Relationship between valve activity, microalgae concentration in the water and toxin accumulation in the digestive gland of the Pacific oyster Crassostrea gigas exposed to Alexandrium minutum

► Evaluation of behavioural responses of the Pacific oyster C. gigas to A. minutum exposure. ► Are behavioural changes related to concentration of harmful microalgae in water and/or to toxin concentration in oyster digestive gland? ► A dose-response relationship between the frequency of micro-closures and the concentration of A. minutum in the ambient water. ► A dose-response relationship between opening-duration and the PSP concentration in the digestive gland. ► Analysis at the individual level suggest that oysters exhibiting different sensitivity to PSPs exist within an oyster stock.