manabique prefer to dive and extract marine resources from nearby Belizean Cays. Turtle nesting is common on the beaches of Puma de Manabique; but, eggs extraction is occasional and for domestic consumption (Centro de Estudios Conservacionistas 1995). Tourist visitation to Puma de Manabique is sporadic, and although it has increased in the last decade and the region has a high potential for greater increase (Centro de Estudios Conservacionistas 1995). Recently, a dive store was established at Amatique Bay, and it is promoting tourism. This could be positive if a good regulation plan is implemented. 5. PROTECTION AND MANAGEMENT Reef banks on the Caribbean coast of Guatemala are within the Punta de Manabique Wildlife Refuge (15~176 88013'- 88~ This refuge protects an area of 1393 kmz (449 terrestrial and 944 marine). It comprises the peninsula, 27 km east to the Motagua river, 12 km offshore in the Honduras Gulf, and the Amatique and Graciosa Bays (Centro de Estudios Conservacionistas 1995). This is the only marine park in Guatemala. However, for protection a management plan for the refuge and regional river basins must be implemented. Particularly, fishing and tourism must be regulated. Guardianship at the refuge needs to be reinforced and the environmental consciousness of the population should be promoted. Reefs from the Caribbean coast of Guatemala are within the Mesoamerican Reef System ("Sistema Arrecifal Mesoamericano", SAM) which is considered a priority for conservation worldwide. This reef system extends from the northern end of the Yucat~in Peninsula in Mexico, to the Bay Islands in Honduras, including the Barrier Reef of Belize and the Caribbean coast of Guatemala. It has been recognized by national governments at the meeting of Tulum in 1997, where they committed their countries to support its management and conservation (Marin 2000). From the species found on Punta de Manabique reefs (Tables 1, 2 and 3), all hard corals, the lace coral Stylaster roseus, and the fire coral Millepora alcicornis are included in the second category of the CITES list. This means that these species cannot be extracted from their natural environments. At present they are not in the Red List of the IUCN. Today, the most pressing research need for Guatemala's coastal ecosystems is to determine the distribution, abundance, and status of the main coral species. The location,

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composition and extent of these coastal ecosystems may be a crucial indicator of water quality and overall health of coastal resources. Unless these resources are identified and research is begun on their ecosystems, there will be few objective criteria for the formulation of management policies to foster scientifically based resource conservation. ACKNOWLEDGMENTS Mario Yon, Luisa Paredes and Eddy helped dm2ng the exploration to the reefs of Punta de Manabique. PANADIVERS store provided logistical support and valuable information. Mario Dary Foundation (FUNDARY) and The Nature Conservancy (TNC) provided coordination and funding. REFERENCES ArriviUaga, A. 2000. Ecology of seagrass fishes and macroinvertebrates on Guatemala's Atlantic coast. Ph.D. dissert., Louisiana State Univ., Baton Rouge, Louisiana. 163 p. Arrivillaga, A. & D.M. Baltz. 1999. Comparison of fishes and macroinvertebrates on seagrass and bare-sand sites on Guatemala's Atlantic coast. Bull. Mar. Sci. 65:301-319. Bortone, S.A., R.L. Shipp, W.P. Davis & R.D. Nester. 1988. Artificial reef development along the Atlantic coast of Guatemala. Northeast Gulf Sci. 10: 45-48. Cazali, G.M. 1988. Inventario de pelecipodos de la costa Atl~intica de Guatemala con enfasis en especies comestibles. Thesis, Universidad de San Carlos, Ciudad de Guatemala. 134 p. Centro de Estudios Conservacionistas. 1995. Estudio t6cnico del firea de protecci6n especial "Punta de Manabique". Propuesto Biotopo Protegido. Facultad de Ciencias Quimicas y Farmacia, Universidad de San Carlos de Guatemala, Ciudad de Guatemala. 82 p. Cort6s, J. & M.E. Hatziolos. 1998. Status of coral reefs of Central America: Pacific and Caribbean coasts. 32-37. In: C. Wilkinson (ed.), Status of Coral Reefs of the World: 1998. GCRMN, Australian Institute of Marine Science. Cort6s, J. & M.J. Risk. 1985. A reef under siltation stress: Cahuita, Costa Rica. Bull. Mar. Sci. 36: 339-356. Cort6s, J., R. Soto, C. Jim6nez & A. Astorga. 1992. Earthquake associated mortality of intertidal and coral reef organisms (Caribbean of Costa Rica). Proc. 7th Int. Coral Reef Symp., Guam 1: 235-240. Echeverria de Le6n, A.G. 1994. Caracterizaci6n de la actividad pesquera artesanal en la Peninsula de Manabique, Puerto Barrios, Izabal. Facultad de Agronomia, Instituto de Investigaciones Agron6micas, Universidad de San Carlos de Guatemala, Ciudad de Guatemala. 89 p. Foer, G. & S. Olsen. 1992. Las costas de Centro Am6rica: diagn6sticos y agenda para la acci6n. ROCAP-USAID-University of Rhode Island. 290 p. Fonseca E., A.C. 2000. Evaluaci6n ecol6gica rfipida de los arrecifes coralinos de Punta de Manabique, costa Caribe de Guatemala. Report for The Nature Conservancy (TNC), Washington D.C. 23 p. Hay, M.E. 1984. Patterns of fish and urchin grazing on Caribbean coral reefs; are previous results typical? Ecology 65: 446-454.

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Hughes, T.P., D.C. Reed & M.-J. Boyle. 1987. Herbivory on coral reefs: community structure following mass mortalities of sea urchins. J. Exp. Mar. Biol. Ecol. 113: 3959. Kramer, P., P.R. Kramer, E. Arias-Gonz~ilez & M. McField. 2000. Status of coral reefs of northern Central America: M6xico, Belize, Guatemala, Honduras, Nicaragua and E1 Salvador. 287-313. In: C. Wilkinson (ed.), Status of Coral Reefs of the World: 2000. GCRMN and Australian Institute of Marine Science. Marin, S. 2000. Unidos por un tesoro mundial en Mesoam6rica. WWF, Centroam6rica, 3 (2): 7-12. Prado, L.M. 1990. Colecta, clasificacidn y distribucidn de las especies de gaster6podos en la costa Athintica de Guatemala. Thesis, Universidad de San Carlos, Ciudad de Guatemala. 120 p. PROARCA 1996. Gulf of Honduras: preliminary site overview. PROARCA/Costas, TNC, WWF and University of Rhode Island. 22 p. Rogers, C.S., G. Garrison, R. Grober, Z.M. Hillis & M.A. Franke. 1994. Coral reef monitoring manual for the Caribbean and Western Atlantic. Natl. Park Serv., Virgin Islands. Salaverria, A. & F. Rosales. 1993. Ecologia pesquera de la costa Atl~intica de Guatemala: evaluaci6n inicial, Bahia de Amatique, Izabal. Informe de Avance. Universidad de San Carlos, Ciudad de Guatemala. 105 p. Wilkinson, C.R. 1992. Coral reefs of the world are facing widespread devastation: can we prevent this through sustainable management practices? Proc. 7th Int. Coral Reef Symp., Guam 1:11-21. Ygfiez-Arancibia, A., D.J Zarate-Lomeli, M. Gomez Cruz, R. Godinez Orantes & V. Santiago Fandino. 1999. The ecosystem framework for planning and management the Atlantic coast of Guatemala. Ocean Coastal Manag. 42:283-317. Young, C.J., T. Lay & C.S. Lynnes. 1989. Rupture of the 4 February 1976 Guatemalan earthquake. Bull. Seism. Soc. Amer. 79: 670-689.

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The reefs of Belize J. G i b s o n a and J. Carter b aCoastal Zone Management Authority and Institute, P.O. Box 1884, Belize City, Belize. bUniversity of New England, Department of Life Sciences, Biddeford, Maine 04005, U.S.A. ABSTRACT: The Belizean Barrier Reef complex includes the largest continuous reef system in the western Atlantic and includes three offshore atolls, numerous patch reefs, unique faro formations, and fringing reefs. It ranges from 10 km to 32 km in width and extends for a distance of 220 km parallel to the mainland coast. The present-day patterns of reef development along the barrier reef and within the shelf lagoon are related to the southern dip of underlying fault blocks that support the modem reef topography, regional differences in wave-energy conditions, and terrestrial runoff, particularly in the south. At its northern limit, it begins as a fringing and bank-barrier reef just offshore of the Pleistocene Ambergris Cay peninsula. Further south, it forms long sinewy stretches of barrier reef intermingled with deeper broken patches and shallow pavements dotted with various coral colonies. Interconnected coastal areas are characterized by extensive strips of mangrove forests, river deltas and estuaries, and coastal lagoons. First noted for their magnificence by Charles Darwin, these reefs have been well researched, beginning with detailed scientific studies in the late 1950s. In the early 1960s several geological and biological studies and baseline surveys were carried out by the international scientific community. In the early 1970s the Smithsonian Institution established a marine research station at Carrie Bow Cay in the central province of the Belize barrier reef, and has since completed a large number of seminal reef studies. More recently, additional research stations have been established by other agencies and organizations to foster conservation objectives as well as to conduct basic research, adding further to the quantity and quality of reef research in Belize. Despite this comprehensive research work, however, it is only recently that studies have started to document the actual health or status of Belize's coral reefs. Several monitoring initiatives are revealing that signifycant changes are occurring, such as a general decrease in percentage of coral cover in several locations and a change in coral communities. Hurricanes, coral disease, bleaching, siltation, nutrient enrichment and over fishing are the primary causes of disturbances to the reefs. Management strategies to address these impacts are a major part of the national integrated coastal zone management program, with the network of marine protected areas forming the backbone of reef protection efforts. Other significant activities of this program include land use planning, environmental impact assessments, and a mooring buoy system. This integrated approach, in coordination with a proposed regional initiative, is considered the best hope for the future conservation of the reefs of Belize.

I. H I S T O R Y

OF RESEARCH

A l t h o u g h C h a r l e s D a r w i n d e s c r i b e d the reefs o f f the coast o f B e l i z e "as the m o s t m a g n i f i c e n t .... " in his b o o k o f 1842 entitled The Structure and Distribution of Coral Reefs, r e s e a r c h on these reefs started only about four d e c a d e s ago. T h e first investigations b e g a n in 1959 and w e r e carried out by the C a m b r i d g e E x p e d i t i o n to British H o n Latin American Coral Reefs, Edited by Jorge Cort6s 9 2003 Elsevier Science B.V. All rights reserved.

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duras (Thorpe and Stoddart 1962). Their research focused on the coral species found around Rendezvous Cay. One of the expedition members, David Stoddart, later surveyed the country's three atolls: Turneffe Islands, Lighthouse Reef and Glover's Reef (Stoddart 1962). Stoddart also published a series of reports on the effects of hurricanes on the Belize reefs and their subsequent recovery (Stoddart 1963, 1969, 1974). During the 1960s, several geological studies of the reef were carried out, led by E.G. Purdy of Rice University (Purdy 1974). Other geological studies were undertaken by Robert Ginsburg and Noel James and focused on the morphology, sediments and organisms of the deep barrier reef (James and Ginsburg 1979). General reef descriptions were provided by Wantland and Pusey (1971) who described the patch reefs of Southern Belize, and by Miller and Macintyre (1977) who published a guidebook to the Belize reefs. Detailed studies of shallow barrier reefs were conducted by James et al. (1976) and on the patch reefs of Glovers Atoll by Wallace and Schafersman (1977). Since 1972, the Smithsonian Institution has run a marine research station on Carrie Bow Cay located in the central portion of the barrier reef. This station is the site of the Institution's Investigations of Marine Shallow-Water Ecosystems (IMSWE) and Caribbean Coral Ecosystems (CCRE) programs. Through these Program a large number of reef research projects and publications have been produced (Riitzler and Macintyre 1982), with scientists studying in great detail the ecology and geology of the Carrie Bow Cay reef system. More recently, scientists based on Carrie Bow Cay have studied the reefs of the Pelican Cays area (Goodbody 1995, 1996; Littler et al. 1995). Two additional research stations have been established over the past five years. These are the Wildlife Conservation Society's station on Middle Cay, Glovers Reef, and the University of Belize's marine research centre on Calabash Cay, Turne-ffe Islands. Investigations carried out by these field stations will add significantly to the volume of reef research in Belize.

2. DESCRIPTION OF REEF AREAS All the typical reef zones are present in Belize, as well as almost the entire suite of Caribbean coral species (Rtitzler and Macintyre 1982). Recent studies have led to new observations in Belize, with 61 species of stony corals (Scleractinia, Milleporidae, and Stylasteridae) now recorded (Fenner 1999). The variety of reef types includes barrier reef, atolls, patch reefs, fringing reefs and faros (Fig. 1). 2.1. Barrier reef The Belize Barrier Reef is the longest reef in the Atlantic, stretching for approximately 220 kin along the entire coast of the country, from the border with Mexico in the north to the Gulf of Honduras in the south. Its structure is determined to a large extent by the submarine geology of the area. Belize is located on the Yucatan continental block, which is separated from the Nicaraguan-Honduras block to the south by an eastwest fracture zone that forms the Cayman Trench (Perkins 1983). Along the eastern edge of the Yucatan block, a series of five parallel, north-northeast trending submarine ridges and scarps were formed (Fig. 2), and the Belize Barrier Reef is situated on the inner three of these ridges (Dillon and Vedder 1973). The ridges are on a southerly dipping

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Fig. 1. Map showingthe Belizebarrierreef and the three outeratolls (fromGarciaand Holterman 1998). platform, and during the Holocene sea level rise they were inundated at different rates due to their different elevations (Burke 1993). Between the mainland and the barrier reef lies a lagoon that is 20 to 40 km wide, and only a few meters deep in the north, deepening to 50 m towards the south.

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Fig. 2: Map showing the parallel submarine ridges along the Yucatan Block (after Dillon and Vedder 1973). The barrier reef complex is comprised of a reef crest several meters in width, a series of spurs and grooves extending seaward for about 100 meters, and a wide barrier reef platform. The reef complex varies in width from several kilometers in the north, to less than 100 meters in the south (Burke 1979). Burke (1982) has distinguished three provinces of the barrier reef system, each having distinct communities and geomorphological characteristics, a reflection primarily of the different wave energy reaching them as a result of the sheltering influence of the atolls. The northern province runs for 46 km of shallow-water reefs, extending as far as the northern tip of Gallows Point Reef. Although this province has an elevation conducive to good reef development, the factors of poor water quality and exposure to high energy waves have resulted in these being for the most part discontinuous "ribbon reefs", except for those along Ambergris Cay. The reef in the Bacalar Chico region in the north, along the border with Mexico, has the unusual formation of a double reef crest (Gill et al. 1996). Just south of the border with Mexico, the reef actually runs onto the shore at Rocky Point (McField et al. 1996). The passes in the reef in this province are typically wide and shallow.

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The central province, extending for 91 km from Gallows Poim Reef to Gladden Spit, is the best developed due to its elevation, good water quality and moderate wave action (Burke 1993). The reefs are wide and continuous, with a high-relief fore-reef and the greatest abundance of coral species. This province is the most protected from ocean waves, which has contributed to the development of the most luxuriant and extensive reefs, particularly those near Columbus and Tobacco Cays. A unique double high spur and groove system occurs in this central section of reef, extending for approximately 16 km. The southern province, running for only 10 km from Gladden Spit to the Sapodilla Cays, is characterized by discontinuous reefs, mainly adjacent to islands. Burke (1993) explains that this province is less developed due to its deeper elevation and more open exposure. The channels in the reef are narrow and deep. In this province the barrier reef ends in a J-shaped hook in the Gulf of Honduras, some 40 km from the mainland. Purdy (1998) discusses the origins of this peculiar hook-shaped configuration, proposing that the eroded limbs of an underlying syncline dictate its shape. These three provinces of shallow-water reef communities extend for a total of 147 km, with the remaining shelf edge consisting of channels, carbonate shoals, algalcovered pavement, and deeper reef communities (Macintyre and Aronson 1997). A typical cross-section of the reef can be seen in Fig. 3 as described in Rtitzler and Macintyre (1982), with the reef divided into four major zones: back reef, reef crest, inner fore reef, and outer fore reef. Burke (1979) gives a detailed description of the reef zonation through a series of transect analyses across the barrier reef. In summary, the barrier reef is composed of the common Caribbean reef communities, with varying degrees of development. Along the central barrier reef, Agaricia sp., Millepora complanata and Porites porites dominate the spurs. The spurs of the northern and southern sections, however, are comprised of coralline algae, Millepora complanata, Porites astreoides, and Diploria sp. A ridge of Acropora cervicornis characterizes the central section. (However, this has changed in recent years, due to the loss of A. cervicornis to whiteband disease, as described in section 4.2). In contrast, the northern and southern provinces have a high diversity coral community comprised primarily of Agaricia sp., Montastraea spp., Mycetophyllia spp. and Colpophyllia spp. 2.2 Atolls Three atolls lie east of the barrier reef: Tumeffe Islands, Lighthouse Reef and Glover's Reef. These are separated from the barrier reef by water 360 to 1100 m deep (Perkins 1983). 2.2.1 Turneffe Islands atoll. The Turneffe Islands atoll lies about 9 to 23 km from the barrier reef on the second submarine ridge. It is the largest atoll with an area of 531 km 2, a length of 48 km, and up to 16 km wide. It consists primarily of mangrove islands surrounding a shallow lagoon with few coral patches. It has a Segmented reef rim with 23 cuts or channels, most of which are narrow and shallow (Stoddart 1962). The windward reef is narrow and well-defined. Stoddart (1962) describes its zonation near Calabash Cay as having a Cervicornis zone, followed by an Annularis zone, a reef crest comprised of Agaricia, and an outer slope with Montastraea, Porites and Siderastrea. In contrast, the atoll's leeward reef is wider, the reef crest is not defined, and the reef is submerged. The zonation is described by Stoddart (1962) as first a sandy area with

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Fig. 3. Reef transect at Carrie Bow Cay showing zonation (from RUtzler and Macintyre 1982).

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gorgonians, then the main reef at about 3 - 5 m with Montastraea annularis, Diploria spp., Porites porites and Agaricia agaricites. The rubble-covered bottom then slopes steeply into deep water. Tumeffe Islands Atoll does not have a deep central lagoon, its reefs do not form an entire margin, and there is no reef flat, all of which are features of a true atoll. Stoddart (1962) proposes that "bank reef' would be a more appropriate term for describing this structure. 2.2.2. Lighthouse Reef atoll Lighthouse Reef is the easternmost of the atolls and, along with Glover's Reef, lies on the third submarine ridge. Extensive pavements of encrusting Lithothamnion, a feature that does not occur on the other reefs, characterize the windward reefs of both atolls. With an area of 203 km 2, Lighthouse Reef is the smallest atoll. It has a well-developed rim broken by three channels. Stoddart (1962) described the zonation of the eastern or windward reefs as first a Lithothamnion pavement, followed by a Palmata zone, a mixed reef zone with A. palmata, P. astreoides, P. porites and A. agaricites, an elevated reef-rock zone comprised of dead, eroded reef rock with Millepora, and an outer slope which falls steeply from about 1 m to over 7 m, and which then levels off to a platform with large, massive A. palmata. The western reefs are characterized by a cominuous rim of coral, with only a couple of channels, that falls steeply from the reef crest to deep water. The zonation is as follows (Stoddart 1962): a gorgonian zone, a Cervicornis zone, the reef crest dominated by M. annularis, with A. palmata, Millepora spp., A. agaricites, P. porites and Dendrogyra cylindrus, and finally a vertical wall of Montastraea. Many patch reefs are located in the fairly shallow central lagoon. However, these patches are small and without pronounced zonation (Stoddart 1962). The southeast side of the atoll has a large bight, which may have resulted from submarine slumping, resulting in the great depths off Half Moon Cay (Stoddart 1962; Meyer 1992). Meyer (1992) also suggests that additional support for this theory is provided by the narrowness of the living reef on this crescent-shaped rim. The eastern reefs of this atoll have a very wide back reef apron with an equally wide zone of living reef fronting the back-reef zone. In contrast, the reef along the Half Moon Cay bight is much narrower and the structure is compressed. This possibly represents a stage in the recovery of the windward reef following a collapse of the atoll margin. The famous "Blue Hole" is located on this atoll. This is a large circular sinkhole with a diameter of approximately 318 m and a maximum depth of 125 m (Dill 1971). Cave systems formed on offshore limestone platforms and atolls during the Pleistocene lowering of sea the level. The Blue Hole formed when the ceiling of a large cavern collapsed. The upper rim of the Blue Hole has lush coral growth, with narrow passages of only 50 meters on the northem and eastem sides. Many large stalactites extend from an overhanging ceiling, some of which tilt at an angle of 10 to 13 degrees. This indicates that during their formation, there was regional tilting by tectonic movements. Following this event, the sea levels rose and the cave was submerged. 2.2.3. Glover's Reef atoll. Glover's Reef atoll, with an area of 212 km z, has been described as a prototypic atoll: it possesses the best-developed reef growth and the greatest variety of reef types in the Caribbean (Dahl et aL 1974). Stoddart (1962) describes it as

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"a splendid example of a true atoll, comparable to anything in the Pacific or Indian oceans". The southernmost of the atolls, Glover's Reef has an almost completely emergent peripheral reef broken by only three channels (Perkins 1983). The windward reef's zonation is characterized by first a Porites zone, followed by an Annularis zone, a Porites-Lithothamnion zone, then the reef crest of dead reef-rock encrusted with A. agaricites, P. porites, Millepora, and finally a well-defined groove-and buttress zone mainly of massive A. palmata colonies on the outer slope (Stoddart 1962; Perkins 1983). (This composition has changed as a result of Hurricane Mitch in 1998; see section 4.1.). The leeward reef is also continuous with only a few openings. The zonation, as described by Stoddart (1962), is comprised of a mixed Cervicornis zone, a mixed Palmata zone, followed by an Annularis zone to depths of 5 m that continues down to 10 m with taller and massive colonies in deeper water, and then long buttresses of M. annularis and pillars of D. cylindrus. The deep central lagoon is studded with over 700 patch reefs. James and Ginsburg (1979) noted the deepest known living hermatypic corals in Belize occur off the eastern side of Glover's Reef at a depth of 103 rrL They also recorded live specimens of Halimeda commonly growing as deep as 80 m, with one observed at 110 m. This species of algae generally grows to depths of 67 to 73 m. 2.3. Patch reefs Patch reefs vary in size from small clumps of coral heads to patches 80 m wide. They are virtually absent in the northern shelf lagoon, except for areas off Ambergris Cay and near discontinuous segments of the barrier reef. However, patch reefs and "sand bores" are plentiful in the central and southern shelf lagoon and in the central lagoons of Lighthouse Reef and Glover's Reef atolls (Perkins 1983). The patch reefs of the southem lagoon have formed on Pleistocene topographic highs (Halley et al. 1977). Most patch reefs have the following zonation (Perkins 1983): seaward slopes of M. annularis and A. palmata, and a leeward slope covered with A. cervicornis and P. porites. They are often surrounded by an apron of Halimeda, sand and coral rubble. The patch reefs off Ambergris Cay, however, are dominated by M. annularis (Macintyre and Aronson 1997). Yorke (1971) conducted a comprehensive study of the southem patch reefs and noted nine types of zonations which can be grouped into three major reef zones: the coastal, inner and barrier reefs. The coastal zone patch reefs have low relief and are speciespoor, forming in brackish and often turbid water; the inner or shallow zone patch reefs form in clear water and have low relief but are species-rich; and the barrier reef zone patches have high relief with varying coral composition depending on factors such as surface currents and wave action. Halley et al. (1977) studied the structure of the Boo Bee patch reef, providing a sketch of the generalized zonation. The study also included drilling a core through the patch reef, reaching Pleistocene limestone, and providing a cross section of the reef with a sample of the sediment types at various depths. They estimated the underlying patch reef was submerged 8000 year BP. Wallace and Schafersman (1977) described the structure of patch reefs on Glover's Reef, and Wallace (1975) gives an account of the coral assemblages of three zones of patch reefs within this atoll's central lagoon. However, McClanahan and Muthiga (1998)

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show that these patch reefs have undergone a major ecological change over the past 25 years, exhibiting a 75% reduction in hard coral cover. An interesting feature is the "Spires" located on the southwest side of Glover's Reef. These are patch reefs/coral heads with a diameter of 30 to 50 m starting at a depth of 50 m, tapering off to a diameter of 3 to 8 m as they rise to the surface. They occur in a chain, running parallel with the southwest reef wall (Moore 1992). Recent research has also been conducted on the patch reefs of Mexico Rocks, off Ambergris Cay. In this region there are hundreds of patch reefs ranging in size from a meter to more than 10 m. They lie in the barrier reef lagoon, opposite a break in the reef, and along a linear high ridge of Pleistocene bedrock (Mazzullo et al. 1992). These patch reefs are considered unique because they are virtually monospecific, composed of 83% M. annularis (McHenry 1996). These reefs are younger than those found in the southern shelf lagoon, the latter area being inundated earlier during the Holocene. 2.4. Faros Faros, or rhomboidal-shaped atolls within the lagoon, are unusual reef types. They are rims of reef growing on strike-slip fault features, with steep sides enclosing a deep central lagoon, and lying in a parallel pattern reflecting the influence of faulting (Perkins 1983; Macintyre and Aronson 1997). In Belize, they are located in the widest section of the southem shelf lagoon between two deep channels, the Inner Channel and the Victoria Channel. Examples of faros include the Pelican Cays and the Laughing Bird Cay faro, which has a dramatically pinnacled lagoon. WestphaU (1986) describes three distinct units of these rhomboid reefs: the outer rims, intra-lagoons, and the inner reefs. The outer rims are generally narrow and steep-sided. The intra-lagoons can vary from small shallow areas, only a few meters across, to large deep lagoons. The inner reefs are located within the outer rim and are often linear in pattern, dissecting the intra-lagoons. The coral zonation of the faros is similar to that of other lagoon reefs. Macintyre and Aronson (1997) provide a description of the coral zonation of one of these low wave-energy patch reefs in the Pelican Cays. Westphall (1986) gives a detailed description of the Channel Cay reef complex, one of the smaller rhomboid reefs. Scientists operating from the Smithsonian's base at Carrie Bow Cay have been conducting extensive taxonomic and ecological surveys on the Pelican Cays, a faro which has experienced very little human disturbance and which has an exceptionally rich biodiversity. Goodbody (1995, 1996) has described the rich and unique ascidian communities that occur in this reef system. Littler et al. (1995) noted the very high plant diversity in the small geographic area of the Pelican Cays, stating that the main factor for this is the juxtaposition of "complex mangrove, coral, seagrass and algal biomes under stable pristine seawater conditions." This faro represents a lowenergy environment dominated by photosynthetic and filter-feeding populations.

2.5. Fringing reefs Fringing reefs occur close to the mainland in an area between Placencia and Punta Ycacos, at the northern entrance to Port Honduras (Perkins 1983). This reef community has a low diversity, dominated mainly by the hardy species of Siderastrea and Porites. These corals can tolerate variations in salinity and turbidity, which are experienced in these inshore waters.

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3. PRESENT STATE The coral reefs of the Caribbean are among those under greatest threat, possibly as a result of the Caribbean Sea being small and enclosed, its interconnection via ocean currents, and the high density of coastal human populations (Wilkinson 1993). On the other hand, Belize's relatively small population and low level of industrial development have resulted in corresponding low levels of impact on its reefs. Wells (1988) noted that the major threat was from hurricane damage, but warned that new threats may arise from runoff from agriculture and coastal tourism development. This predicted situation is materializing as a result of a population growth rate of 2.8% (NHDAC 1998), and the rapid pace of coastal development related to tourism, agriculture and aquaculture. Ian G. Macintyre of the Smithsonian Institution, who has a long history of reef research in Belize, is quoted in The State of the Coastal Zone Report: Belize 1995 (McField et al. 1996) as saying that the barrier reef can no longer be considered pristine, but it is still the best in the Caribbean. Due to the relatively good condition of its reefs, Belize is considered one of the region's most important source areas of larvae and juveniles of corals and other reef species (Cort6s 1997). 3.1. Past data

Although there has been extensive work on the geology and morphology of Belize's reefs as described above, there is a lack of consistent data which reflects the general state and health of the country's coral reef ecosystems. Results from preliminary monitoring efforts, however, illustrate some changes. For example, some sites studied show a decrease in coral cover or a change in coral composition. At Carrie Bow Cay, cover has decreased from 30-35% in the 1970s to 12-20% in 1995 at the 10-13 m depth range, due primarily to loss of A.cervicornis (Koltes et al. 1998). Macintyre and Aronson (1997) noted that, following the loss of Acropora cervicornis due to white-band disease (WBD) similar to the mass destruction of this species throughout the Caribbean, staghom rubble is now covered with brown algae, primarily Lobophora variegata in the forereef zone. In the backreef area, the loss of A. cervicornis has been replaced by Porites porites. In the area of Carrie Bow Cay the algal cover has increased, with fleshy macroalgae comprising 63% of cover in surveys carried out in 1991 (Aronson et al. 1994). In their studies conducted on the Channel Cay faro, Aronson and Precht (1997) documented a reduction in total coral cover of 30%, from 85% in 1986 to 60% in 1995. McClanahan et al. (1999) report that this macroalgal dominance is evident along the barrier reef, from Ambergris Cay in the north to the Sapodilla Cays in the south, regardless of the increasing distance of these areas from the mainland and thus from human influence. Similarly, the replacement of staghorn coral by fleshy algae has been the case at Glover's Reef atoll, where McClanahan and Muthiga (1998) have documented a decline in coral cover from 80% to 20% on the patch reefs, with the greatest change being a 99% reduction of Acropora spp. When Wallace (1975) studied the patch reefs of this atoll in 1970-1971, he reported a cover of 80% hard coral and 20% algae. The cover composition has therefore been reversed. Such high algal cover is often associated with high nutrients, but Glover's is an oceanic atoll, a long distance away from land-based influences. McClanahan and Muthiga (1998) suggest that the cause for this radical change over the past 25 years may be a combination of white-band disease and low

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herbivory, rather than nutrients, sedimentation or pollution. It is important to note, however, that the Acropora on the fore-reef was abundant and the changes only occurred on the patch reefs (McClanahan and Muthiga 1998). The fore-reef obviously has been more resilient to those factors that have resulted in the mortality of Acropora and the growth of algae on the patch reefs in the atoll's lagoon. Preliminary results of a recent investigation of the level of nutrients on the atoll, however, show that levels are high (Mumby 1998). It is proposed that these nutrients are due to upwelling on the fore-reef, and the decomposition of organic matter within the lagoon. Recent observations from satellite imagery also indicate that the run-off of nutrients from watersheds in northern Honduras can extend as far north as the Glover's Reef atoll, and could possibly be a cause of the high nutrient levels being measured (M. McField, per. com.). Further studies on the interplay of herbivory, nutrients and wave exposure are therefore required to explain this phase shift from coral-dominated to algaldominated patch reefs within the Glover's Reef lagoon. Aronson et al. (1998) describe a change in the southern lagoon reefs in which the dominant staghom coral Acropora cervicornis has been replaced by Agaricia tenuifolia. The A. cervicornis here was also decimated by an outbreak of white-band disease over the past decade. In most other places in the Caribbean, the mass mortality of staghom coral by white-band disease (WBD) has led to its replacement by fleshy macroalgae (Ginsburg 1994). On these Belize lagoon reefs, however, this is thought to have been averted by the abundance of the herbivorous sea urchin Echinometra viridis that has prevented algae from becoming established. 3.2. Current studies There are four major monitoring or rapid assessment studies which are ongoing and which should help to improve the knowledge of the health and general status of the Belize reefs. These are included in the nationwide coral reef monitoring program initiated by the Fisheries Department and the Coastal Zone Management Institute, CARICOMP, the CPACC monitoring program, and the AGRRA program. 3.2.1. National reef monitoring program. The National Coral Reef Monitoring Program, spearheaded by the Coastal Zone Management Program of the Fisheries Department, began in 1992 with the collection of data from four sites on the barrier reef using the chain transect method. Data were subsequently collected from an additional two sites located on one of the atolls. Preliminary results from these studies showed a hard coral cover ranging from 17% to 30% (Young et al. 1993; Young 1994). Young (1994) also noted a macro-algae percent cover ranging from 22% to 40% at the barrier reef sites. As the chain transect method proved to be very time-consuming and labor-intensive, the general monitoring technique was changed to the video-transect method as described by Aronson et al. (1994). Since 1995 this method has been used, in collaboration with the studies of a doctoral student, and the program has been extended to 17 sites located on the barrier reef (including northern, central and southern regions), the atolls, and a faro. Preliminary results have been recorded on species richness, number of corals bleached and diseased, reef complexity index, benthic cover, and fish abundance (McField 2001). A Coral Reef Monitoring Working Group, with representatives from government, NGOs

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and the university, has been established to coordinate the Program and to encourage additional efforts throughout the country. 3.2.2. CARICOMP. Caribbean Coastal Marine Productivity (CARICOMP) is a regional program to study land-sea interactions, which focuses primarily on productivity. In view of the mounting evidence that Caribbean coastal ecosystems are degrading because of increasing anthropogenic stresses, as well as natural and global impacts, it was recognized that a long-term monitoring program such as CARICOMP was required to document changes (CARICOMP 1997a). For the monitoring of coral reefs, CARICOMP employs the chain transect method at permanently marked sites. In Belize there are three official CARICOMP sites: one at Carrie Bow Cay monitored by the Smithsonian Institution, one at the Hol Chan Marine Reserve monitored by reserve staff, and most recently, one at Calabash Cay, Tumeffe Islands monitored by staff of the Marine Research Centre, University of Belize. CARICOMP is the first Caribbean-wide review of coral reefs that is yielding quantitative data (CARICOMP 1997a). Preliminary results for the Carrie Bow Cay site in 1995 show a mean percent cover (for 10 transects) of 59.2% for algae, and 16.6% for hard corals (CARICOMP 1997a). Comparing data for four successive years, up to 1995, very little change has occurred in community composition. This site is considered to be little influenced by the land, but experiences natural stresses of hurricanes, D i a d e m a mortality, bleaching and white-band disease, and the human impact of overfishing (CARICOMP 1997a). 3.223. CPACC program. CPACC (Caribbean Planning for Adaptation to Climate Change) is a regional project with the objective of supporting Caribbean countries in preparing to cope with the adverse effects of global climate change in coastal marine areas. It has a coral reef monitoring component that focuses primarily on the impacts of climate change on coral reefs, and which is based in the three countries of Belize, Jamaica and the Bahamas. In a workshop held in Belize in early 1998, the appropriate monitoring methodology was determined, including the criteria for site selection. It was agreed generally that Belize will monitor at least four sites, representative patch reefs located in the northern and central sections of the barrier reef lagoon and on two of the three atolls, using the video-transect technique (Walling 1998). Following another workshop held in the Bahamas in early 1999, the protocols were refined further and training was received in data analysis. Belize has subsequently started collecting data from three sites: the Glover's Reef, Hol Chan, and South Water Cay marine reserves. The results of this program should add to the knowledge base of the general status of Belize's reefs. 3.2.4. AGRRA program. AGRRA, or the Atlantic and Gulf Rapid Reef Assessment, program arose from an expressed need to develop a rapid assessment protocol to determine the status of the many reefs in this region for which there is little or no data available. This group has completed a revised protocol that uses both line transect and quadrat methods (Ginsburg et al. 1998). Belize is currently using this technique to assess several sites along its reef. It is expected that results from the data collected can contribute to the distinction between anthropogenic and natural impacts, and also identify reefs that require special protection (Ginsburg et al. 1998).

