Toxin production in the dinoflagellate Protogonyaulax tamarensis.

Many clones of Protogonyaulax tamarensis were collected from Ofunato Bay in the same season and cultured under the same conditions. The toxicity of the cultured cells of these clones was remarkably different from each other (maximum of 100-fold). Significant differences (maximum of 20-fold) in toxicity of cultured cells were also observed among subclones isolated from a single clonal culture. It is unlikely that this variation in toxicity among subclones is due to mutation during culture. From these observations we suggest that toxin production in P. tamarensis is not a hereditary characteristic.