Comparative Toxicity of Gonyaulax monilata and Gymnodinium breve to Annelids, Crustaceans, Molluscs and a Fish

SYNOPSIS. Toxicities of laboratory cultures of the dinoflagellates Gonyaulax monilata and Gymnodinium breve were compared using fish, annelids, crustaceans and molluscs. Toxicity was evaluated as mortality over a 48‐hr test period in 100%, 75% 50%, 25% and 10% concentrations of dinoflagellate cultures. Responses of the assay animals indicated that the dinoflagellates do not produce the same toxins. Effects of the toxins seemed uniform within each major group of animals tested. Fish were most sensitive to both G. breve and Gonyaulax monilata; crustaceans were resistant to both; annelids and molluscs were more sensitive to G. monilata than to G. breve.