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4. NATURAL DISTURBANCES It is often difficult to determine whether disturbances are entirely natural or humaninduced, or a combination of both. For example, hurricanes are generally classified as natural disturbances. However, as a result of global warming, which is considered to be human-induced to a large extent, the intensity and frequency of hurricanes could increase (Mitchell 1990). Nevertheless, the following influences have been included as natural disturbances: hurricanes, coral diseases, bleaching, Diadema mortality and sea level rise. 4.1. Hurricanes Hurricanes have been the most powerful factor affecting the reefs of Belize (Perkins 1983; Wells 1988). Given the country's location in the hurricane belt, they will no doubt remain as possibly the greatest threat to the reefs in terms of magnitude and rate of destruction (McField et al. 1996). Major hurricanes of this century in Belize have occurred in 1931, 1955 and 1961. Stoddart (1963) documented in detail the effects of Hurricane Hattie in 1961, which had winds of 300 km/hr and high tides of 3 to 5 m. Between Rendezvous and English Cays, up to 80% of the corals were destroyed, with a belt of heavy damage extending for 5065 km, north to St. George's Cay and south to Cay Glory. No extensive colonies of A. cervicornis remained over this tract of barrier reef. Moderate damage extended as far south as Curlew Cay, presently a shoal that lies south of Carrie Bow Cay. Tumeffe Islands atoll reefs suffered extensive damage, particularly from Pelican Cay north to Mauger Cay. Branching species of coral were more susceptible to hurricane damage than massive species. The most resistant species was Montastraea annularis, the least resistant were A. cervicornis, Porites spp., and small unattached corals such as Manicina areolata and Siderastrea radians (Stoddart 1963). Destruction of coral may also have continued after the passage of the storm, as movement of the coral rubble and debris created can damage a much larger area and also hamper recolonisation (Stoddart 1963). Stoddart (1969, 1974) subsequently resurveyed these reefs, three and ten years after the passage of Hattie. By 1963 near Carrie Bow Cay, living coral in shallower spurs approached pre-hurricane luxuriance, but deeper ones were still bare. By 1972, there was no obvious evidence of storm damage (Stoddart 1974). In contrast, by 1965 at Tumeffe, living corals were still almost nonexistent. Ten years later the tract of severely damaged reef had not recovered. Based on these surveys, Stoddart (1974) concluded that it would take more than 25 to 30 years for a reef to recover to a mature stage after a catastrophic hurricane. Other hurricanes that have caused damage to the reefs include Laura in 1971, Fifi in 1974, and Greta in 1978. Near Carrie Bow Cay, Hurricane Fifi caused a proliferation of Acropora cervicornis in the back reef and lagoon, and Hurricane Greta also had a major impact on A. cervicornis, damaging the back reef and resulting in a great deal of coral debris (Wells 1988). More recently, Hurricane Mitch, which was the fourth strongest storm documented this century with winds of 290 km/hr, passed approximately 120 miles southeast of Glover's Reef during the last days of October 1998. Preliminary investigations showed that this storm caused substantial damage to the reefs. Reports received from Glover's Reef atoll (T. Bright, per. com.) note that the windward fore-reef

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was extensively damaged, with both branching and massive corals affected. Many of the corals remaining were severely abraded, with little living tissue remaining. Using survey techniques adapted from AGRRA, Kramer et al. (1999) conducted a rapid assessment of Hurricane Mitch damage at 75 reef sites in Belize, and concluded that damage to shallow reefs was highest along northeast sides of the barrier reef and atolls. In contrast, damage to deep reefs was localized and minor. It must be noted that the occurrence of Hurricane Mitch followed a severe bleaching event. Thus, the damage to the reef resulted as a series of events, beginning with elevated sea-water temperatures and the bleaching event, followed by the storm damage from Hurricane Mitch, and ending with a prolonged period of turbid freshwater flowing over the reef. The heavy rainfall associated with hurricanes can lower seawater salinities enough to affect corals adversely, causing them to eject their zooxanthellae (Stoddart 1969).

4.2. Coral diseases As mentioned earlier, WBD has been the cause of a large die-off of Acropora on many reefs in Belize. This has led to either an increase in algal cover or a change in coral species (Ginsburg 1994; Macintyre and Aronson 1997; McClanahan and Muthiga 1998; Aronson et al. 1998). Black band disease (BBD) has been recorded at sites on the barrier reef and the three atolls. It has been very prevalent in the highly used Hol Chan Marine Reserve, where treatments have been attempted (McField et al. 1996). Treatments were discontinued, however, as they proved to be ineffective. Studies in Belize (Grosholz and Ruiz 1997) have shown that black-band disease commonly infects Montastraea annularis and Diploria strigosa. The occurrence of the disease was randomly distributed and the overall cover was low, with a prevalence of 4% at the study site. Other studies have shown that BBD seems to develop more in May and June, when the seas are calm (Perkins 1983). Although it is not known whether the frequency of this disease is increasing in Belize, studies in Jamaica have shown that it can contribute to the progressive elimination of massive corals on reefs (Bruckner and Bruckner 1997). A component of the National Reef Monitoring Program is also recording the frequency of coral diseases. Preliminary results show that in addition to WBD and BBD, there are also occurrences of white plague (mainly on M. annularis and A. agaricites), yellow band disease (primarily on M. annularis), and purple blotch (on Siderastrea siderea) (McField 2001). Kramer et al. (1999) also recorded extensive damage to massive corals (Montastraea annularis) from black band disease and white plague, possibly as a result of warmer sea temperatures and the passage of Hurricane Mitch. 4.3. Diadema mortality The mass mortality of the black sea urchin Diadema antillarum in 1983, which occurred throughout the Caribbean (Lessios et al. 1984), also affected the reefs of Belize. Prior to this die-off, densities recorded on the spur and groove zone of the barrier reef at Carrie Bow Cay were as high as 4.3 urchins rn2 (Lewis and Wainwright 1985). Very few urchins, which are important herbivores on the reef, now occur. Counts carried out at the CARICOMP site near Carrie Bow Cay in 1995 showed a few very small individuals at a density of 0.07 urchins rn"2 (CARICOMP 1997a). McClanahan and Muthiga (1998) report a very low density from Glover's Reef of less than 1 per 1000 m E.

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4.4. Bleaching Coral bleaching, or the process in which corals expel their symbiotic algae, is a recent phenomenon in Belize. Low levels of "background" bleaching have been recorded in the past. For example, in 1992 reports were received of bleaching in the Laughing Bird Cay faro (Clark 1992). The species most affected was Sidereastrea siderea, with other species affected including Agaricia agaricites, Montastraea annularis, Siderastrea radians, Acropora cervicornis and M. cavernosa. Nevertheless, prior to 1995, other bleaching events reported in many areas of the Caribbean had not significantly affected Belize. 4.4.1. Mass bleaching. Widespread bleaching took place for the first time in Belize in September 1995, a time that coincided with high water temperature, calm weather and increased solar radiation. At this time, bleaching occurred throughout the Caribbean (CARICOMP 1997b). During this event 7 sites were surveyed and 59 hard corals tagged (CARJCOMP 1997b). Results showed that within 6 months partial mortality had taken place in some species, and partial to full recovery in others. In back-reef locations along the barrier reef, Montastraea annularis and Agaricia agaricites were the species most affected; on the fore-reef on the atolls, M. annularis and Siderastrea siderea were most affected. Near Carrie Bow Cay, the most severely affected species were Agaricia lamarcki and A. grahamae. McField (1999) recorded that 52% of corals surveyed in November 1995 were affected by bleaching. This survey was carried out as part of the National Reef Monitoring Program, and used a new technique, the "weighted-bar swimming transect method" (McField 1999), to rapidly and quantitatively assess the extent of bleaching. Results of this study showed that the most affected species was M. annularis, followed by S. siderea and A. tenuifolia. The extent of bleaching varied by depth for some species. S. siderea and M. annularis were more bleached in fore-reef sites, with P. porites, A. tenuifolia and other species of Agaricia more bleached in back-reef sites. By May 1996, only 7% of corals surveyed were bleached, with 25% of the tagged bleached corals showing at least partial mortality. Agaricia tenuifolia had the highest rate of partial mortality of 43%, followed by Montastraea annularis with 26%. In contrast, all the Acropora spp. had fully recovered. As previously mentioned, many reefs are now dominated by A. tenuifolia (Aronson and Precht 1997). The susceptibility of this species to bleaching and its subsequent mortality is therefore a matter of concern (McField 1999). Similarly, the significant effect of bleaching on M. annularis, a dominant coral in the Caribbean, is also a grave concern.

Burke et al. (1997) recorded the effects of bleaching on the patch reefs at Mexico Rocks, Ambergris Cay, during the 1995 bleaching event. This area also experienced 50% bleaching. Prior to the event, the patch reefs had a 35% cover of dead coral. Six months after the bleaching, this area had increased to 49%. Many of the degraded surfaces were covered with fleshy macro-algae, for example, Turbinaria spp., Padina spp., and Caulerpa racemosa. By 1997, however, a survey showed that these surfaces were free of algae. In early September 1997, reports were received of a bleaching event on the reefs of Port Honduras (W. Heyman, per. com.). Surveys showed sea temperatures as high as 34~ and salinities of 17 - 24. Down to a depth of 8 m, bleached species were recorded and included M. annularis, M. cavernosa, S. radians, S. siderea, P. astreoides, Diploria spp.,

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M. areolata, and Solenastrea bournoni. The high temperatures, coupled with the low

salinity, are thought to have triggered this bleaching. In early September 1998, first reports of bleaching were recorded for the reefs off Ambergris Cay (G. Smith, per. com.). By mid-September, the bleaching was reported to be widespread, including areas on the barrier reef, lagoonal reefs and atolls (T. Bright, per. com.). This bleaching event coincided with a time of high sea temperatures (up to 32~ and calm weather, and preliminary investigations report that it was comparable in severity to the event in 1995 (M. McField, per. com.). Kramer et al. (1999) describe the mortality from this bleaching event as extensive for shallow water reefs, with the main species affected being Agaricia tenuifolia and Millepora complanata. On deep reefs, the recovery from bleaching has been slow, with massive corals still pale and partially bleached 8 months after the event. Agaricia tenuifolia, the main species that colonized the former A. cervicornis flanks on the shoals in the south-central lagoon, experienced almost 100% mortality during this bleaching event (R. Aronson, per. com.). This change may provide the opportunity for invasion by pathogens and algae, eventually leading to a long-term decline in the reefs (McField, 1999). In summary, given the apparent increasing frequency of these events and the predicted increase in global temperature and UV radiation associated with global climate change, the longterm effects of coral bleaching could be severe and generally undermine the reef framework (Burke et al. 1997; McField, 1999). As a result of the impacts of bleaching and Hurricane Mitch, the shallow-water reefs of Belize have sustained "catastrophic losses" (Kramer et al. 1999). 4.5. Sea-level rise The impact of rising sea levels on low-lying countries fringed by coral reefs, such as Belize, is obviously of great importance. Rising sea levels bring to mind the inundation of vast expanses of coastal regions with subsequent erosion. But there is consensus among the scientific community that the threat is not immediate (Houghton et al. 1990). Controversy exists concerning the significance of the present rate of global sea-level rise, and how it may relate to the greenhouse effect (Chui 1991). Although the present rate of sea level rise and its interpretation are subject to disagreement among experts, it is a fact that sea level is rising in Belize, as it is in most coastal regions, with the potential to cause major problems just at the time when rapid coastal development is taking place. If global warming and associated sea-level rise continue to occur in the next century, these problems will be exacerbated. Recent analysis indicates that global sea level has risen about 2 mm per year for at least the last century (Trupin 1990; Douglas 1991), and probably at a much smaller rate for the previous several millennia (Keamey and Stevenson 1991; Varekamp et al. 1992). In contrast many scientists argue that global sea level will rise at a faster rate than at present because of global warming. The Intergovernmental Panel of Climate Change (IPCC) (Houghton et al. 1990) reports continued global warming and additional sealevel change of 18 cm by 2030 and 44 cm by 2070. In a separate study Church et al. (1991) calculate a rise of 35 cm by 2050. Presently the effect of rising sea level in Belize is minimal. However, should the rate of rise in sea level in future years exceed the ability of coral growth to keep pace, Belize could experience major structural damage to its unprotected coast line as well as catastrophic faunal extinction in the

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marine coastal environment. Observing and interpreting this small but highly significant acceleration of global sea level in a timely manner is a critical aspect of any climatemonitoring program. Various agencies within and outside of Belize are involved in large-scale intergovernmental efforts to monitor sea-level changes in the coming years. 5. ANTHROPOGENIC IMPACTS 5.1. Nutrient enrichment

Nutrification is one of the main anthropogenic threats to reefs in the Caribbean region (Ginsburg 1994; Szmant 1997). The two major sources of nutrients entering coastal waters in Belize are the run-off of fertilizers and the discharge of domestic sewage. Large amounts of fertilizers are used on the banana plantations located in the central and southern parts of the country and cover approximately 5,000 acres (McField et al. 1996). In 1994, the amount of fertilizers applied to banana farms totaled 3,685 tons (Usher and Pulver 1994). All the banana plantations are located near rivers and in areas of high rainfall, factors which may increase the rate of runoff (McField et al. 1996). Several studies have shown that high amounts of these chemicals enter the sea. Another area of concern is the citrus plantations in the Stann Creek Valley and the coastal plains to the south. It is believed that the run-off from the valley region could be high enough to cause eutrophication of coastal patch reefs (Hall 1994). The coastal plains, which are less fertile, require higher levels of fertilizer and lime, and drainage systems. This increases the risk of pollution of nearby coastal waters. In the case of domestic sewage, the major areas of concern are discharges from treatment facilities, septic tanks, and direct outfalls. These are concentrated in the areas of Belize City, Dangriga and populated Cays (McField et al. 1996). The only treatment facilities are located in Belize City and San Pedro, both of which provide secondary treatment. Inadequate sewage treatment and disposal, such as faulty septic tanks and direct discharge into rivers and the sea, have resulted in high nutrient levels in coastal waters in the following areas: Chetumal Bay, Belize River and Haulover Creek estuaries, Belize City area, North Stann Creek, Placencia, Punta Gorda, San Pedro, Cay Caulker and several other Cays (Archer 1994). Other important sources of nutrients include runoff from aquaculture farms and deforestation activities (McField et al. 1996). Although no studies have documented a link between nutrient enrichment and an effect on the reefs of Belize, measurements at sites along the barrier reef indicate levels ranging from undetectable to 3 ~tM of nitrates, and from undetectable to 0.6 ~tM of phosphates (Belize CZM Institute Report 1999). Studies conducted by LaPointe et al. (1992) have shown that the availability of P is the limiting factor controlling productivity and dominance of macroalgae along the Belize Barrier Reef. The threshold level concentrations for dissolved inorganic N (DIN) and soluble reactive phosphorus (SRP) that will result in enhanced macro-algae growth are >0.10 ~tM and >1.0 ~tM, respectively. The study also suggests the removal of P from wastewaters and land-based runoff as a good strategy to control eutrophication. 5.2. Siltation

Siltation of coastal waters is increased by soil erosion arising from agricultural practices in the Stann Creek and Toledo Districts, deforestation, particularly along river

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banks, destruction of mangroves and seagrass beds, and marine dredging (McField et al. 1996). Citrus plantations often include the riparian riverbanks, causing increased erosion. Milpa farming, or shifting cultivation, in the Toledo district often takes place on steep slopes, also increasing the risk of soil erosion. Several agrochemicals are sedimentbinding, and thus their transport out to coastal waters is enhanced by increased soil erosion and siltation of the rivers. The loss of mangroves along the coast can also lead to increased siltation of coastal waters. Mangroves act as a buffer, filtering runoff from the land and trapping sediments. In the Belize City area, the rate of mangrove clearance was estimated at 3.6% per year (McShane 1991), and clearance rates may have increased nationally over recent years. Marine dredging activity has been increasing in recent years with most operations carried out to fill low-lying areas for tourism or real estate development (McField et al. 1996). There is concern that many of the sites are in sensitive areas near coral reefs, and also are inadequately managed in terms of mitigating measures such as use of silt curtains. More than half the quarry or mining permits issued in 1995-1997 were for sites located near the Cays, mainly Ambergris Cay, Cay Caulker, and Cay Chapel. For example, a mining permit was issued in 1999 for the area around Cay Chapel for the extraction of 150,000 m 3. Many dredge sites have damaged seagrass beds which are important natural sediment traps, preventing silt from reaching the reef (Birkeland 1985). In general, conditions dealing with the equipment, methods, and other requirements for environmental protection are included as a term of the license issued. Regular monitoring, however, to ensure these conditions are implemented, is lacking. A study is currently underway to assess the movement of sediments from three southern watersheds into the coastal waters and the impact of these sediments on the reef (WRISCS 1998). The pattern of land use differs in each of the watersheds under investigation. This research should provide information on the links between sediment dynamics and land use patterns. 5.3. Overfishing Evidence for the effects of fishing on populations and communities of coral reef fishes in Belize and elsewhere throughout the tropics is available from a growing number of studies (Ralston and Polovina 1982; Alcala 1988; Carter et al. 1990; McClanahan and Muthiga 1994, 1997; Roberts 1995). Although these and other studies provide general information about overfishing coral reefs, there is an increasing number of studies in recent years showing that overfishing reduces the size and fecundity of fish species compared to non-fished areas (Murray et aI. 1999). For example, no-take reserves were shown to be effective at protecting exploitable species from fishery depletion and provided fish to support surrounding fisheries by increasing the abundance and larger size classes of exploitable species in reserve areas (Johnson et al. 1999). Less published evidence exists to suggest fishing on coral reefs has been directly harmful to recruitment except for a few studies on sharks and large predatory fishes. Unlike most temperate fisheries, many families of commercially important coral reef fishes (e.g. groupers) are sequential hermaphrodites and as such are theoretically highly vulnerable to overfishing (Bannerot et al. 1990). A few studies have reported direct evidence of the effects of fishing on the sex ratios of populations of sequential

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hermaphrodites (Moe 1969; Shapiro and Lubbock 1980; Colin 1992). A study of commercial catches in Belize comparing a heavily fished vs. lightly fished grouper spawning aggregation showed that the population structure of these fishes shifted toward smallersized fishes and a higher female/male sex ratio as fishing pressure increased (Carter et al. 1990). There is more evidence available that intensive fishing can alter community structure of coral reef fishes over short (Russ and Alcala 1989) and long (Koslow et al. 1994) periods of time. Two years after fishing ceased along targeted sections of the Belize barrier reef, Sedberry et al. (1992) reported higher relative abundance values and higher species diversity values for protected areas of the reef in contrast to heavily fished habitats. In a later study of similar sites, investigators again reported significant differences in fish abundance and diversity between habitat types and depths for many coral reef dependent species (Polunin and Roberts 1992). Of the commercially important coral reef fish exploited in Belize, grouper and snapper comprise the bulk of the catch. Fish are captured by hook and line seasonally at traditional spawning banks scattered throughout the reef complex (Craig 1966; Carter et al. 1990). Data from studies in Belize and elsewhere indicate that sustained and tmmanaged fishing pressure on these banks may result in changes to population structure, leading to a collapse of the fishery (Shapiro 1986; Carter et al. 1990; Colin 1992). In general, these and similar studies suggest coral reef fisheries in Belize and elsewhere are highly vulnerable to exploitation (Carter and Sedberry. 1996; Jennings and Polunin 1996; McField et al. 1996), and that marine fisheries yields on coral reefs are near or beyond their estimated maximum economic yields (Ngoile et al. 1988; Sanders et al. 1988; McClanahan and Kaunda-Arara 1996). This vulnerability to overexploitation, in contrast to fishes commonly caught in higher latitudes, is believed due in part to their peculiar life history traits (Bohnsack 1990). Unlike most temperate water fishes, reef fishes are usually restricted to the hard substrate, are often territorial, many species exhibit sex reversals, and most have limited ranges of habitat and depth (Munro and Williams 1985) and exist in "nutrient deserts" (Odum and Odum 1955; Marshall 1980). Stocks of many commercially important reef fish in Belize are faced with increasing fishing pressures and their populations are at risk of collapse or show serious signs of stress. In addition, the reductions in fish grazers attributed to overfishing (Hay 1984), particularly in combination with mass mortality of Diadema, are often cited as a cause of a switch in the dominant cover of the substratum from stony corals to fleshy algae (Levitan 1988; Shulman and Robertson 1996). Overfishing may also be responsible in part for a major change in the ecology of one of the largest and most remote reef atolls just offshore of Belize (McClanahan and Muthiga 1998). In the absence of effective conservation measures, it is likely genetic diversity will diminish in reef-dependent fishes over time, and important species will become permanently scarce or diminutive in size with reduced fecundity (Cuellar et al. 1993). In the past, conservation and management of the Belize coral reef fishes has been based on the biology of target species using conventional management techniques such as catch quotas, gear restrictions, size limits, limited entry and temporary area closures. Unfortunately these methods in Belize, as elsewhere in the Caribbean have been largely ineffective (Roberts 1997). More recently, the Belize Fisheries Department has adopted a strategy based on recommendations whereby selected habitats are set aside as fisheries

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reserves while the remaining area is managed by conventional options (Carter et al. 1992; Carter and Sedberry 1996). Strict no-take zones replicated within this broader string of protected areas are promising management tools because of their potential to 1) protect all living resources regardless of taxa; 2) enhance or maintain sustainable fisheries by preventing stock collapse and enhancing larval production by protecting brood stock (Bohnsack and Ault 1996; Roberts 1997). A high priority for Belize at the present time is the rigorous evaluation of the short and long-term effectiveness of existing marine reserves throughout the Barrier Reef Ecosystem. Strong scientific evaluation of marine reserve effectiveness is necessary to provide the empirical evidence to support theoretical assumptions. And it is equally important to disseminate the results of these evaluations to the public at large. By doing so the goals, economic and social benefits of marine reserves will be better understood to fishers and other user groups.

5.4. Direct damage Direct damage to corals has been reported from areas with intensive boat and diving activity. This includes anchor damage, boat groundings, and direct impact from divers. A large percentage of the 134,289 tourists visiting Belize in 1997 (Belize Tourist Board, 1998), went diving or snorkeling during their stay. For example, a study conducted in 1995 showed that of 305 tourists surveyed, 51% went diving and 72% participated in snorkeling (CZMP 1995). A more recent survey of 5,974 visitors showed that 31.1% went diving and 59.4% went snorkeling (Belize Tourist Board 1998). The Hol Chan Marine Reserve received 41,380 visitors during the year 1997/1998; in contrast, the number of visitors in 1991/1992 was 33,669 (Belize Tourist Board 1998). There is a clear need for these activities to be carefully managed in order to maintain a healthy reef ecosystem. Anchor damage is also a growing concern. There have been a couple of instances of severe damage from small cruise boats anchoring on the reef at Lighthouse Reef and at Glover's Reef atolls. Although the number of visitors on cruise ships had declined from a high of 13,661 in 1994, to only 2,678 in 1997 (Belize Tourist Board 1998), the industry has revived, and 1999 has so far witnessed a 28% increase in cruise-ship visitors. 5.5. Oil spills The threat of an oil spill is a potential major threat to the coral reefs of Belize. The long-term impacts of oil on reefs are well documented as the result of a major spill in Panan~ in 1986 (Jackson et al. 1989). International fuel tankers enter Belizean waters once a month, and local fuel barges transport fuel to the Cays and atolls on a weekly basis. To date, however, there have been only a few very minor spills. Risks of oil spills also occur during offshore drilling operations, and the southern section of the reef is believed to have substantial oil reserves (McField et al. 1996). Fourteen offshore wells have been drilled, the most recent one being in early 1997 at a site located between the barrier reef at Gladden Spit and the Glover's Reef atoll. No active offshore drilling, however, is presently taking place. Environmental impact assessments are required for all oil exploration projects through the provisions of the Environmental Protection Act 1992. In addition, an oilspill contingency plan is in the process of being prepared by the Department of the Environment.

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6. PROTECTION AND MANAGEMENT The protection and management of the reefs of Belize are reviewed in detail by Gibson and McField (2001). As the impacts caused by anthropogenic threats to reefs and other coastal habitats in Belize increased, the need for adopting an integrated approach to management became apparent. Early legislation in Belize targeted management of particular species, such as lobster and conch, which are important commercial fisheries species. This was followed more recently by broader legislation governing the management of habitats, such as the establishment of marine reserves and provision for the protection of mangroves. It has been recognized, however, that the integrity of protected areas may be threatened by lack of appropriate policies and legislation addressing issues that may be far removed from the boundaries of reserves, such as the impacts of landbased activities. Thus, the approach of integrated coastal zone management, which takes an even broader ecosystems approach to management, was initiated in 1990. Some of the ICZM activities undertaken which specifically relate to coral reefs include the following: (1) Expanding the network of marine protected areas; (2) Introducing land-use planning and zoning; (3) Formulating of policies, guidelines and regulations; (4) Establishing a mooring buoy system; (5) Creating a data base to provide information aimed at improving management; (6) Conducting basic monitoring and research (discussed above). 6.1. Network of Marine Protected Areas

The system of marine protected areas in Belize forms the backbone of the coastal management Program, and is one of the main strategies aimed at conserving coral reefs and their biodiversity (Bohnsack 1996). Presently there are 10 marine protected areas (MPAs), listed in Table 1 and shown in Fig. 4. All existing sites include reef habitat, with exception of the Corozal Bay Wildlife Sanctuary. Three sites are located on the offshore atolls: Glover's Reef Marine Reserve, which encompasses the entire atoll, and the Half Moon Cay and Blue Hole Natural Monuments, which are located on Lighthouse Reef. Four sites include reef tracts on the northern, central and southern provinces of the barrier reef: Bacalar Chico Marine Reserve, Cay Caulker Marine Reserve (northern province), South Water Cay Marine Reserve (central province) and Sapodilla Cays Marine Reserve (southern province). The Laughing Bird Cay National Park protects one of the faro-reef formations of the central lagoon. The Port Honduras Marine Reserve provides protection to some inshore reefs. Seven of these MPAs (Bacalar Chico Marine Reserve and National Park, Blue Hole Natural Monument, Half Moon Cay Natural Monument, South Water Cay Marine Reserve, Glover's Reef Marine Reserve, Laughing Bird Cay National Park, and Sapodilla Cays Marine Reserve) have been designated a World Heritage Site, the Belize Barrier R e e f Reserve System. This protected-area network is attempting to include representative areas of the different types of marine habitats located within the territorial waters of Belize. To this end, marine habitats were mapped from Landsat TM imagery as part of the GEF/UNDPfimded CZM Project (Matus 1997). The habitat classification scheme for this mapping

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TABLE 1 Marine-Protected Areas in Belize (adapted from Gibson et al. 1998).

Existing protected areas Hol Chan Marine Reserve Glover's Reef Marine Reserve Half Moon Cay Natural Monument Bacalar Chico National Park and Marine Reserve Laughing Bird Cay National Park South Water Cay Marine Reserve Sapodilla Cays Marine Reserve Blue Hole Natural Monument Corozal Bay Wildlife Sanctuary Cay Caulker Forest Reserve and Marine Reserve Port Honduras Marine Reserve Total

Total area (ha)

Marine area (ha)

1 116 30 784 3 925 11 303 4 286 29 789 12 742 410 71 939 4 362 40 521

1 024 30 735 3 907 6 118 4 261 29 153 12 722 410 71 939 4 299 39 848

211 177

168 867

u u u

u u u

Proposed Protected Areas Tumeffe Atoll Mexico Rocks Belize River mouth and cays u = not yet defined

exercise was developed by Mumby et al. (1998), and includes both geomorphological and benthic categories. It is expected that this marine habitat map will be analyzed in view of the existing and proposed protected area sites to determine where the gaps are and to make recommendations for additional representative areas to be added to the protected- area system. The marine-protected areas are managed either by the Fisheries Department or the Forest Department, but in some instances a joint approach to management is being taken, such as for the Bacalar Chico National Park and Marine Reserve. In some cases collaborative management with NGOs is taking place as for example, between the Forest Department and the Belize Audubon Society for the Half Moon Cay Natural Monument. This integrated approach to management, which involves more direct management by the communities involved, is also under negotiation for the management of the Laughing Bird Cay National Park and the Cay Caulker Marine Reserve. The marine-protected areas are a means for providing protection to coral reefs, particularly in relation to tourism and exploitation. Many of the MPAs have zoning schemes that provide for multiple use, such as traditional fishing and recreational activities, but with a core or "no-take" zone. Several of the reserves include within their boundaries important spawning grounds, e.g., for the Nassau grouper. More research needs to be carried out to determine the "source and sink" areas in order that marine reserves are located in the most optimum areas in terms of replenishing marine populations. However, as this is a very difficult process, the recommended action to achieve fishery and conservation goals is to establish dense networks of reserves that encompass a significant area and variety of habitats (Roberts 1998). More emphasis needs to be placed on tourism management and it is expected that this need will be addressed when the current management plans are revised or updated.

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Fig. 4, Map of existing and proposedmarine-protectedareas.

6.2. Land-use planning As many of the threats to the reef are caused by activities on land, land-use planning is a focal point of the ICZM program. Existing planning powers are being used whereby

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development plans are being prepared for many coastal areas. Two pieces of legislation allow for land-use planning in Belize: the Land Utilization Act, and the Housing and Town Planning Act (McField et al. 1996). The former provides for a type of strategic planning in which the land is zoned for the most appropriate use (rural, urban, residential, reserve, etc.) and also governs the density for subdivisions (Gibson et al. 1998). Several of the areas zoned, known as Special Development Areas, are located along the coast. In the case of subdivisions, many are also located on the coast and Cays. Under the Central Housing and Planning Authority, Ambergris Cay and Cay Caulker have been declared as special planning areas. A master plan has been developed for Ambergris Cay, and through the CZM Program a development plan is currently being prepared for Cay Caulker. Also, through the CZM Program, development guidelines have also been prepared for the Cays of the Turneffe Islands atoll and for the Cays near Belize City. These guidelines recommend specific types of development, population density, and methods for waste management, and identify particularly sensitive areas that should remain as reserve land. There are plans to zone the marine waters for particular uses under the CZM program. Apart from the zones within the MPA area system, the only existing zones are for shipping channels, no-anchoring areas, and slow-speed or no-wake areas (Gibson et al. 1998).

6.3. Policies, guidelines, and legislation The CZM Program has been active in developing policies, guidelines and legislation aimed at protecting coastal resources, particularly the reefs of Belize. Through the CZM Advisory Council, a multi-disciplinary committee, the views of the all the relevant agencies are represented. This Council is actively involved in drafting policies and guidelines to improve management of the country's coastal resources. A major issue identified was the development of the Cays or small islands, formed from either sand or mangroves, and which total over 1,000. To address the various concerns, a Cays Development Policy was prepared and will be submitted to the Cabinet for consideration. This policy document includes aspects such as land use, clearance and extraction, infrastructure, waste disposal, recreation and tourism, all of which have direct bearing on the health of the nearby coral reefs. Other policy documents prepared under the CZM Program that relate to coral reefs include those on Marine Dredging, Cruise Ships, and Small Recreational Vessels. The CZM Program has also been instrumental in contributing to the development of various guidelines, including the detailed guidelines for the development of Cays on the Turneffe Island atoll and the Cays adjacent to Belize City (see Section 6.2 above). Unfortunately, however, these guidelines and policies have not yet been formally adopted and are implemented on an a d hoc basis. Important legislation that controls development on the coast and Cays is the requirement for environmental impact assessment. Such assessments are required for large-scale developments or those that are in fragile environments, such as the Cays. As a result of the impact assessment process, mitigation measures are included which minimize any detrimental effects on coastal ecosystems. The CZM Program has also developed a CZM Act that was passed in April 1998. This Act provides for the establishment of a CZM Authority that is charged with the responsibility of coordinating all activities in the coastal zone and preparing and over-

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seeing the implementation of a comprehensive management plan for the coast. This plan should ensure the sustainable use and protection of the coastal resources of Belize. 6.4. Mooring buoy system It has been long recognized that the anchoring of boats on or near corals can cause considerable amount of damage to reefs. Anchor damage has been on the increase in Belize with the growth in marine tourism, and a national mooring buoy program was initiated to address this problem. The first "John Halas" type buoys were installed in the Hol Chan Marine Reserve in 1988. They proved to be very successful, and in 1990 the San Pedro Town Board installed a series of mooring buoys off Ambergris Cay (Azueta 1998). This was followed by installation of buoys off Cay Caulker in 1993. In collaboration with the Belize Tourist Board, the Fisheries Department installed 52 mooring buoys countrywide, starting in late 1997 (Azueta 1998). These buoys are colorcoded and mapped in a GIS data base, which includes information on buoy type, depth, GPS position, and installation date. Azueta (1998) notes that the Fisheries Department intends to conduct an educational program on the use of these buoys, holding special meetings with the dive tour guides. 6.5. Coastal resources data base The CZM Program recognized from an early stage the value of mapping data on coastal resources, their use and conservation (McField et al. 1996). Emphasis has been placed on developing a data center with geographical information system (GIS) capabilities. The CZM Institute has information available on many topics, which is used in planning, to address management issues, and to guide management decision-making. Data gathering and mapping is an ongoing process and will continue to be a central component of the CZM program. In specific relation to coral reefs, a marine habitat map for the country was developed in 1997 from Landsat TM satellite imagery.

7. CONCLUSION The health of Belize's coral reefs will depend to a large extent on the success of the integrated approach to management that is being undertaken by the Coastal Zone Management Authority and Institute, along with the implementation of the national CZM Plan. This will need to involve strengthening the management of the marine protected areas, including the implementation of on-the-ground management for those areas that are "paper parks", improving the level of reef monitoring that is directly related to management, and increasing the emphasis on surveillance and enforcement. This is recognizably an enormous challenge for Belize, to develop the capability of managing its marine resources in an effective manner that keeps pace with the country's rapid development. The success of management measures will also depend on collaboration with the adjacent countries, as the coral reef is affected by land-based activities from throughout the region. Management of the marine system should therefore also take place at the regional level. With the introduction of the Mesoamerican Barrier Reef Initiative which includes Mexico, Belize, Guatemala and Honduras, this regional approach is being addressed, and provides hope for the future of Belize's coral reefs.

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ACKNOWLEDGMENTS

We are very grateful to UNDP/GEF for financial assistance to the CZM program in Belize. REFERENCES

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Ralston, S. & J.J. Polovina. 1982. A multispecies analysis of the commercial deep sea handline fishery in Hawaii. Fish. Bull. 80: 435-448. Roberts, C.M. 1995. Rapid build-up of fish biomass in a Caribbean marine reserve. Conserv. Biol. 9:815-826. Roberts, C.M. 1997. Ecological advice for the global fisheries crisis. Trends Ecol. Evol. 12: 35-39. Roberts, C.M. 1998. Sources, sinks and the design of marine reserve networks. Fisheries 5:16-19. Russ, G.R. & A.C. Alcala. 1989. Effects of intense fishing pressure on an assemblage of coral reef fishes. Mar. Ecol. Prog. Ser. 56: 13-27. Riitzler, K. & I.G. Macintyre (Eds.) 1982. The Atlantic Barrier Reef Ecosystem at Carrie Bow Cay, Belize I: Structure and Communities. Smithson. Contr. Mar. Sci. 12:539 p. Sanders, M.J., P. Sparre & S.C. Venema. 1988. Proceedings of the workshop on the assessment of the fishery resources in the Southwest Indian Ocean. FAO NTIS RAF/79/065/WP/41/88/E: 277 p. Sedberry, G.R., J. Carter & P.A. Barrick. 1992. A comparison of fish communities between protected and unprotected areas of the Belize reef ecosystem: implications for conservation and management. Proc. Gulf Carib. Fish. Inst. 45: 95-127. Shapiro, D.Y. & R. Lubbock. 1980. Group sex ratio and sex reversal. J. Theor. Biol. 82: 411-426. Shapiro, D.Y. 1986. Reproduction in groupers: 295-327. In: J.J. Polovina & S. Ralston (eds.), Tropical Snappers and Groupers. Biology and Fisheries Management. Westview Press Inc., Boulder, Colorado. Shulman, M.J. & D.R. Robertson. 1996. Changes in the coral reef of San Bias, Caribbean PanamA: 1983 to 1990. Coral Reefs 15: 231-236. Stodddart, D.R. 1962. Three Caribbean atolls: Tumeffe Islands, Lighthouse Reef and Glovers Reef, British Honduras. Atoll Res. Bull. 87:1-151. Stoddart, D.R. 1963. Effects of Hurricane Hattie on the British Honduras reefs and cays, October 30-31, 1961. Atoll Res. Bull. 95: 1-142. Stoddart, D.R. 1969. Post hurricane changes on the British Honduras reefs: re-survey, 1965. Atoll Res. Bull. 131: 1-31. Stoddart, D.R. 1974. Post hurricane changes on the British Honduras reefs: re-survey, 1972. Proc. 2"d Int. Coral Reef Symp., Brisbane 2: 473-483. Szmant, A.M. 1997. Nutrient effects on coral reefs: a hypothesis on the importance of topographic and trophic complexity to reef nutrient dynamics. Proc. 8th Int. Coral ReefSymp., PanalT~ 2: 1527-1532. Thorpe, J.E. & D.R. Stoddart. 1962. Cambridge Expedition to British Honduras. Geogr. J. 128: 158-171. Trupin, A.W. 1990. Spectroscopic analysis of global tide gauge sea level data. Geophys. J. Int. 100: 453-551. Usher, W. & E. Pulver. 1994. Evaluation of pesticide and fertilizer usage in bananas and potential risks to the environment. NARMAP/Banana Growers Association, Winrock Intemational Institute for Agricultural Development, Belize City. 92 p. Varekamp, V.C., E. Thomas & T.E. Van de Plasche. 1992. Relative sea level rise and climate change over the last 1500 years. Terra Nova 4: 293-304.

