Observations complementaires sur les causes possibles des anomalies de la reproduction de Crassostrea gigas (Thunberg) dans le bassin d'Arcachon.

The spat production in the Bay of Arcachon has been recently disturbed. Bioassays using algae used as food for oyster larvae have shown that the organotin paints affect or inhibit growth of Isochrysis galbana and Chaetoceros calcitrans . Fresh waters coming into the bay and shore sediment did not affect the growth of these algae. Bioassays proposed by Woelke (1967) using embryos and larvae of Crassostrea gigas have shown that the quality of the sea water from Arcachon harbour has been improved a few months after the use of organotin paints has been prohibited. Likewise fresh waters are free from any micropollutants that could drastically disturb the reproduction of C. gigas in the bay.