Possible association of marine bacteria with paralytic shellfish toxicity of bivalves

Abstract

Significant amounts of paralytic shellfish toxins (PSP toxins) were detected in particles in the slze fraction 0.45 to 5 pm in seawater from Ofunato Bay, Japan, collected at a time when the toxicity of scallop increased in the absence of the causative organism Protogonyaulax tarnarensis. Toxin in the same fraction was negligible when scallop toxicity was decreasing. PSP toxins were also detected in the bacterial fraction from cell-free cultured medium of P. tamarensis. Pre- viously, we reported that Moraxella sp. isolated from P. tarnarensis produces PSP toxins. About 17 and 60 '10 respec- tively of bacteria in the seawater and the cultured medium of P tamarensis reacted with anti-Moraxella sp. serum. These results suggest that PSP toxin-produc~ng bacteria are present in the environn~ental water and are responsible for bivalve toxicity.