Assessment of genetic diversity of the European oyster (Ostrea edulis) in Nova Scotia using microsatellite markers
The European oyster (Ostrea edulis) was introduced to the Nova Scotia aquaculture industry 30 years ago using stocks imported from naturalized populations in Maine whose ancestors originated from the Netherlands. In past years, Nova Scotian hatcheries had successfully produced Ostrea edulis spat, but in 2001 and 2002 the two remaining hatcheries in the province suffered 100% larval mortality. One of the factors that may have contributed to the collapse is a suspected loss of genetic diversity due to the limited number of individuals used to establish the Maritimes stocks, and the inevitable subsequent inbreeding during propagation of these populations. This study used microsatellites, neutral molecular markers, to assess the level of genetic diversity in several hatchery stocks and naturalized populations from Nova Scotia, New Brunswick, Maine, and British Columbia. We found that some genetic erosion has occurred in the Maritimes populations, with the largest loss of alleles being found in the hatchery stocks. In spite of this loss, genetic diversity and heterozygosity in the Maritimes populations is still relatively high. The data from this study was also used to look at the relationships between the populations, and an unrooted tree illustrating these relationships was constructed using genetic distances. The results were consistent with our knowledge of the historical transfers of oysters between different locations. Preliminary recommendations for broodstock management of Ostrea edulis and the direction of future studies of this species are summarised in the end of the report.
2002 - 2003
Atlantic: Gulf of Maine, Scotian Shelf
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