Status of Caribbean coral reefs after bleaching and hurricanes in 2005

Status of Caribbean Coral Reefs after Bleaching and Hurricanes in 2005The bleaching event developed rapidly and simultaneously on deep and shallow reefs on boththe west and southwest coasts of the island. The first signs of bleaching in the most susceptiblespecies appeared when SSTs rose above 30 o C for more than 1 week. As the length of exposureincreased, virtually all hard coral species eventually bleached, regardless of whether they wereon degraded inshore or healthy offshore reefs. This demonstrated that elevated SSTs can causecoral bleaching on a massive scale and override other stress signals.The onset of bleaching mortality was rapid in some corals, notably Millepora and Porites porites,whilst the vast majority remained bleached for many months without significant mortality. InFebruary 2006, there was a mean of 37.5% of colonies still bleached, although mortality wasonly 3.8%. By June 2006, bleaching persisted in 17.2% of colonies and recent mortality wasmuch higher at 18.7%. Inshore reefs were harder hit, with 20.1% colony mortality, comparedwith 17.4% mortality for the offshore reefs.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 ResponsesThe events of 2005 are of great concern for tropical islands like Barbados; particularly as theglobal warming trend is predicted to continue. If SSTs rise by 2-3 o C, annual bleaching willprobably become common in the Caribbean. Therefore, a well-coordinated, regional monitoringprogram is required so that more effective management strategies can be implemented at boththe regional and local levels.Coral reefs are recognized as being particularly important to the Barbados economy; thus theGovernment, through its Coastal Zone Management Unit, has developed a coastal managementplan with sections devoted specifically to coral reef protection. This includes a long-termprogram of monitoring for reefs at 5 yr intervals on 21 west coast, 16 southwest coast fringingand patch reefs and 6 west and southwest coast bank reefs. Previous monitoring indicates thatmuch of the reef deterioration on the west coast was the result of increasing nutrients from theland. In response, the Government constructed the South and West Coast Sewage TreatmentProject to reduce pollution. This was part of a coastal zone management plan that outlinespermitted coastal development and is enforced through the Coastal Zone Management Act,which protects all corals from physical damage, and the Marine Pollution Control Act, whichprotects corals from land-based sources of pollution.The Government has recognized that healthy reefs are more resilient to coral bleaching andother effects of climate change (e.g. potentially greater incidence of coral disease) than degradedreefs. As a result, increasing efforts to reduce anthropogenic stress has become a managementpriority. Efforts to manage and conserve coral reefs must include all reef types to cover thespectrum of resistance and resilience to bleaching demonstrated by the various coral speciesin different reef habitats. Small, vulnerable states like Barbados should strive to minimizeanthropogenic effects on corals to conserve coral reef resources locally, and put pressure onthe international community to reduce global greenhouse gas emissions.100