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Wallace, R.J. 1975. A reconnaissance of the sedimentology and ecology of Glover's Reef Atoll, Belize (British Honduras). Ph.D. dissert., Princeton Univ., Princeton. 140p. Wallace, R.J. & S.D. Schafersman. 1977. Patch reef ecology and sedimentology of Glover's Reef Atoll, Belize. In: Reefs and Related Carbonates: Ecology and Sedimentology. Amer. Asso. Petrol. Geol., Studies in Geology 4: 37-53. Walling, L.J. 1998. The Proceedings of the Technical Workshop for the Implementation of Component 5: Coral Reef Monitoring for Climate Change, March 10-12, 1998, Belize City, Belize. CPACC/RPU, Barbados. 21 p. Wantland, K.F. & W.C. Pusey III. 1971. A guidebook for the field to the southern shelf of British Honduras. Gulf-Coast Asso. Geol. Soc., 21st Ann. Mtg.: 1-87. Wells, S.M. 1988. Coral Reefs of the World. Vol 1: Atlantic and Eastern Pacific. UNEP, Nairobi, IUCN, Gland. 373 p. Westphall, M.J. 1986. Anatomy and history of a tinged-reef complex, Belize, Central America. M.Sc. thesis, Univ. Miami, Coral Gables, Florida. 135 p. Wilkinson, C.R. 1993. Coral reefs of the world are facing widespread devastation: can we prevent this through sustainable management practices? Proc. 7th Int. Coral Reef Symp., Guam 1:11-21. WR/SCS. 1998. Watershed-Reef Interconnectivity Scientific Study Newsletter No. 1, May 1998. WRISCS, Raleigh International, Belize. 2 p. Yorke, M.E. 1971. Patch reef communities of southern British Honduras and illustrated catalogue of common British Honduras corals. In: K.F. Wantland & W.C. Pusey (eds.), A guidebook for the field trip to the southern shelf of British Honduras. 21st Ann. Meet. Gulf Coast Ass. Geol. Soc., Appendix 1:1-41. Young, E.R. 1994. Community descriptors for four sites along the barrier reef of Belize. Fisheries Dept., Ministry of Agriculture and Fisheries, Belize, TR-93-004, in collaboration with Caribbean Environmental Health Institute, St. Lucia. 14 p. Young, E.R., H. Mora, E. Castillo, M. Dotherow & S. Auil. 1993. An analysis of coral cover and lobster and conch population densities at Glover's Reef. Fisheries Dept., Ministry of Agriculture and Fisheries, Belize TR-93-003.20 p.

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Nicaragua's coral reefs: status, health and management strategies Joe R y a n ~'b and Y a m i l Z a p a t a r

aUniversity of Maryland, Center for Environmental Science - AEL, 301 Bradock Rd., Frostburg, Md 21532-2307, USA. bCentre for Tropical Ecosystems Research, University of Arhus, Dept. of Ecology & Genetics, Bldg. 540, DK 8000 Arhus C., Denmark. CDANIDA Programa de Transporte, Puerto Cabezas, Nicaragua. ABSTRACT: Although corals are found on both of Nicaragua's coasts, reef-building corals have only been reported to occur on the extensive Nicaragua Shelf on the Caribbean coast. This is presumably due to differences in average nutrient concentrations, water depth and temperature on the two continental shelves. Given that coral reef formations are uncommon on the Pacific continental shelf, this chapter focuses almost entirely on the country's Caribbean reef formations, which occur in three zones on the Nicaraguan shelf- the nearshore shelf, the central shelf and the shelf edge. While the nearshore reefs were once well-developed, many of the reefs have been hit hard during the past two decades by increasingly greater volumes of fresh water and suspended sediments from 13 major rivers that drain 90% of the country's entire surface water drainage. The best-studied reefs are those on the central shelf, around the Corn Islands, where live coral cover was found to range between 5 and 55%. Average live coral cover averaged 30% at the five permanent transects at the CARICOMP site on Big Corn Island since the reef-monitoring program began in 1993. No information is available for the shelf slope. While increasing suspended sediment loads appear to be the greatest human threat to Nicaragua's nearshore reefs, fishing activities have also damaged corals in the nearshore and central zones. Direct fishing impacts include chemicals (e.g., chlorine) used by lobster divers, lobster traps dropped onto the reefs and anchor damage, whereas indirect impacts include the capture of reef herbivore and juvenile species as by-catch in Jamaican fish traps and shrimp trawlers, as well as physical destruction of seagrass nursery habitats by shrimp trawlers. Despite these multiple threats to the country's coral reefs, Nicaragua still lacks a coherent strategy for managing these ecologically important habitats. While there are many reasons for this shortcoming, much of it is related to a general lack of awareness at high political levels about the important role that coral reefs play in supporting fishery resources and biodiversity. Another reason is due to inadequate legislation for protecting corals, serious institutional gaps and overlaps in managing marine resources and biodiversity, as well as the lack of human capacity to conduct monitoring, research and integrated reef management.

1. I N T R O D U C T I O N N i c a r a g u a is one o f s e v e n Latin A m e r i c a n countries h a v i n g Pacific and C a r i b b e a n territorial waters (Fig. 1). As with the other countries, the extent o f coral r e e f d e v e l o p m e n t Latin American Coral Reefs, Edited by Jorge Cort6s 9 2003 Elsevier Science B.V. All rights reserved.

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Caribbean S e a

BELIZE

./

GUATEMALA HONDURAS

~

TmilMnm

g l l gllfftm

Nicaragua

Shelf

Pacific

Shelf

Pacific Ocean

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Fig. 1: Map showingthe relative location, size and shape of Nicaragua and its two continental shelves. varies greatly between these two physiographically distinct coastal zones. Based on the limited available information, large coral reef formations have only been found on the extensive Nicaragua Shelf on the Caribbean coast. Only small patches of solitary pocilloporid and octocorals have been reported on the considerably smaller Pacific shelf, near the Costa Rican border. Although there are insufficient data for completely explaining the observed differences in coral reef growth on the two shelves, factors such as the size and morphology of the two continental shelves offer some explanation. Average water depths on the smaller Pacific continental shelf are deeper and waters are cooler as a result of seasonal upwelling and deep currents that rise to cover the shelf, thereby limiting coral reef formations. Conversely, the larger Nicaragua Shelf (25,277 km 2) is relatively shallow (average depth is 30 m). The size and depth of the shelf create conditions that enhance the warming of overlying shelf waters (Ryan 1992a), which are conducive to coral reef growth across the shelf. Available data on nutrients for Nicaragua's Pacific and Caribbean waters are sparse, but several inferences could be made regarding the differences in nutrient concentrations from the different life history strategies of the fish fauna (S/mchez 1996) on the two coasts. In general, Birkeland (1990) suggests that the response of the Pacific fish fauna to seasonally induced upwelling of nutrients has been to develop short-life cycles, with high annual species turnover rates and high population densities for most species. Alternatively, most Caribbean species tend to be long-lived species having low species turnover rates and high diversity, but they are characterized by low species population

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densities (S/mchez 1996). Such characteristics are common in nutrient-poor waters where coral reefs are found (Birkeland 1990). Given that coral reef formations appear to be uncommon on the Pacific continental shelf, the remainder of this chapter will focus on the reef building corals on the Nicaraguan Shelf located on the Caribbean coast. 2. HISTORY OF CORAL REEF RESEARCH The first global attention on Nicaragua's coral reefs began in the early 1970s, when Nietschman (1973) made qualitative observations of the reefs used by turtle fishermen from Tasbapaunie on the Caribbean coast. Several years later, Geister (1983) carried out qualitative surveys and mapping of reef formations on the northern part of Big Corn Island, while several other investigators followed with studies of physical processes on the shelf. Roberts and Suhayda (1983) examined the wave energy diffraction patterns caused by the fore-reef at Big Corn Island, while Roberts and his colleagues conducted qualitative surveys ofhermatypic corals in the Pearl Cays (Roberts and Murray 1983) and bathymetfic surveys of the middle shelf (Murray et al. 1982) at the same time. Ironically, this period leading up to us backed war produced some of the best work describing coral reefs, bathymetry and physical processes since the British Admiralty Commanders Owen and Barnett surveyed the shelf (British Admiralty charts between 1836-1843). The 1980s marked a quiet period for coral reef investigations in Nicaragua, even though this was a time when coral reef research, monitoring and advanced academic training in marine science were blossoming in other Latin American countries (Cort6s 1997). During this time, Nicaragua was engaged in a major civil war and a crippling economic embargo in Nicaragua, in which security concerns made marine research difficult, funds for sampling and equipment were lacking, and there was no institutional capacity for studying or managing the country's reefs. However, Ryan and his colleagues carried out several rapid surveys in the late 1980's on the Corn Islands (Ryan et al. 1990) and Pearl Cays (Ryan 1992b) to assess the coral damage inflicted by Hurricane Joan 1990, as well as their subsequent recovery (Ryan 1992b, 1994a, b). This generated some interest by the Government and it eventually led to the development of an integrated reef management strategy for the two islands and the establishment of the permanent CARICOMP reef site and monitoring between 1992 and 1997 at Big Corn Island. After the war ended, a US-supported five-year project was launched within the Ministry of Natural Resources and the Environment (MARENA) to develop a management strategy for the marine and coastal resources in the northern part of the shelf within an area later designated as the Cayos Miskitos Reserve. However, the project paid surprisingly little attention to the abundant coral reef habitats scattered throughout the Miskito Cays, nor to the benefits of linking the fishery and coral reef management program to help protect one of the most critical habitats for what is one of the most economically important fish and lobster populations in Central America (Ryan et al. 1993, Ryan 1995). When USAID's lavish project terminated, it had only succeeded in making only a few qualitative reef surveys (Alevizon 1992; Jameson 1996; Marshall 1996) and in establishing a small reference collection of relatively common Caribbean corals at the Smithsonian (Jameson 1996). Today, the ecological relationships and the physical conditions within the Reserve are poorly understood and it remains a "paper park".

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3. ENVIRONMENTAL CONDITIONS AND ECOLOGICAL RELATIONSHIPS It is helpful to conceptualize coral reef formations as occurring in 3 geographic zones that extend across the shelf (Fig. 2), which differ with respect to the influence of rivers draining through Nicaragua's Caribbean coastal lowlands and the composition of shelf bottom sediments. They include the following: beginning from the Mean High Water Level on the mainland, extending seaward to 15 k m - shelf bottoms are a mixture of terrigenous sediments of which silt is abundant in those areas that are influenced by rivers; here bottom sediments contain less than 40% CaCO3 (Murray et al. 1982); 9 Central S h e l f - extending from a point 15 km offshore, to the edge of the continental shelf, which is composed of hard calcareous bottoms whose flat profile is interrupted by several large reef formations; bottom sediments contain between 40% and 80% CaCO3 (Murray et al. 1982); 9 Shelf Edge and S h e l f Slope - the point where the shelf drops steeply into the Caribbean; little is known about the composition of the biodiversity of this area, but it appears to be composed of Halimeda banks with some coral formations; bottom sediments are dominated by more than 80% CaCO3 (Murray et al. 1982). 9Inner S h e l f -

Some of the major coral formations found in each geographic zone, as well as available information on the physical, chemical and ecological processes on the shelf are briefly described below.

3.1. Physico-chemical processes Morphological features such as the shelf's size, shape and depth are responsible for controlling physical events such as wave energy, rainfall patterns, water temperatures and current patterns throughout much of Nicaragua's Caribbean coast (Roberts and Murray 1983). The shelf is roughly triangular in shape, extending seaward to 250 km in the north while narrowing to approximately 20 km near the Costa Rican border (Fig. 2). Water depths drop rapidly within the first few kilometers of the coastline and thereafter, they average approximately 30 meters (Roberts and Murray 1983) until reaching the edge of the shelf, where the continental slope plunges almost vertically into the deep Caribbean. The Tradewinds, which are the dominant forces responsible for surface waves on the Shelf most of the year (Fig. 2), become most intense between December and March. Data for the Corn Islands indicate that winds blow steadily from the ENE at 7-10 m s~, with a steadiness factor of 90% (Roberts and Suhayda 1983) for most of the year. As with most of the Caribbean, the strongest occur between December and late February (exceeding 30 m s~), while the calmest months are between March and May, when winds averaging less than 1 m s"l. Currents circulating on the shelf fall into three categories - the strong Caribbean Current directed toward the coast, several local currents and the Coastal Boundary Layer (CBL) running parallel to the coast. Local currents and the CBL are largely influenced by winds, but deeper currents are part of the general circulation patterns in the Caribbean (Roberts and Murray 1983).

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Fig. 2. Map of the Nicaragua's Miskito coast and the Nicaragua Shelf showing the three different zones of coral reef formations.

The Caribbean Current originates from the deeper portions of the Caribbean Sea and flows westward toward the nearshore shelf. As it encounters the shallow, warm waters of the shelf, it also warms as it spreads across the shelf. Local currents have been measured in shallow areas above the continental shelf, and they vary seasonally in both their direction and velocity (Robinson 1999; Ryan 1999). In general, local currents on the shelf run from north to south, or southeast at approximately 1-2 knots (CIP 1980; Roberts 1997). The Coastal Boundary Layer (CBL) is one of the most conspicuous currents in the nearshore zone and today it appears to be an important factor in controlling reef growth within 25 km from the coast. Visually, it appears as a sharp boundary separating turbid nearshore waters and the blue Caribbean. The CBL is established during the rainy

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season each year (see Ryan 1992a), when thirteen major rivers discharge their suspended sediment loads onto the shelf at different locations. Roberts and Murray (1983) reported that the cumulative annual water discharge (260 x 1 0 9 m 3 y-l) of the major rivers flowing through the Caribbean coastal lowlands represented 90% of the entire freshwater drainage in Nicaragua. This includes three of the five largest rivers on the isthmus. Murray and Young (1985) reported that annual sediment loads from five of these rivers were approximately 25 x 1 0 6 metric tons. During the rainy season as these rivers carry large volumes of water and suspended sediments toward the nearshore shelf, they encounter resistance from the combined forces of the Trade winds and the Caribbean Current. These counter-forces push the out-flowing river water against the coast. This produces a turbid, brackish water body with differences in water density (e.g., salinity and turbidity) relative to seawater, which results in the establishment of a weak (0.5-1.0 m/sec) coastal boundary current running southward and parallel to the coast during much of the wet season (Crout and Murray 1978; Murray et al. 1982; Murray and Young 1985; Roberts and Murray 1983; Ryan video documentation). The direction of current movement of the CBL is variable (north-south in the wet season and south north in the dry season), as are other currents on the shelf (Ryan pers. obs.; Robinson 1991, 1999). The seasonal variability of current direction on the Nicaraguan Shelf contradicts the broad generalizations made by others (CIP 1980; Roberts 1997), who assumed that current flows on the shelf are southerly. Other anecdotal information from fishermen and observations by the authors suggests that currents also flow northward during the spring, carrying turbid waters from the Rio San Juan to the Corn Islands (Ryan per. obs.) Continuous water transparency data for the Nicaragua shelf are lacking, but horizontal secchi disk measurements taken at the Corn Islands during the CARICOMP surveys between 1993 and 1997 (Ryan unpubl, data) suggested that water transparency consistently ranged between 3 m (July and November) and 25 m (March and April). While long-term, continuous salinity data are also lacking for the shelf, continuous measurements at nearby San Andrrs Island showed reported that average concentrations there were reported to be between 34 and 36 psu (Diaz and Garz6n-Ferreira 1993). Ryan et al. (1998) reported similar salinity values at the Corn Islands between July-August and March. Data on nutrient concentrations are also lacking for the Nicaraguan Shelf, although Diaz and Garz6n Ferreira (1993) have observed that seawater in the Western Caribbean is characterized by low biological productivity (500 mg C m 2 dl). Hine et al. (1988) and Hallock et al. (1988) suggest that nutrients in the Western Caribbean are heterogeneously distributed and that nutrients are found in areas ofupwelling and in the plumes of large rivers that penetrate the Caribbean for great distances. Although there are no continuous air temperature, rainfall records or seawater temperatures for the Shelf, some limited temperature data were collected for the Corn Islands using Hobo-Temp probe measurements between 1994-1995 (Ryan et al. 1998). However, continuous readings were impossible because underwater Hobo-Temp probes were repeatedly stolen by lobster divers. For the available data, temperature ranged between 26 ~ and 29.5~ which were consistent with data reported by Triffelman et al. (1992) and longterm data collected between 1959-1981 for nearby San Andrrs Island reported by Diaz and Garz6n Ferreira (1993). The latter authors also reported that the annual mean air

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temperature for San Andr6s was 27.4~ and the relative humidity was 81% (Diaz and Garz6n-Ferreira 1993). Water temperatures during the coolest months on the Caribbean coast were from December to March, with an average of 26~ or lower, whereas average water temperatures of 28~ occur during the warmest months between May-September (Ryan et al. 1998). Average monthly rainfall is 50 nma, although rainfall varies greatly between the northern and southern part of the shelf and highest rainfall rates occur between July-November (Ryan 1992a, 1994a). 3.2. The ecological setting and environmental conditions of reefs The Nicaragua shelf contains a mosaic of corals, seagrasses and mangroves. Seagrass meadows (Thalassia testudinum) on the shelf are believed to be among the most extensive beds in the Caribbean, if not the world (Zieman per. com.). Given their widespread occurrence on the shelf, it is likely that the ecological relationships between seagrasses and coral reef complexes warrant further investigation. Reef residents such as lobster, juvenile parrotfishes and grunts are commonly observed either during the day or night within seagrasses adjacent to reefs on the central shelf (Ryan unpubl, data). Seagrasses also represent an important habitat for other reef inhabitants such as green turtles (Chelonia mydas), which may comprise the largest populations in the entire Atlantic basin (Cart et al. 1978; Mortimer 1983). Turtle fishermen frequently set their nets for green turtles around the "rocks" (corals) of the Pearl, Tara and King's Cays (Nietschman 1973; Ryan unpubl, data) and the Miskito Cays (Nietschman, per. com.). Although coral reefs, seagrasses and mangroves are believed to be closely linked through having close ecological relationships in much of the Caribbean, such a generalization is not possible for the Nicaragua shelf. These three habitats co-ocurre only in the Miskito Cays, and to a limited extent, on the middle portion of the nearshore shelf at the Pearl Cays (Ogden and Zieman 1977; Fry et al. 1982; Ogden and Galdfelter 1983). While the development of the three habitats is greatest at the Miskito Cays, only a few of the Pearl Cays contain mangroves, and seagrasses, and there is poor coral reef development (Ryan unpubl, data). On the Com islands, mangrove coverage is less than 1% of the total area of each island, but there are healthy reefs and seagrasses found on both islands. Algal flats are another ecologically important habitat associated with Nicaragua's coral reefs. Halimeda is one of the most abundant vegetative covers of shelf bottoms (Phillips et al. 1982) and on the adjacent Nicaragua Rise (Hine et al. 1988). Phillips et al. (1982) and Vadas et al. (1982) identified 77 algal species that are associated with shallow coral reefs and ridges on the northern shelf, whereas Ryan (1993) reported a total of 102 reef-associated algal species for the Miskito Cays, Corn Islands and Pearl Cays. 4. NATURAL EVENTS, HUMAN IMPACTS AND REEF CONDITIONS Until recently, the primary threat to corals on the Nicaraguan Shelf has been periodic tropical storms and seawater warming events. Hurricanes that have hit the shelf for millennia, but there have been several that have been especially strong during the past thirty-five years, including Hattie (1961), Irene (1971), Joan (1988), C6sar (1996) and Mitch (1998). Hurricane Joan hit Big Com Island directly and caused considerable damage the shallow reefs ( 10 m yachts) anchored nearby or on coral heads, tearing up the bottom. Other problems are caused by inexperienced divers or snorkelers who break Pocillopora branches by kicking, grabbing or using them to move underwater or to submerge. A preliminary study of the divers that visit Pulmo reef indicated that more than 50% of them had done less than 10 dives, and that such persons touch corals much more frequently than skilled divers. This may be a common pattem in most coral communities of Mrxico. 5.3. Sedimentation The Mexican west coast receives abundant fluvial discharges, but the most important reefs are not located near rivers. So, natural sedimentation is not a problem. Unforttmately, deforestation caused by coastal development and bad management policies has seriously increased the amount of terrigenous material deposited on mainland reefs, in particular

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during the wet season (May to November). Data are anecdotal at best, but several reefs in the Gulf of California, Nayarit, Guerrero and Oaxaca seem to have been damaged during the construction of tourist facilities (Reyes-Bonilla 1993a, c). In the only documented case of induced sedimentation, Ochoa-L6pez et al. (1998) described how the feeding and trampling of vegetation by feral sheep caused excessive siltation and coral mortality in 1994 at Socorro Island (Revillagigedo Archipelago). As this mammal has lived in the island for the last century and its population is rising (Alvarez et al. 1994), it is possible that noticeable differences between the coral communities of the south and north of Socorro (the former dominated by massive, sediment resistant corals like Porites lobata, and the latter by Pocillopora spp.; Ketchum-Mejia 1998) may result from the sheep's activities. 6. MANAGEMENT AND CONSERVATION M6xico is known as a country interested in protecting its natural resources and biological communities, and it has also been successf~al in conserving many endemic and key species. However, marine taxa have received little official and public attention, especially those of the Pacific coast. For example, of the fishes and invertebrates officially protected, less than 10% occur in the Pacific and no stony or soft coral is listed (Anonymous 1994). Among marine protected areas in western M6xico, six have coral communities: the Gulf of California islands, the Revillagigedo Archipelago, Cabo Pulmo reef, the Los Cabos region, Los Arcos, and Huatulco. They differ in their conservation category (the first two are Biosphere Reserves and the others, federal or state Parks) and consequently, in the level of human use they receive; in M6xico, a Biosphere Reserve grants complete care of the habitat and species, while Marine Parks allow some level of use, previously determined in the management plan. Unfortunately, only at Huatulco is a management plan being implemented to date, and thus anthropogenic impacts are common, although limited, elsewhere. Research related to the proposal of Cabo Pulmo as a protected area began in 1987 and proceeded slowly. Nevertheless, in 1994 the work was finished and the following year the park decree was published (Reyes-Bonilla 1997). As the management plan is still not operational, several protection methods have been established in the area by the local residents and diving operators; among the most important are the complete prohibition of fishing on the reef (except for subsistence purposes), the installation of mooting buoys to avoid boat anchoring, and the rotation of diving areas to prevent overuse and damage to the portions of the reef most used by tourists. In the Revillagigedo islands, the only regulations are fishing prohibitions, and avoidance of the use of knives by tourists, encouraged by dive guides. Even though official response has been slow, organized conservation efforts have taken place in Los Arcos and Huatulco. There, local dive shops, fishermen, residents and researchers have instituted or proposed methods to protect coral communities, even though these procedures are not officially supported. They include the installation of mooring buoys for small vessels and boats, and restriction of use of knifes or gloves by divers (Glynn 1997a). However, while government agencies dedicated to conservation matters do not take an active role in this problem, local protection efforts will be useless, because of strong economic pressures to develop M6xico's coastal areas.

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ACKNOWLEDGMENTS

This review was greatly improved by the comments, suggestions and additions of Jorge Cortrs (Universidad de Costa Rica), Peter W. Glynn (University of Miami) and Hrctor GuzmAn (STRI, Panarrm). Also, Oscar Arizpe (UABCS), James Ketchum (CICIMAR, La Paz), Edgardo Ochoa (STRI-PanaroA), Michael S. Foster (Moss Landing Marine Laboratories), Andrrs L6pez (University of Iowa), Jos6 Carriquiry (UABC, Ensenada), Martha L6pez-Forment (UC-Berkeley), Eric Jor&in, Roberto Iglesias, Victor Hugo Beltrfin, Tito Livio-Prrez (ICMyL-UNAM, Puerto Morelos), Gerardo Leyte (UMar), Amilcar Cupul, Emesto L6pez (UdG, Puerto Vallarta and Guadalajara), Gabriela Cruz (ECOSUR, Chetumal), Alma Dora Morelos (CINVESTAV-Mrrida), and Gabriela Anaya (SEMARNAT, La Paz), read and criticized parts of the manuscript. Dinorah Herrero (CICIMAR) and countless students and friends have heard and discussed the ideas here presented in seminars and talks (formal and informal), and their questions and remarks were extremely valuable. Most of the mentioned persons and others, especially Carlos Cintra (University of Arizona), Zeida Foubert (UABCS), Sergio S. Gonzfilez (CIBNOR, La Paz), IrOn Su~rez (CICIMAR), Pedro Medina (UdG, Puerto Vallarta) and Juan Carlos Solis (UABCS) collaborated in the extensive field work done. The paper is dedicated to my father (d. 2001), to Dr. John W. Wells (d. 1994), and to the new generation of Mexican coral researchers, who are duty-bound to make our "new data" completely obsolete as soon as they can. REFERENCES

Alvarez, S., A. Castellanos, P. Galina, A. Ortega Rubio & G. Amaud. 1994. Aspectos de la poblaci6n y el habitat del borrego dom~stico (Ovis aries): 301-318. In: A. Ortega Rubio & A. Castellanos-Vera (eds.), La Isla Socorro, Reserva de la Bi6sfera Archipirlago de Revillagigedo, Mrxico. Publicaci6n Especial No. 8, CIBNOR, La Paz. Anonymous. 1988. Coral Reefs of the World. Vol. 1. Atlantic and eastern Pacific. IUCN, Cambridge. 373 p. Anonymous. 1994. Norma Oficial Mexicana NOM-059-ECOL-1994, que determina las especies y subespecies de flora y fauna silvestres terrestres y acu~ticas en peligro de extinci6n, amenazadas, raras y las sujetas a protecci6n especial, y que establece especificaciones para su protecci6n. Diario Oficial de la Federaci6n. May 16, 1994.32 p. Barham, C.G., R.W. Gowdy & F.G. Wolfson. 1973. Acanthaster (Echinodermata: Asteroidea) in the Gulf of Califomia. Fish. Bull. 71: 922-942. Bautista-Romero, J., H. Reyes-Bonilla., D. Lluch-Cota & S. Lluch-Cota. 1994. Aspectos generales de la fauna marina: 247-275. In: A. Ortega-Rubio & A. Castellanos-Vera (eds.), La Isla Socorro, Reserva de la Bi6sfera Archipirlago de Revillagigedo, Mrxico. Publicaci6n Especial No. 8, CIBNOR, La Paz. Beltr~in-Ramirez, V.H. 1999. Estructura de la comunidad de los corales hermatipicos (Anthozoa: Scleractinia) de siete arrecifes del sur del Golfo de Califomia. B.Sc. thesis, Universidad Aut6noma de Baja California Sur, La Paz. 88 p. Bemal, G.R. & J.D. Carriquiry. 2001. Stable isotope paleoenvironmental record of a coral from Cabo Pulmo, entrance to the Gulf of Califomia, Mrxico. Cienc. Mar. 27: 155-174.

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Ketchum-Mejia, J.T. 1998. Comunidades coralinas del Archipi61ago de Revillagigedo, M6xico. B.Sc. thesis, Universidad Aut6noma de Baja California Sur, La Paz. 167 p. Ketchmn, J.T. & H. Reyes-Bonilla. 1997. Biogeography of the hermatipic corals of the Revillagigedo Archipi61ago, M6xico. Proc. 8th Int. Coral Reef Symp., Panamfi 1" 471-476. Ketchum, J.T. & H. Reyes-Bonilla. In press. Taxonomia y distribuci6n de los corales hermatipicos (Scleractinia) del Archipi61ago de Revillagigedo, Pacifico de M6xico. Rev. Biol. Trop. 49: Leyte-Morales, G. 1997. La colecci6n de corales de la Universidad del Mar. Cienc. y Mar 1: 3-16. L6pez-P&ez, R.A. 1998. Morfometria del G6nero Porites (Anthozoa: Poritidae) del Pacifico mexicano. M.Sc. thesis, Universidad Aut6noma de Baja California, Ensenada. 168 p. Ochoa-L6pez, E., H. Reyes-Bonilla & J. Ketchum-Mejia. 1998. Effects of sedimentation on coral communities of southern Socorro Island, Revillagigedo Archipelago, M6xico. Cienc. Mar. 24: 233-240. Palmer, R.H. 1928. Fossil and recent corals and coral reefs of western Mexico. Proc. Amer. Philos. Soc., Philadelphia 67:21-31. Reyes-BoniUa, H. 1992. New records for hermatypic corals (Anthozoa: Scleractinia) in the Gulf of California, M6xico, with an historical and biogeographical discussion. J. Nat. Hist. 26:1163-1175. Reyes-Bonilla, H. 1993a. Biogeografia y ecologia de los corales hermatipicos (Anthozoa: Scleractinia) del Pacifico de M6xico: 207-222. In: S. Salazar-Vallejo & N. E. Gonz~ilez (eds), Biodiversidad Marina y Costera de M6xico. CONABIO /CIQRO, Chetumal. Reyes-Bonilla, H. 1993b. Estructura de la comunidad, influencia de la depredaci6n y biologia poblacional de corales hermatipicos en el arrecife de Cabo Pulmo, Baja California Sur. M.Sc. thesis, Centro de Investigaci6n Cientifica y Educaci6n Superior de Ensenada, Ensenada. 169 p. Reyes-Bonilla, H. 1993c. Corales hermatipicos (Anthozoa: Scleractinia) de la regi6n de Los Cabos, Baja California Sur. Rev. Inv. Cient. UABCS 4: 1-9. Reyes-Bonilla, H. 1993d. The 1987 coral bleaching at Cabo Pulmo reef, Gulf of California, Mexico. Bull. Mar. Sci. 52: 832-837. Reyes-Bonilla, H. 1995. Asteroidea and Echinoidea (Echinodermata) of Isla San Benedicto, Revillagigedo Archipelago, M6xico. Rev. Inv. Cient. UABCS 6: 29-39. Reyes-Bonilla, H. 1997. Cabo Pulmo reef: a new marine reserve in the Gulf of California. Conserv. Biol. 11: 838. Reyes-Bonilla, H. 2001. Effects of the 1997-1998 E1 Nifio-Southem Oscillation on coral communities of the Gulf of California, M6xico. Bull. Mar. Sci. 69:251-266. Reyes-Bonilla, H. 2002. Checklist of valid names and synonyms of stony corals (Anthozoa: Scleractinia) from the eastern Pacific. J. Nat. Hist. 35: 1-13. Reyes-Bonilla, H. & L.E. Calder6n-Aguilera. 1994. Par/Lmetros poblacionales de Porites panamensis (Anthozoa: Scleractinia), en el arrecife de Cabo Pulmo, M6xico. Rev. Biol. Trop. 42: 121-128. Reyes-Bonilla, H. & L. E. Calder6n-Aguilera. 1999. Population density, distribution and consumption rates of three corallivores at Cabo Pulmo reef, Gulf of California, M6xico. P.S.Z.N. I: Mar. Ecol. 20: 347-357.

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Verrill, A.E. 1864. List of the polyps and corals sent by the Museum of Comparative Zo61ogy to other institutions in exchange, with annotations. Bull. Mus. Comp. Zool., Harvard College. 1: 29-60. Verrill, A.E. 1868. Review of the corals and polyps of the west coast of America. Trans. Connecticut Acad. Arts Sci. 1: 377-558. VerriU, A.E. 1870a. On the geographical distribution of the polyps and corals of the west coast of America. Trans. Connecticut Acad. Arts Sci. 1: 559-567. Verrill, A.E. 1870b. Descriptions of echinoderms and corals from the Gulf of California. Amer. J. Sci. 49: 93-100. Villalobos, A. 1960. Notas acerca del aspecto hidrobiol6gico de la isla. In: J. Adem, E. Cobo, L. Bl~quez, A. Villalobos, E. Miranda, T. Herrera. B. Villa & L. V~isquez (eds.), La Isla Socorro, Archipi61ago de las Revillagigedo. Monog. Inst. Geofis., UNAM 2: 154-180. Wells, J.W. 1983. Annotated list of the scleractinian corals of the Gal~pagos Islands: 212-295. In: P.W. Glynn & G.M. Wellington, Corals and Coral Reefs of the Gal~pagos Islands. Univ. California Press, Berkeley. Wilson, E.C. 1990. Mass mortality of the reef coral Pocillopora on the south coast of Baja California Sur, M6xico. Bull. So. Calif. Acad. Sci. 89:39-41. Wilson, E.C. 1991. Geographic ranges of Recent hermatypic coral genera in Baja California Sur, M6xico. Bull. So. Calif. Acad. Sci. 90: 134-136. Williams, E.H. & L. Bunkley-Williams. 1990. The world-wide coral reef bleaching cycle and related sources of coral mortality. Atoll Res. Bull. 335:1-71.

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Corals and associated marine communities from El Salvador H r c t o r R e y e s - B o n i l l a a and Jos6 E n r i q u e B a r r a z a b *Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098 USA bMinisterio de Medio Ambiente y Recursos Naturales, Direcci6n General de Patrimonio Natural, San Salvador, E1 Salvador

ABSTRACT: The segment of coast from Nicaragua to Guatemala, known as the "Pacific Central American Faunal Gap", has been scarcely studied but it is relevant from the biogeographic point of view. Apparently, this region lacks coral communities except at Los C6banos, a small rocky area in western E1 Salvador (13~ 89~ and in two other locations of that country (the Gulf of Fonseca and Maculis). We describe the general conditions of these assemblages (with special attention to Los C6banos) on basis of information from literature and underwater surveys conducted in October 2001. The Los C6banos area is extremely turbid (visibility less than 2 m), but nonetheless is inhabited by numerous marine species that aggregate on rocky substrata; among the most conspicuous ones are bivalve mollusks (e.g. Pinctada mazatlanica), sea urchins (Eucidaris thouarsii) and fishes (especially damselfishes; Stegastes spp.). We also found 9 species of stony corals (Anthozoa: Scleractinia) from 5 genus and 3 families, which added to those reported in the literature, yield a total of 15 species (10 zooxanthellate and 5 azooxanthellate) from 7 genus and 5 families, for the Pacific coast of E1 Salvador. Judging from field observations, the reef coral Pocillopora damicornis was dominant in shallow water at Los C6banos, while the dendrophylliid Cladopsammia eguchii was the most abundant in deeper areas (5 to 20 m). Human impacts on coral communities of E1 Salvador are multiple, and had occurred from many years. Among them, removal of carbonate rock and corals to produce cement, extraction of colonies to be sold as souvenirs, and damage to target populations by uncontrolled fisheries. In addition, deforestation has increased coastal sedimentation, and the runoff transported several types of pollutants to the coast and coral areas. Considering the high local species richness, and the fact that rocky and coral environments are very scarce in E1 Salvador, we recommend the Los C6banos area to be officially protected, in order to guarantee safeguard of its marine diversity.

