A Survey of Comparative Toxicity in the Good Chain of Ciguatera

Abstract

In order to elucidate the transmission of ciguatoxin through the food chain and thus determine the primary source of the toxin, fish and mollusks of various feeding habits were collected from three ciguatera-endemic areas of French Polynesia. The specimens included carnivores, herbivores, surface grazers, coral feeders, sediment feeders, and filter defers. Despite such diversity in feeding habits, all the fish specimens were more of less toxic by our screening method for ciguatoxin. The mollusks were non-toxic. Subsequent tests on the diets of these fish disclosed strong toxicity in a sample consisting of algae and detritus collected from the surface of dead coral of the Gambier Islands. Microscopic observation revealed the presence of a large number of a species of dinoflagellate in this sample. Comparison of similar samples from other places indicated that the dinoflagellate might be the cause of the toxicity.