Survey of toxic epiphytic dinoflagellates from the belizean barrier reef ecosystem

Abstract

Benthic epiphytic dinoflagellates, associated with the human disease ciguatera fish poisoning (CFP), were found in low abundance on four species of macrophyte from eight separate sampling sites from the Belizean barrier reef ecosystem. Clonal cultures of Gambierdiscus toxicus, Prorocentrum lima, P. belizeanum, P. hoffmannianum, and P. mexicanum were found to be toxic. Highest densities of dinoflagellates were found as epiphytes on the rhodophyte, Acanthophora spicifera, while lowest densities were found as epiphytes on the angiosperm, Thalassia testudinum. 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 associated with the dominant macrophyte, Thalassia testudinum, may be responsible for the low incidence of ciguatera in the Southern Belizean barrier reef ecosystem. However, with the increased inhabitation of this area, cases of ciguatera may rise.