Seasonal occurrence of

On the basis of hydrological and biological data collected between 1983 and 1987 along the French coast, and especially in the southern approaches to Brittany. it has been possible to compare different parameters in an attempt to explain the seasonal variations of a toxic dinoflagellate: Dinophysis sp. speveral species were identified and their seasonal distribution patterns are described. The origin of the blooms, from either coastal endemic or offshore populations, is considered