| Following the high mortality which killed the Portuguese oysters Crassostrea angulata cultivated on the French coasts, the massive establishment of Pacific oysters Crassostrea gigas, resisting the disease and the creation of artificial deposits for the latter was decided. In most culture areas, the mortality was estimated at more than 80 % of the stock, but, in some regions, some small populations of Crassostrea angulata subsisted and kept on reproducing. A genetic control of the spawner stocks had to be made. The first step was to know if the oysters living in the same areas were of the same species in order to foresee the next generations and try to improve them (selection). |