1. I N T R O D U C T I O N C o r a l c o m m u n i t i e s a n d reefs o f the eastern tropical Pacific w e r e t a k e n as inexistent in all m o n o g r a p h s on r e e f corals p u b l i s h e d b e f o r e the 20 th Century, b u t r e s e a r c h cond u c t e d e s p e c i a l l y in the last 20 years c h a n g e d that idea ( C o r t r s 1997). Studies at P a n a nail, E c u a d o r , C o s t a Rica, M r x i c o and C o l o m b i a h a v e d i s c o v e r e d w e l l d e v e l o p e d reefs in those areas, and also d e m o n s t r a t e d that they are e x p o s e d to v e r y s e v e r e environLatin American Coral Reefs, Edited by Jorge Cortds 9 2003 Elsevier Science B.V. All rights reserved.

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mental conditions due, among other factors, to upwelling and the repeated occurrence of E1 Nifio Southern Oscillation, that caused severe coral bleaching and mortality in 1983 and 1997 (Glynn 1990; Glynn et al. 2001). Among the least known marine areas of the eastern Pacific is the coastal stretch between Guatemala and Nicaragua, labeled by Springer (1958) as the "Pacific Central American Faunal Gap". Current publications mentioned that there are practically no reefs or coral communities of consideration there (Spalding et al. 2001). Notwithstanding, the zone is in~ortant from the biogeographic point of view, since it separates the two main areas of coral occurrence in the region (Glynn and Ault 2000): the western coast of M6xico (including the Gulf of California and the Revillagigedo Islands), and Central and South America (from Costa Rica to Ecuador, and the Gal~ipagos Islands). The only place in the faunal gap where the literature refers to the presence of significant coral communities is the coast of E1 Salvador, a small country with a coastal margin of about 300 km (Cotsapas et al. 2000; Fig. 1). Information on marine communities of E1 Salvador is scarce, and was reviewed in Gierloff-Emden (1976), Orellana-Amador (1985) and Barraza (2000). These authors mentioned that the most important coral assemblages are located 11 km south-east of Acajutla, in a locality known as Los C6banos (Fig. 2), and that they are not true reefs, but only groups of isolated colonies growing on rocky substrata ("coral communities"). In E1 Salvador, the only scientific repository with marine taxa from Los C6banos is in the Museo de Historia Natural de E1 Salvador, and other material is deposited in the Escuela de Biologia, Universidad de E1 Salvador, but both of these are very small. Fortunately, the collections of the former institution were enriched recently (2001) with the incorporation of specimens collected in expeditions sponsored by the Smithsonian Tropical Research Institute. The objective of this paper is to describe the coral communities of E1 Salvador, but also aims to provide valuable information to be included in a future proposal for establishing the first marine protected area of E1 Salvador, at Los C6banos. 2. LOS COBANOS The rocky reefs of Los C6banos (Fig. 2) harbor the most well developed and diverse marine communities described to date in E1 Salvador. According to TRD (1989; cited by Foer 1992) and Barraza (in prep.), the reefs are actually small outcrops of volcanic rock (most of them not larger than 30 m2), that occupy a total of 159 km z of a large marine terrace that fringes the coast (8,000 ha in area). The patches of hard bottom occur from as the intertidal to 30 to 40 m deep, but in the intertidal and upper subtidal zone, volcanic rocks and sand with crumbled shells are the dominant elements (OrellanaAmador 1985). Marine communities are under continuous sedimentation stress at Los C6banos, which is more intense from May to October, during the rainy season. The particulate material comes from eight rivers located in the Acajutla area (GierloffEmden 1976), and is deposited at depths up to 35 rn. Salinity in the area fluctuates from 35 psu in the dry season, to 28 psu in September and October, months when rainfall is over 500 mm (Molina 1996). In October 2001, three locations in Los C6banos were inspected by SCUBA diving at depths of 5 to 25 m (La Zavaleta: 13~ 89~ Jaj/L: 13~ 89~ La Pichelera: 13~ 89~ Fig. 1). In addition, the adjacent beaches were surveyed in search of coral fragments, which were found in abun-

353

Corals and associated marine communities from El Salvador

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354

H. Reyes-Bonilla&J.E. Barraza

dance at "Del Amor" beach (13~ 89~ The specimens were taxonomically determined following Cairns (1991), Cort6s and Guzmfin (1998), Veron (2000) and Ketchum and Reyes-Bonilla (2001) criteria. Voucher specimens (fragments of live coral colonies) were collected underwater, and other samples were gathered from the beach; all material was deposited at the Ministerio de Medio Ambiente y Recursos Naturales, E1 Salvador. Conditions for underwater observation were not good at the time of our visit, as visibility was less than 2 m and strong currents were present. However, this was not an unusual situation when diving in this site. 2.1. Corals

During our survey we found 9 coral species (5 zooxanthellate and 4 azooxanthellate; three of these are tentative identifications. Table 1). In relation to reef corals, no specimens were observed when diving but nevertheless, abundant fragments of colonies of Pocillopora were found stranded at "Del Amor" beach. According to local residents and literature (Orellana-Amador 1985; Gotuzzo 1996), there is a small coral community composed of corals of this genus, growing around large rocks and boulders placed about 200 m from the beach. The colonies are small (30 cm or less in height) and do not form a true framework. The fragments gathered in the beach were in good shape, and from them we could positively identify three species: P. capitata, P. meandrina and P. damicornis. The latter was also reported by Gotuzzo (1996, Fig. 13-22) from Los C6banos. Other coral pieces were similar to branches of P. elegans, and P. effusus (sensu Veron 2000) but they were eroded enough to prevent positive taxonomic deter minations. In shallower areas of the same location, colonies of Porites lobata were reported by Lemus et aL (1994) and Molina (1996), and illustrated by Gotuzzo (1996, Fig. 13-23), but specimens were not observed during the surveys or on the beach. Molina (1996, p. 19) presented an illustration of a coral identified as Porites lobata, but that actually appears to be P. panamensis. In addition, Hodgson (1995) indicated the presence of Pavona gigantea in E1 Salvador, a report taken as valid by Reyes-Bonilla (2002). Taking in consideration the literature reports and the conducted field work, reef coral species richness at Los C6banos may be eight (including two dubious records). In deeper water, turbidity was extreme at the time of our visit; visibility was no more than 2 m. Notwithstanding, we found large populations of the dendrophyllid azooxanthellate coral Cladopsammia eguchii. The record of this species is relevant because in the eastern Pacific, it has only been collected or reported in the Galfipagos Islands, Panamfi Bay, the southern Gulf of California (Cairns 1991, 1995; Reyes-Bonilla 2002) and Costa Rica (J. Cort6s per. com.). This was the most abundant scleractinian observed at Los C6banos; at any depth, practically all stones had many small colonies (from 3 to 8 cm in larger diameter) or individual corallites growing on their undersides. This species has no symbiont algae in its tissues, and apparently thrived in the turbid, dynamic conditions of the region, which may constantly provide colonies with abundant food. Another species of the Family Dendrophylliidae observed at Los C6banos was Tubastraea coccinea, pictured by Gotuzzo (1996, Figs. 13-24 and 13-26). This species appeared in the same habitat and depth that C. eguchii, however, its abundance was lower; colonies were found in less than half of the rocks surveyed. In addition, the size of T. coccinea colonies at Los C6banos was small. Usually, they can attain over 10 cm in larger diameter in eastern Pacific localities (Wells 1983; Cairns 1991; Reyes-Bonilla et al. 1997), but in E1 Salvador, the largest colony observed was about 7 cm in diameter. It was

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TABLE 1 Systematic list of scleractinian corals reported or found at E1 Salvador. (*) Species recorded in the field in 2001. (**) Report from literature; all references are presented in the text. (?) Taxonomic determination not confirmed. (+) Zooxanthellate species. (=) Azooxanthellate species. Phylum Cnidaria Hatschek, 1888 Class Anthozoa Ehrenberg, 1834 Order Scleractinia Bourne, 1900 Family Pocilloporidae Gray, 1842 Genus Pocillopora Lamarck, 1816 (+) P. capitata Verrill, 1864 (*) (+) P. damicornis (Linnaeus, 1758) (*) (+) P. effusus Veron, 2000 (*) (?) (+) P. elegans Dana, 1846 (*) (?) (+) P. meandrina Dana, 1846 (*) Family Poritidae Gray, 1842 Genus Porites Link, 1807 (+) P. lobata Dana, 1846 (**) (+) P. panamensis Verrill, 1866 (**) Family Agariciidae Gray, 1847 Genus Pavona Lamarck, 1801 (+) P. gigantea Verrill, 1869 (**) Family Rhizangiidae D'Orbigny, 1851 Genus Astrangia Milne Edwards and Haime, 1848 (=) Astrangia sp. (*) Genus Oulangia Milne Edwards and Haime, 1848 (=) O. bradleyi Verrill, 1866 (*, **) Family Dendrophylliidae Gray, 1847 Genus Cladopsammia Lacaze-Duthiers, 1897 (=) C. eguchii (Wells, 1982) (*) Genus Tubastraea Lesson, 1829 (=) T. coccinea Lesson, 1829 (*, **) (=) T.faulkneri Wells, 1982 (**) (?)

also interesting to notice that polyps of T. coccinea were extended during the day, a behavior that is common only at night. The color of the specimens of C. eguchii and T. coccinea was vermillion to orange, and yellow to orange, respectively, which corresponds to that described in the literature. Gotuzzo (1996) referred the presence of T. faulkneri at E1 Salvador, a report that has to be taken with caution because that species has only been found at the Gakipagos Islands (Wells 1983, Cairns 1991), and was not observed at Los C6banos during field work. Similarly, Gotuzzo (1996) cited BalanophylIia badiiana (sic; it may be an error of spelling of B. bairdiana) and Scolymia australis for the country, but shows no specimens or indicated where they are located. However, as none of those corals is reported for any other location of the eastern Pacific (Reyes-Bonilla 2002) and they exclusively live in the central and western Pacific (Cairns et al. 1999), it is quite possible that the material studied by the author was misidentified. Considering the morphology of B. bairdiana (corallum strongly compressed, with elliptical calices; Cairns and Parker 1992), Gotuzzo (1996) may have confused that species with C. eguchii, as both have the same general form (Cairns 1991, 1995), although they are very different in size (greater calicular diameter of B. bairdiana is 28 mm, while in C. eguchii is less than 10 rrma). Also, pictures of small individuals of S. australis resemble coralla of Oulangia bradleyi, a species that lives in the area (see be-

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low), and that may have caused confusion, but again, the calicular diameter of the former species is much larger than of the latter (Veron 2000). Two other corals have been recorded for Los C6banos, both belonging to the Family RhJzangiidae, but we were not able to get specimens. We found a solitary corallite of Oulangia bradleyi under a rock boulder at 20 m depth. According with the observations done with artificial light, the color of the polyp was dull brown and the primary and secondary septa (larger than the rest) were conspicuous. An illustration of the same species found at E1 Salvador (but not determined taxonomically) was published by Gotuzzo (1996, Fig. 13-25). The other coral of this family that we encountered was Astrangia sp. One small live colony was examined on the underside of a large volcanic rock at 10 m depth, and another eroded colony was located on the beach. There are eight species of this genus reported for the eastern Pacific (Reyes-BoniUa 2002) and taxonomic determination of most of them requires analysis of calicular structures, impossible to do in the field or with damaged material. Notwithstanding, the record at genus level is valid. Recapitulating the information that was presented, we propose that richness of scleractinian corals of E1 Salvador is 13 species (8 zooxanthellate; 5 azooxanthellate), although some of those reports have to be confirmed. 2.2. Invertebrates As mentioned in Section 2, outcrops of volcanic rock characterized the sea bottom at Los C6banos. At the time of our visit, the upper surface of those structures was completely covered by very f'me sediment, turf algae and abundant specimens of the colonial octocoral, Carijoa multiflora. Most of the soft coral species in the area occur deeper than 2 m; for example, the octocorallians Pacifigorgia adamsii, P. agassizii, Pacifigorgia sp. and Muricea sp. are common between 4 and 8 m deep (Lemus et al. 1994; Molina 1996). Moreover, in dredges done during the cruise conducted by the Smithsonian Institution in March 2001, colonies of the black coral Antipathes galapagensis were found at 25-meter depth in a station located in front of Los C6banos. In the undersurfaces of the large boulders that characterize the bottom of the site, animal diversity was noticeably high. We observed numerous sponges, stony and soft corals (including hydrozoans like Aglaophenia sp., anemones, and octocorals such as Lophogorgia sp. cf. alba), bryozoans, tube polychaetes and arrow crabs (Stenorhynchus sp.). In interstices and sediment-free areas between rocks we noticed larger invertebrates; especially abundant were bivalves (including commercial species such as Pinctada mazatlanica, Spondylus calcifer, and Nodipecten subnodosus), small fasciolarid gastropods, and sea urchins (Eucidaris thouarsii), and we also saw several juvenile lobsters (Panulirus gracilis). Guti6rrez (1996) reported that the macroalgae Briopsis, Halimeda, Codium, Caulerpa (chlorophytes), Sargassum, Padina (phaeophytes) and calcareous algae (rhodophytes) are common at Los C6banos, although as mentioned, turf algae were dominant on rocky substrata in 2001. 2.3. Fishes Fishes were not abundant, but we noticed the presence of several species that are typically associated to rocky and coral reefs throughout the eastern Pacific. Among them are the moray eel Gymnothorax castaneus, the squirrelfishes Myripristis leiognathos and Sargocentron suborbitalis, the scorpionfish Scorpaena sp., the basses Dermatolepis dermatolepis, Epinephelus labriformis, the wrasses Halichoeres notospilus, Thalassoma

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lucasanum, the snapper Lutjanus viridis, the grunt Haemulon sexfasciatum, the chub Kyphosus analogus, the angelfishes Pomacanthus zonipectus and Holacanthus passer, the butterflyfish Chaetodon humeralis, the darnselfishes Chromis atrilobata, Stegastes acapulcoensis, S. rectifraenum and .4budefduf troschelli, the surgeonfish Prionurus punctatus, the triggerfish Pseudobalistes naufragium, the blenny Ophioblennius steindachneri, and surprisingly, the golden puffer Arothron meleagris, a well known corallivore (Guzrrfin and Robertson 1989), as well as the Moorish idol Zanclus canescens, a typical species of coral reefs in the western Pacific (Allen and Robertson 1994). Five of these fish species (M. leiognathos, D. dermatolepis, L. viridis, H. passer and Z. canescens) are new records for the area, according to the list provided by OrellanaAmador (1985). 3. OTHER AREAS OF THE COUNTRY WITH PRESENCE OF CORALS Researchers have repeatedly visited the coast of E1 Salvador since 1999, and stony corals have been observed in localities other than Los C6banos, especially in the Gulf of Fonseca and Maculis (Fig. 1). The gulf is an area of high primary productivity, with a predominantly sandy coast, and is well known as a wetland area that includes RAMSAR sites and wildlife refuges (Spalding et al. 2001). Nevertheless, there are small rocky outcrops in the coast and also a number of islands with hard substrata available for coral colonization. The scleractinian assemblages recorded in those islands are composed of azooxanthellate species, and the dominant elements are colonies of Tubastraea and Astrangia, which mostly occur in the undersides of large boulders or in small caves at depths from 2 to 30 m. Soft corals (gorgonians in particular) are much more abundant in this area than at Los C6banos, and colonies of Carijoa multiflora also appear quite frequently in underwater surveys. Data on Maculis are scarce; water turbidity is high in the area, but Gotuzzo (1996) indicated the presence of unidentified stony corals there. Gorgonians are the dominant type of anthozoan in the area, especially Pacifigorgia spp. 4. ANTHROPOGENIC IMPACTS Coral communities of E1 Salvador are small, and consequently, very delicate. Notwithstanding, tourists commonly visit them, and the local resources are under exploitation by fishermen. These activities have to be adequately regulated, but the task is difficult to execute because there are no marine protected areas in the cotmtry and in consequence, any kind of management or conservation effort is difficult to accomplish. Fortunately, the government of E1 Salvador and a number of NGO's has shown interest in protecting the marine environment, and it is expected that the situation will change in coming years. Human impacts on E1 Salvador reefs are multiple, and had occurred for many years. In the 1950's, a company used intertidal calcareous rock from Los C6banos (including scleractinian corals) to produce cement, and although the impact was never assessed, Lemus et al. (1994) assumed that it was significant and depleted the shallow areas of reef corals. The main anthropogenic activities these days are fisheries, especially concentrated in fish and oyster populations. No clear regulation on catch existed, and again, no estimation of its effect at community level is available. However, a new fisheries law was promulgated in 2002 and this updated legislation imposes more strict

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regulations on fishing activities. The principal problem here is not the legal background, but the lack of personnel to conduct vigilance and assure implementation of the rules. The fishing activities have not only impacted the target species but also damaged corals because of the breakage of colonies by anchors, and the stranding of nets (Molina 1996). Finally, there are indications that at least in some degree, the excessive sedimentation at Los C6banos and nearby coastal areas is caused by bad management of forests and other near-coastal vegetation. The runoff also transports pollutants to the ocean, as evidenced by the presence of DDT-related chemicals, copper, polychlorinated biphenols (PCB's) and polynuclear aromatic hydrocarbons (PAH's) in oysters collected at Acajutla Port and Los C6banos (RPI 1995). The pollutants eventually reach the coral area by littoral transportation and tide cycles. In addition, contamination by solid wastes (especially garbage and plastics) and extraction of corals, gastropods and gorgonians to be sold as souvenirs to tourists are two problems that have not been addressed, and consequently their impact on reefs is undetermined. Molina (1996) suggested that from 30 to 40 colonies are collected daily at Los C6banos, and commercialized. 5. CONSERVATION ISSUES AND FUTURE STUDIES A recent review of the marine fauna of the coast of Mesoamerica (from central west M6xico to Panarnfi; Reyes-Bonilla 2001) indicates that assemblages in E1 Salvador are qualitatively very similar to those from Guatemala to Nicaragua, and that they are relatively rich for a country with so small a coastline. If we take into account this information and the fact that the visited reefs are unique habitats in E1 Salvador, it is easy to understand why we patently recommend that Los C6banos have to be officially protected, in order to safeguard its marine diversity. The formal proposal is currently in preparation, and will probably be ready in 2002. The creation of a marine park in this area will be a milestone in the history of environmental conservation in E1 Salvador, and also will represent another advance in the development of a network of marine protected areas in the tropical eastern Pacific, an initiative that is being discussed as complementary to the Mesoamerican Biological Corridor. There is still much work to be done in areas with presence of corals in E1 Salvador. For exmrqale, Reyes-Bonilla (2001) indicated that most species that have been reported south and north of any given country of the tropical eastern Pacific, conceivably have populations occupying areas in between. If this is the case, the presence of reef coral species such as Gardineroseris planulata, Leptoseris papyracea or Psammocora stellata in Costa Rica and southern M6xico (Reyes-Bonilla 2002) suggests that they actually live in E1 Salvador, although their populations must be small and geographically restricted to the scarce rocky outcrops of the country. To look for these isolated demes has to be a priority for research in forthcoming years. On the other hand, it would be stimulating to search for clues to explain the remarkable resilience of the coral assemblage of Los C6banos, that has not built a true reef but nevertheless it has been long lasting (at least during the last three decades) in an environment clearly not suitable for reef corals. Finally, coral bleaching and mortality caused by positive thermal anomalies of surface water resulting from E1 Nifio in 1982-83 and 1997-98, were observed practically in the entire eastern Pacific region (Glynn et al. 2001). It would be interesting to analyze size structure or growth anomalies of massive colonies, to evidence if corals from Los C6banos were also affected by those events.

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ACKNOWLEDGMENTS

The visit of HRB to E1 Salvador and Los C6banos was financed by the Organizing Committee of the V Congreso de la Sociedad Mesoamericana para la Biologia y la Conservaci6n, and the Ministerio de Medio Ambiente y Recursos Naturales de E1 Salvador. Alex Hasbfin (El Salvador Divers) provided diving and logistic support in the study area. Peter W. Glynn (University of Miami) and Jorge Cort6s (Universidad de Costa Rica) reviewed the manuscript. Wilfredo Fuentes (MARN) collaborated in preparing the figures. REFERENCES Allen, G.R. & D.R. Robertson. 1994. Fishes of the Tropical Eastem Pacific. Univ. Hawaii Press, Honolulu. 332 p. Barraza, J.E. 2000. Comentarios sobre la diversidad de macroinvertebrados marinos de E1 Salvador. Publicaci6n Ocasional No. 2. Ministerio de Medio Ambiente y Recursos Naturales, San Salvador. 15 p. Cairns, S.D. 1991. A revision of the ahermatypic Scleractinia of the Gal~ipagos and Cocos islands. Smiths. Contrib. Zool. 504: 1-32. Cairns, S.D. 1995. The marine fauna of New Zealand: Scleractinia (Cnidaria: Anthozoa). New Zealand Ocean. Inst. Mem. 103:1-210. Cairns, S.D. & S.A. Parker. 1992. Review of the Recent Scleracfinia (stony corals) of south Australia, Victoria and Tasmania. Rec. S. Austral. Mus. Monog. Ser. 3: 1-82. Cairns, S.D., B.W. Hoeksema & J. van der Land. 1999. List of extant stony corals. Atoll Res. Bull. 459: 13-46. Cort6s, J. 1997. Biology and geology of eastern Pacific coral reefs. Coral Reefs 16 Suppl.: $39-$46. Cort6s, J. & H.M. Guzrr~n. 1998. Organismos de los arrecifes coralinos de Costa Rica: descripci6n, distribuci6n geogr~fica e historia natural de los corales zooxantelados (Anthozoa: Scleractinia) del Pacifico. Rev. Biol. Trop. 46: 55-92. Cotsapas, L., S.A. Zengel & J.E. Barraza. 2000. E1 Salvador: 106-137. In: C.R.C. Sheppard (ed.), Seas at The Millennium: An Environmental Evaluation. Pergamon, London. Foer, G. 1992. Diagn6stico de los recursos costeros de E1 Salvador: 106-137. In: G. Foer & S. Olson (eds.), Las Costas de Centroam6rica: Diagn6sticos y Agenda para la Acci6n. US-AID, Narragansett, Rhode Island. Gierloff-Emden, H.G. 1976. La costa de E1 Salvador. Ministerio de Educaci6n. Direcci6n de Publicaciones, San Salvador. 286 p. Glynn, P.W. 1990. Coral mortality and disturbances to coral reefs in the tropical eastern Pacific: 55-126. In: P.W. Glynn (ed.), Global Ecological Consequences of the 198283 E1Nifio-Southem Oscillation. Elsevier, Amsterdam. Glynn, P.W. & J.S. Ault. 2000. A biogeographic analysis and review of the far eastern Pacific coral reef region. Coral Reefs 19: 1-23. Glynn, P.W., J.L. Mat6, A.C. Baker & M.O. Calder6n. 2001. Coral bleaching and mortality in Panama and Ecuador during the 1997-1998 El Nifio-Southem Oscillation event: spatial/temporal patterns and comparisons with the 1982-1983 event. Bull. Mar. Sci. 69: 79-109.

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Gotuzzo, R. 1996. Celenterados: 51-64. In: F. Serrano (ed.), Historia Natural y Ecologia de E1 Salvador. Tomo II. Ministerio de Educaci6n, San Salvador, E1 Salvador. Guti6rrez, L.A. 1996. Algas. 13-22. In: F. Serrano (ed.), Historia Natural y Ecologia de E1 Salvador. Tomo II. Ministerio de Educaci6n, San Salvador, E1 Salvador. Guzrn~n, H.M. & D.R. Robertson. 1989. Population and feeding responses of the corallivorous pufferfish Arothron meleagris to coral mortality in the eastem Pacific. Mar. Ecol. Prog. Ser. 55: 121-131. Hodgson, G. 1995. Corales p6treos masivos (Tipo Cnidaria, Orden Scleractinia): 83-97. In: W. Fisher, F. Krupp, W. Schneider, C. Sommer, K.E. Carpenter and V.H. Niem (eds.), Guia FAO para la identificaci6n de especies para los fines de la pesca. Vol. I. Algas e invertebrados. FAO, Roma. Ketchum, J.T. & H. Reyes-Bonilla. 2001. Taxonomia y distribuci6n de los corales hermatipicos (Scleractinia) del Archipi61ago de Revillagigedo, M6xico. Rev. Biol. Trop. 49: 727-773. Lemus, L.G., J.A. Pocasangre & T.D. Zelaya. 1994. Evaluaci6n del estado actual de la distribuci6n y cobertura de los arrecifes coralinos de la zona de Los C6banos, Departamento de Sonsonate. B.Sc. thesis. Escuela de Biologia, Facultad de Ciencias Naturales y Matem~tica, Universidad de E1 Salvador, San Salvador. 40 p. Molina, O. A. 1996. Comparaci6n de la cobertura de los arrecifes coralinos antes y despu6s del derrame de petr61eo. Los C6banos, Sonsonate. 1993-1995. Intemal Report, Escuela de Biologia, Univ. E1 Salvador, San Salvador. 36 p. Orellana-Amador, J.J. 1985. Especies marinas de Los C6banos. Peces de E1 Salvador. Mandarin Offset International LTD, Hong Kong. 126 p. Research Planning, Inc. (RPI). 1995. Diagn6stico ambiental en el medio costero marino de la zona de Acajutla, San Salvador, E1 Salvador. RPI, San Salvador. 75 p. Reyes-Bonilla, H. 2001. La costa occidental de Mesoam6rica: Luna unidad biogeogrfifica marina? Res. V Cong. Soc. Mesoam. Biol. Conserv., San Salvador, E1 Salvador: 104-105. Reyes-Bonilla, H. 2002. Checklist of valid names and synonyms of stony corals (Anthozoa: Scleractinia) of the eastern Pacific Ocean. J. Nat. Hist. 39: 1-13. Reyes-Bonilla, H., T.L. P6rez Vivar & J. Ketchum Mejia. 1997. Nuevos registros del coral ahermatipico Tubastraea coccinea Lesson, 1829 (Scleractinia: Dendrophylliidae) en el Pacifico de M6xico. Rev. Inv. Cient. UABCS, Ser. Cienc. Mar 8: 31-34. Spalding, M.D., C. Ravilious & E.P. Green. 2001. World Atlas of Coral Reefs. UNEP/ WCMC and Univ. California Press, Berkeley. 424 p. Springer, V.G. 1958. Systematics and zoogeography of the clinid fishes of the subtribe Labrisomini Hubbs. Pub. Inst. Mar. Sci. Univ. Texas 5:417-492. Veron, J.E.N. 2000. Corals of the World. Volumes 1-3. Australian Institute of Marine Science, Townsville. Wells, J.W. 1983. Annotated list of the scleractinian corals of the Gal~ipagos: 213-292. In: P.W. Glynn & G.M. Wellington, Corals and Coral Reefs of the Galfipagos Islands. Univ. California Press, Berkeley.

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Corals and coral reefs of the Pacific of Costa Rica: history, research and status Jorge Cort6s a and Carlos Jim6nez a' b aCentro de Investigaci6n en Ciencias del Mar y Limnologia (CIMAR), and Escuela de Biologia, Universidad de Costa Rica, San Pedro, San Jos6 2060, Costa Rica. bZentrum for Marine Tropen6kologie, Universit~itBremen, Fahrenheitstr. 6, D-28359 Bremen, Deutschland.

ABSTRACT: Coral communities, reefs, and isolated coral colonies can be found along the Pacific coast of Costa Rica and offshore islands. In this chapter a brief history of research, and descriptions of the coral communities and reefs of the Pacific coast of Costa Rica are presented. On the north, the reefs are exposed to seasonal upwelling but they are well-developed and the growth rates of several species are higher than in non-upwelling areas. On the south, some reefs have been growing for over 5,000 years, resulting in thick accumulations. There are also reefs at Isla del Coco, 500 km from the coast. Species that are absent or rare in other eastern Pacific sites are found in Costa Rica, e.g. Porites rus and Leptoseris papyracea. The main impact on Pacific reefs has been bleaching and death of corals associated with E1 Nifio warming events. Other reefs exposed to high sediment loads are greatly degraded. Most coral reefs and coral communities of the Pacific coast of Costa Rica are located within protected areas. 1. I N T R O D U C T I O N

1.1 The Pacific coast of Costa Rica The Pacific coast o f Costa Rica is 1,160 km long. It has a high diversity of habitats: rocky shores o f a wide variety of rock types, sandy beaches of several compositions and grain sizes, mangrove forests, estuaries, a tropical fjord, islands o f various sizes, and several gulfs and bays (Fig. 1). The northern section of the coast is characterized by a dry tropical forest, with a dry season that extends from December to April, and a rainy season from M a y to November. The southern end of the coast is covered with tropical rain forest. Here it rains year-round, with a low between December and April. The central section of the coast is a transitional area from dry to humid climate (Herrera 1986). Tides are semi-diurnal, with a range of about 3 m. The Costa Rican Current runs from the southeast to the northwest, paralleling the coastline. Closer to shore eddies m o v e in the opposite direction. The northern section of the coast experiences upwelling of cool, nutrient-rich waters during the dry season, when the NE Trade Winds cross the lowlands from the Caribbean to the Pacific (Legeckis 1988; McCreary et al. 1989). The Latin American Coral Reefs, Edited by Jorge Cort6s 9 2003 Elsevier Science B.V. All rights reserved.

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Fig. 1. Map of the Pacific coast of Costa Rica with the divisions used in this chapter (see below).

high mountains of the central and especially the southern parts of the country block the Trades, preventing coastal upwelling in the area. The absence of upwelling has resulted in the continuous development of coral reefs in the south. Coral communities, reefs and isolated coral colonies can be found on the Pacific coast of Costa Rica, which we have divided into seven regions (Fig. 1): 1. Santa Elena, the northern section of the coast next to the border with Nicaragua; 2. Bahia Culebra, to the south of Santa Elena and north of Peninsula de Nicoya; 3. Peninsula de Nicoya, including mainly the seaward side of the peninsula, since the inner section is an estuarine environment with very little coral growth; 4. Pacifico Central, extending from the east end of Golfo de Nicoya to the largest mangrove area of Costa Rica, the SierpeT6rraba complex; 5. Peninsula de Osa, including the outer section of the peninsula and part of the entrance to Golfo Dulce; 6. Golfo Dulce, including the reefs within the gulf; and 7. Offshore islands, including Isla del Carlo (15 km from the coast) and Isla del Coco (more than 500 km from the coast). In this chapter, we describe the coral communities and reefs of the Pacific coast of Costa Rica. Information concerning natural and anthropogenic impacts is also provided, as well as comments on protection and management.

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1.2. History of research Marine organisms from Costa Rican waters were first described in the early 19th century (Sowerby 1832). By mid-century, several works were published on mollusks (M6rch 1859, 1860) and octocorals (Verrill 1869/70). Those collections were made by ship captains or traveling naturalists. In the late 19th and early to mid 20th century, several expeditions sampled along the Pacific coast of Costa Rica, visiting some of the coral reef areas, incluiding also Isla del Coco: the U.S. Fisheries Commission Expedition lead by Alexander Agassiz in 1891; the Hopkins-Stanford Expedition of 1898-1899; the California Academy of Sciences expeditions of 1921 and 1928; the Arcturus Oceanographic Expedition of 1925 headed by William Beebe; the 1932 Templeton-Crocker Expedition; the expeditions to the eastern Pacific of the New York Zoological Society in 1937 and 1938; F. D. Roosevelt's Presidential Cruise of 1938; the Allan Hancock Foundation's Expeditions to the eastern Pacific between 1931 and 1954; the 1968 Stanford Oceanographic expedition; and finally the Searcher expedition of 1972. As a result of the Allan Hancock expeditions, J.W. Durham published a series of papers on the scleractinian corals of the region, including specimens from Costa Rica, mostly from Isla del Coco (Durham and Bamard 1952; Durham 1962, 1966). In the following years, individual scientists studied the coral reefs in Costa Rica. Dawson (1960) described several species of algae from the reefs at Isla del Carlo. Bakus (1975) published a description of a reef from Isla del Coco. In the mid 1970s, Peter W. Glynn studied the coral communities and reefs of the Pacific coast of Costa Rica and published the first synoptic map of coral communities, and live and dead coral reefs along Costa Rican Pacific shores (Glynn et al. 1983). By the late 1970s, studies of the coral reefs of Costa Rica by Costa Rican scientists were initiated. The first comprehensive study of the Pacific coral reefs was published by Cort6s and Murillo (1985). Other papers followed in which reefs of different areas were described in more detail: Isla del Carlo (Guzrn~n 1986; Guzn~n and Cort6s 1989a, 2001), Golfo Dulce (Cort6s 1990a, b), Isla del Coco (Guz-rr~n and Cort6s 1992), the southern section of the coast (Cort6s and Jim6nez 1996), and the northern section of the coast (Cort6s 1996/1997a). Areas being studied in detail at the present time include: Bahia Culebra (Jim6nez 1997, 1998, 2001; Jim6nez et al. 2001) and the Archipi61ago de las Islas Murci61ago (Jim6nez and Cort6s in prep.). Several papers concerning the ecology and/or taxonomy of organisms associated with reef formations have been published: corallivores (Guzm~ 1988a, b), meiofauna (Guzmfin et al. 1987), zooplankton (Guzm~ and Obando 1988; GuzroAn et al. 1988), and bioeroders (Scott and Risk 1988; Cort6s 1991; Fonseca and Cort6s 1998). Two papers were published on sediments adjacent to reefs (Cort6s et aL 1996; Hebbeln et al. 1996), and two papers on the Holocene growth history of reefs in Golfo Dulce, Isla del Carlo, and Isla del Coco (Macintyre et al. 1992; Cort6s et al. 1994). Four papers have been published on the stable isotopic signature of E1 Nifio-Southem Oscillation (ENSO) events in Porites lobata from Isla del Carlo (Carriquiry et al. 1988, 1994; Carriquiry 1994; Wellington and Dunbar 1995). The ~SiSOsignal at Isla del Carlo records strong to very strong ENSOs (Wellington and Dunbar 1995). Also, stable isotope analyses were used to compare the conditions in Golfo Dulce about 1,000 years ago with conditions today (Cort6s 1990a). The gulf today has a much higher freshwater discharge which has altered reef growth compared to previous conditions, when the isotopic signal was similar to today's corals from Isla del Carlo (Cort6s 1990a).

