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Selective breeding of Pacific oysters to improve resistance to summer mortality syndrome



Oyster farms in British Columbia (B.C.) continue to experience high rates of oyster mortality due to summer mortality syndrome. The specific causes of these mortality events are unknown, but summer mortalities in Pacific oysters in temperate climates have been historically associated with elevated water temperatures, low salinity events, and harmful algal blooms. This complex interaction of environmental and biological factors is further influenced by age class, reproductive state, and the presence/absence of bacterial infection (e.g. Vibrio spp.)

The primary goal of this project is to evaluate the level of genetic resistance to summer mortality in the B.C. Pacific oyster population in order to recommend a selective breeding strategy that promotes resilience. To this end, the project will produce 42 pair-mated families and evaluate their survival and growth rates in the field (at commercial farm sites) and in the laboratory under controlled stress conditions (e.g. temperature, Vibrio infection).

Even a modest reduction in mortality rates would grow the value of the B.C. shellfish industry by millions of dollars. Further, the development of a selective breeding program would enhance the industry’s sustainability and aid in safeguarding the resource under the context of a changing marine environment. 

Program name

Aquaculture Collaborative Research and Development Program (ACRDP)


Three years: 2019-2022

Principal investigator

Chris Pearce, research scientist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region

Team members

Timothy Green, Canada Research Chair in Shellfish Health and Genomics, Vancouver Island University
Clara Mackenzie, Post-doctoral Fellow, Institute of Aquaculture, University of Stirling


Darlene Winterburn, Executive Officer, British Columbia Shellfish Growers Association

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