Irish Oyster Populations: A Historical and Genetic Study

Research into the history of oyster transplantations among Irish beds revealed a great deal of mixing of native stocks. Throughout the last one hundred years native beds, both private and public, have been restocked with huge amounts of oysters transplanted from Irish and foreign populations, so that a truly native oyster no longer exists. Because it is claimed that local stocks of oysters in Ireland are distinguishable from one another, starch gel electrophoresis was used to test for genetic differences between these stocks. The resulting allozymic patterns indicate that some differences do exist, but they are small compared with the variations previously reported to exist between Irish and Norwegian populations, and are hardly large enough to warrant the claim that the populations represent real genetic strains or races. This has some relevance to present restocking policies. Genetic variability in Ostrea edulis is considerably lower than in other shellfish species.