TWENTY-FIFTH ANNUAL EASTERN FISH HEALTH WORKSHOP MARCH 10-13, 2000   Dynamics Of A Fungal Epizootic Of Sea Fan Corals In The Caribbean     Kiho Kim1 and C. Drew Harvell2   1Center for the Environment and 2Ecology & Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.     Sea fan corals (Gorgonia ventalina) are dominant members of shallow water coral reef communities in the Florida Keys and elsewhere in the Caribbean. In some areas of the Florida Keys, Gorgonia ventalina occurs at densities >2 colonies per m2 and represents as much as 21% of coral cover. In 1995, a fungal disease (aspergillosis) of sea fans was discovered and although we have found chemical resistance in sea fans against the fungus, the impact of aspergillosis has been significant. At the start of our monitoring (September 1997, n = 8 sites x 3 transects per site), Keys-wide disease prevalence was 42.7% (±3.18 SE), with disease severity (the amount of infected tissue per affected colony)at 23.2% (±3.34 SE). Repeated surveys (most current data from May 1999) of these transects indicate that disease prevalence has been declining; however, severity has remained unchanged. There does not appear to be consistent seasonality to the disease, although prevalence tended to increase in early summer during some years. Laboratory experiments indicate that increasing water temperature favors the fungal pathogen and reduces the efficacy of host resistance. Photomonitoring of individual sea fan colonies indicates that the disease can cause rapid demise of the host. At the population level, aspergillosis has caused a substantial decline in the abundance of G. ventalina in the Florida Keys. At one site, density decreased by more than 20% and sea fan coral cover was reduced by more than 60%. Coral reefs of the Florida Keys have been in decline over the last several decades and our study shows that this decline has been exacerbated by disease.     Return to 25th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page