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Fig. 2. Protected areas of Costa Rica includingtheir marine territory. Six theses have been written on Costa Rican Pacific coral reefs: reef structure at Isla del Carlo (GuzroAn 1986), Holocene growth history of a reef in Golfo Dulce (Cort6s 1990a), coral communities and reefs of Bahia Culebra (Jim6nez 1998), reef fishes of Bahia Culebra (Dominici 1999, Alperman 2001) and bioerosion at Golfo Dulce and Isla del Carlo (Fonseca 1999). Work in progress include: environmental and coral reef monitoring, biodiversity of invertebrates, environmental education, paleoclimate reconstructions, and coral population dynamics. 2. DESCRIPTION OF THE REEF AREAS 2.1. Santa Elena Communities and coral reefs to the north and south of Peninsula de Santa Elena (mostly within the Area de Conservaci6n Guanacaste, Figs. 1, 2, 3) have been described by Cort6s (1996/1997a). Ten species of reef-building corals (Cort6s 1996/1997a, b; Cort6s and Guzmfin 1998; Jim6nez and Cort6s, in prep.) and three species of ahermatypic corals (Cort6s in prep.) were reported for the northern section of the coast. Corals norreally found in low densities in other parts of the eastern Pacific formed small patch reefs there. A reef constructed by Pavona gigantea was found northeast of Santa Elena, and one 50 m Ereef formed exclusively by Pocillopora eydouxi was located off the central northern section of the peninsula. Porites panamensis, which is rare in the southem part

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Fig. 3. Coralreefs and reef communitiesof the Santa Elena section. of Costa Rica, was found in abundance in the Santa Elena region, while its congener, P. lobata, had the opposite distribution; it was rare in the north and predominant in the south section of the coast of Costa Rica. Gardineroseris planulata and Pavona gigantea are minor components of reefs in the south, but major reef builders in the north. Coral communities formed by various species assemblages were found at the Archipi61ago de las Islas Murci61ago, on the south side of Peninsula de Santa Elena (Fig. 3). One reef extending over 2,000 m 2, and from 2 to 12 m in depth, is constructed mainly by Pocillopora damicornis and Pocillopora elegans. Other species present are Pocillopora eydouxi, P. meandrina, Pavona clavus, P. varians and a new species, Pocillopora inflata (Glynn 1999). This reef grows on the north side of Isla San Pedrito, one of the Islas Murci61ago (Fig. 3), and is thus protected from the full impact of the seasonal upwelling in the region, and from strong wave action. Live coral coverage ranged from 47.5 to 95.2%.

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Fig. 4. Coral reefs and reef communities Bahia Culebra. Pocillopora damicornis predominate in the shallow section, while Psammocora stellata predominate in the deeper sections. Patch reefs from a few meters to several hundred square meters of other species have been found in several protected bays of the Islas Murci61ago. These include reefs of Pavona clavus and of Gardineroseris planulata. Some of those G. planulata colonies are the largest found to date in the country for that species, 1.2 m high by 1.5 m in diameter. Rocky substrates are covered by dense stands of octocorals and barnacles down to 15 - 20 m; below 20 m, black corals over 1 rn high predominate. Other species present, in order of abundance, included Pavona gigantea, Tubastrea coccinea, and Carijoa sp.; Porites lobata is rarely observed. Leptoseris scabra, a rare species in the eastern Pacific except at Clipperton Atoll (Glynn et al. 1996a), was found in the deep environments (Jim6nez y Cort6s in prep.). 2.2. Bahia Culebra The section of the coast including Bahia Culebra extends from the southem end of the previous section, i.e. from the border of the Area de Conservaci6n Guanacaste to Punta Gorda, where the next section begins (Figs. 1, 4). The coral reefs and communities of Bahia Culebra were briefly described by Glynn et al. (1983), Cort6s and Murillo

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(1985), and in more detail by Jimrnez (1997, 1998, 2001). The reef fish community structure of Bahia Culebra was described by Dominici (1999), with emphasis on four important aquarium (commercial) species. 2.2.1. Corals. Sixteen species of reef-building scleractinian corals (Cortrs and Guzmfin 1998), including rare species such as Pocillopora meandrina, Leptoseris papyracea and Fungia (Cycloseris) curvata, and four species of ahermatypic corals (Cortrs in prep.) are present in this region. Pocillopora meandrina was not a common species in the eastern Pacific, but it was found in abundance in Bahia Culebra in the early 1980's. However, it is now a rare species due to overexploitation for commercial purposes (Cortrs and Murillo 1985). Recently, Jimrnez (1998) examined the growth rates of seven species of corals. For three species that have been studied elsewhere in the eastern Pacific, coral growth at Bahia Culebra is the highest (Table 1). These high rates in what appears to be a marginal area of reef development (due to the upweUing) may be the result of heterotrophic feeding by the corals and less dependance on the zooxanthellae (work in progress). TABLE 1 Growth rates (mm/year) of coral species from Bahia Culebra, data from Jimrnez (1998 and unpublished data), compared to means and extreme values reported from other regions in the eastern Pacific, data from Guzm~inand Cortrs (1989b, 1992). Species

Bahia Culebra Mean Range

Eastern Pacific Mean Extreme values

Pavona clavus Pocillopora damicornis Pocillopora elegans Pocillopora eydouxi Pocillopora inflata Pocillopora meandrina Psammocora stellata

20.6 47.8 44.5 30.8 31.5 38.5 13.9

13.2 5.4- 17.4 38.6 17.3 -43.7 34.8 19.3 - 38.6 No data available No data available No data available No data available

8.5 - 28.0 28.0 - 75.6 29.0 - 67.2 21.0- 39.0 20.0 - 44.0 18.0- 56.0 6.0 - 21.6

2.2.2. Coral communities and reefs. Bahia Culebra is characterized by rare and unique coral communities and reefs. One of the coral reefs consisted almost exclusively of large colonies of Pavona clavus; with one colony 10 m in diameter, growing laterally by shedding blocks to the sides (Jimrnez 1998; Jimrnez and Cortrs in prep.). Another build-up is constructed by Leptoseris papyracea, but was severely reduced by the 1997-98 E1 Ni_~o warming event (Jimrnez et al. 2001). The mushroom coral, Fungia (Cycloseris)curvata, has only been found alive on this reef. Dead coral reefs in the area, due to the intensification ofupwelling during the Little Ice Age, were studied and described by Glynn et al. (1983). Bahia Culebra has nine live coral reefs, ranging in size from 0.8 to 2.3 hectares. Pocilloporid corals are the main reef builders in shallow waters (13 m). Coral thermal tolerance and exposure to cool upwelling waters during the dry season may play a role in structuring the species dominance observed in the bay (Jimrnez 2001). Three rhodolith beds with abundant P. damicornis colonies occur in the inner littoral of the bay.

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Live coral cover is high (average 44.0 + 3.3%, n = 52) among reefs of the bay, followed by coral communities on sand (21.5 + 2.3%, n = 156) and basalt (19.5 _+ 1.1%, n = 48). On the reefs, branching (mainly Pocillopora damicornis) and massive (mainly Pavona clavus) corals accounted for 42% and 30% of live cover, respectively. Other important contributors were Leptoseris papyracea (12%) and Psammocora spp. (16%). For coral communities on sand substrates, the major contributors were branching species (mostly Pocillopora elegans, 68%) followed by massive corals (Pavona clavus, 29%). Branching species (mainly P. elegans) accounted for more than 80% of coral cover, while massive corals (Pavona gigantea) contributed only 19% of the surface of coral communities on basalt substrate. The octocoral Carijoa sp. was the most abundant community member (more than 40%) inhabiting deep waters (>20 m depth). From Bahia Culebra south to Punta Gorda, many submerged or exposed banks were found; e.g., Bajo Tiburones (Fig. 5). These are popular diving sites, and the cnidarians present in decreasing order of abundance were: Pavona clavus, Pavona gigantea, Tubastrea coccinea, Carijoa sp., Pavona varians, Pocillopora elegans, Porites lobata, and Porites panamensis. These coral communities are abundant down to 20 m; in deeper waters, there are more octocorals and some black corals. The small coves in this area had patch reefs from a few square meters to several hectares (particularly in Matapalo, Fig. 5), growing on dead reefs. Abundant corals included, in decreasing order, Pocillopora

elegans, Pocillopora damicornis, Pocillopora meandrina, Pavona clavus, Pavona gigantea, Porites panamensis, and Pavona varians. In addition, a recent study found seventy five species of reef fishes in the Bahia Culebra area. The most abundant species included Chromis atrilobata, Thalassoma lucasanum, Abudefduf troschelii and Halichoeres dispilus. Shallow and deep-water fish communities differed in species composition (Dominici 1999).

2.3. Peninsula de Nieoya From south of Bahia Culebra (Punta Gorda) to the entrance of the largest estuary in Costa Rica, is the Peninsula de Nicoya (Figs. 1, 5). This large section of the coast contains coral communities and a few small coral reefs (Glynn et al. 1983, Cort6s and Murillo 1985). Seven species ofhermatypic corals (Cort6s and Gttzrr~n 1998) and seven species of ahermatypic corals (Cort6s in prep.) have been collected from this area. Most of this section of the coast is exposed to strong wave action, which may preclude the development of coral reefs. One area, Samara (Fig. 5), stands apart with small Pocillopora or Porites lobata fringing and patch reefs present. Also, the only specimens of Porites (Synarea) rus that have been collected in the eastern Pacific come from this area (Cort6s and Murillo 1985). Dendrophyllia californica has been collected only from S~imara on the mainland coast of Costa Rica (Cort6s 1996/1997b). Octocorals and isolated coral communities are abundant on rocky outcrops, and on islands and islets off Peninsula de Nicoya, especially at the Reserva Natural Absoluta Cabo Blanco (Figs. 2, 5). Patch reefs made up of Pocillopora spp. grow over large dead reefs in protected bays; e.g., Playa Muertos in Bahia Ballena (Fig. 5). There are many coral communities between Bahia Ballena and C t ~ (Jim6nez and Cort6s in prep.), where the predominant species were Pavona gigantea, Porites lobata, Pavona clavus, Pocillopora elegans, Pavona varians, and Tubastrea coccinea. These communities extend from the rocky cliffs, where P. gigantea is particularly abundant, down to 12 - 18 m deep, where isolated corals can be observed on the sandy bottom.

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Fig. 5. Coralcommunitiesof Peninsula de Nicoya. The inner section of Golfo de Nicoya extends north of a line across the mouth of the gulf from Islas Negritos to Herradura (Figs. 1, 5, 6). There, no reef develops because of the presence of freshwater and sediments. On the outer section of the gulf several small dead coral communities have been located. One of these consists mainly of Pavona gigantea and Pocillopora elegans, and is located on the western littoral zone of the gulf (Fig. 5), where it was found covered with sediments. Three dead reef patches of Pocillopora spp. and Psammocora spp. were observed buried under sediments at Punta Coral (Fig. 5). Dead patches of Pocillopora damicornis have been observed at Punta Leona (H.M. Guzmfin, per. com.). Only one ahermatypic coral, Astrangia sp., was found inside the gulf (Cort6s in prep.). 2.4. Paeifieo Central

The central section of the Pacific coast of Costa Rica, from Herradura to the SierpeT6rraba mangrove complex (Figs. 1, 6), supports few reefs (Glynn et al. 1983; Cort6s and Murillo 1985). Nine species of reef-building corals (Cort6s and Guzrnfin 1998) and two species of ahermatypic corals (Cort6s in prep.) have been reported from this section of the coast. Isolated corals and small coral communities can be found on rocky outcrops along the coast, including Parque Nacional Manuel Antonio and Parque Marino Ballena (Figs. 2, 6). Patch reefs of Porites lobata have been found in protected coves and near sandy beaches. Also, dead Pocillopora frameworks overgrown with live colonies of P. elegans, P. damicornis, and Psammocora spp. have been observed. Coral communities present on the islets of the Park, particularly in their deeper areas (below 15 m), consist mainly ofPorites lobata, some Pavona gigantea, and a few pocilloporid colonies.

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Fig. 6. Coral communities and reefs of the Pacifico Central. Porites lobata patch reefs have been observed near Punta Dominical and Punta Uvita, which are part of the Parque Marino Ballena (Figs. 2, 6). Rich coral communities have been found on the islands and islets of Parque Marino Ballena. The exposed flanks of these structures were covered with octocorals, and there were submerged banks with coral communities, consisting mainly of Porites lobata and Pavona gigantea, and with some Pavona varians. Average coral cover was: 19.7 + 2.0% (range 0.34 - 51.8%) with the remainder of the epibionts consisting mainly of algae, with some octocorals and sponges. The predominant species at all depths, down to 20 m, was P. lobata. P. gigantea was more common than P. clavus, and branching corals were scarce and found only in small communities (Jim~nez and Cortes 2001); these corals were severely affected by the 1992 E1 Nifio event. Over 50% of all observed colonies were bleached, and covered by sediments and algae. More than 80% of all branching corals observed were bleached (Jim6nez and Cort6s 2001). The large fresh water lens between Parque Marino Ballena and Peninsula de Osa, a result of the Sierpe-T&raba mangrove-river complex (Fig. 1, 6), precludes or interferes with the development of coral reefs.

2.5. Peninsula de Osa The second largest peninsula on the Pacific coast of Costa Rica is Peninsula de Osa (Figs. 1, 7). Ten species of zooxanthellate corals (Cort6s and Jim6nez 1996; Cort6s and Guzm,Sn 1998) and one species of ahermatypic coral (Cort6s in prep.) have been found so

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Fig. 7. Coralreefs and communitiesof Peninsula de Osa. far in communities at Peninsula de Osa. Cort6s and Jim6nez (1996) described the coral communities and reefs at Peninsula de Osa; a 250 m z Pocillopora patch reef at Punta Llorona (Fig. 7) consisted of close to 100% live cover of Pocillopora damicornis. Exposed rocky substrates were covered by octocorals, and isolated corals were found on all rocky outcrops. 2.6. Golfo Dulce

2.6.1. Extant reefs. Golfo Dulce, located in the southem part of Costa Rica, is about 50 km long by 10 to 15 km wide, and is oriented NW to SE (Figs. 1, 8). It is an enclosed embayment of tectonic origin with a 60 rn deep sill and depths of 200 rn in its deeper parts (Hebbeln et al. 1996). The deep waters are anoxic most of the time, which is why it is considered a tropical fjord (Richards et al. 1971; Thamdrup et al. 1996; Hebbeln and Cort6s 2001). Several types of coral reefs and coral communities have been found in the gulf. They can be divided into two groups based on species diversity and reef structure: those of the inner section of the gulf, and those of the outer section (Cort6s 1990a, b). Ten species of reef-building corals (Cort6s and Guzmfin 1998) and four species of ahermatypic corals (Cort6s in prep.) have been collected in the gulf. The inner gulf reefs consisted of live and dead Porites lobata on the reef front, and dead Pocillopora damicornis and Psammocora stellata on the reef fiat. Coral diversity was low and topographic relief was high, with steep reef-fronts and sides. Live coral cover ranged from less than 1 to 8%. The outer gulf reefs were characterized by a relatively high live coral coverage (ranging from 29 to 46%), high coral diversity, and low topographic relief. The shallow areas of the reef at S~indalo (Fig. 8) were composed of

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Fig. 8. Coral reefs and coral communitiesof Golfo Dulce.

Porites lobata, while several species were found in the deeper section, the most abundant being Pocillopora damicornis. Also in this deeper section, the largest colonies of Pavona frondifera that have been found in the eastem Pacific were observed (Cort6s 1990b, Cort6s and Guzmfin 1998). Another outer reef, Punta E1Bajo (Fig. 8), had 100% live coverage ofPsammocora obtusangula (Cort6s 1990b; Cort6s and Guzmfin 1998). The reefs at Golfo Dulce are being destroyed by several species of extemal and intemal bioeroders (Fonseca 1999). The main internal bioeroders (Cort6s 1991) included two species of Lithophaga and Gastrochaena rugulosa. Other intemal bioeroders (Fonseca and Cort6s 1998) are the sipunculan Aspidosiphon (,4.) elegans, with densities as high as 300 individuals per 1,000 cm 3, and the upogebid crustacean Pomatogebia rugosa. Taking into account accretion and bioerosion, the reefs in Golfo Dulce have a net production of-2.05 to -0.30 kg m "2 year l, i.e. they are being destroyed faster than they are accreting (Fonseca 1999). 2.6.2. Holocene growth history. The coral reef at Punta Islotes (Fig. 8) started growing over on Cretaceous basalt about 5,500 years ago. The Holocene growth history of this reef can be divided into four stages (Cort6s 1991; Cort6s et al. 1994). First, the initial reef: was formed when Pocillopora damicornis was recruited to elevated basaltic areas, forming small patch reefs. The fragments from these reefs covered the surrounding muds, and over them massive corals later grew. Next, the reef entered its establishment

Corals and coral reefs of the Pacific of Costa Rica

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stage; a period extending from 4,000 to 1,500 years Before Present (yr BP). It was characterized by continual accumulation of Pocillopora, culminating in a fringing reef which masked the antecedent topography. During this stage, Porites lobata started growing on the reef front and talus slope. Between 1,500 and 500 yr BP, the reef passed through a flourishing stage, where it grew vigorously, resulting in accumulation rates of 5 to 8.3 m 1,000 yr 1. The last 500 years have seen a slow degradation of the reef at Punta Islotes as it entered the fourth stage, final reef degradation. First, there was an increase in freshwater (Cort6s 1990a), and then during the last 50 years there was a significant increase in terrigenous sediment loads, which have almost completely killed the reef (Cort6s et aL 1994). 2.7. Offshore islands 2.7.1. lsla del Carlo Description o f the reefs. Isla del Carlo is located 15 km offshore of Peninsula de Osa

(Fig. 1). The coral reefs of the island were described during the 1980's (Guzrnfin 1986). The sediments arotmd the island are of terrigenous origin, with minor contributions of carbonates from the island's coral reefs (Cort6s et al. 1996). Isla del Carlo has five coral reef fiats, ranging in size from 0.8 to 4.2 hectares (Fig. 9). These fringing reef fiats are built mainly by dead pocilloporid corals, covered by crustose coralline algae, with

Fig. 9. Coralreefs of Isla del Carlo.

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J. Cortes & C Jim~nez

isolated live colonies of pocilloporids and poritids, and microatolls of Porites lobata. The reef slope and base are dominated by the massive coral Porites lobata, which is the most abundant species found at the island. The shallow sections of the reef were structured mainly by physical factors: wave action, temperature and salinity fluctuatiom, and low tidal exposure. In contrast, the deeper sections is controlled by biological interactions: bioerosion, damselfish algal lawns, and corallivores (Guzrrfin 1988a; Gtmnfin and Cort6s 1989a). The corals of Isla del Carlo were impacted by the 1982-83 E1 Nifio disturbance, with losses of up to 50% of the live coral coverage (Guzrrfin et al. 1987). Again, during 1992 and especially during the 1997-1998 E1 Nifio, there was extensive bleaching of corals at the island, but mortality was low, reaching only about 5% (Guznfin and Cort6s 2001). Reef growth at Isla del Carlo is recent, with radiocarbon dates ranging from 180 to 450 yrBP (Macintyre et al. 1992). With a growth rate for Porites lobata of 11.7 mm yr~ (Guzmfin and Cort6s 1989b) the largest colonies are less than 300 to 400 years old, corroborating the recent age of the reefs at Isla del Carlo. Macintyre et al. (1992) proposed that on oceanic islands of the eastern Pacific, reefs have difficulties becoming established and developing became of widely fluctuating oceanic water temperatures. Isolated corals are found all around the island. The south side is exposed to heavy wave action, and extensive octocoral fields occur there on submerged rock pinnacles or banks (Guzmfin and Cort6s 1989a, work in progress). One of these pinnacles, located west of the island, Bajo E1 Diablo, has strong currents, and about 10% live coral cover: pocilloporids were the most abundant, followed by Tubastrea, and octocorals covered around 12% (unpublished data). Another bank located between the island and the continent, called Paraiso, has mainly pocilloporids and some Pavona gigantea. Extensive rhodolith beds are present on the south side of the island. Corals. Fifteen species of reef-building corals (Cort6s and Gtmmfin 1998) and three ahermatypic coral species (Cort6s in prep.) have been identified from Isla del Carlo. Guzmfin and Cort6s (1989b) determined the growth rate of eight of the reef-builder corals. Growth rates of the predominant species, Porites lobata, and pocilloporids, were greater during the dry season. It seems that temperature was not a controlling factor, instead light (i.e., turbidity, cloud cover) and other physical factors probably control the seasonal growth of corals at Isla del Carlo (Guzm,Sn and Cort6s 1989b). Studies on the reproductive ecology of six species of reef-building corals (Gardineroseris planulata, Pavona gigantea, Pavona varians, Pocillopora damicornis, Pocillopora elegans, Porites lobata and Porites panamensis) from Isla del Carlo (Table 2) showed that all species exhibit year-round reproduction; twenty to 76% of all colonies had gonads present. In these species, gonadal activity increased around the full and/or new moon, and the maximum number of annual spawning cycles were estimated to range from one to seven. All species are gonochoric with more females than males, except for Pocillopora elegans and Porites panamensis, which have male-biased sex ratios. All species also have hermaphroditic colonies, except P. panamensis. The hermaphroditic form is dominant in P. gigantea and in the pocilloporids (Table 2). Oocytes of all species studied had zooxanthellae (Glynn et al. 1991, 1994, 1996b, 2000). Colonies of P. lobata were collected from Costa Rica, Pananfi, and the Gal/lpagos Islands, but only those from Isla del Carlo were hermaphroditic (Glynn et al. 1994). Fecundity estimates of annual egg production of Pavona varians were significantly higher at Isla del Carlo than at Panamai or Gal/lpagos (Glynn et al. 2000).

375

Corals and coral reej~ of the Pacific of Costa Rica

TABLE2 Reproductive ecologyof seven speciesof corals fromIsladel Carlo. Sourceof information:Pocillopora damicornis and P. elegans fromGlynnet al. (1991);Porites lobata and P. panamensis fromGlynn et al. (1994); Pavona gigantea and Gardineroserisplanulata from Glynn et al. (1996b); Pavona varians from Glynn et al. (2000). Herm= hermaphroditic, gono = gonochoric, m = males, f = females. Species G. planulata P. gigantea P. varians P. damicornis P. elegans P. lobata P. panamensis

No. colonies 81 95 88 78 117 104 5

% with male female herm gonads 19.8 36.8 76.1 32.0 59.5 48.0 60.0

6 3 21 2 7 11 2

9 10 41 3 3 25 1

1 22 5 20 59 7 0

sex ratio m:f

gono:herm

1:1.40 1:1.30 1:1.77 1:1.50 1:0.43 1:1.78 1:0.50

1:0.07 1:1.69 1:0.08 1:4.00 1:5.90 1:0.14

Another study at Isla del Carlo focused on the ultrastmcture of Pocillopora damicornis and P. elegans spermatozoa and found that they have bullet-shaped nuclei and elongated mitochondria. These characteristics are distinctive of the Suborder Astrocoeniina, while Pavona gigantea had a conical-shaped sperm head, typical of gonochoric species (Steiner and Cort6s 1996). Even though there was gonadal development in all species studied at all eastern Pacific localities (Glynn et al. 1991, 1994, 1996b), only at Isla del Carlo has significant recruitment been observed (GuzmAn and Cort6s in press). Another important form of reproduction is by fragmentation (GuzroAn 1988b, 1991; Guzrrfin and Cort6s 1989a). The massive coral Porites lobata had high densities of the boring bivalves Lithophaga spp., which weaken the skeletal structure (Scott and Risk 1988). Two triggerfish species, Sufflamen verres and Pseudobalistes naufragium, remove fragments of coral in their search for bivalves. The fragments of P. lobata often survive and sometimes can form new colonies (GuzmAn 1988a, per. obs.). In a study on bioerosion, Fonseca (1999) found 23 species of macro-bioeroders at Isla del Carlo. The main bioeroders are bivalves, Lithophaga spp. and the sipunculan, Phascolosoma perlucens. The reefs at Carlo have a net carbonate production of 2.76 kg m "2 year "1 (Fonseca 1999). 2.7.2. lsla del Coco. Isla del Coco World Heritage Site (1997) is located at 5~ and 87~ (Fig. 1), approximately 500 km southwest of the Costa Rican mainland. Seventeen species of zooxanthellate corals (Cort6s and Guzrnfin 1998), and 13 ahermatypes (Cairns 1991; Cort6s in prep.) have been reported from Isla del Coco. Isla del Coco has the highest number of zooxanthellate corals of any Pacific site in Costa Rica, followed by Bahia Culebra with 16 and Isla del Carlo with 15 (Cort6s and Guzrnfin 1998). Isla del Coco also has the highest number of ahermatypic corals, but more than half of these corals were collected in deep water, below 100 m in depth (Cairns 1991; Cort6s in prep.). Fringing reefs ranging in size from less than one hectare to more than 50 hectares have formed around Isla del Coco (Fig. 10). Most of the reefs were constructed of Porites lobata, but there were also extensive zones of agariciids: Pavona spp. and Gardineroseris

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Fig. 10. Coral reefs and coral communitiesof Isla del Coco. planulata. Most of the coral died during the 1982-1983 E1Nifio (Guzm~ and Cort6s 1992). In 1987, live coral cover was between 2.6 and 3.5% (GuzmAn and Cort6s 1992), but by 1994 live coral cover had reached 30% in some reefs (Cort6s and Jim6nez unpublished

data).

Densities of the corallivorous seastar Acanthaster plancL the pufferfish Arothron meleagris, and the sea urchin Diadema mexicanum were relatively high. For example, densities of D. mexicanum ranged from 3 to 45 ind m 2, with an average of 25.5 + 9.5 ind m "z, n=25). The feeding and erosional activities of D. mexicanum were concentrated on colonies that had survived the 1982-83 E1 Nifio and were responsible for most of the erosion of the reefs. From field measurements, Guzrrfin and Cort6s (1992) predicted that recovery of the original reef-framework thickness would require on the order of centuries. Unfortunately, the 1997-1998 E1 Nifio event bleached large amounts of coral in these same populations, probably reversing the recovery trend observed in 1994. Isla del Coco is important in the eastern Pacific because it is one of the first shallow platforms in the region encountered by the easterly flowing North Equatorial CounterCurrent, potentially transporting larvae from the Central Pacific (Glynn et al. 1996a). The island acts as a stepping stone for organisms that can colonize tropical eastern Pacific continental shores.

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of Costa Rica, was found in abundance in the Santa Elena region, while its congener, P. lobata, had the opposite distribution; it was rare in the north and predominant in the south section of the coast of Costa Rica. Gardineroseris planulata and Pavona gigantea are minor components of reefs in the south, but major reef builders in the north. Coral communities formed by various species assemblages were found at the Archipi61ago de las Islas Murci6lago, on the south side of Peninsula de Santa Elena (Fig. 3). One reef extending over 2,000 m 2, and from 2 to 12 m in depth, is constructed mainly by Pocillopora damicornis and Pocillopora elegans. Other species present are Pocillopora eydouxi, P. meandrina, Pavona clavus, P. varians and a new species, Pocillopora inflata (Glynn 1999). This reef grows on the north side of Isla San Pedrito, one of the Islas Murci61ago (Fig. 3), and is thus protected from the full impact of the seasonal upwelling in the region, and from strong wave action. Live coral coverage ranged from 47.5 to 95.2%.

378

J. Cortds & C. Jimdnez

3.3. Low tidal exposure Mid-day low tidal exposures affecting eastern Pacific reefs during La Nifia years can cause extensive mortality of reef-fiat organisms (Eakin and Glynn 1996). Mortality due to low tidal exposures has been observed at Isla del Carlo (Gtmm,Sn 1986), Samara (O. Breedy per. com.) and at Peninsula de Osa (per. obs.). 3.4. Storms Gtmmfin (1986) showed coral blocks that were probably deposited on the reef flat at Isla del Carlo by storms. Jimtnez (1998) described the impact of a very strong storm, in June 1996, on reefs at Bahia Culebra. The few large patches of seagrass (Ruppia maritima) on the Pacific coast were uprooted from the inner part of Bahia Culebra during this storm. One of the largest known Costa Rican populations of the bivalve Pinna rugosa living in the seagrass community, was killed due to the loss of the seagrass. At Islas Pelonas (Fig. 4), waves mainly from the west broke up patches of Pocillopora, and the destruction reached a depth of 7 m. The damage to corals was caused directly by the waves and by rocks moved by the surge. The most affected species, in decreasing order, were Pocillopora elegans, P. eydouxL and P. damicornis. Mean fragment length was 16.9 + 0.69 cm (range 1 to 47 crn; n = 234). The fragments were piled in crevices or between colonies and rocks, and in channels between rocky platforms. Some fragments were bleached (> 3%), but very few were dead at the time of the survey (26.VI.1997). Over 93% of the fragments were larger than 4 crn, the minimum size considered to have 80% survivorship (Guzrnfin 1991). A high survivorship was noted five months later, with fusion and growth reorientation in many of the colonies. With the breakage of large branching corals, bottom topographic relief (index sensu Bythell and Bythell, 1992) was significantly reduced (t-student, p 1.5 m in height) are present. These colonies probably died during the 1982-83 E1Nifio (Glynn et al. 1988). Colonies of Gardineroseris planulata up to 50 cm in diameter are commonly seen. 3.2.3. Iguana Island. The Iguana Island coral reef (site 12, Fig. 1A), located on the southwest side of the island, has a maximum reef thickness of 6.1 m (Glynn and Macintyre 1977) and an extension of 16 ha (GuzmAn et al. 1991). Both measurements are the largest reported for a reef in the Gulf of Panarn,5. This coral reef probably has the highest coral cover and healthiest corals in the entirely coast of Panarrui. Eleven zooxanthellate coral species are found around the island (Guzrnfin et al. 1991; Mat6 2001). Pocillopora damicornis and P. elegans are the main reef-building species with Porites lobata, Pavona gigantea and Gardineroserisplanulata being the most common massive species. Total live coral cover has been estimated at 36.7%, of which pocilloporid corals were responsible for 94.6%, Porites lobata 2.4%, and Pavona clavus 1.7% (Guzmfin et al. 1991). The large Porites lobata and Pavona clavus colonies attain sizes > 4 m in diameter and three meters in height. The oldest of four Porites colonies dated by ~4C was 410-a:70 years old (Guzrnfin et al. 1991). Despite its geographic location, the coral fauna of Iguana more closely resembles that of the Gulf of Chiriqui than the Gulf of Panamfi, due to the presence of Pocillopora eydouxi and Pavona chiriquiensis. The east side of the island lacks any reef formation and is dominated by sand-rubble plains and large basaltic boulders. There are extensive coral communities along rocky extensions near these boulders, where corals are in excellent condition. Large colonies of Pavona clavus and Porites lobata are extremely abundant here. 4. CORAL REPRODUCTIVE ECOLOGY In 1984, a major scientific effort was initiated in Costa Rica, PanamA, and the Gal~pagos Islands to study the reproductive ecology of eastern Pacific corals. Five publications involving eight species in four genera have resulted from this work (Glynn et al. 1991, 1994, 1996b, 2000; Smith 1991). These studies have indicated that the reproductive activity in the eastern Pacific is related to thermal regimes. High incidence of gravid corals is observed at sites with stable, warm water conditions or during wamfing periods in areas that experienced significant seasonal variation (Glynn et al. 1991, 1994, 1996b, 2000).

Corals and coral reefs of the Pacific coast of Panamti

403

4.1. Pocilloporidae Even though Pocillopora damicornis and P. elegans have not been observed to spawn, histological data indicates they are broadcast spawners (Glynn et al. 1991). Both in the Gulf of Panamfi and the Gulf of Chiriqui, few gonads are present in both species during the dry season (mid-December to mid-April). Gonad maturity increases during the wet season particularly around the new and full moons regardless of sex. Pocillopora inflata is the only pocilloporid observed to spawn in PanaroA (Glynn 1999). Spawning occurred at 0730- 0930 on 23rd March 1998 at Saboga Island. In contrast to what histological examination ofP. damicornis and P. elegans may indicate, P. inflata spawned at the peak of the upwelling season. 4.2. Poritidae Two reproductive modes are evident in Panamanian Porites. Porites lobata is a gonochoristic and presumably broadcast spawner (Glynn et al. 1994). Porites panamensis is a gonochoristic brooder (Smith 1991; Glynn et al. 1994). As it has been observed in the genus Porites (Kojis and Quinn 1981), zooxanthellae are present in mature oocytes of both species as well as in all planulae stages of P. panamensis. Sex ratios of P. lobata are 1:1 (Glyrm et al. 1994). In the GulfofChiriqui, Porites lobata gametogenesis is especially high in the dry season but, also increases during the wet season suggesting two reproductive peaks in the year. Lunar patterns are better defmed than seasonal patterns with gametogenesis being more frequent at or near full moon. In the Gulf ofPanarrfi, P. lobata gametogenesis occurs only after the dry season upwelling. In both the Gulf of Panarrfi and the Gulf of Chiriqui Porites panamensis is sexually active throughout the year but, in the former locality there is a decline during the strongest upwelling (Smith 1991; Glynn et al. 1994). 4.3. Agariciidae Two gonochoric species, Pavona gigantea and Gardineroseris planulata increase their reproductive activity following the cold dry season and continue through the warm postupwelling season (Wellington and Glynn 1983; Glynn et al. 1996b). Minimum reproductive size in these species is >200 cm2 (Glynn et al. 1996b). Even though, no spawning has been observed in these species, the sudden emptying of gonads following new and full moons provides strong circumstantial evidence that both species undergo at least two annual spawning cycles. Two other species, Pavona varians and Pavona sp. a (now P. chiriquiensis) have their reproductive peak during the dry season in the Gulf of Chiriqui and have been observed to spawn then. At Uva Island, spawning occurred between January and May; P. varians spawned just before sunrise and Pavona chiriquiensis spawned just after sunset (Glynn et al. 2000). 4.4. Other species The azooxanthellate coral Tubastrea coccinea has been observed to planulate monthly from February to April (Richmond 1985; Richmond and Hunter 1990) and by the author around the new moon of May. However, the amount of planulac released appeared to indicate that most of the brooding occurred in previous months. Glynn's laboratory is analyzing samples of T. coccinea, Psammocora stellata, P. superficialis, Pavona clavus, and Millepora intricata. Preliminary results indicate that all species, with the exception of T. coccinea and M. intricata are spawners following lunarpattems similar to those of the species previously described. T. coccinea is a brooder and M. intricate releases medusa.

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J. L. Matd

5. NATURAL DISTURBANCES I have identified six natural disturbances that play an important role in shaping coral reefs in the Panamanian Pacific. Some of the disturbance events may have catastrophic impacts on the coral communities (e.g. severe E1 Nifio events) or may just cause routine chronic mortalities in reef corals (e.g. upwelling, subaerial exposures). 5.1. El Nifio-Southern Oscillation (ENSO) The warm waters of E1 Nifio are responsible for extensive bleaching and mortality in eastern Pacific corals (Glynn 1984a). Two major E1Nifio events have severely disturbed the Panamanian Pacific reefs in the last two decades, the 1982-83 and the 1997-98 events. During both events, the hydrocorals were among the first zooxanthellate species to bleach and subsequently experienced the highest mortalities of all affected reef organisms (Glynn and de Weerdt 1991, Glynn et al. 2001). These mortalities resulted in the local disappearance ofMillepora platyphylla and Millepora boschmai following the 1982-83 and 1997-98 E1Nifio events respectively (Glynn 1990; de Weerdt and Glynn 1991; Glynn et al. 2001). Thus, E1Nifio events may be in~ortant in reducing the coral diversity in the eastern Pacific.

