Accumulation of paralytic shellfish poisoning toxins in bivalves and an ascidian fed on Alexandrium tamarense cells

Cultured cells of the dinoflagellate Alexandrium tamarense were fed to four species of bivalves and an ascidian to examine the interspecific differences in the ability to accumulate paralytic shellfish toxins. The specimens of each species were reared in the same tank. All the species ingested almost all the cells fed and became toxic. Marked individual differences in toxin accumulation was observed in all the species. However, the average amounts of accumulated toxins increased during feeding. When the animals were fed on the same amount of cells, they accumulated almost the same amounts of toxins, indicating that interspecific differences in toxin accumulation observed in nature is due to the difference in ingestion behavior of the animals under natural conditions.