Status of Caribbean coral reefs after bleaching and hurricanes in 2005

More documents

Recommendations

Info

Status of Coral Reefs of the Lesser Antilles after the 2005 Coral Bleaching EventIm p a c t s o f Hu r r i ca n e s in 2005The three island groups, Guadeloupe, Martinique, and Saint-Barthélemy and Saint-Martinwere not affected by hurricanes in 2005. Previous hurricanes caused some damage: Iris, Luisand Marilyn in 1995; and Lenny in 1999.So c i o e c o n o m i c Im p a c t s a n d Ma n ag e m e n t ResponsesIn Guadeloupe, the Grand Cul-de-Sac Marin marine reserve was created in 1987 and anexperiment to farm the branching corals Acropora palmata and A. cervicornis was initiatedby the Université des Antilles et de la Guyane in 2005 in the lagoon. The project was achievingencouraging results, until the bleaching event killed all the farmed corals. This indicates thatcoral farming in an uncontrolled environment may not be a good palliative solution to coralrepopulation. The alerts issued about potential bleaching in the MPAs resulted in increasedsurveillance and monitoring, but there was no other specific management intervention.Co n c l u s i o n s - 2005 Bl e a c h i n g in t h e Fr e n c h West In d i e s.Coral mortality on the outer reef slopes of the FWI islands ranged between 25% and 52% atdifferent reefs. The variation in mortality was primarily associated with the species compositionof the reefs, rather than differing ecological conditions between the reef sites. Coral speciesshowed a large range of bleaching responses to the increased sea temperatures, for example,corals of the families Agaricidae, Favidae and Mussidae were particularly susceptible tobleaching. There was a significant positive correlation between the delayed coral mortality seenand the degree of bleaching in most of the corals. However, some species that bleached rapidlyin 2005 recovered well during 2006 e.g. the Poritidae. The hydrocoral, Millepora squarrosa,which was common on the reefs previously, appears to have almost disappeared from the FWIand no recruits were seen in 2006 and 2007.As the three-dimensional structure of the reefs and their capacity to provide shelter for theassociated animals have not changed significantly as a result of the bleaching event, thespecies richness, abundance and community structure of reef fish assemblages have remainedsimilar.The Netherlands AntillesIn t r o d u c t i o nThere are 2 distinct island groups in the Netherlands Antilles: Bonaire and Curaçao are smalloceanic islands 70 km north of Venezuela, with continuous fringing reefs around the islandsthat are particularly well developed on the leeward sides; and St. Maarten, Saba and St. Eustatiusare on the northern arc of the Lesser Antilles and are volcanic with steep cliffs, narrow shelvesand limited reef development along the windward coasts. There is limited coastal developmenton St. Eustatius and Saba, thus anthropogenic effects are minimal. St. Eustatius has truecalcareous reefs and also corals growing on the volcanic rocks. The only true reefs on Saba areon the eastern side of the island and most sheer walls are populated by sponges. St. Maarten,which is shared between the Dutch (southern portion) and the French (northern portion),has seen rapid population growth and unmanaged expansion of tourism such that the reefshave been degraded by pollution, deforestation, sedimentation, eutrophication from sewage,recreational boating and anchors, particularly along the south and west coasts. A submergedatoll with actively growing reefs, known as the Saba Bank, is also within Netherlands Antilleanwaters.93
Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005Stat u s o f Co r a l Reefs Pr i o r to 2005Bonaire and Curaçao: The greatest diversity of corals are on the leeward (western) side on a30 m to 150 m wide terrace that slopes gently to about 12 m depth. The prominent corals areAcropora palmata, A. cervicornis and Montastraea annularis, with many large hard coral headsand a variety of gorgonians. After the drop-off at 10–15 m depth, the fore-reef slopes downwardsat 30-60 degrees to a sediment bottom between 30 m and 50 m depth. The dominant corals areM. annularis, M. faveolata, and Agaricia agaricites, with M. cavernosa and Stephanocoeniain deeper waters. On the northern side of Bonaire at Boca Bartol and Playa Benge, the reefshave unusual shallow water spur and groove formations, while the southern facing shore hasbuttresses that slope steeply down to the sediment platform