Status of Coral Reefs of the World 2000

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Status of Coral Reefs of the World: 2000 populations of Diadema. Acroporid reefs are in decline, presumably because of whiteband disease; other hard corals are affected by white plague and other diseases, and seafans by aspergillosis. Exceptionally intense coral bleaching occurred on both coasts in 1998, but there was widespread recovery. Low carnivorous and herbivorous fish populations and biomass occur in several reefs, which may partly explain the abundance of coral predators and scrapers, and macroalgae. Reefs at Herradura (31% coral cover), west of Havana, and in the Archiepelago de los Canarreos are reported to be in good condition. Dominican Republic Numerous surveys since 1992 all document the progressive degradation of Dominican coral reefs and other coastal environments due to human and natural impacts. High coral cover is found only at some deep or offshore reefs e.g. hard coral cover can be as high as 50% (average 35%) on the outer part of the Montecristi barrier reef. At the Silver Banks, mean coral cover is 40%, with turf algae at 51%. On inaccessible steep slopes below high cliffs at Samaná, cover by corals is about 40%, and by tube sponges 28%. Leeward (west) of the Parque Nacional del Este and south of Isla Saona are spur and groove reefs, far from the coast, at the northern part of which coral cover reaches 34% (with 25 species) with algal cover at 35%. Coral cover is generally less than 10% on most fore-reef slopes, although a back-reef at 3m depth had 25% cover, with 14 species. dominated by Porites furcata. Other examples of high coral cover (33%) were found on deep spurs beyond the highly impacted reefs of the south coast, exceeding algal cover (26%). Most nearshore reefs have been damaged by terrestrial runoff. Some watersheds have been deforested for centuries but sedimentation and other agricultural and industrial pollution continue today, especially from the many rivers. Shallow reefs near rivers on the central and south coast consist of mostly dead colonies, covered by turf algae, detritus and garbage. On deeper spurs at Boca Chica, coral cover is 20%, and that by algae 56%. At Parque Nacional Submarino La Caleta, the corresponding figures are 28% and 41%, while sponges and octocorals cover 13% each. On shallow, less disturbed coasts away from rivers, recent development for tourism has destroyed mangroves and wetlands, thus removing natural sediment traps and bringing nutrient pollution. Recent studies on shallow (3-10m) reefs of the north coast (Puerto Plata and Las Terrenas) show 80% coral mortality and 92% cover by algae. The poor status of reefs is partly due to the diseases affecting Acropora, Diadema (the absence of which enhances the spread of algae) and Gorgonia in the last 20 years. Still erect stands of dead A. palmata were seen from Bávaro and Boca Chica, with signs of white band disease in A. cervicornis at Bahía de Las Aguilas in the south-west, but there are also some recent recruits and healthy stands of both species. Haiti While it is presumed that reefs have suffered from the recent Caribbean-wide mortalities in Acropora and Diadema, as well as the effects of extreme deforestation, over-fishing and local pollution, few data are available. Urban runoff from Port-au-Prince has caused obvious impacts. Jamaica There have been dramatic changes in Jamaican coral reefs in the last 20 years: once dominated by corals, they are now dominated by algae. Major causes have been white- 266
Status of Coral Reefs in the Northern Caribbean and Western Atlantic band disease in Acropora spp., hurricanes Allen (1980) and Gilbert (1988), and the loss of herbivores through extreme over-fishing and the mortality of Diadema. Sewage pollution has been implicated at many sites. The thickets of elkhorn and staghorn that dominated the north coast reefs are gone. On fringing reefs around the island, mean coral cover at 10m depth fell from 52% in the late 1970s to 3% in the early 1990s, while mean algal cover rose from 4% to 92%. Since then, studies at 27 sites along 10km of the north coast around Discovery Bay showed that coral cover has increased slightly. In 1997, at 5m it was 15% (algae 35%), at 10m it was 16% (algae 56%), and at 15m it was 11%, up from 2%, although algal cover was 63%. This increase was mainly due to recruitment by opportunistic species such as Porites astreoides, P. porites and Agaricia agaricites, rather than by the original frame-builders such as the Acropora spp. and massive corals. An AGRRA survey in August 2000 from the south-west, along the north coast to the east reported that 10 sites above 5m (mean depth 2m) had live coral cover of 5%, and at 47 sites below 5m (mean 9m) coral cover was 12%. Deeper reefs, especially on the southern shelf edge, are in relatively good condition with Acropora palmata and A. cervicornis growing actively near Port Royal and with no current signs of white-band disease, in contrast to most of the north coast. But, in the last 10 years, other coral diseases have appeared on Jamaican reefs, with black-band and yellow-band (first seen in M. annularis in 1996) being locally destructive. The most severe occurrence of mass coral bleaching was in 1995 and although there was bleaching again in 1998 and 1999 there was little mortality. Turks and Caicos Islands Reefs are generally in good condition, with some observed pollution damage along the north and east coasts of Providenciales and along the west coast of Grand Turk, some diver impact at heavily used sites, and much Acropora palmata apparently lost to disease. At 5 dive sites on Grand Turk in 1994, coral cover ranged from 26% to 42%, sponges from 0.1% to 16%, while macroalgal abundance was always low. The most frequently dived site showed signs of diver impacts. AGRRA surveys in 1999 at Grand Turk, Providenciales, West Caicos, South Caicos, Ambergris Cay and the Mouchoir Bank found that coral mortality was low (
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Status of Coral Reefs of the World:
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FOREWORD Over the past few years, I
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CONTENTS COUNTRIES, STATES AND TERR
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COUNTRIES, STATES AND TERRITORIES A
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Countries, States and Territories T
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EXECUTIVE SUMMARY CLIVE WILKINSON T
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Executive Summary CORAL BLEACHING I
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Executive Summary South Asia Most r
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Executive Summary parts of Fiji and
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Executive Summary management and mo
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Executive Summary tourism developme
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Executive Summary problem is loomin
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6. STATUS OF CORAL REEFS IN SOUTH A
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Status of Coral Reefs in South Asia
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8. STATUS OF CORAL REEFS OF EAST AN
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Status of Coral Reefs of East and N
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9. STATUS OF CORAL REEFS OF AUSTRAL
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Status of Coral Reefs of Australasi
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10. STATUS OF CORAL REEFS IN THE SO
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Status of Coral Reefs in the Southw
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11. STATUS OF SOUTHEAST AND CENTRAL
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Status of Southeast and Central Pac
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12. STATUS OF CORAL REEFS OF AMERIC
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Status of Coral Reefs of American S
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Status of Coral Reefs in the Easter
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18. STATUS OF CORAL REEFS IN SOUTHE
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Status of Coral Reefs in Southern T
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19. SPONSORING ORGANISATIONS, CORAL
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Sponsoring Organisations, Coral Ree
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LIST OF ACRONYMS AGRRA AIMS ASEAN B
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