Testing of the Argentina oyster, Ostrea puelchana, in several French oyster farming sites

Because of diseases affecting fIat oyster Ostrea edulis, acclimatization of the Argentina oyster Ostrea puelchana has been tested in 1989-90 in five French oyster farming sites. Following ICES recommendations , hatchery produced juveniles, from parents imported from Argentina, were transferred to experimental si tes in summer 1989. Very high mortalities occurred, reaching 46 to 98% in March-Apri1 1990. They continued later on, resulting in the end of experiments in March 1991. The growth of surviving oysters was relatively poor in comparison of the local species. Parasites Marteilia refringens and Bonamia ostreae have been detected but at rates inadequate ta explain the high mortalities. AlI these results lead not to retain this species for breeding on French coasts