Research Product

Coral abundance and the condition of reefs in the Caribbean, and in particular, the Florida Keys have declined substantially over the last 30 years. This study assessed trends in coral condition over five years in a region near high population density (Key West, FL) and an off shore remote region (Dry Tortugas, FL) following massive bleaching during 1997-1998 and Hurricane Georges in 1998. Quantitative SCUBA-based surveys assessed abundance and diversity of 16 scleractinian and two gorgonian species, by evaluating their bleaching status, and prevalence of 10 coral disease types at 12 sites in each region. The prevalence of coral bleaching and disease were greatest following the 1997 -1998 El Nino event, with over 40% mean prevalence of bleaching on some Key West reefs. In the Dry Tortugas, reefs have shown a general trend of recovery since 1999, whereas Key West reefs have shown a continuing decline in total coral abundance. Acroporids have shown precipitous declines on reefs in the vicinity of Key West, from an average of 45 colonies per site in 1998 to less than 4 in 2002. The prevalence of disease in Key West corals remained below 6% between 1999 and 2001, then exhibited a significant increase in 2002. These results suggest differential sensitivity to bleaching and disease, and the decreased potential for recovery of reefs in proximity to areas of higher anthropogenic influences compared to more remote location