5.1.1. The 1982-83 El Nifio. The first report of coral mortality during the 1982-83 event in PanaroA came from Glynn (1983a), "we are presently suffering very heavy mortality on the Pacific side of PanaroA - to a degree I have never seen before: it is astounding". Bleaching was first observed in the Gulf of Chiriqui on 18 March 1983, and by the end of April bleaching had reached 83.1% (Glynn 1984a). Coral mortality associated with this disturbance reduced the total living cover at Uva Island to 1.0% (18.6% before the disturbance) and at the Secas Islands to 5.1% (16.5% before the disturbance) (Glynn 1984a). The four most affected species in the Gulf of Chiriqui were Millepora intn'cata, M. boschmai, M. platyphylla and Porites panamensis. Other species such as Pavona gigantea and Psammocora stellata showed only slight bleaching or no bleaching at all (Glynn 1983b, 1984a). Bleaching in the Gulf of Panarrfi began three months after the Gulf of Chiriqui (Glynn 1984a). By mid-September, bleaching at the Pearl Islands reached 22.7-80%. The delay in responses between both Gulfs was attributed to the 1983 seasonal upwelling that kept sea surface temperatures (SSTs) low until it ended in late May - early June (Glynn 1990, PodestA and Glynn 1997). Bleached and partially bleached specimens exhibited varying degrees of tissue atrophy and necrosis (Glynn et al. 1985a). Podestfi and Glynn (1997) provided evidence that the SST threshold in Pananfi is 30~ and that only strong E1 Nifio-Southern Oscillation events have a SST signature in Panarrfi. After the 1983 seasonal upwelling ended in late May - early June, SSTs of 30~ were reached in the GulfofPanamfi and bleaching was first reported (Glynn 1990). There is a strong geographical relationship between coral mortality and the intensity of SST warming in Panama (Glynn et al. 1988; Podest~ and Glynn 1997). Total coral mortality was lower (75%) in the warm stable waters of the Gulf of Chiriqui than in the seasonal cool waters of the Gulf ofPanamfi (85%) (Glynn et al. 1988). Pocilloporid mortality was 75% in the Gulf of Chiriqui and 92% in the Gulf of PanamA. Densities of the sea urchin Diadema mexicanum at Uva Island increased from 3 ind rn"2 before the 1982-83 E1 Nifio to 50-80 ind. mz after the disturbance (Glynn 1988; Eakin 1992). Although, sea urchin densities have now decreased to 1 m in diameter) as well as pocilloporid corals in the path of the grounding were either completely smashed into pieces or crushed with no live fragments evident. At the coral reef at Urabfi Island (Gulf of Panamfi) there is a large ship grounding that occurred in the first half of 1900's. This ship did not directly impacted the coral reef and now serves as settlement place for the azooxanthellate coral Tubastrea coccinea as well as many hydroids and sponges. Other ship groundings affecting the reef framework in the Gulf of Panama are seen at Iguana Island. Also, at this site, the path of anchor damage is noted as crushed Pocillopora fragments paths several meters in length. Shrimp boats have also been observed to anchor in the vicinity of the reef. 6.3. Herbicides The Chiriqui Province in the western sector of Panarnfi is an area subject to intense agricultural activity and in consequence an intensive use of herbicides and pesticides. High

410

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levels of pesticides and insecticides have been found in corals, however, they have not been responsible for any coral mortality (Glynn et al. 1984). The herbicides 2,4-D and 2,4,5-T as well as phenoxy acids were found in the coral tissues of seven scleractinians and one hydrocoral species collected from the Uva Island coral reef(Glynn et al. 1984). Pocillopora damicornis had the highest concentrations ofphenoxy acid in its tissues (20,050 ng g'~ dry wt of 2,4-D and 19,380 ng g~ dry wt of 2,4,5-T).

6.4. Overfishing The extraction of coral reef fishes has been reported as affecting detrimentally the coral reef at Iguana Island (Guzrnfin et al. 1991). While no other published study makes reference to the removal of organisms from Panamanian reefs, their disappearance or drastic reduction in numbers is evident in our study sites. For example, at Uva Island, we were able to observe large numbers of the conch Strombus galeatus Swainson. Currently, few and small individuals are present, and, many shells are found on the beaches of the island with their apical ends broken off. This offer good evidence that the mortality of these gastropods is caused by local fishermen and is not due to natural causes. Another example is the shark fisheries which were a common practice in PanaroA. We use to observe several white tip reef sharks (10 or more resting on the bottom of larger coral colonies) in our study site at Uva Island, however, in the last five years we have not observed a single shark in the area. It is a common practice for fishermen to clean their capture on the shores of several islands (e.g., Uva, Cavada and Iguana Islands) where the fresh carcasses of the animals can be seen. A third example, during our visit to Restinge Island in July 1998, the lack of fishes and invertebrate species normally used in artisanal fisheries was evident. This suggests that there may be an overexploitation of the resources in the area. No lobsters and conch were observed in the area even though the local fishermen made the assertion that they were common there. A similar situation has been observed in most other reef areas visited during our surveys. While already treated above, additional damage to the reef is caused by the fishermen when they drop their anchors and deploy their nets on the reef, that most of the time get entangled on the coral colonies and have to be left there, resulting to the death of the coral. 7. M A N A G E M E N T AND P R O T E C T I O N Chapter 7 of the Ecological Regime of the Political Constitution of the Republic of Panarrfi established on Article 116 that the State will regulate, supervise and enforce the necessary actions to warrant the protection, renovation and permanence of natural resources in the country. In this regard, Panarrfi has ratified most International and Regional Protocols that intend to regulate the dmnping of toxic waste into the ocean, as well as the Conservation and Management of Marine and Coastal Protected Areas of the Southeast Pacific. Recently, concrete steps taken to define a national policy to manage the coastal zone and its resources have resulted in the creation of the Maritime Authority of Panan~ (AMP, Autoridad Maritima de Panarrfi) and the National Authority of the Environment (ANAM, Autoridad Nacional del Ambiente). AMP is responsible for the management, conservation and exploitation of the marine coastal resources as well as the coordination and the execution of the National Marine Strategy. ANAM is in charge of establishing the policy about natural resources and environment on the Republic of Panarrfi as well as the management and protection of Wildlife Protected Areas in Panarrfi.

Corals and coral reefs of the Pacific coast of Panam6

411

Fig. 8. Protected areas in the Republic of Panam~i that include coral reefs or extensive coral communities within their boundaries: the National Parks (Gulf of Chiriqui): Cerro Hoya, Coiba and Marino Golfo de Chiriqui; and the Wildlife Refuges (Gulf of Panama,): Iguana Island, and Taboga Island. TABLE 3 Wildlife protected areas containing coral reefs or coral communities in the Republic of Panam~i. cc: coral communities, no true coral reef present; u: unknown; *: estimated.

Managment Status 9 National Park Cerro Hoya

Coiba Marino Golfo de Chiriqui Wildlife Refuge lsla Iguana Taboga

Surface (ha)

Date of creation

Reef area (ha)

32,557

Oct. 2, 1984

270,125

Dec. 17, 1991

cc 136

14,740

Aug. 2, 1994

u

58

Jun. 15, 1981

16

258

Oct. 2, 1984

> 4*

Specific regulations to warrant the protection of coral reef species include the Resolution No. JD-037-93 approved by Director's Board of INRENARE on 29 September 1993. This resolution forbid the extraction and exportation, for commercial reasons, of live or death corals in the Panamanian Territory (INKENARE 1993). In addition, Pananfi is signatory of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES 1996). ANAM is the institution responsible for granting the permits to collect, research, and export the species listed in CITES. There are five Protected Areas in the Panamanian Pacific that include coral reefs or extensive coral communities within their boundaries (Fig. 8, Table 3): three National Parks, Cerro Hoya, Coiba and Marino Golfo de Chiriqui; and two Wildlife Refuges: Iguana Island and Taboga. 7.1. The case of the Coiba National Park Coiba Island harbors a 136 ha coral reef which is considered the largest continental coral reef in the eastern Pacific Ocean (Glynn and Mat6 1997). The establishment of a penal

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colony on the island in 1919 and the presence of a custodial police force have combined to preserve the area for more than 80 years. Thus, the reef and the island have remained relatively unaltered. Coiba, 50,340 ha in area, is the largest island in the Panamanian Pacific. On 17 December 1991, the Government of Panama established Coiba National Park, encompassing a 270,125 ha area, of which 53,528 ha are insular territory and the remaining 216,543 ha marine (Fig. 8). The park includes not only the best-developed and diverse coral reefs in the continental Pacific coast of America but also coral species that are endemic and several endangered species (Glynn et al. 2001). The penal colony is scheduled to close by the end of September 2001, and the remaining prisoners will transfer to mainland facilities. The closure of the penal colony and removal of the police force make the park immediately vulnerable to illegal loggers, poachers, and over-fishing. These activities threaten to start a sequence of events leading to major disturbance, including the degradation of the coral reef communities. So far the major impact on coral communities in the area is from E1Nifio sea-warming episodes (Glynn et al. 2001). Coral reefs have been recovering slowly from this natural disturbance, but additional human-induced stress may hamper the recovery potential of this community, as has occurred in other Pacific reefs (Maragos and Payri 1997; Chou 1997; White et al. 1997). ACKNOWLEDGMENTS I would like to thank Jorge Cort6s for inviting me to write this chapter. I would like to give special thanks to Andrew Baker, Jorge Cort6s, Luis D'Croz, Peter Glynn and H6ctor Gtmm,Sn, Jos6 H. Leal and Nancy Knowlton for providing comments to the manuscript. To Villay Aswani, Zeida Batista, Magnolia Calder6n, Marcos Diaz, Mark Eakin, H6ctor Guznfin and Xenia Guerra for providing and helping with the photos and digitized maps. To Indra Candanedo, Dinis Ramos, and Leticia Polo of the Autoridad Nacional del Ambiente (ANAM) for providing information about Protected Areas in Panarrfi. REFERENCES

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Glynn, P.W. 1973. Acanthaster: Effect on coral growth in PanarnL Science 180: 504-506. Glynn, P.W. 1974a. Rolling stones among the Scleractinia: mobile coralliths in the Gulf of Panarr~. Proc. 2nd Int. Coral Reef Symp., Brisbane 2" 183-198. Glynn, P.W. 1974b. The impact of Acanthaster on corals and coral reefs in the eastern Pacific. Environm. Conserv. 1: 295-304. Glynn, P.W. 1976. Some physical and biological determinants of coral community structure in the eastern Pacific. Ecol. Monogr. 46:431-456. Glynn, P.W. 1977a. Coral growth in upwelling and nonupwelling areas off the Pacific Coast of Panama. J. Mar. Res. 35: 567-585. Glynn, P.W. 1977b. Interactions between Acanthaster and Hymenocera in the field and laboratory. Proc. 3rd Int. Coral Reef Symp., Miami 1:209-215. Glynn, P.W. 1981. Acanthasterpopulation regulation by a shrimp and a worm. Proc. 4thInt. Coral ReefSymp., Manila 2: 607-612. Glynn, P.W. 1982. Coral communities and their modifications relative to past and prospective Central American seaways. Adv. Mar. Biol. 19: 91-132. Glynn, P.W. 1983a. Astounding coral death alert. Reef Encounter 1: 14. Glynn, P.W. 1983b. Extensive bleaching and death of reef corals on the Pacific coast of Panama. Environm. Conserv. 10: 149-154. Glynn, P.W. 1983c. Increased survivorship in corals harboring crustacean symbionts. Mar. Biol. Lett. 4:105-111. Glynn, P.W. 1983d. Crustacean symbionts and the defense of corals: coevolution on the reef?.: 111-178. In: M.H. Nitecki (ed.), Coevolution. The University of Chicago Press, Chicago. Glynn, P.W. 1984a. Widespread coral mortality and 1982-83 E1 Nifio warming event. Environm. Conserv. 11: 133-146. Glynn, P.W. 1984b. An Amphinomid worm predator of the crown-of-thorns sea star and general predation on asteroids in Eastern and Western Pacific coral reefs. Bull. Mar. Sci. 35: 54-71. Glynn, P.W. 1985a. E1 Nino-associated disturbance to coral reefs and post disturbance mortality by Acanthaster planci. Mar. Ecol. Prog. Ser. 26: 295-300. Glynn, P.W. 1985b. CoraUivore population sizes and feeding effects following E1 Nifio (1982-1983) associated coral mortality in Panama. Proc. 5th Int. Coral Reef Congr., Tahiti 4:183-188. Glyma, P.W. 1987. Some ecological consequences of coral-crustacean guard mutualisms in the Indian and Pacific Oceans. Symbiosis 4: 301-324. Glynn, P.W. 1988. E1 Nifio warming, coral mortality and reef framework destruction by echinoid bioerosion in the eastern Pacific. Galaxea 7:129-160. Glynn, P.W. 1990. Coral mortality and disturbances to coral reef in the tropical eastern Pacific: 55-126. In: P.W. Glynn (ed.), Global Ecological Consequences of the 19821983 E1 Nifio-Southem Oscillation. Elsevier, Amsterdam. Glynn, P.W. 1996. Coral reef bleaching: facts, hypotheses and implications. Global Change Biol. 2: 495-509. Glynn, P.W. 1997a. Eastern Pacific reef coral biogeography and faunal influx: Durham's dilemma revisited. Proc. 8th Int. Coral Reef Symp., Panam~ 1: 371-378. Glynn, P.W. 1997b. Bioerosion and coral-reef growth: A dynamic balance: 68-95. In: C. Birkeland (ed.), Life and Death of Coral Reefs. Chapman & Hall, New York.

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Glynn, P.W. 1999. Pocillopora inflata, a new species of scleractinian coral (Cnidaria, Anthozoa) from the tropical eastern Pacific. Pac. Sci. 53: 168-180. Glynn, P.W. & J. Ault. 2000. A biogeographic analysis and review of the far eastern Pacific coral reef region. Coral Reefs 19: 1-23. Glynn, P.W. & W.H. de Weerdt. 1991. Elimination of two reef-building hydrocorals following the 1982-83 E1Nifio warming event. Science 253: 69-71. Glynn, P.W. & J.S. Feingold. 1992. Hydrocoral species not extinct. Science 257:1845. Glynn, P.W. & I.G. Macintyre. 1977. Growth rate and age of coral reefs on the Pacific coast of Panama. Proc. 3rd Int. Coral Reef Symp., Miami 2:251-259. Glynn, P.W. & J.L. Mat& 1997. Field guide to the Pacific Coral Reefs ofPanamL Proc. 8th Int. Coral ReefSymp., Panarnfi 1: 145-166. Glynn, P.W. & R.H. Stewart. 1973. Distribution of coral reefs in the Pearl Islands (Gulf of Panama) in relation to thermal conditions. Limnol. Oceanog. 18: 367-379. Glynn, P.W. & G.M. Wellington. 1983. Corals and Coral Reefs of the Gal~pagos Islands. University of California Press, Berkeley. 330 p. Glynn, P.W., J.L. Mat6 & T. Stemann. 2001. Pavona chiriquiensis, a new species of zooxanthellate scleractinian coral (Cnidaria: Anthozoa: Agariciidae) from the eastern tropical Pacific. Bull. Biol. Soc. Wash. 10:210-225. Glynn, P.W., R.H. Stewart & J.E. McCosker. 1972. Pacific coral reefs of Panama: structure, distribution and predators. Geol. Rundschau 61: 483-519. Glynn, P.W., L.S. Howard, E. Corcoran & A.D. Freay. 1984. The occurrence and toxicity of herbicide in reef building corals. Mar. Pollut. Bull. 15: 370-374. Glynn, P.W., J. Cort6s, H.M. Guzrrfin & R.H. Richmond. 1988. E1 Nifio (1982-83) associated coral mortality and relationship to sea surface temperature deviations in the tropical eastem Pacific. Proc. 6th Int. Coral Reefs Syrup., Australia 3: 237-243. Glynn, P.W., N.J. Gassman, C.M. Eakin, J. Cort6s, D.B. Smith & H.M. Guzrnfin. 1991. Reef coral reproduction in the eastern Pacific: Costa Rica, Panama, and Galfipagos Islands (Ecuador). I. Pocilloporidae. Mar. Biol. 109: 355-368. Glynn, P.W., S.B. Colley, C.M. Eakin, D.B. Smith, J. Cort6s, N.J. Gassman, H.M. Guzm~, J.B. Del Rosario & J.S. Feingold. 1994. Reef coral reproduction in the eastern Pacific: Costa Rica, PanamA, and Galfipagos Islands (Ecuador). II. Poritidae. Mar. Biol. 118" 191-208. Glynn, P.W., J.E.N. Veron & G.M. Wellington. 1996a. Clipperton Atoll (eastern Pacific): oceanography, geomorphology, reef-building coral ecology and biogeography. Coral Reefs 15:71-99. Glynn, P.W., S.B. Colley, N.J. Gassman, K. Black, J. Cort6s & J.L. Mat6. 1996b. Reef coral reproduction in the eastern Pacific: Costa Rica, Panama, and Galfipagos Islands (Ecuador). III. Agariciidae (Pavona gigantea and Gardineroseris planulata). Mar. Biol. 125: 579-601. Glynn, P. W., S. B. Colley, J. H. Ting, T. J. L. Mat6 & H. M. Guzn~n 2000. Reef coral reproduction in the eastern Pacific: Costa Rica, Panamfi, and Gal~tpagos Islands (Ecuador). IV. Agariciidae, recruitment and recovery ofPavona varians and Pavona sp.a. Mar. Biol. 136:785-805. Glynn, P.W., J.L. Mat6, A. Baker & M.O. Calder6n. 2001. Coral bleaching and mortality in Panarnfi and Ecuador during the 1997-98 E1Nifio-Southem Oscillation event: spatial/ temporal patterns and comparisons with the 1982-83 event. Bull. Mar. Sci.69(1): 79-109.

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Gonzfilez, E.E.C. & E.M.G. Polo. 1982. Efectos de la sedimentaci6n en el crecimiento de algunas especies de corales de Panarr~. Thesis, Univ. Panarn~. 74 p. Guzrr~n, H.M. & I. Hoist. 1994. Inventario biol6gico y estado actual de los arrecifes coralinos a ambos lados del Canal de Panarr~. Rev. Biol. Trop. 42:493-514. GuzmAn, H.M. & D.R. Robertson. 1989. Population and feeding responses of the corallivorous pufferfish Arothron meleagris to coral mortality in the eastern Pacific. Mar. Ecol. Prog. Ser. 55:121-131. GuzmAn, H.M., J. Cort6s, P.W. Glynn & R.H. Richmond. 1990. Coral mortality associated with dinoflagellate blooms in the eastern Pacific. Mar. Ecol. Prog. Ser. 60: 299-303. GuzroAn, H.M., D.R. Robertson & M.L. Diaz. 1991. Distribuci6n y abundancia de corales en el arrecife del Refugio de Isla Iguana, Pacifico de Panarr~. Rev. Biol. Trop. 39: 225-231. Hoist, I. & H.M. GttzmAn. 1993. Lista de corales hermatipicos (Anthozoa: Scleractinia; Hydrozoa: Milleporina) a ambos lados del Istmo de Panarn~. Rev. Biol. Trop. 41: 871-875. INRENARE. 1993. Resoluci6n No. J.D. 073-93. (de128 de septiembre de 1993). Jackson, J.B.C. & L. D'Croz. 1997. The Ocean Divided: 38-71. In: A.G. Coates (ed.), Central America: A Natural and Cultural History. Yale University Press, New Haven and London. Kojis, B.L. & N.J. Quinn. 1981. Reproductive strategies in four species of Porites (Scleractinia). Proc. 4 th Int. Coral Reef Symp., Guam 2: 145-151. Macintyre, I.G. 1991 a. Crustacean guarding small colony ofPocillopora damicornis drive off an attacking Acanthaster. Coral Reefs 10: 132. Macintyre, I.G. 199 lb. Acanthaster damage to unprotected Gardineroseris. Coral Reefs 10: 28. Maragos, J.E. & C. Payri. 1997. The status of coral reef habitats in the insular south and east Pacific. Proc. 8th Int. Coral Reef Symp., Panarr~ 1:307-316. Mat6, T.J.L. 2001. Ecological, genetic and morphological differences among Pavona (Cnidaria: Anthozoa) species from the Pacific coast of Panarrfi. Ph.D. Dissertation. University of Miami. Coral Gables. 199 pp. Podest~, G.P. & P.W. Glynn. 1997. Sea surface temperature variability in Panan~ and Gahipagos" Extreme temperatures causing coral bleaching. J. Geophys. Res. 102" 15,749-15,759. Porter, J.W. 1972. Ecology and species diversity of coral reefs on opposite sides of the Isthmus of Pananfi. In: M.L. Jones (ed.), The Panamic Biota: Some Observations Prior to a Sea-level Canal. Bull. Biol. Soc. Wash. 2:89-116. Porter, J.W. 1974. Community structure of coral reefs on opposite sides of the Isthmus of PanamA. Science 186: 543-545. Richmond, R. 1985. Variations in the population biology ofPocillopora damicornis across the Pacific Ocean. Proc. 5th Int. Coral Reef Cong., Tahiti 6:101-106. Richmond, R. & C. Hunter. 1990. Reproduction and recruitment of corals: comparisons among the Caribbean, the tropical Pacific, and the Red Sea. Mar. Ecol. Prog. Ser. 60: 185-203. Smith, D.B. 1991. The reproduction and recruitment ofPorites panamensis Verrill at Uva Island, Pacific of Panamh. M.Sc. thesis, Univ. Miami. Coral Gables. 64 p. Weft, E. 1992. Genetic and morphological variation in Caribbean and eastern Pacific Porites (Anthozoa, Scleractinia). Proc. 7th Int. Coral Reef Symp., Guam 2: 643-656.

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White, A.T., M.F. Fouda & A. Rajasuriya. 1997. Status fo coral reefs in south Asia, Indian Ocean and Middle East Seas (Red Sea and Persian Gulf). Proc. 8th Int. Coral Reef Symp., Panam6 1:301-306. Wellington, G.M. 1982. Depth zonation of corals in the Gulf of Panarn~: control and facilitation by resident reef fishes. Ecol. Monogr. 52:223-241. Wellington, G.M. & P.W. Glynn. 1983. Environmental influences on skeletal banding in eastern Pacific (Panama) corals. Coral Reefs 1" 215-222. Wooster, W.S. 1959. Oceanographic observations in the Panan~ Bight: Askoy Expedition, 1944. Bull. Amer. Mus. Nat. Hist. 118:113-152.

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Corals and coral reefs of the Pacific coast of Colombia F e m a n d o A. Zapata" and B e m a r d o V a r g a s - A n g e l b "Departamento de Biologia, Universidad del Valle. Apartado A6reo 25360, Cali, Colombia bNational Coral Reef Institute, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, Florida 33004 USA ABSTRACT: Based on a literature review and our own research, we examine coral reef development on the Pacific coast of Colombia. Several. We provide a historical outline of the research, a summary of studies on coral community distribution, composition and ecological structure, a discussion on natural and anthropogenic impacts and effects, and finally, an overview of the current conservation and management status. Coral reef development in this area of the eastern Pacific is marginal, and communities are small, species poor (only 21 species of zooxanthellate corals), and discontinuously distributed. They occur in a variety of environmental settings ranging from coastal (Ensenada de Utria and Tebada), to continental insular (Gorgona Island), to oceanic (Malpelo Island). The largest (--10 ha), most developed (up to ---8 m thick), and species-rich coral reefs are located at Gorgona Island. These fringing reefs show a diffuse zonation pattern characterized by the dominance of pocilloporid corals on the shallow reef fiat and the presence of massive colonies of Pavona and Gardineroseris on the deeper outer reef base. Coral and coral reef development on the Pacific of Colombia is limited due to suboptimal climatic and oceanographic conditions such as a narrow continental shelf, intense rainfall (which results in elevated terrestrial run-off and turbidity, and reduced light and salinity conditions), and extreme temperature fluctuations caused by sporadic upwelling and E1 Nifio. Most important among these are El Nifio warming events, which have caused coral bleaching and mortality since at least 1983. In addition to recurrent E1 Nifio conditions, other natural disturbances affect the coral reefs in this region, including periodic sub-aerial exposure during extreme low tides, high sedimentation, seasonal upwelling, and tectonic activity. Most of the areas with coral reef development on the Colombian Pacific are legally protected. However, all are subject to sporadic anthropogenic impacts. Human disturbances are lowest on the remote Malpelo Island and highest on the northern coastal reefs. Corals reefs of the Colombian Pacific constitute a key marine biotope, and provide economic and social assets as habitats for artisanal fisheries, as well as recreation and educational activities. Further studies addressing basic questions and management and conservation issues are necessary.

1. I N T R O D U C T I O N T h e first o b s e r v a t i o n s on coral formations f r o m the C o l o m b i a n Pacific coast w e r e m a d e b y C r o s s l a n d (1927), w h o r e p o r t e d results o f the S.Y. St. G e o r g e E x p e d i t i o n to the south Pacific, and b y D u r h a m and B a r n a r d (1952), w h o r e p o r t e d results o f the V e l e r o III and I V cruises in the eastern Pacific. In 1968 the S t a n f o r d O c e a n o g r a p h i c E x p e d i t i o n 18 a b o a r d de R V T e V e g a m a d e short visits to G o r g o n a , B a h i a S o l a n o and Latin American Coral Reefs, Edited by Jorge Cortfs 9 2003 Elsevier Science B.V. All rights reserved.

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F.A. Zapata & B. Vargas-,4ngel

Bahia Cupica and briefly described subtidal stations and made limited observations on coral formations and associated fauna (Youngbluth 1968a, b). The first formal description of a coral formation in the Colombian Pacific was made by Birkeland et al. (1975) for Malpelo Island. The late H. von Prahl and his co-workers made qualitative descriptions of coral reef structure at Gorgona Island and discussed diverse ecological aspects (Prahl et al. 1979). Their pioneering work was later complemented by quantitative studies on the distribution, zonation, and community structure of corals and corallivores (Glynn et al. 1982; Cantera 1983). The structure and species diversity of coral formations in the northern portion of the Colombian coast, particularly at Ensenada de Utria, was later described (Vargas-Angel 1988, 1989, 1996). Species lists, illustrations, and accounts for identification purposes of Colombian Pacific corals were provided by Prahl (1985a, 1986b, 1987a) and Prahl and Erhardt (1985). Other works on corals and coral reefs from the Colombian Pacific include studies on coral growth at several localities (Prahl 1986d; Prahl et al. 1987; Prahl and Vargas-Angel 1990), coral growth forms and their implications for coral taxonomy and systematics (Cantera et al. 1989; Prahl and Estupififin 1990), biogeographical studies (Prahl 1986c; Prahl et al. 1990a, b), effects of the 1982-83 E1Nifio event (Prahl 1983a, 1986e, 1987b; Prahl et al. 1989), and the contribution of sea urchins (Toro 1998) and parrot fishes (Jim6nez 1999) to reef erosion. Taxonomic and ecological studies on animal communities associated with coral reefs in the Colombian Pacific include studies on symbiotic crustaceans associated with pocilloporids (Abele 1975; Castro 1982; Prahl 1982, 1983b, 1986f; Rios 1986, 1987; Escobar and Barbosa 1992; Navas 1993; Barbosa 1994), molluscan assemblages (Cantera et al. 1979; Cosel 1986; Cantera and Contreras 1988; Ocampo and Cantera 1988; Cantera and Arnaud 1995), echinoderms (Neira and Prahl 1986; Pardo 1989) and fishes (McCosker and Rosenblatt 1975; Findley 1975; Zapata 1982, 1987; Rubio 1986, 1990; Rubio et al. 1987, 1992; Estupifi~n et al. 1990; Guzmfin and L6pez 1991; Zapata and Morales 1997; Giraldo et al. 2001; Mora et al. 2001; Mora and Ospina 2001; Zapata and Herr6n in press). Much of the early information had already been summarized (Prahl and Erhardt 1985; Prahl 1986b; UNEP/IUCN 1988). This chapter provides a synthesis of current knowledge on the ecology of coral communities and coral reefs in the Colombian Pacific Ocean. Major emphasis is placed on the distribution of coral formations, the community structure of corals, and the effects of natural and anthropogenic disturbances on the reefs. 2. DESCRIPTION OF CORAL REEF AREAS 2.1. Distribution and community structure The distribution of corals and coral reef communities in the Colombian Pacific Ocean is directly related to the presence of hard substrates and clear waters, away from the influence of major fiver discharge and mangrove forests. According to their geographical location and following a nearshore-offshore gradient, coral formations in Colombian Pacific waters can be divided into three main groups (Fig. 1): 1) the northern, coastal reefs of the Gulf of Cupica and Ensenada de Utria; 2) the southern, continentalisland reefs of Gorgona; and 3) the oceanic-island coral formations of Malpelo. In general terms low species richness and strong dominance by one or two species characterize coral communities along the Pacific coast of Colombia and adjacent waters. A total of 21 coral species has been observed, with a minimum of 7 and a maximum of

Corals and coral reefs of the Pacific coast of Colombia

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PANAMA

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i

, Punta Cruce'~,BahIa Cupical

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Fig. 1. Map of the Pacific coast of Colombia showing the location of major coral formations (Tebada, Ensenada de Utria, Gorgona Island and Malpelo Islands). Other reference points mentioned in the text are also shown.

18 species occurring at any one locality (Table 1). Although these estimates are based on the best available information, the state of knowledge on coral taxonomy and systematic in the tropical eastern Pacific (TEP) is still inadequate. Despite the depauperate nature of the TEP coral fauna (Glynn and Ault 2000), new species are still being described (e.g., Glynn et al. 2001). A major revision of the genus Pocillopora is badly needed, and a revision of the genus Pavona is currently under way (J.L. Mat6 per. com.). Four new records have recently been added to the list of previously known coral species reported for the Colombian Pacific ocean (Table 1) and it is likely that a few other species will be added to the list as knowledge of coral taxonomy in the area improves. Climatic and oceanographic conditions in the Colombian Pacific are thought to be suboptimal for coral reef development (Glynn et al. 1982). On the one hand, narrow and steep platforms restrict reef development. On the other hand, salinity and light levels are severely reduced due to high river input and high cloud cover in one of the rainiest regions of the world. Mean annual precipitation exceeds 5000 mm over most of the coast,

F.A. Zapata & B. Vargas-,4ngel

422

TABLE 1 Known zooxanthellate scleractinian coral species from the Colombian Pacific Ocean. + = species present, ? = unconfirmed record. Numbers in parentheses indicate information sources as follows: 1 = Birkeland et al. (1975), 2 = Glynn et al. (1982), 3 = Cantera (1983), 4 = Prahl and Mejia (1985), 5 = Prahl and Erhardt (1985), 6 = Prahl (1986b), 7 -- Prahl (1990), 8 -- Guzm~in and Cort6s (1993), 9 = Vargas-Angel (1996), 10 = J. Garz6nFerreira, photographic record, 11 = Garz6n-Ferreira and Pinz6n, (1999), 12 = H.M. Guzm~in, per. com., 13 = B. Vargas-Angel, unpubl, data, 14 = F.A. Zapata, per. obs.

Species Malpelo

Pocillopora damicornis (Linnaeus) Pocillopora eydouxi Edwards & Haime Pocillopora capitata Verrill Pocillopora elegans Dana

+ (7) + (1, 7) + (5)

+ (1, 5, 7)

3, 5, 6) 3, 5, 6) 3, 5, 6) 5)

+ (2, 3, 5, 6) + (2, 3, 5, 6) +(8, 12) + (2, 3, 5, 6)

+(8,12)

+ + + +

(5, 9) (9) (5, 9) (5, 9)

+(13)

+ (9) + (5)

+ (13)

+ (5, 9)

+ (13) +(13)

+ (1, 5, 7) + (1, 5, 7)

+ (2, 3, 5, 6) + (2, 3, 5, 6)

+ (5, 9) + (5, 9)

+ (13)

+ (5, 7) ?(10) +(11)

+ (2, 3, 5, 6)

+ (5, 9)

+ (13)

+(12) + (5) + (2, 5, 6)

+ (9)

+ (1, 5, 7)

+(14)

+ (2, 5, 6)

Cycloseris curvata (Verrill) Total = 21 species

(2, (2, (2, (2,

Tebada

?(13)

Psammocora brighami Vaughan Psammocora obtusangulata (Lamarck) Psammocora stellata (Verrill) Psammocora superficialis Gardiner Psammocora sp. Pavona clavus (Dana) Pavona varians Verrill Pavona sp. aft. frondifera (Lamarck) Pavona gigantea Verrill Pavona maldivensis (Gardiner) Pavona chiriquiensis Glynn et al. Leptoseris papyracea (Dana) Gardineroseris planulata (Dana)

+ + + +

Localities Ensenada de Utria

+ (4, 5, 6)

Acropora valida (Dana) Porites lobata Dana Porites panamensis Verrill

Gorgona

10 species

18 species

11 species

7 species

although it is lower in the south and greater in the north, reaching 7000 mm or more in some areas (West 1957; Eslava 1993). Intense rainfall during the rainy season increases the concentration of suspended particulate matter at sea, often leads to topsoil rtmoff, and even occasional landslides. Finally, coral reefs of the Pacific coast of Colombia are also subject to periodic, severe natural disturbances. Intense upwelling in the Gulf of Panama (Legeckis 1988) lowers sea surface temperatures (SST) down to as low as 16~ (Vargas-Angel 1996), whereas occasional very-strong E1 Nifio events increase SST causing thermal stress, bleaching and coral mortality (Prahl 1983a; Vargas-Angel 1996 per. obs.). 2.1.1. Coastal reefs. Few true coral reefs occur along the Colombian Pacific coast. Except for the small reefs in Ensenada de Utria and the Gulf of Cupica (Tebada), only isolated coral colonies and small build-ups are sparsely distributed along the coast at localities such as Cabo Corrientes, Bahia Solano, and Punta Cruces (Prahl and Erhardt

Corals and coral reefs of the Pacific coast of Colombia

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II

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Fig. 2. Location of the northern, coastal reefs of the Pacific coast of Colombia. A) Ensenada de Utria with planar view of La Chola Reef. Other sites with coral reefs (triangles) or coral communities (circles) are also shown. B) Locationof Tebada Reef. 1985; B. Vargas-/~mgel per. obs.). Isolated colonies of Pocillopora spp. occur as far south as Isla de Palma (Bahia de M~laga: Escobar and Neira 1992; per. obs.). Ensenada tie Utria. Coral reefs at Ensenada de Utria National Park have developed on relatively shallow substrates in sheltered bays. Two main coral reefs occur in the Utria region: these are La Chola reef (following Prahl and Erhardt 1985) and Diego reef (Fig. 2a). La Chola reef, is the largest coral reef (ca. 10.5 ha), and is located on the east margin of Ensenada de Utria. According to Prahl (19860, in 1981 La Chola reef was characterized by a lush and diverse coral assemblage, including several species of Pocillopora, as well as Psammocora stellata, Pavona clavus, Pavona gigantea and Porites spp. To date (Vargas-.~gel 1996, 2001), little or no evidence of the past occurrence of a complex and diverse coral community at La Chola reef has been found. Coral community surveys conducted in 1988-89 (Vargas-,~ngel 1996) showed that La Chola reef was composed predominantly of thin-branched ecomorphs of Pocillopora

424

F.A. Zapata & B. Vargas-Angel

damicornis (80% of colonies), and Psammocora stellata (16%). Other species present included Pocillopora capitata (approx. 4%), Pavona varians and Pavona gigantea (< 1%). Also, mean live-coral cover at La Chola reef was not greater than 33% and the spatial distribution of live corals was highly patchy. All areas where live cover exceeded 60% were associated with dense monospecific stands of Pocillopora damicornis. Lower coral cover (< 20%) occurred in areas where P. damicornis was less abundant or absent. In addition, diversity indices (Shannon-Wiener's H') were overall low (0-1.6), not only because of the reduced coral species richness, but also due to the overwhelming dominance of P. damicornis. Although mean percent cover at La Chola reef was greater along the northern sector (45.3%) than at the central and southern sectors (26.5% and 26.8%, respectively), differences were not significant. By contrast, coral cover was significantly lower on the seaward slope than on the reef flat and leeward zones. Live coral cover varied inversely with coral species diversity and richness, which were highest at the central and southern sectors of the reef. Only a weak coral zonation pattern was evident at La Chola reef, where coral cover decreased from north to south and from inshore to offshore (Vargas-/~mgel 1996). Coral community surveys conducted in 1995-96 (Vargas-.~-agel 2001) showed that neither mean coral cover nor species relative abundance had changed substantially at La Chola reef since 1989. By contrast, shifts in community composition have occurred, including: 1) the spatial re-distribution of the dense monospecific stands of Pocillopora damicornis from the leeward area to the central reef flat, and 2) a notable increase in macro-algal cover (Vargas-/~,ngel 2001). Although La Chola reef seems to have suffered a long history of sedimentation and siltation stress (discussed below, but see Murphy 1939; Prahl and Vargas-Juagel 1990; Vargas-/~uagel 1996, 2001), it is still premature to consider these recent changes in community structure as evidence of degradation. In fact, spatial and temporal heterogeneity in coral reef communities can result from adaptation and recovery to various stressors on numerous and complex scales (Cormell 1978; Brown and Howard 1985; Grigg and Dollar 1990; Reice 1994; Grigg 1995). Other coral communities at Utria include Diego reef, as well as sparse, small coral aggregations and build-ups at Punta Diego, Playa Blanca and Cocalito, which do not form true constructional reefs. In comparison to La Chola reef, Diego reef is a much smaller formation (ca. 1.5 ha). The reef flat starts at approximately I00 rn offshore; it extends seaward for approximately 150 rn at a depth of 2.0-2.5 m, and then slopes gradually to 6.0 to 8.0 rn depth at the reef base. Diego reef is covered mainly by coral rubble and encmsting coralline algae. According to Vargas-/~'agel (1996 and per. obs.) live cover does not exceed 2%; it consists mainly of Psammocora stellata, with very few sparsely scattered colonies of Pocillopora damicornis. No live or dead massive coral colonies have been found on Diego reef, yet large colonies of Pavona elavus, P. gigantea, and Porites lobata occur along the wave-exposed basaltic rocks of Punta Diego (Vargas/~gel per. obs). In 1981, when Prahl visited the zone, he characterized Diego reef (referred to as Playa Blanca reef by Prahl and Erhardt 1985, p. 281, see Vargas-/~gel 1996) as having a mature structure dominated by Pocilloporids and Psammocora, with isolated colonies of Pavona gigantea, P. r P. varians and Porites panamensis. Present day coral community composition and structure suggest that Diego reef has been severely disturbed, and community recovery to a pre-disturbance stage has not yet occurred. Severe bioerosion in excess of accretion (Vargas-/kngel in progress) seems to have been an important factor in reducing this reef structure to rubble and sediments.

