Abstract

In this study we report on the prevalence of Bonamia ostreae in stocks of flat oyster (Ostrea edulis L.), from different origins (natural settlement, hatchery, Italy and England), cultured in several areas of the Galician coast (estuaries of Vivero, Ortigueira, Camariñas, Noya, Arosa and Vigo, and inlets of S. Ciprián and Anllóns) during 1994. We found significant differences in the infection rate of B. ostreae in the different growing areas. In some of them the parasite was not detected (0 Freixo and Coroso in the estuaries of Noya and Arosa respectively and in the estuary of Camariñas), while in other areas, the prevalence reached values higher than 50% (Raia and Fornelos in the estuary of Ortigueira, A Creba in the estuary of Noya and Noalla in the estuary of Arosa).