Documenting genetic diversity of wild Eastern Oyster populations towards improving production

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The eastern oyster, Crassostrea virginica, is a commercially and ecologically important species whose naturalrange includes all the Maritime Provinces. It is also cultivated in Quebec and Newfoundland. Despite theirimportance, we know very little about their population-genetic structure. This information is critical not only tothe management of wild oyster introductions and transfers, but also in the establishment and management ofhatchery broodstock programs. L'Étang Ruisseau Bar Ltd. (ERB) owns and operates Atlantic Canada's largestshellfish hatchery, exporting seed to all Atlantic provinces. The proposed project aims at finalising a thoroughanalysis and publication based on cutting-edge population-genomics analyses that allowed quantifying keyfeatures of wild oyster populations, including critical information such as the amount and extent of geneticdifferentiation, estimates of effective population size, and evidence for local adaptation. Our results to dateshowed that despite the massive rehabilitation transfers of disease-resistant PEI broodstock, there is highlysignificant population differentiation at local and regional scales. These results represent a profound shift in ourview of oyster diversity in Eastern Canada and raises questions about the origin and maintenance of oystergenetic diversity in the face of considerable historical and contemporary disturbance. The proposed project willextend ongoing analyses to uncover the driving forces behind this pattern of diversity. We will develop specificrecommendations for current broodstock collection activities and breeding program, as well as prepare andsubmit our results for publication. This will enhance ERB's broodstock management strategy, increasing theperformance of their seed in aquaculture production, inform their selective breeding program, and minimize thepotential genetic impacts of large-scale transfers on neighbouring wild populations.