Corals and coral reefs of the Pacific coast of Colombia

425

Trying to assess and characterize the causes of coral reef community deterioration at Utria (i.e., La Chola and Diego reefs) has been difficult due to the lack of data prior to 1989, when the first quantitative surveys were conducted. It has been suggested (Vargas,~mgel 1996) that natural and anthropogenic disturbances, including E1 Nifio Southern Oscillation (ENSO), terrigenous siltation, dynamite fishing, recurrent low tides (discussed below) and bioerosion must have played pivotal roles in coral community deterioration and demise at Utria. Sclerochronological and sedimentary studies have provided evidence that ENSO events and chronic siltation are important stressors limiting coral growth and reef development at Utria (Vargas-/~age12001; see bellow). Tebada. Tebada reef, (ca. 6~ 77~ is located south of Bahia Cupica (Fig. 1), and not at the north of it as presented in Prahl and Erhardt (1985 p. 279). Tebada reef is separated from the mainland by a channel of ca. 500 rn, and is protected from ocean surge by a chain of small islets and rocky outcrops (Fig. 2b). The reef is a shallow, gently-sloping platform of approximately 4.5 ha, which is not subaerially exposed during extreme low tides (mean depth close to 2.0 m). Although several species of reef corals are present, including Pavona varians, Pocillopora damicornis, and Pavona gigantea, Psammocora spp. are dominant, accounting for over 80% of the total live coral cover. Reef probings done in 1996 indicate that this reef has a vertical buildup of at least 4 rn on the reef fiat (B. Vargas-Juagel unpubl, data). 2.1.2. Insular reefs. There are two contrasting insular environments with significant coral formations within Colombian Pacific waters: Gorgona Island and Malpelo Island. Gorgona (2~ 78~ is a continental island located approximately 35 km off the nearest point on the Colombian Pacific coast (Fig. 1) within the area of influence of the Intertropical Convergence Zone (ITCZ). The periodical displacement of the ITCZ produces a unimodal, biseasonal pattern of precipitation at Gorgona with a wetter season between May and October. Mean annual precipitation is about 6700 mm at Gorgona and 4900 mm at the mainland in front of it (Rangel and Rudas 1990). Even though sea surface temperatures around Gorgona (normally between 26-29~ are within the range of temperatures for vigorous coral growth and reef development, salinity (between 30-33 ppt) and water clarity (< 5-25 m) are decreased by the freshwater input caused by the abundant rain. Therefore, the strong influence of the nearby continental estuarine environment most likely limits the development of coral reefs at Gorgona Island. In contrast, Malpelo (3~ ~ , 81 ~ is a small oceanic island of volcanic origin located approximately 400 km west of the Pacific coast of Colombia (Fig. 1). It is the only emergent pinnacle of the Malpelo ridge (Chase 1968), separated from mainland Central and South America by depths greater than 3000 m (Graham 1975). Malpelo island is thus surrounded by clear oceanic waters which allow corals to be present as deep as 30 m, which is close to the maximum depth for the occurrence of corals in the Panamic Province (Graham 1975) and second only to Clipperton Island in the TEP, where corals occur as deep as 60 rn (Glynn et al. 1996). SST at Malpelo normally ranges from 26-28~ but temperatures below 30 rn depth are often below 20~ Salini'ty is relatively constant, varying between 32-33 ppt, although occasionally it drops down to 30 ppt (Stevenson et al. 1970). Gorgona Island. Like most reefs in the tropical eastern Pacific, the coral reefs of Gorgona Island cover a small area, are patchily distributed and show modest development. Yet Gorgona's reefs are among the best developed within the region, similar to those in the Gulf of Chiriqui in Panama (Glynn and Wellington 1983; Guzrrfin and Cortrs

426

F.A. Zapata & B. Vargas-,4ngel 78~ I'

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Fig. 3. Map of Gorgona Island showing distribution of coral formations, major topographic features and distribution of freshwater streams. Planar view of major coral formations are shown. Reefs with relatively high live coral cover are indicated in solid black, whereas formerreef areas reduced to rubble or significantly deteriorated are indicated with a dashed pattern. Based on aerial photographs from Institute Geogr~ifico "Agustin Codazzi", a map in Glynn et al. (1982), and personalobservations. 1993; Cortrs 1997). Additionally, Gorgona's reefs are unique in that they are located in a non-upwelling area of the TEP and are free of predation by a major corallivore, the crown-of-thorns starfish (Acanthaster planci: Glynn et al. 1982; Glynn and Wellington 1983). Coral formations around the island show varied degrees of development, including coral communities, incipient reefs, and well-developed fringing reefs. Some of these reefs are the most mature and best studied coral reefs of the Colombian Pacific (Prahl et al. 1979; Glynn et al. 1982; Prahl and Erhardt 1985; Prahl 1986b). Except for one small reef, all coral formations at Gorgona are located on the eastern, leeward side of the island (Fig. 3). Prahl et al. (1979) speculated about the causes of this uneven distribution of coral formations around Gorgona and attributed it to: 1) low salinity stress due to an assumed greater number of freshwater streams discharging on the west side of the island; 2) lower and more variable water temperatures on the western

Corals and coral reefs of the Pacific coast of Colombia

427

side of Gorgona; 3) stronger wave action on the westem shore causing resuspension of sediment, increased turbidity and decreased light penetration in addition to substrate fragmentation and instability; and 4) a smaller shelf area on the westem side. However, except for the fact that the number of freshwater streams on either side of the island is almost identical (west = 12, east = 11) thus not lending support to the first hypothesis, there is a lack of detailed knowledge on the local oceanography and the physical environment around Gorgona necessary to test the above hypotheses (but see general oceanographic descriptions by Prahl et al. 1979; Glynn et al. 1982; Prahl 1986a). Additionally, the relative inaccessibility of the western shore by both land and sea has made it difficult to study this side of the island. Coral communities. Coral communities (i.e., characterized by the dominance of hermatypic corals but lacking a significant reef frame buildup) are common around Gorgona. Several coral communities, with up to 30% live coral cover, are patchily distributed on rocky substrates from the northernmost tip of Gorgona and moving southward along the eastern coast (Fig. 3). These are briefly mentioned by most authors (Prahl et al. 1979; Glylm et al. 1982; Cantera 1983; Prahl and Erhardt 1985; Prahl 1986b), but remain largely undescribed except for limited observations (Glynn et al. 1982; L6pezGiraldo 1992). These communities are located at E1 Homo, E1 Remanso, Yundigua, and Playa Pizarro. These communities, but particularly those at E1 Remanso and Playa Pizarro appear to be the remains of former fringing reefs judging by the amount of coral rubble present in the area. Other coral formations previously reported at Gorgona (Glynn et al. 1982) but now reduced include those at La G6mez, La Ventana, and the Paso de Tasca area. Most likely, these reefs deteriorated significantly during the strong E1 Nifio event of 1982-83 and unlike other reefs at Gorgona have not yet recovered. Incipient reefs. At least four areas around Gorgona (Fig. 3) have incipient coral reef developments, which have been briefly described (Glynn et al. 1982; L6pez-Giraldo 1992). At La G6mez there is a series of linear ridges formed by pocilloporids, similar in appearance to those at La Camaronera (see below). The linear ridges appear to be formed in response to prevailing wind and wave conditions. The shallow shelf in the areas of La G6mez and La Ventana support dense stands of Pocillopora spp. with a vertical buildup of approximately 1 m (Glynn et al. 1982). In the Paso de Tasca area, the strait between Gorgona and the islet of Gorgonilla, there is one small reef (ca. 200-250 m long) located at the northern tip of Gorgonilla and a few, small coral patches built mainly by pocilloporids. This reef, also known as Los FaraUones reef, has a vertical buildup of 1-2 m, and is similar in structure and zonation to La Azufrada and Playa Blanca reefs (Glynn et al. 1982; Prahl and Erhardt 1985; Prahl 1986b; L6pez-Giraldo 1992). Much of the reef flat consists of a dead pocilloporid frame tightly bound by coralline algae, whereas the reef crest and upper slope are dominated by living pocilloporids (Glyrm et al. 1982). The outer reef base consists of a sandy and bioclastic plain dominated by many large colonies of massive species, mainly Pavona gigantea, growing a few meters apart (F.A. Zapata per. obs.). The main reef on the western side of the island, known as La Camaronera reef, is located on a rocky headland between the sandy beaches of La Camaronera and E1 Cocal. This area is characterized by strong wave action. Two kinds of coral formations in this area have been briefly described (Glynn et al. 1982): 1) a series of small, shallow reefs consisting of a reef flat formed by a tightly intermeshing framework of Pocillopora spp. lying on a basalt substrate, and sloping sharply to a sandy bottom at 4 m depth. 2) Several

428

F.A. Zapata & B. Vargas-,4ngel

linear spurs located further offshore and oriented parallel to the prevailing wave direction, formed by pocilloporids and having a vertical buildup of 2-3 rn. Some spurs lack any live coral and appear to be accumulations of coral rubble bound together by coralline algae. Along with these and further north, at the southern end of La Camaronera Beach, there are numerous hillocks of various sizes built also by pocilloporids. All of these formations lack any evident zonation. Crustose coralline algae binding the reef frame were more evident on these windward reefs than on those on the leeward side of the island (Glynn et al. 1982; F.A. Zapata per. obs.). Fringing reefs. Old Pier reef This small fringing reef (about 45 rn long and covering an area of about 0.16 ha) is located south of the remains of a large wooden pier destroyed in 1984. Although a total of 10 species of corals, including species of Psammoeora, Porites and Pavona, have been previously observed on this reef (Cantera 1983), it is now made up almost entirely of pocilloporids, mainly Pocillopora damicornis (F.A. Zapata per. obs.). Total live coral cover varies from 20% in the backreef and lower slope to 85% on the reef front. Whereas species richness tends to be greater on the reef flat and crest, species diversity increases steadily from the backreef to the reef front (Cantera 1983). Despite its small size, the reef is similar in structure and zonation to other larger fringing reefs on the island (see below). It has a relatively extensive reef flat followed by a steep (ca. 60 ~ reef front, and at about 6 m depth, by a sand plain composed of bioclastic and carbonate debris (Glynn et al. 1982; Cantera 1983; Prahl and Erhardt 1985; Prahl 1986b). The reef frame may have a vertical buildup of up to 6 m (Glynn et al. 1982). La Azufrada reef This is the largest, continuous coral reef of Gorgona Island, as well as the best studied (Prahl et al. 1979; Glynn et al. 1982; Prahl and Erhardt 1985; Prahl 1986b; see also Cantera and Arnaud 1995; Zapata and Morales 1997). Direct measurements made recently, however, indicate that it is slightly smaller (780 m long and 80-180 rn wide) than previously reported (Glynn et al. 1982), covering about 11.2 ha (F.A. Zapata et al. unpubl, data). Glynn et al. (1982) observed 10 coral species on this reef; it is clearly dominated by pocilloporids, but also includes (in decreasing order of in~ortance) species of Psammocora, Pavona, Porites, and Gardineroseris. Live coral cover varies from < 50% in the backreef up to > 80% on the reef crest and front (Glynn et al. 1982; Prahl 1986b; F.A. Zapata et al. unpubl, data). On the backreef and reef flat, the continuity of live coral is occasionally interrupted by relatively large patches of dead pocilloporid fragments, among which many small, live colonies of Psammor are found covering a significant proportion of the substrate (ca. 40%). Species richness and diversity are variable but overall higher on the reef crest and upper slope than elsewhere. The reef has a coral framework buildup varying from 2 to 8.3 m (Glynn et aL 1982). A unique feature of La Azufrada reef is the presence of a crater-like depression located on the northern portion of the reef near the crest. The depression is circular with a 40 m diameter and is completely surrounded by the thick coral growth typical of the reef crest. On the inner side of the rim coral cover decreases with increasing depth reaching a uniform soft-sediment bottom at approximately 10 rn depth. A few very large colonies of Gardineroseris planulata, with a high proportion of their surface dead and covered by algae, are scattered around the inner edge of coral growth. Glynn et al. (1982) speculated that the origin of this depression was likely the result of coral growth around a small submarine valley. This depression appears to have been present on the reef for at least a few decades since it is visible on aerial photographs taken in 1957 and 1962. A second

Corals and coralreefs of the Pacificcoast of Colombia

429

interesting feature of this reef is the unusually high abundance of Pocillopora eydouxi at the reef crest on the northernmost portion of the reef (F.A. Zapata per. obs.). Playa Blanca reef The reef at Playa Blanca consists of two patches separated by a channel approximately 60 m wide. The smaller, northernmost patch is ca. 240 m long and has a relatively uniform width of ca. 40 m due to the rapid increase in depth as one moves seaward. This patch exhibits a very diverse and "healthy" appearance, and has very dense coral growth. As on other reefs, pocilloporids dominate the shallow areas whereas massive corals, particularly Pavona varians and Gardineroseris planulata form large clusters at the outer reef base. Of particular interest at this site in early 1997 were 1) the high frequency of scars apparently caused by fish corallivores on massive species, 2) the frequent presence of dense patches of Poeillopora eydouxi, and 3) the presence of an as yet undentified species of Pavona, very similar to Pavona frondifera from the Indo-Pacific and previously unreported for Gorgona (F.A. Zapata per. obs.). Although Pavona frondifera has been previously reported for other localities in the TEP (GuzmAn and Cort6s 1993; Glynn 1997; Cort6s and Guzrnfin 1998), there remains some doubt about the specific status of the specimens collected at these localities and it is plausible that they belong to a species as yet undescribed (J.L. Mat6 per. com.). The second, southernmost reef patch at Playa Blanca is slightly longer (ca. 930 m) but more variable in width (ca. 60-230 m) than La Azufrada reef. Nonetheless, it is similar in areal coverage (9.9 ha; F.A. Zapata unpubl, data), general shape, structure and zonation to the reef at La Azufrada (Glynn et al. 1982; Prahl and Erhardt 1985). However, the backreef zone is wider and closer to the beach, the reef crest is not as noticeable, the forereef has a steeper slope, and the bioclastic sandplain is shallower than at La Azufrada. This reef's framework is also made up mostly of pocilloporids with large colonies of Pocillopora eydouxi abundant on the crest and forereef. Large colonies of Pavona clavus and P. gigantea are relatively abundant at the reef base (Glynn et al. 1982), but show a conspicuous patchy distribution. Patches of Gardineroseris planulata are occasionally found at the reef base as well. Zonation of Gorgona's fringing reefs. The coral reefs of Gorgona are in general characterized by their diffuse zonation pattern, although it is more defined on the larger than on the smaller coral formations. Nevertheless, published descriptions of zonation on the main reefs of Gorgona generally agree with the identification of major zones (Prahl et al. 1979; Glynn et aL 1982; Cantera 1983; Prahl and Erhardt 1985; Prahl 1986b; see also Zapata and Morales 1997). The following is a generalized zonation scheme from the beach seaward based on the latter works and our own observations (Fig. 4): 1) The reef is separated from the beach by a shallow, boat channel, 20-100 m-wide, characterized by fine-sediment substrate (partly derived from land runoff), and by the lack of coral growth. At Playa Blanca, a strip of coral rubble several meters wide and covered by algae follows the channel. 2) At La Azufrada, a few isolated coral colonies begin to appear at the boat channel-backreef interface, whereas at Playa Blanca the transition from coral rubble to denser live coral is more abrupt. The backreef is characterized by a low and patchy distribution of live-coral cover, which increases seaward from < 10% to < 50% over a stretch of 20-30 rn. Dominant species in this zone are in order of decreasing cover: Psammocora stellata (more abundant at La Azufrada), Pocillopora spp. (mostly P. damicornis) and very few, small Pavona varians. 3) Moving seaward, pocilloporids, particularly Pocillopora damicornis and P. elegans, dominate the reef fiat, although colonies of Porites panamensis, Pavona varians and Psammocora stellata are

F.A. Zapata&B. Vargas-Angel

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Fig. 4. Depth profiles of three transects at La Azufrada Reef, Gorgona Island, showing the approximate width of five reef zones as follows: B = backreef, F = reef flat, C = reef crest, Fr -- reef front, and S -- upper reef slope. Inset shows planar view of the reef and adjacent coastline with approximate location of transects. found interspersed amongst the pocilloporids. P. stellata can be abundant, particularly within pockets of dead coral and consolidated calcareous rock. Total live coral cover varies both within and between reefs in this zone and may reach up to 70%, whereas the remaining substrate is composed of consolidated calcareous algae, sand, and coral rubble. 4) Like many flinging reefs, Gorgona's reefs lack a true reef crest. Nonetheless, the outer portion of the reef fiat is slightly elevated, making it the shallowest portion of the reef, and thus a distinct zone frequently referred to as the crest. It is densely covered by Pocillopora spp., mainly P. damicornis, although notably large colonies of Pocillopora eydouxL P. elegans and P. capitata are more abundant here than elsewhere on the reef. Total live coral cover can be as high as 80%-90% due to the close packing of colonies. The backreef, the reef fiat, but particularly the crest, are occasionally exposed during extreme low tides. The effects of subaerial exposure create a mosaic of dead coral covered by algae patchily distributed over live coral, and contribute to the spatial heterogeneity of the reefs (see section "Natural disturbances, extreme low tides"). 5) In the reef front the bottom begins to slope steeply although live coral cover and species composition continue to be similar to those in the reef crest. The limit of the pocilloporid reef framework is located at the outermost portion of this zone. Relatively large blocks (up to 2 m long by 0.5 m wide) of the pocilloporid frame are often found tom off at this level. 6) On the upper reef slope, concomitant with a pronounced decrease in pocilloporid coral cover (to 20% or less) there is an increase in the amount of coral rubble and abundance of large (up to 2-3 m in diameter), massive colonies of Porites lobata, Pavona gigantea and Pavona clavus, or clusters of Pavona varians or Gardineroseris planulata, which produce high topographic complexity. Psammocora stellata becomes once again a dominant member of the community in terms of cover, whereas Pocillopora spp. occur as scattered, isolated colonies. 7) Finally, reefs may be followed by either a sand plain composed of bioclastic and carbonate debris (Old Pier reef and Playa Blanca) or by a lower slope largely

Corals and coral reefs of the Pacific coast of Colombia

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composed of coral rabble and fine sediment, Psammocora stellata and a few and widely separated, small colonies of Pocillopora spp. and Pavona varians (La Azufrada reef). Malpelo Island. Because of its geographic location, both oceanic and continental currents influence Malpelo Island (Wyrtld 1965). However, despite the biogeographic importance of oceanic islands in the TEP as potential stepping stones for the invasion of Indo-Pacific species (Graham 1975; see also Glynn et aI. 1996; Robertson and Allen 1996; Glynn and Ault 2000), Malpelo Island has been overlooked. Due to the remote location of this small island few studies have addressed the ecological aspects of Malpelo's marine communities. After initial work by Birkeland et al. (1975), only three contributions have considered the coral formations at Malpelo (Prahl 1990; Brando et al. 1992; Garz6n-Ferreira and Pinz6n 1999). Steep cliffs and vertical walls characterize the perimeter of Malpelo Island. Hermatypic corals occur mostly as a veneer, interspersed with other benthic invertebrates, especially barnacles (Balanus peninsularis) and octocorals (Anthozoa: Alcyonaria). In some cases corals occur as shingled overhanging masses on the vertical rocky walls (Birkeland et al. 1975). Rich coral aggregations and build-ups occur only on the gradually sloping substrates. These observations led Birkeland et aL (1975) to conclude that no true reefs occur at Malpelo. However, there is no information about the extent of coral build up at Malpelo and reef probings are needed to confirm such conclusion. Of special interest is the coral formation found by Birkeland et aL (1975) in a small protected embayment on the east coast of the island. This is the largest and most developed coral formation at Malpelo and is known as "El Arrecife" (Fig. 5). Whereas Birkeland et al. (1975) reported that cover by hermatypic corals varied between 42% and 89% at E1 Arrecife in 1972, Garz6n-Ferreira and Pinz6n (1999) found values between 15% and 60% at the same reef in 1999. Here corals exhibit a clear zonation pattern (Birkeland et al. 1975). Colonies of Pocillopora capitata dominate (80-94% of live coral cover) between 9 and 12 m. In contrast, massive corals are more abundant on deeper substrates, also presenting specific depth preferences. Porites lobata and Pavona clavus are most abundant (80% and 54%, respectively) between 14 to 18 m. The deepest substrates (26-27 m) are dominated by Gardineroseris planulata (53%). These zonation results are in accordance with recent observations b), Garz6n-Ferreira and Pinz6n (1999). Similar observations were made by B. Vargas-Angel and F. Estupifi~n (unpub. data), who visited the island in 1990 and found a small coral community (ca. 0.1 ha) on the west coast of the island at the site known as "El Mirador". The shallow substrate between 5 and 10 m depth was dominated by low-profile colonies of Pocillopora capitata and Pocillopora eydouxi. Of special interest in these areas were the few colonies of P. eydouxi, which exhibited very broad and flattened branches. The second zone, between 10 and 20 m was densely covered (93-99%) by shingle-like colonies of Porites lobata. Below 20 m depth Pavona clavus and Pavona varians were abundant. Other smaller, undescribed, coral formations are located at two other sites known as "El N~ufrago" and "Bajo de Junior" (Fig. 5; S. Bessudo per. com.). The rich development of reef corals in the two coral formations described above suggests that conditions are favorable for coral growth at Malpelo (Birkeland et al. 1975). However, hermatypic coral growth is limited elsewhere around the island (~10%). Birkeland et al. (1975) suggested that two main factors limit reef development at Malpelo Island, namely sunlight and lack of a gently sloping shelf. Vertical surfaces are frequently shaded due to the sun angle and vertical irregularities of the walls. Moreover,

432

F.A. Zapata & B. Vargas-Angel 81~ ' W ( ~ ) ~ ) LOSTres Mosqueteros 0 D'Artagnan

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3059' N

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Fig. 5. Map of Malpelo Island showing distribution of coral formations (black circles) and major topographic features. Names of sites are those commonly used by sport divers (S. Bessudo, per. com.).

vertical walls provide little or no support at all on which corals can build and develop a reef. Low water temperatures may also limit the depth distribution of corals at Malpelo. The occurrence of temperatures as low as 19.5~ below 30 m depth are evidently cold enough to limit coral growth (Birkeland et al. 1975). Additionally, oceanic swells may have a profound in~act on the development of coral formations at Malpelo. First, strong wave action is most likely the major cause of erosion of the island, causing frequent rockfalls (Stead 1975) that affect the development of coral buildups (Birkeland et al. 1975). Second, unusually strong wave action during occasional storms has long been known to disturb coral reefs (Brown 1997) and it is likely that it does at Malpelo as well. For instance, in June 1999 strong oceanic swells caused the breakage of many pocilloporid colonies, overturned many large colonies of massive species and caused severe perturbations to Malpelo's main reef in just one night (Garz6n-Ferreira and Pinz6n 1999).

Corals and coral reefs of the Pacific coast of Colombia

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3. NATURAL DISTURBANCES 3.1. EL Nifio-Southern Oscillation

During 1982 and 1983 an increase in sea surface temperature (SST) occurred along the Colombian Pacific coast that lasted at least 16 months, causing bleaching and death of hermatypic corals. The bleaching event was preceded by increases of 1-2~ above the long-term norm over an 11-month period (June 1982 to April 1983: Prahl 1985b; Glynn 1990), while the greatest temperature deviation (3.5~ occurred in March of 1983. However, one temperature reading of 31.5~ obtained from Gorgona Island in February 1983 (3.2~ above the mean), suggests that coral reefs in this location may have experienced even greater sea warming (Glynn 1990). As at many other locations in the TEP, the first sign of coral thermal stress was the loss of endosymbiotic algae by corals. On the Pacific coast of Colombia, coral bleaching was only noticed in April 1983, although it may have begun as early as February. It reached widespread and catastrophic proportions by June 1983, when Prahl (1983a) reported coral bleaching in excess of ca. 85% in all the coral reefs of Gorgona Island. Massive corals along the reef base (> 6 m depth) showed bleached surfaces, while the bases of the colonies remained with normal coloration (Prahl 1983a). In addition, coral bleaching at Gorgona Island was accompanied also by decreased mucus release, mainly in pocilloporid corals, and a dramatic reduction of coral commensal symbionts (Prahl 1985b). In situ coral skeletal staining (Prahl 1986d) demonstrated not unexpectedly that bleached corals were incapable of calcification. By July 1983, most of the bleached coral colonies at La Azufrada reef were dead, and covered by macroalgae. However, Pocillopora eydouxi at La Azufrada and Playa Blanca reefs was the coral least affected by the warming event (Prahl 1983a). Recovery of coral reefs at Gorgona Island since 1983 has been slow, not only because most live corals were severely reduced by the 1982-83 warming event, but also because of low coral growth and recruitment rates, and secondary environmental disturbances. In November 1984, Prahl visited the island and noticed a slight recovery in coral cover of ca. 15%, mainly due to regeneration of pocilloporid colonies; however, no signs of recovery by the massive coral G. planulata was observed (Prahl 1985b). In October 1985 B. Vargas-Angel and C. Moreno (unpubl. data) still observed large extensions of dead coral at La Azufrada reef. In December 1987, reef corals, predominantly Psammocora stellata and Pocillopora damicornis, had recolonized most of the dead coral platform at the northern portion of La Azufrada reef (Prahl et al. 1988). Although substantial coral regeneration has occurred since 1983, full recovery of the coral community to a pre-disturbance stage has apparently not occurred yet any of the reefs in fiat Gorgona Island. However, comparisons of coral community structure at La Azufrada between 1979 (Glynn et al. 1982) and 1993, 1995 and 1996 showed that 1) live coral cover was similar across all years in all zones except the backreef (which was lower in 1979 due to high sedimentation); 2) species richness and diversity (H') did not differ significantly among years although they tended to be higher in the reef crest and front in 1979; and 3) evenness (J') was significantly greater in the reef fiat and reef front in 1979 (C.E. Bhrcenas et al. unpubl, data). Although massive corals, including species of Pavona, poritids and Gardineroseris planulata, are still present in all reef zones (but particularly on the upper reef slope), they occur only in relatively low abundance (Prahl et al. 1988; Guzm,Sn and L6pez 1991; per. obs. by the authors). Post-disturbance coral

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growth rates (23.6 mm yr-l for P. damicornis) were low compared to those reported by Glynn and Stewart ~1973) for Panama and were ascribed by Prahl (1985b) to slow coral regeneration after the 1982-83 warming event. However, reports of reduced coral growth rates during 1985-86 could have been the result of two non-mutually exclusive factors: 1) stained colonies were unattached to the bottom and free to wander on the reef, (E.J. Pefia per. com.), and 2) other disturbances after the ENSO event, such as the strong upwelling in the Gulf of Panama of 1985 (Legeckis 1988; Guzn~n et al. 1990), or extreme low tides, may have affected coral growth. Although the 1982-83 E1 Nifio warming lasted between 10 and 20 months (depending on location; see Glynn 1990), still little is known about long-term ecological changes affecting corals and coral reefs on the Pacific coast of Colombia. Glynn (1990) implicitly proposed that the 1982-83 E1 Nifio event was responsible for the extinction of Acropora valida at Gorgona Island, hence the eastern Pacific. However, the colonies of A. valida at Gorgona had a normal appearance when they were found in September of 1983, at the end of the warming episode (Prahl and Mejia 1985). Nonetheless, the occurrence of A. valida at Gorgona or elsewhere in the TEP was never confn'rned. It is thus unclear whether the 1982-83 E1 Nifio event drove A. valida to extinction in the TEP. Comparisons of maps of coral reef distribution around Gorgona made before the 1982-83 E1 Nifio (Prahl et al. 1979; Glynn et al. 1982) with maps made after (Prahl and Erhardt 1985; Prahl 1986b; L6pez-Giraldo 1992), in addition to our own observations, suggest that some reefs at Gorgona were more affected than others. Whereas the larger reefs of La Azufrada and Playa Blanca appear today almost as large and with similar live coral cover and species richness as before 1982, the smaller reefs at E1 Remanso, Yundigua, Playa Pizarro, E1 Muelle, La G6mez, La Ventana and Paso de Tasca are much smaller and show little coral buildup. Lack of detailed descriptions of most of these reefs prior to 1983, however, make it difficult to establish whether these changes were the result of the 1982-83 E1Nifio event. Between May 1997 and June 1998 the second strongest ENSO event of the century occurred. A particular feature of this event was the occurrence of two intensity peaks, one in August 1997 and another in May 1998. Satellite-obtained data images indicate that in the Pacific coast of Colombia SST increased up to 2~ above the long term mean between May-September 1997, and more than 3~ between April-June 1998. In coincidence with the occurrence of this event there was widespread coral bleaching in tropical reefs around the world (ISRS 1998, Strong et al. 1998). In the Pacific coast of Colombia moderate to severe coral bleaching and mortality were observed at Utria, Gorgona, and Malpelo (Vargas-.~mgel et al. 2001). The first unequivocal signs of bleaching were observed at Gorgona in September 1997, when patches of Pocillopora at various depths showed bleaching on the distal portion of branches. At this time, the extent of bleaching on massive species (mainly Pavona spp.) was much greater than on branching species, with a high proportion of the upper surface of colonies bleached. The extent of bleaching at the scale of the reefs was, however, low (ca. 1%). By December 1997 bleaching was evident reaching on average 21% by April 1998 and 25% by June 1998 at Playa Blanca reef. Similarly, at La Azufrada reef, coral bleaching was low during October 1997 (< 1%) but had reached 21% by May 1998 (Vargas-Angel et al. 2001). At Playa Blanca reef the extent of coral bleaching was not uniformly distributed among reef zones. In June of 1998 bleaching had reached 17% on the reef slope and 30% on the reef crest.

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Evidently the extent of bleaching and mortality during the 1997-98 ENSO event did not reach the catastrophic proportions of the 1982-83 event. Casual observations made in August 1998 on Gorgona's main reefs revealed that, although coral mortality inevitably occurred, much of the coral previously bleached had recovered its normal coloration. Massive corals, however, were less capable of recovery than branching corals and thus suffered the greatest mortality. This differential mortality of corals as a result of sea warming and bleaching provides yet another reason to explain the high dominance of pocilloporids on TEP coral reefs (Vargas-.~gel et al. 2001). Meanwhile, the effects of E1 Nifio events for locations such as Malpelo Island, Tebada, and Utria still remain to be studied. Sclerochronological evidence indicates that corals at Utfia and Tebada were also severely impacted by the 1982-83 E1 Nifio warming event. During this disturbance, skeletal growth in massive corals was halted across the region, and regeneration of tissues over dead coral surfaces required as long as 2-3 years (Vargas-.~mgel et al. 2001). In some cases, corals never recovered and eventually died. Interestingly, the skeletal growth interruption associated to the 1982-83 E1 Nifio was more prevalent and conspicuous in corals from Gorgona Island than from Utria and Tebada, suggesting that the impacts of the disturbance may have been greater at Gorgona than farther north (Vargas-/kngel et al. 2001). Nonetheless, growth records of massive reef corals can only provide evidence for individual colonies, and therefore inferences on ENSO effects at the community level can only be speculative. Because our knowledge about coral reef community structure at Utria, Tebada and Malpelo prior to the 1982-83 warming event is limited or nonexistent, a full understanding of the predisturbance/post-disturbance dynamics for those reefs is still precluded. A study of the possible synergistic effects of E1 Nifio with other anthropogenic or natural disturbances such as upwelling, sedimentation, and aerial exposure should provide a more complete understanding of the interplay among the varied disturbance regimes and their effects on reef dynamics. 3.2. Extreme low tides Aerial exposure of coral reefs during extreme low tides is an abiotic factor potentially important for population regulation and community organization of coral species in the TEP (Glynn 1976). Based on knowledge of the tidal regime and on the observation of large tracts of dead coral on the shallowest portions of a coral reef, Glynn et al. (1982) suggested the occurrence of tide-related mortality of corals at Gorgona Island. Indeed, anecdotal accounts indicate that aerial exposures of reef corals at Gorgona have long been known, and verified events have occurred regularly at least since 1993 when one of us (F.A.Z.) began to study this phenomenon. Aerial exposure of corals at La Azufrada reef occurs when the tidal level drops to - 0.4 m relative to MLLW, which is the relative position of the shallowest corals. The frequency of occurrence and duration of potential, diurnal, aerial exposure events at La Azufrada has been examined based on tidal predictiom for the period 1966-1996. For this purpose, one aerial exposure event was defined as the emersion of corals on one or more consecutive days during a single spring-tide series. This analysis revealed that aerial exposure events occur on average every 90 d, although intervals between two consecutive events range between 25 and 441 d. On average, reefs arc exposed more than twice during one spring tide series and occasionally up to five times. Exposure events occur only between January and April and between August and December (F.A. Zapata et al. unpubl, data). Because this analysis was based

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on tidal predictions, it is only indicative of the importance of aerial exposures as an agent of disturbance. In fact, aerial exposure of reefs may be more or less dramatic depending on local climatic conditions (e.g., atmospheric pressure, winds) during spring tides, and on large scale climatic and oceanographic conditions. For instance, under conditions of an E1 Nifio event, when sea level is higher, aerial exposures may be reduced both in frequency and magnitude, while the converse may occur during La Nifia, when sea level is depressed. Nocturnal emersiom do occur as well, but may be less impacting than diurnal ones. Not all aerial exposure events affect corals, but after repeated and prolonged exposures, exposed tissues (usually at the distal portions of branches) are bleached and later die. Filamentous algae rapidly colonize dead portions and eventually grow to cover the entire colony. As a result, abundant algal patches of varied sizes are typically formed on the most elevated portions of the reef crest and reef flat. This effect appears to be widespread at Gorgona since it is readily visible on most reefs around the island one to three months after the occurrence of an emersion event. Comparisons of algal cover and coral richness and diversity on the reef crest of La Azufrada reef at Gorgona Island following the occurrence of one or more verified exposure events for two pairs of consecutive years (1992-93 and 1995-96) indicate that filamentous algal cover increased from almost 0% in previous years to a maximum of 24% following aerial exposure. Whereas coral species richness and diversity were not affected in 1993 when compared to 1992, both decreased in 1996 relative to 1995 levels (F.A. Zapata et al. unpubl, data). At la Chola reef (Ensenada de Utria), extreme low tides are also potentially deleterious to reef corals. For example, in October 1988 severe and widespread bleaching was observed resulting from a prolonged sub-aerial tidal exposure (-0.4 m), which coincided with elevated mid-morning air temperatures (2930~ Unexpectedly, this event did not cause coral mortality and corals recovered their normal pigmentation within two weeks (Vargas-Angel 1996). Not only are corals affected by the aerial exposure of reefs, but their associated fauna can be severely affected as well. Anecdotal accounts (R. Franke per. com.) indicate the occurrence of high mortality in a broad variety of reef associated organisms during extreme low tides. This mortality appears to be related to increased water temperature, and to oxygen depletion in the pools formed during the exposure of reefs. These pools act also as traps for many species, particularly fish. In addition, stressed corals appear to release great amounts of mucus that accumulates on the water surface and may contribute to the deterioration of water conditions. At present we have only observed the short-term effects of aerial exposure of reefs. Following the succession of algal patches, particularly focusing on their use by reef herbivores and measuring any potential bioerosion caused by them, will allow a better evaluation of the long-term effects of aerial exposures on coral community structure and reef development. Furthermore, a more detailed assessment of the impact of aerial exposures on the reef-associated fauna is needed. 3.3. Sedimentation Terrigenous sediment influx in coral reef ecosystems can lead to coral bleaching, as well as coral tissue necrosis and colony death (Cort6s and Risk 1985; Hubbard 1986; Cort6s 1990). On the Pacific coast of Colombia, coral reefs have not been exempt from this kind of disturbance. From 1960 to 1983, Gorgona Island was the site of Colombia's

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top-security prison. During this time extensive forest clearing occurred as well as largescale enterprises, including the construction of the penal facility to accommodate about 2000 people, a pier, a road and several trails, and a landing strip for small aircraft. According to Prahl et al. (1979) extensive coral death was observed on the backreef at La Azufrada as a consequence of sediment accumulation, mainly caused by the runoff of unstable top soils due to indiscriminate excavation for the construction of the landing strip. Even after >15 years of natural reforestation, corals at the boat channel-backreef interface in front of the landing strip at La Azufrada reef are still covered with fine sediment. In addition, recent concem has arisen about the possibility of siltation stress to the marine fauna of Gorgona Island due to the Naranjo channel. The Naranjo channel is a major engineering pitfall of the early 1970's, responsible for the diversion of more than 80% of the waters and the formation of a new delta for the Patia river, on the Colombian mainland about 50 km south of Gorgona Island. Possible impacts of this disturbance to the marine communities of the island were never considered at the time of construction. Recent satellite imagery suggests that the sediment plume discharged from the new delta of the Patia River may have been reaching Gorgona during the last twenty years (C. Monge per. com.). Preliminary measurements of sedimentation rates made in 1996 at La Azufrada reef (L.H. Chasqui and G. Morales un_publ, data) suggest that these are greater on the reef slope (7.9 g m-2 d-1) than in the backreef (2.7 g m-2 d-l). This result is contrary to what one would expect if sediments were primarily derived from Gorgona itself, and compatible with the idea that sediments arrive from the mainland. However, estimates obtained between November 1999 and March 2000 reveled greater overall sedimentation rates and a more complex spatial patterns (Lozano et al. unpubl, data). Sedimentation rates on the slope of La Azufrada and Playa Blanca were lower (34 and 47 gm2 d"l, respectively) than on the back reef at both sites (95 and 293 gm2 d ~, respectively), suggesting that terrestrial run-off from the island is important. Nonetheless, because surrounding currents generally flow in a north-eastern direction, the greater rates of sedimentation at Playa Blanca than at La Azufrada are still compatible with the idea that continentally derives sediments may be reaching Gorgona, but more comprehensive studies are clearly needed. Prahl and Vargas-/~mgel (1990) proposed that suboptimal environmental conditions in association with high rates of sedimentation were causative factors for reduced growth rates (12.7 mm yr-1) of the main reef builder, Pocillopora damicornis at La Chola reef, Ensenada de Utria. Moreover, the fact that La Chola reef is dominated by freely branching ecomorphs of Pocillopora damicornis can be considered as supplementary evidence in support for coral sedimentation and turbidity stress at Utria (Prahl and Erhardt 1985; Prahl and Estupifi~in 1990). In addition, Vargas-/kngel (2001) observed an increase in macroalgal biomass cover at La Chola reef and severe coastal erosion, in contrast to earlier observations in 1988 (Vargas-/kngel 1996). It is possible that elevated sediment loads, turbidity levels and concomitant nutrient loading have led to coral stress, fostering the proliferation of macroalgal patches at La Chola reef. Macroalgal cover may have also increased, however, due to the effects of aerial exposures during extreme low tides. Sediment stratigraphic studies by Vargas-,~-agel (2001) offer evidence of chronic siltation stress at La Chola reef during part of its Holocene growth history. The development of a relatively vital calcifying community under environmentally "poor" conditions is thought to occur due to the interplay of physical and biological factors,

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including climate, water circulation, the presence of mangrove forest and coral colony morphology.

