As a part of hydrological sampLing operation in South Brittany, 8 transects for 26 sampling stations were made in order to determine horizontal, and vertical distribution of Dinophysis sacculus in the 10 m layer. Un like to 1986, results do not show any correlations between Dinophysis concentrations and stability index. That may, nevertheless, be due to lower cells densities in 1987 when compared to 1986. A thermal, gradient, lower than in 1986, is still observable in the Bouthern of Loire Mouth. And, as a last point, when chlorophyll a concentrations are higher in - 10 m layer than in surface layer (Audierne and Noirmoutier areas), it can be observed hight densities of an other toxie Dinoflagellate : Gyrodinium aureolum . |