Morphologycal and microstructual study of Crassostrea gigas in stuaries and yachting harbours of the western Biscay coast

This work analyses the morphology and the microstructural characteristics of some specimens of Crassostrea gigas collected in diferents points of the Biscay coast. Oysters recollected in yachting harbours, where they are in contact with tributyl-tin (TBT), have morphologycal and microstructural shell anomalies. The presence of TBT in the sea water and the associated shell anomalies in oyster are more obvious and detectables in spring because of the maintenance of the ships. In other sampling areas, although the bivalves have not shown any malformations, other morphologycal variations associated to the abundance of nutrients have been determinate