Status of Caribbean coral reefs after bleaching and hurricanes in 2005

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Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005been slowly recovering, however, coral cover was still low and the threats from increasinghuman populations and economic pressures continued to grow.The first warning of problems came from NOAA in late May 2005 that indicated ‘HotSpots’developing in the Northern Caribbean, especially around the Virgin Islands. These warningsalerted the scientists and NGOs in the region to examine their reefs in more detail. The resultsof subsequent surveys of bleaching and mortality in each country are summarized below.U N I T E DS T A T E S80° W70° WBERMUD AN ORTH ATLANTICOCEA NGu lfofMexi coGrandBaham aIsLEGENDCoral Reefs0 11 0 220 440F l o r i d aBAHAMA SKilometersAndros I sSan SalvadorHavanaSabana Camaguey23° N 23° NBatabanoTURKS andCA ICOS I slandsGuanahacabibesIs la de Pino sCUBATurks BankGuacanayaboGrand C ay ma n Li ttl e CaymanCayman IslandsGonaveHA IT IDOMINICA NREPU BLICPUERTOR ICOBritish VirginIslands80° WJA MAIC APedro CaysJaraguaMorant Cays70° WC a r i b b e a n S e aUS VirginIslandsMap of the Northern Caribbean region.Ec o l o g i c a l a n d So c i o e c o n o m i c Im p a c t s o f Co r a l Bl e a c h i n g a n d Hu r r i ca n e sin 2005BahamasGeographic Distribution and Extent of Coral Reefs: The Bahamas contain 13 major islandsand more than 2000 smaller islands or cays, distributed over 260,000 km 2 on 2 large, shallowbanks (Great Bahama Bank and Little Bahama Bank) separated by depths exceeding 4000 m.They are aligned northwest to southeast for more than 1400 km, from near Florida almost toHaiti. Coral reefs fringe most of the north and east windward coasts and bank edges and cover1832 km 2 of the Great Bahama Bank and 324 km 2 of the Little Bahama Bank. Andros Islandis the largest island with the third longest barrier reef system in the world (229 km). Reefdevelopment in the Bahamas is limited by hurricanes in exposed regions, cold winters in thenorthern Bahamas and by turbid, hypersaline waters on the leeward bank margins.74
The Effects of Coral Bleaching in the Northern Caribbean and Western AtlanticStatus of coral reefs prior to 2005: Prior to 2005, live coral cover in the Bahamas was highlyvariable between sites, with cover ranging between 1% at Lindsay Reef at 4 m depth to 47%at Strip Reef at 10 m.Impacts of Coral Bleaching in 2005: Reef Check conducted one survey at Turtle Rocks inAugust 2005 during the coral bleaching episode. This survey determined that live coral coverwas 14%; 17% of coral colonies were affected by bleaching; and bleached colonies exhibitedbleaching over 25-50% of their surface. No recently killed coral was recorded during thesurvey and a subsequent survey conducted in August 2006 recorded live hard coral coverof 18%, indicating that the 2005 bleaching event caused little or no coral mortality in theBahamas.BermudaGeographic Distribution and Extent of Coral Reefs: Bermuda is an isolated island chain 920km off the coast of North Carolina on the Bermuda Platform. Together with the Challenger andArgus Banks, they occupy about 900 km 2 . The fringing, bank-barrier and lagoonal patch reefsform the most northerly coral reef system in the Atlantic and are supported by warm watereddies from the nearby Gulf Stream. Coral diversity is, however, limited by cool winters.Status of coral reefs prior to 2005: There has been little change in these coral reefs, which arethe most northerly reefs of the region (Latitude 32°20’N), during the 10 years to 2005. Coralcover remained at 20% around the rim, 10-15% on lagoon patch reefs, and 45-50% on terracereefs. There are healthy herbivorous fish populations, and the reefs escaped serious impactscaused by coral bleaching that damaged reefs to the south in 2005. A comparison with the firstsurveys 25 years ago illustrates the stability: hard coral cover on the terraces - 52.4% in 1981vs 54.0% in 2005; and 22.5% in 1981 on outer rim coral-algal reefs vs 24% in 2005. Much ofthe stability on Bermudan reefs could be the result of a predominance of slow growing massivegrowth forms (Diploria, Montastraea and Porites species) and few branching and bleachingsensitive corals like Acropora.Impacts of Coral Bleaching in 2005: Some coral bleaching was observed on Bermudan reefsin 1988, 1991, 1992, 1995, 1998 and 2003, however, only the 1988 and 2003 events wererecorded in detail. In 2005, seawater temperatures peaked at 30.3°C in mid to late August atmost locations, except at 10-15 m depth on the terrace reef sites, which peaked at 28.7°C inearly September. All sites cooled with the passage of tropical storm Philippe. Thus, seawatertemperatures during 2005 were not unusual compared with previous summers and nowidespread bleaching or disease of corals was observed. Hard coral cover was 22.7% in 2005;the same as 2004 and a slight increase on the 14 year mean (20.8%). Black-band disease andwhite plague on Diploria, Montastraea and Porites astreoides are the most common diseasesin Bermuda, and occur mostly on the outer rim and lagoonal patch reefs. Yellow blotch diseaseis also relatively common in Montastraea franksii.Impacts of Hurricanes in 2005: In 2005, there were 3 tropical storms (‘Franklin’, ‘Harvey’ and‘Philippe’) and 2 hurricanes (‘Nate’ and ‘Wilma’) near Bermuda. However, peak wind speedsdid not exceed 90 km/h (i.e. generally less than regular winter storms). The major effects ofthese storms were to temporarily lower seawater temperatures by 1-2°C, with no significantdamage to the coral reefs.75
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Stat u s o fCa r i b b e a nCo r a
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Dedication: This book is dedicated
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Status of Caribbean Coral Reefs aft
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Status of Coral Reefs in the Caribb
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Status of Caribbean coral reefs after bleaching and hurricanes in 2005

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