|Observations on bonamiasis in the stock of the European flat oyster, Ostrea edulis, in the Netherlands, with special reference to the recent developments in Lake Grevelingen|
Van Banning, P. (1991). Observations on bonamiasis in the stock of the European flat oyster, Ostrea edulis, in the Netherlands, with special reference to the recent developments in Lake Grevelingen. Aquaculture 93(3): 205-211
In: Aquaculture. Elsevier: Amsterdam. ISSN 0044-8486, more
Oyster culture; Parasites; Ostrea edulis Linnaeus, 1758 [WoRMS]; ANE, Netherlands, Grevelingen L. [gazetteer]; Marine
The stock of the oyster Ostrea edulis in the Netherlands is located in an estuary on two sites, Yerseke Bank and Grevelingen. The Yerseke Bank became infected with the protozoan oyster pathogen Bonamia ostreae in 1980, as a result of importations of infected oysters from France. Due to bonamiasis, the oyster production of the Yerseke Bank suffered increasing losses and finally ceased because of lack of commercial possibilities. The oyster stock of the Grevelingen has been checked since 1980 and was found to be free of bonamiasis until 1988. In the summer of that year the first presence of bonamiasis was observed. A rapid spread, with increasing prevalences, followed, both in wild stock and in commercial stocks. In 1989 maximum prevalence levels of 48% and maximum prevalences of dead oysters up to 80% were reached. The bonamiasis situation is considered serious for Dutch Ostrea edulis production in the coming years. A 5-year research programme has been started to monitor the spread of bonamiasis in the wild stock of the Grevelingen and to select the best management strategy for commercial production of O. edulis despite bonamiasis. From the first results it was concluded that bonamiasis was introduced into the Grevelingen by transport of infectious material, probably by ships. Further, it was concluded that the level of prevalence and development of bonamiasis is related in some way to (fishery) stress factors of the oysters and to environmental factors, but stocking density does not appear to affect the prevalence of bonamiasis.