| Since several years, the French oyster farming copes with high mortality affecting juveniles and some adults of the Pacific oyster Crassostrea gigas. Studies conducted in the framework of a multidisciplinary project (MOREST) showed that mortality was related to several factors like physiological and genetic status of oyster, pathogens including bacteria of the genus Vibrio, and revealed that the sediment, on which the oyster cages are installed, might play a particular role. This has been suggested because of the concomitance of the mortalities and increased toxic compounds like ammonia and sulphides in the sediment. Moreover, the presence of Vibrio bacteria in the sediment indicates a dual role of sediment in the mortality onset. The physico-chemical... |