3.4. Strong upwelling Seasonal upwelling along the coast of Central America is most apparent from December to March. The main driving force for these events is the intermittent arrival of high atmospheric pressures from Canada to the Caribbean and Central America. Under these conditions, coastal surface waters can be rapidly blown offshore, coastal level is depressed, and coastal upweUing can reduce surface water temperatures by nearly 10~ in less than a day (Legeckis 1988). During March 1985, unusually persistent upwelling off the Gulfs of Panama and Papagayo caused red tides severely affecting corals and coral reefs in Central America (Guzm,Sn et al. 1990). According to Legeckis (1988) this phenomenon depressed SST by 6 to 10~ relative to the surrounding waters, and cooler waters extended southwest off Panama reaching the Galapagos Islands. There are no reports, however, of the effects of this event on the corals of the Pacific coast of Colombia. Nonetheless, corals at Utria and Gorgona may have been affected, both by long-term exposure to low water temperature, as well as to toxicity, oxygen depletion and reduced light penetration caused by the dinoflagellate bloom (see GuzmAn et al. 1990). In February 1989, low SST (16-18~ in association with red tides resulted in widespread coral bleaching at La Chola reef, Ensenada de Utria (Vargas-.~mgel 1996). On this occasion, blooms of Gymnodynium sp. were responsible for the red tides (B. Vargas-/~ngel and F. Estupifi~n unpubl, data). Bleaching of corals was observed only at Utria, where corals regained their normal pigmentation in about a week. In contrast, although SSTs as low as 18~ also were recorded for Gorgona Island at this time (F. Estupifi~in unpubl, data), no red tides or coral bleaching were observed. 3.5. Tectonism Tectonic activity is common along the Pacific coast of Colombia, and strong earthquakes are not infrequent in this area (Oppenheim 1952; Case et al. 1971; Wilches-Chaux et al. 1993). Tectonic subsidence is the main process occtmSng along coastal southwestem Colombia (Herd et al. 1981). During the great Tumaco earthquake of December 12, 1979 (magnitude 7.9-8.1), which occurred 80 km southwest of the town of Tumaco and 200 km southwest of Gorgona, the sea floor at the Strait of Tasca (which separates Gorgona Island from the islet of Gorgonilla) reportedly subsided by 0.8 m (Herd et al. 1981). Neither substrate collapse and subsidence nor the accompanying tsunami were reported to have caused negative impacts to the corals and coral reefs at Gorgona Island. Nonetheless, episodic events of this nature can, not only seriously affect reef corals (see Woesik 1996), but also exacerbate the effects of other natural disturbances (Cort6s et al. 1992). However, moderate subsidence of the magnitude recorded at Gorgona in 1979 could, at least temporarily, reduce the negative impacts of tidal-caused emersion. In contrast with Colombia's southwestern coast, tectonic uplift is more prevalent farther north along the coast of Choc6. Although several major earthquakes have shaken this region (e.g., at Bahia Solano in 1970: Rarnkez 1971a, b), there are no reports on the effects that these occurrences might have had on the coral communities in the area. However, earthquake-caused landslides, such as the one that occurred on the coastal Panamanian-Colombian border in 1976 (Garwood et al. 1979), could cause serious damage to coral reefs in this region (see also Cort6s et al. 1992).

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4. ANTHROPOGENIC IMPACTS, PROTECTION AND MANAGEMENT Most coral formations in the Colombian Pacific region are within legally protected areas. These were originally under the supervision and management of the Park Division of the Institute of Natural Renewable Resources (INDERENA, Spanish acronym). Law 99 of 1993 (known locally as the Law of the Environment) created the Ministry of the Environment, under which INDERENA's Park Division became the Special Administrative Unit of the System of National Natural Parks (UAESPNN, Spanish acronym), now in charge of protected and special management areas in Colombia. The first coral reef area in the Colombian Pacific to be protected was Gorgona Island, which was declared as National Natural Park in November 1983 and became fully operative as such in July 1984, once the prison had been removed. The park encompasses the entire islands of Gorgona and Gorgonilla, and adjacent waters covering 61,000 ha. The Utria National Natural Park was created in December 1986 becoming functional in October 1987. This park covers approximately 54,200 ha, including portions of the continental and marine areas of Ensenada de Utria. Since 1987, it has been managed under a joint program between a private environmental NGO (Fundaci6n Natura), and the UAESPNN. Management activities for the coral areas of the park have included: 1) demarcation and delimitation of La Chola reef using buoys to prevent boat traffic, and 2) the implementation of a coral replenishment experiment and monitoring program. Malpelo Island was designated as a Sanctuary of Flora and Fauna in October 1995, and is under the care of the Colombian Navy, which maintains a small post on this remote island. All areas have been subject to some degree of anthropogenic impact, although as one would expect, impact has varied inversely with ease of access. Thus, while Malpelo is perhaps the least disturbed area, Ensenada de Utria seems to be the most disturbed. Alvarado (1992) listed 13 types of anthropogenic impacts likely to occur on Colombian coral reefs. Of these only two occur at Malpelo (direct contact by divers and fishing). At Gorgona, anchoring, sailing activities, direct contact by divers, and fishing were common during the years of the prison and first years after becoming a park. During the 1960's and 1970's some coral was regularly used as primary material for craft making by prison inmates. Most trails on the island used to be covered with coral rubble, which mixed with cement and sand was also used for the construction of some of the buildings' floors. It is most likely, however, that this coral rubble was collected on the beaches rather than extracted from the reefs. Today, except for one site (Yundigua), the coral reefs of Gorgona Island are closed to visitors, although they remain open to researchers. This has reduced significantly the amount of damage caused by careless divers and boat anchoring, which used to be perhaps the major sources of human disturbance on these otherwise wellpreserved reefs. At Ensenada de Utria, landslides, coastal erosion, siltation, dynamite blasting, and coral collecting and plundering have been reported as significant anthropogenic impacts (Vargas-Angel 1996). Despite being protected, coral formations of the Pacific coast of Colombia are not totally exempt from human induced perturbations. For instance, fishing still occurs in all areas and is a major source of conflict between local fishermen and park authorities, although coral reef fishes are not preferred target species. Nonetheless, some species are used as bait for larger fish caught outside coral reef areas. At Malpelo it is not unusual to see foreign fishing boats exploiting the abundant fish populations. Some coral collecting still occurs on probably all coral reef areas of the Colombian Pacific, but particu-

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larly at Utria. Pocilloporids are used for making crafts, which are commonly sold in Buenaventura and other coastal towns. In 1998, 800 kg of coral collected at Gorgona were confiscated by park authorities in Buenaventura showing that protection efforts are still insufficient to prevent coral collecting and trading. Evidently, park authorities lack sufficient resources for effectively enforcing conservation and management policies. Although rare, oil spills are another source of human disturbance to coral reefs in the Pacific coast of Colombia. Since 1996 at least two crude oil spills have reached Gorgona Island, apparently transported from Ecuador by northward moving currents. During the latest event, in March of 1998, an oil spill passed about 8 km southeast of Gorgona. Although it not directly hit Gorgona, about 2000 kg of tar were collected from the beaches by park personnel. No significant mortality of marine organisms was observed, however. Few studies have been conducted with the aim of providing scientific knowledge that will serve as the basis for sound conservation and management policies of the coral reef areas of the Colombian Pacific coast. Fundaci6n Natura, under agreement with park authorities, carried out a study to provide a basic cartography of habitat types and an ecological zonation scheme at Ensenada de Utria (Vieira 1992). Similarly, L6pez-Giraldo (1992) did a relatively detailed characterization of community types and provided a zonation scheme for the management of the marine area around Gorgona Island. Under contract with park authorities, Villa (1999) did a preliminary evaluation of the artisanal fisheries resources at Gorgona to provide information on which to base management decisions to ease the conflict between fishermen and park authorities. Park authorities have recently tried to get scientists to increase their contribution to the solution of specific conservation and management problems within protected areas. However, a weakly developed marine scientific community and an overall insufficiency of f'mancial resources for both research and management make this a challenging problem for all. ACKNOWLEDGMENTS We thank Jorge Cort6s for his invitation to write this chapter, and P.W. Glynn, J. Cort6s, and H.M. Guzm~n for their comments and suggestions on an earlier version of the manuscript. The Unidad Administrativa Especial del Sistema de Parques Nacionales Naturales del Ministerio del Medio Ambiente (UAESPNN) has granted permits and provided logistic support for our continuing work at Gorgona, Utria, and Malpelo. We thank the park's chief officers, particularly C. Acevedo and G. Mayor. F.A.Z. gratefully acknowledges the help and motivation of his students, particularly, Y.A. Morales, C.E. Bilrcenas, J.M. Jim6nez, P.A. Herr6n, V. Francisco, S. Lozano, C. Mora, L.A. Serrano, and A.F. Ospina. F.A.Z. also thanks J.L. Mat6 and H.M. Guzm~n for sharing their knowledge about TEP corals, D. Fenner for help in obtaining literature on Pavona frondifera, and S. Bessudo for sharing her knowledge of Malpelo. Universidad del Valle, Fundaci6n para la Promoci6n de la Investigaci6n y la Tecnologia del Banco de la Repfiblica, and the Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnologia (Colciencias) have provided financial support for F.A.Z.'s work. B.V.A. wishes to thank F. Estupifi~n, C. Moreno, A. Salinas and F. Ortega for their valuable collaboration with the field work. Financial support for B.V.A.'s work at Tebada, Utria and Gorgona has been provided by a doctoral scholarship from Colciencias and the Reitmeister fellowship from the University of Miami. Most of the original work by

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B.V.A. mentioned here is part of his Ph.D. dissertation at the University of Miami and will be presented in greater detail elsewhere. REFERENCES

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Coral communities and coral reefs of Ecuador Peter W. Glynn Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149-1098 USA

ABSTRACT: Reef-building coral formations along the mainland coast of Ecuador and in the Gal@agos

Islands are described with reference to coral species richness, community structure, relationship to physical and biotic controls, framework development and distribution. A brief history of coral studies in Ecuador is traced from the first notice of corals in the Gal~pagosIslands by C. Darwin in 1835 to the discovery of small patch and fringing coral reefs in the Gal~ipagosby G.M. Wellingtonin 1974. Recent ecologicalwork through 1998 is noted in the context of physical and biotic processes controllingthe developmentand maintenanceof these marginal eastern Pacific coral formations. Coral reefs also occur in the coastal waters of mainland Ecuador, but these have not yet (as of 2000) received detailed study. Most natural disturbances in the Gal~ipagos are local and varied, including, for example, tectonic uplift, rock slides, extreme low tidal exposures, and sea urchin bioerosion. Protracted sea warming associated with E1Nifio-SouthernOscillation (ENSO) events have in recent years caused extensive coral bleaching (i.e., the loss of zooxanthella endosymbionts from coral hosts), high mortality and the subsequent loss of reef frameworks by intense bioerosion. Anthropogenic disturbances from anchoring, entanglement of fishing lines and nets, coral extraction and, along the mainland, poor land use leading to extensive soil erosion, siltation and eutrophication, result in coral degradation. Despite the existence of the Machalilla National Park, whose boundaries include incipient coral reef frameworks at La Plata Island and the Machalilla fringing reef, no provisions for the protection of corals have been incorporated in the Machalilla park management plan. A management plan that provides for the protection of all wildlife in the Gal~ipagosreserve, including a 40 km perimeter in surrounding waters, is to some degree compromised by a lack of resources to ensure enforcement. With increasing fishing pressure, tourism and population buildup, the likelihoodof continued degradation of ENSO-damaged coral communities is high.

1. I N T R O D U C T I O N Reef-building corals are locally abundant along certain portions o f the Ecuadorean coast, on nearby coastal islands, and in the Gal~pagos Islands, located about 1,050 k m west o f continental South America (Fig. 1). Little is known o f the coral formations o f mainland Ecuador, which p r o b a b l y represents the s o u t h e m - m o s t limit o f significant coral d e v e l o p m e n t in the eastern Pacific region. Only occasional collections and m o d e s t reconnaissance studies have b e e n carried out along coastal mainland Ecuador. According to the U N E P / I U C N (1988) survey o f the coral resources o f mainland Ecuador, and a recent global assessment o f reefs at risk (Bryant et aI. 1998), no information is available either on the corals or their conservation status in this region. To help fill this void, some new inforLatin American Coral Reefs, Edited by Jorge Cort6s 9 2003 Elsevier Science B.V. All rights reserved.

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Fig. 1. Locationofprincipal surfacewatermassesnorth(TropicalSurfaceWater)and south(EquatorialSurface Water) of the Equatorial Front, which migrates seasonallyacross the equatorial eastern Pacific. PF (Panam~i Flow)denotesa southerly-movingsurfacecurrentactiveduringthe northernhemisphericwinter(January-April), and EUC (EquatorialUndercurrent),a localizedareaof upwellingin the westernsectorof the Gal~pagosIslands. CC (ColombiaCurrent) is the northerlyflowingeasternbranchof the PanamaBightgyreand AENC(AnnualE1 NifioCurrent), formingduringthe PF period,followsthe Ecuadoreancoastto Peru (afterFiedler, 1992;Strubet al., 1998).

mation from surveys conducted along the central mainland coastal region in the 1990s (1991 and 1998) will be presented in this account. In contrast to the limited knowledge base of coastal Ecuador, the reef-building corals and coral formations of the Galfipagos Islands are reasonably well known, in large measure a result of the high level of interest in these celebrated islands. Ecological studies in the Galfipagos have disclosed some level of understanding vis-fi-vis the physical and biotic controls of coral abundance and distribution. Ironically, not long aiter the discovery of coral communities and coral reefs in the Galfipagos, the reefs have all but disappeared and most coral communities have been severely degraded following the 1982-83 E1Nifio-Southem Oscillation (ENSO) event. As a result, overall coral cover was reduced by 95 to 99% of the pre-disturbance amounts. This disturbance event was due mainly to prolonged sea warming, which resulted in widespread coral bleaching (i.e., the loss of symbiotic zooxanthellae), mortality and subsequent coral framework erosion. The present condition of coral formations in the Galfipagos is notably degraded compared with their pristine state in the 1970s, as described in Glynn and Wellington (1983). In order to better understand these changes, pre- and post-ENSO differences in community structure and reef integrity will be briefly examined. Also, the present condition of mainland and Gal/Lpagos coral communities is contrasted in light of the 1997-98 ENSO event. To help develop a broader perspective of Ecuadorean coral community development, additional topics discussed below are: (1) the history of reef-coral studies, from Darwin to the present (2000), (2) the oceanographic setting of the region, (3) the coral fauna, including the composition and structure of coral communities, and the distribution and current condition of coral reefs, (4) natural and anthropogenic impacts, and (5) existing measures for the protection and management of reef-coral resources.

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2. HISTORY OF REEF-CORAL STUDIES 2.1. From Darwin to Durham (1835-1966) One may begin the history of coral studies in Ecuador with Charles Darwin's visit to the Gal/tpagos Islands aboard HMS Beagle in 1835. Notwithstanding Darwin's keen observations and insights relative to the biology and ecology of numerous organisms, especially in the terrestrial realm, precious few words were written on the corals. Indeed, in his book "The Structure and Distribution of Coral Reefs" (1889) Darwin concluded, "There are no coral-reefs in the Galapagos archipelago, as I know from personal inspection,...". Darwin also concluded, from the observations of others, that the western shores of America were entirely without coral reefs. During the voyage of the Beagle, only one non-reef building coral (Tubastraea coccinea Lesson) was collected by Darwin and described several years later by Duncan (1876). Aside from the naming of two new Gal~ipagos species by Milne Edwards and Haime, a non-reef building coral (Flabellum gallapagense in 1848) and a doubtful record of a reefbuilder (Madrepora [Acropora] crassa in 1857-1860), the first noteworthy account of the presence of reef-building corals in the Gal~pagos was by Pourtal6s (1875). Pourtal~s documented the occurrence of 5 species collected on beaches during the brief visit of the Hassler in 1872 with Louis Agassiz in charge of the scientific party. Two decades later, Alexander Agassiz (1892), who served as chief scientist aboard the U.S. Fish Commission Steamer Albatross in 1891, remarked on the abundance of eroded corals on Gal~pagos beaches, concluding that nearly all islands in the archipelago have coral sand beaches. While not recognizing the presence of coral reefs, members of the Albatross expedition did observe sizeable coral communities -- "The coral is mainly made up of fragments of Pocillopora, which is found covering more or less extensive patches off these coral sand beaches, but which, as is well known, never forms true coral reefs in the Panamic district." This conclusion was repeated by Hornell in Crossland' s (1927) account of coral studies in the Gal/tpagos during the expedition of the St. George to the South Pacific in 1925. From collections made by the Velero III and Velero IV expeditions in the 1930s, and the Gal/tpagos Expedition of the Xarifa during 1953-1954, several new corals were added to the Gal~pagos inventory (Durham and Barnard 1952; Durham 1962). This work was supplemented by extensive collecting by scuba divers during the 1964 Gal~ipagos International Scientific Project, resulting in a total of 32 coral species, with 11 representing reefbuilding or zooxanthellate species (Durham 1966). 2.2. Discovery of Coral Reefs and Recent Studies (1974-2000) During subtidal surveys to develop a marine resource inventory in the early 1970s (report completed in 1974), G.M. Wellington, while a Peace Corps volunteer, was the first worker to observe and recognize the importance of coral reef formations in the Gal/Lpagos Islands. Wellington was joined by C. Birkeland, P.W. Glynn and J.W. Wells in 1975 to continue with coral reef studies. Field work was also performed in 1976, resulting in publication of the first comprehensive account of the systematics and ecology of Galfipagos corals and coral reefs (Glynn and Wellington 1983, with an annotated account by J.W. Wells). Subsequent ecological investigations have examined corallivore activities (Glynn et al. 1979), the role of ENSO disturbances on coral bleaching/mortality and rates of coral reef accretion (Glynn et al. 1988; Colgan 1990, 1991; Glynn 1990, 1994; Glynn and Colgan 1992; Macintyre et al. 1993), bioerosion (Reaka-Kudla et al. 1996), coral reproductive

452

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ecology and recruitment (Glyrm et al. 1991, 1994, 1996, 2000), and the survival of relatively deep (15 m), ENSO-disturbed coral assemblages (Feingold 1995). The Urvina Bay (Isabela Island) coral community that was uplifted in 1954 has served as a model for paleoecologic studies (Colgan 1990, 1991; Malmquist 1991), and the fossil molluscan community at Villamil (Isabela Island south) offers some evidence that a coral reef community may have existed there over 500,000 years ago (Walker 1991). Core drilling of old, massive Galfipagos corals has offered material for several paleoclimate studies, showing skeletal growth patterns and oxygen and carbon isotopic signals that reflect variations in local SST, ambient light levels and ENSO activity (Druffel et al. 1990; Dunbar et al. 1994; Wellington et al. 1996). Analysis of the growth record of an extraordinarily large Urvina Bay P a v o n a colony, spanning a 350-year period, has revealed a pattern of increasing ENSO frequency from about 1700 to 1954. Studies of nutrient-like trace metals (Ba and Cd) on these coral cores can also serve as proxies of seasonal upwelling cycles and offer evidence for interannual interruptions of these cycles by E1Nifio and anti-E1Nifio (La Nifia) conditions (Shen and Sanford 1990; Shen et al. 1991, 1992). 3. OCEANOGRAPHIC SETTING Like the steep coastal margins of Peru and Chile, the continental shelf of Ecuador is narrow with the 200 m isobath located about 30 km from the shoreline north of the Gulf of Guayaquil (Fig. 2). From 10 to 20 km farther west, the continental slope descends abruptly to between 2000 and 3000 m depth. Deep waters also surround the oceanic Gal~pagos Islands, thus limiting shallow habitat areas for reef development. Ocean circulation processes are complex and highly variable over Ecuador's narrow latitudinal position. Major eastern tropical Pacific currents and water masses meet and migrate seasonally offshore, and local coastal currents and upwelling influence inshore areas (Houvenaghel 1984; Chavez and Brusca 1991; Fiedler 1992; Strub et al. 1998). The Equatorial Front (EF), an abrupt boundary separating tropical (TSW) and equatorial (ESW) surface waters, has a mean position at about 2~ near the coast, tilting to about I~ in the vicinity of the Gal~ipagos Islands (Fig. 1). During the northern (boreal) winter (DecemberMarch) the EF may migrate as far as 3-4~ and in the southern (austral) winter (JuneSeptember) it is located around 1-2~ TSW is characterized by temperatures normally in excess of 25~ and salinities less than 33.5 psu (practical salinity unit, -~%0). The relatively low salinities of TSW are a result of excess precipitation over evaporation near the Intertropical Convergence Zone (ITCZ), which migrates seasonally between about 5~ and 12~ A very sharp latitudinal gradient in precipitation occurs along the Ecuadorean coast. During the rainy season when the ITCZ is situated furthest south, the mean rainfall at I~ is 1.3 rn, and at 1o to 2 ~ S it is only 0.1 to 0.2 rm Equatorial surface waters, formed by the mixing of TSW, Perti Coastal Water and Subtropical Surface Water, generally has temperatures ranging between 20 ~ to 24~ and salinities of 33.5 to 35.0 psu. The chief currents that influence coastal Ecuador during the boreal winter are the southward-flowing Panarn,5 Bight gyre, here termed Panamfi Flow (PF), whose eastern-most branch joins the Annual E1Nifio Current (AENC). These currents bring warm, low salinity water (TSW) to the coastal region during the first part of the year (January-March). In this season, the Gal~ipagos also receive PF waters, which originate from the southward-moving

Coral communities and coral reefs of Ecuador

453

Fig. 2. CentralEcuadoreancoast, denotinglocaleswith knownor suspectedcoral formations. western branch of the Panarr~ Bight cyclonic gyre. Additionally, the westerly flowing Peni Current moves through the Galfipagos Islands at this time, and the Equatorial Undercurrent (EUC), a fast-flowing subsurface easterly directed current, results in upwelling where it surfaces in the western sector of the islands. Cool and nutrient-rich surface filaments move through the islands to the east and other branches of the EUC continue toward the South American coast and then poleward as subsurface and surface currents. Where upwelling is pronounced on the western side of the Gal~ipagos, with SSTs occasionally dropping to below 15~ it is not surprising that coral communities are absent. Coral community development does occur, however, in some areas sheltered from strong upwelling, such as in Urvina Bay (see below, '4.2.2 Galfipagos'). In the boreal summer, the Colombia Current is well developed along the Ecuadorean coast, where it moves northward and joins the eastern branch of the Panarmi Bight gyre.

454

P. 11I.Glynn

A southerly coastal current forms off Ecuador in the boreal winter, an extension of the western limb of the Panarrfi Bight gyre, which intensifies at this time due to strong northerly winds (the northeasterly Trades) moving across the Isthmus of Panarrfi. This coastal current flows to about 1 to 2 ~ S where it joins the Annual E1Nifio Current (AENC), which advects TSW to coastal Per6. The northward flowing Perti Coastal On'rent and Perti Current assume a more westerly course at about 5~ and eventually comingle to form a part of the northern edge of the South Equatorial Current. Upwelling on the west side of the Gal~pagos Islands continues during the boreal summer season. 4. CORAL C O M M U N I T I E S AND CORAL REEFS 4.1. The Coral Fauna The chief focus of this inventory will be on the colonial, reef-building or zooxanthellate corals, i.e. those scleractinian cnidarians harboring photosynthetic dinoflagellates in their gastrodermal cells. These endosymbionts facilitate rapid colony growth and skeletal calcification, allowing the host corals to accrete wave resistant structures with topographic relief. When large aggregations of corals build vertically into wave resistant features, often with the help of crustose coralline algae, this process results in the formation of structural coral reefs. Before the 1982-83 ENSO event, several small or incipient coral reefs, ranging from 0.5 to 5 m in vertical thickness (see Table 24 in Glynn and Wellington 1983), were present at several sites around the Gahipagos Islands (Figs. 3, 4). If corals do not build wave resistant structures, but are simply replaced by new generations of corals after death and .'

w

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in I

,~

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~

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Floreono

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Fig. 3. Gal~ipagos Islands, showing locations of chief coral community study sites (1-17) corresponding to those listed in Table 2.

Coral communities and coral reefs of Ecuador

455

Fig. 4. Pocilloporid incipient reef inside an extinct crater at Onslow Island (Devil's Crown) before the 1982-83 ENSO event (5 February 1976, 3 meters depth).

Fig. 5. Pavona clavus colonies exhibiting bleaching during the 1997-98 E1 Nifio event. Sides of colonies are bleached but still alive, tops of colonies are dead and covered with filamentous algae. Large colony in center is approximately 40 cm in diameter. OffPlaya Lapicona, Floreana Island, 12 m depth, 15 May 1998.

456

P. w. Glynn

erosion, then such aggregations are referred to as coral communities (Fig. 5). Notwithstanding this fundamental difference in building potential, both assemblages may exhibit high coral densities, species richness and diversity, and support high abundances of associated species. While coral reefs are relatively rare in the eastern Pacific and Ecuador, coral communities are often common-place under suitable environmental conditions (Glynn and Wellington 1983; Guzmfin and Cort6s 1993; Wellington 1997). With Ecuador's location within the equatorial eastern Pacific reef-coral province, which extends from mainland Ecuador to Costa Rica -- including the Galfipagos and Cocos Islands -- its surrounding waters support a relatively high coral species richness (Glynn and Ault 2000). Twenty-two species ofzooxanthellate corals are presently known from Ecuador, and approximately equal numbers occur at mainland and Galfipagos localities with 18 and 19 species, respectively, presently recognized (Table 1). The coral fauna of Ecuador has a close taxonomic affinity with central Pacific faunas (Wells in Glynn and Wellington 1983; Veron 1995; Glynn 1997; Glynn and Ault 2000). Eighteen of Ecuador's 22 species (81.8%) are also known from such localities as the Line Islands, Hawaii and French Polynesia. Four of Ecuador's coral species (18.2%), Pocillopora capitata, Pocillopora inflata, Porites panamensis and Pavona sp. a, are possibly eastern Pacific endemics, having evolved relatively recently in the isolated eastern Pacific region. Pavona sp. a is an uncommon coral, but occasionally present on volcanic rock substrates on the mainland coast and in the Galfipagos Islands (Fig. 6). Dana (1975) first suggested that the present-day eastern Pacific coral fauna was derived largely from Indo-Pacific migrants that dispersed from west to east via the North Equatorial Counter Current. This hypothesis is supported by the appearance of several central-west Pacific species, e.g. mollusks (Finet 1991; Kay 1991), echinoderms

Fig. 6. Pavonasp. a, an undescribedspeciesexhibitingbleachingduringthe 1997-98El Nifioevent. Colony lengthabout60 cm, encrustinga rockwall. Slightlydarkenedpatchesalonguppermarginofcolonywerepink. Playa Lapicona,FloreanaIsland, 7 m depth, 15 May 1999.

Coral communities and coral reefs of Ecuador

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TABLE 1. Reef-building corals of coastal Ecuador and the Galfipagos Islands, based on swimming surveys over a 25-year period. Relative abundances of corals (maximum numbers of individuals determined from counts in local populations): A, abundant, 10,000; C, common, 1,000; U, uncommon, 100; R, rare, 10; -, unrecorded, t, denotes dredged dead specimens (Durham and Barnard 1952). AI, only a single living population known.

Mainland Ecuador

Gal/LpagosIslands

Pocillopora capitata Verrill

U

U

Pocillopora damicornis (Linnaeus)

U

U

Pocillopora elegans Dana

C

C

Pocillopora eydouxi Milne Edwards & Haime

R

R

Pocillopora inflata Glynn

-

U

Pocillopora meandrina Dana

-

R

Pocillopora verrucosa (Ellis & Solander)

U

Porites lobata Dana

R

Porites panamensis Verrill

R

Psammocora brighami (Vaughan)

R

R

Psammocora stellata (Verrill)

R

U

Psammocora superficialis Gardiner

R

U

Gardineroseris planulata (Dana)

R

R

Leptoseris papyracea (Dana)

Rt

Species

C

Leptoseris scabra Vaughan

-

R

Pavona clavus Dana

C

C

Pavona gigantea Verrill

U

C

Pavona maldivensis (Gardiner)

-

R

Pavona varians Verrill

R

U

Pavona sp. a

U

U

Cycloseris curvata (Hoeksema)

g,

g

Diaseris distorta (Michelin)

Rt

An

(Lessios et al. 1996) and fishes (Groves 1989), at eastern Pacific localities during recent ENSO activity when the volume and velocity of easterly flow increases. In the 1950s-60s, only 5 species were known from mainland Ecuador (Durham and Bamard 1952) and 11 from the Gal~pagos Islands (Durham 1966). The relative abundances in the present species list are current, reflecting changes following the severe mortality events of the 1982-83 and 1997-98 ENSOs. Some of the documented population declines in the Gahipagos Islands are remarkable, with species that were once abundant, i.e. with local populations of 104 or more colonies, now being uncommon, with populations reduced to 102

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colonies (Pocillopora damicornis, Psammocora stellata). Also, some formerly uncommon species (Gardineroseris planulata, Cycloseris curvata) are now rare, with only 1 or a few colonies known. Decadal scale changes in the relative abundances of mainland species cannot be evaluated because coral communities have not yet been monitored there. Two Galfipagos pocilloporid species not known from the mainland are Pocillopora inflata and Poeillopora meandrina, and one mainland species, Pocillopora verrucosa, has not been reported from the Galfipagos Islands. P. inflata is found at several island sites, but is uncommon (Fig. 7). Pocillopora eydouxi is a recently discovered new record from the mainland, with a few colonies occurring at La Plata Island. Porites lobata is seldom seen in mainland coral communities, but is common in the oceanic setting of the Galfipagos, a distribution pattern repeated in the coastal and oceanic localities ofM6xico (Reyes Bonilla in press, this volume). Poritespanamensis occurs only on the mainland. This eastern Pacific endemic species broods planulae, which, once released, have only a limited (few to several hours) free-swimming larval stage (Glynn et al. 1994), a condition that might explain its absence from distant islands. All three species of Psammocora are found at both coastal and oceanic Ecuadorean localities. Gardineroseris planulata also occurs in mainland and Galfipagos coral communities, but is a rare species at both localities. Different species of Leptoseris are known at coastal and oceanic localities. Although not stated, it is likely that only dead specimens of L. papyracea were collected off La Plata Island (Durham & Bamard 1952). Four of five Pavona species are recorded from both localities. Only a few colonies ofPavona maldivensis have been found in the northern (Wenman and Culpepper) Galfipagos Islands. Two fungiid coral species, Cycloseris curvata and Diaseris distorta, are known from Ecuador, but living individuals have been collected only at Floreana Island,

Fig. 7. Pocilloporainflata,a recently-namedcoral species first recognizedin the Gal/LpagosIslands. An approximately 20 cm diametercolony on a basalt substrate, Punta Carri6n, Santa Cruz Island, 5 m depth, 23 November 1999, courtesyF. Rivera.

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Gal/tpagos Islands. These zooxanthellate corals are typically found on coarse sand bottoms in slightly deeper water (12-20 meters) than other species. 4.2. Coral Communities

Coral communities are paucispecific (consisting of few species) in Ecuadorean waters, as is generally the case in the eastern Pacific. They are usually present on fn'rn rocky substrates at shallow depths (_