SURVEY OF TOXIC EPIPHYTIC DINOFLAGELLATES FROM THE BELIZEAN BARRIER-REEF ECOSYSTEM

Benthic epiphytic dinoflagellates, associated with the human disease c iguatera fish poisoning (CFP), were found in low abundance on four spe cies of macrophyte from eight separate sampling sites from the Belizea n barrier reef ecosystem. Clonal cultures of Gambierdiscus toxicus, Pr orocentrum lima, P. belizeanum, P. hoffmannianum, and Il mexicanum wer e found to be toxic. Highest densities of dinoflagellates were found a s epiphytes on the rhodophyte, Acanthophora spicifera, while lowest de nsities were found as epiphytes on the angiosperm, Thalassia testudinu m. Prorocentrum lima was the dominant epiphytic dinoflagellate at all sites except the locations with greatest disturbance. At these sites, the dominant dinoflagellates were Gambierdiscus toxicus and Ostreopsis lenticularis. However, the maximum densities of all species observed were much lower than other ecological surveys on these dinoflagellates from the Caribbean. The low abundance of toxic dinoflagellates associ ated with the dominant macrophyte, Thalassia testudinum, may be respon sible for the low incidence of ciguatera in the Southern Belizean barr ier reef ecosystem. However, with the increased inhabitation of this a rea, cases of ciguatera may rise.