at 100 m depth. The reefs on KleinBonaire are varied with some descending steeply close to the shore to a sediment platform at25-30 m depth. The reefs of Curaçao are similar although there are vertical drop-offs from 6-35m depth on the eastern side.The terrace on the eastern side of Bonaire and the north-eastern side of Curaçao extends 100-200 m offshore and to a depth of 12 m, with primarily crustose coralline algae, Sargassum, andsome gorgonians. The leeward reef slope has less coral cover and abundant brown algae.On Curaçao, there are about 250 fish species and 55 coral species, with an average of 19 coralspecies per 200 m 2 at 6 m depth and 23 species at 12 m. Live coral cover at most sites declinedby 10% between 1997 and 2002, with a greater decline at 6 m depth than at 12 m. In 2002,coral cover at 6 m depth on the leeward side of Curaçao was 30-50%, and 30-70% at 12 m.Since 1983, A. cervicornis has almost disappeared because of white-band disease, except for afew small stands. A. palmata has also declined on both Curaçao and Bonaire. The shallow reefs(0-2 m depth) have completely disappeared since the early 1980s.There are only 20-30 commercial fishers on Bonaire, but many people fish recreationally. Thecommercial targets are mostly pelagic species (tuna, dorado, wahoo) caught with hook andline, although trai (throwing nets) and reda (encircling nets) are used to catch bait and big-eyescad respectively. Spear-fishing is illegal, but still occurs, and the use of kanasters (fish traps) isdiscouraged because of the conflicts they cause with recreational divers. In 2000, reef fish wereabundant and diverse and biomass was high. However, in 2002, grouper, conch and lobsterwere absent from some of Bonaire’s reefs and snapper populations were declining. Parrotfishwere still abundant because they are considered inedible. Illegal poaching of turtles also occurs,killing as many as 20 turtles per month. Collection for the aquarium trade is banned.On Curaçao, there are a few hundred artisanal fishers who mostly target pelagic species. Fishtraps and gill nets are also used and illegal spear-fishing is still practiced. Fish populationshave been severely reduced by heavy fishing pressure; larger fish, particularly groupers andparrotfish, lobsters and conchs are rarely encountered. However, snappers and small parrotfishare still fairly common. Turtles are protected, but are occasionally caught as by-catch.Saba: There are 35 coral species and some gorgonians, with the dominant corals beingMontastraea anularis, M. cavernosa, and Diploria strigosa. Rough seas reduce coral cover inshallow waters (0-7 m) and storms in 1998 and 1999 caused major declines in the abundanceof Acropora palmata. Coral cover does not exceed 20% because of high sediment loads andfrequent benthic algal blooms, and massive corals are often overgrown by bioeroding sponges.94
Page 1 and 2:
Stat u s o fCa r i b b e a nCo r a
Page 3 and 4:
Dedication: This book is dedicated
Page 5 and 6:
Status of Caribbean Coral Reefs aft
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Status of Coral Reefs in the Caribb
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
3. Hu r r i ca n e s a n d t h e i
Page 37 and 38:
Hurricanes and their Effect on Cora
Page 39 and 40:
Hurricanes and their Effect on Cora
Page 41 and 42:
4. Th e 2005 Bl e a c h i n g Ev e
Page 43 and 44:
The 2005 Bleaching Event: Coral-Lis
Page 45 and 46: The 2005 Bleaching Event: Coral-Lis
Page 47 and 48: The 2005 Bleaching Event: Coral-Lis
Page 49 and 50: 5. Stat u s o f t h e Mesoamerican
Page 51 and 52: Status of the Mesoamerican Reef aft
Page 65 and 66: 6. Co r a l Reefs o f t h e U.S. Ca
Page 67 and 68: Coral Reefs of the U.S. Caribbean19
Page 69 and 70: Coral Reefs of the U.S. CaribbeanMe
Page 71 and 72: Coral Reefs of the U.S. Caribbeanwe
Page 73 and 74: Coral Reefs of the U.S. CaribbeanSe
Page 75 and 76: Coral Reefs of the U.S. CaribbeanBl
Page 77 and 78: 7. Th e Effects o f Co r a l Bl e a
Page 79 and 80: The Effects of Coral Bleaching in t
Page 89 and 90: Status of Caribbean Coral Reefs aft
Page 95: Status of Caribbean Coral Reefs aft
Page 107 and 108: 9. Th e Effects o f Co r a l Bl e a
Page 109 and 110: The Effects of Coral Bleaching in S
Page 117 and 118: 10. Ma n ag i n g f o r Ma s s Co r
Page 119 and 120: Managing for Mass Coral Bleaching:
Page 147 and 148:
Page 149 and 150:
show all

Status of Caribbean coral reefs after bleaching and hurricanes in 2005

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?