Seminar Series

Wed, 27 Feb 2019 3:30 PM

SSB 7172


Dr. Ben Sutherland, Fisheries and Oceans Canada (DFO)

Population genomics and metatranscriptomics to better understand large-scale mortality events of Pacific oyster Crassostrea gigas

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Population genomics and metatranscriptomics to better understand large-scale mortality events of Pacific oyster Crassostrea gigas

Ben J. G. Sutherland1,2

1 Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, V9T 6N7, British Columbia, Canada

2 Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, V6T 1Z4, BC, Canada

The Pacific oyster Crassostrea gigas is an introduced species to British Columbia, originally transplanted from Japan in the early 1900s and now propagating in self-recruiting populations throughout the coast. Pacific oyster is an important aquaculture species for BC and globally. Farms source their oysters either from international hatcheries or from self-recruiting spat harvested from local waters, although the latter approach is less frequently applied. In recent years, both globally and in the Pacific Northwest, large-scale mortality events have occurred, in some cases resulting in large crop losses in oysters at a near-market size. It is not clear whether these mortalities are a result of an environmental change (e.g. ocean acidification causing developmental issues), infectious agents (e.g. disease-causing agents associated with mortalities have been identified in France), genetics (e.g. inbreeding), or other factors. To begin to resolve this question, we use high-throughput genotyping of more than 10,000 markers throughout the oyster genome to profile self-recruiting populations around Vancouver Island, France, Japan, and China. We compare these self-recruiting to farmed populations from the same areas and others (e.g. Chile, United Kingdom), as well as self-recruiting populations moved onto farms for grow out. This information provides estimates of inbreeding, genetic diversity, individual relatedness, and population differentiation among these locations. It also provides a picture of the genetic impact from the transplantation history of the Pacific oyster, which is in turn impacted by the underlying biology and ecology of this species. Further, to begin to characterize the environment changes that may be associated with high pCO2 water associated with ocean acidification, we take a metatranscriptomics approach to profile gene expression in microbes entering an oyster hatchery throughout multiple seasons and environmental chemistry levels. Collectively, these results will be presented in the context of the overarching question of what factors may be causing large-scale oyster mortality.