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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research » Research » Research Project #429271

Research Project: Examining Inheritance and Breeding for Resistance to Effects of Ocean Acidification in Pacific Oysters

Location: Forage Seed and Cereal Research

Project Number: 2072-31000-005-02-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 28, 2015
End Date: Sep 27, 2019

The objective of this cooperative research is to identify genetic factors associated with the expression and regulation of economically important traits in cultured Pacific oysters (Crassostrea gigas) and to use this information to develop marker assisted selection techniques that enhances broodstock development with improved characteristics. Specific project objectives are to: 1) Improve performance of oyster larvae in hatcheries exposed to acidified (high pCO2) seawater; 2) Improve resistance of Pacific NW oyster stocks to microvariants of the oyster herpes virus OsHv1; 3) Use quantitative and molecular data from these on-going projects, the Oregon State University shellfish breeding program (MBP) at the Hatfield Marine Science Center (HMSC), and other data sources, to design and implement breeding strategies to improve traits of Pacific oysters of high value to industry.

The levels of genetic (co) variation available in existing and potential shellfish germplasm resources for economically important phenotypic characters as well as the number of loci contributing to these traits and the nature of their effects (genetic architecture) will be examined through quantitative and molecular genetic approaches. A new marine environmental regime characterized by strong upwelling events that bring deep, hypoxic, acidified (high pCO2) seawater into near-shore bays and estuaries on the US West Coast has been shown to adversely affect oyster larvae by increasing shell dissolution rates, hampering shell formation, and potentially affecting metamorphosis and growth. A second major threat is the potential introduction of new microvariants of the oyster herpes virus (OsHv-1 µVar) that have decimated Pacific oyster farms in other countries. On-going breeding programs for oysters haven’t addressed larval survival, growth and setting success as traits for selection because larval production wasn’t previously considered to be a major limiting step in oyster production. On-going projects are designed to research the effects of ocean acidification (OA) on Pacific oysters and determine whether sufficient genetic variation exists within Pacific oyster lines to enable adaptation to changing rearing conditions. The current ARS project plan includes screening US West Coast oyster stocks in collaboration with researchers in France and the Universities of Washington and Maryland to determine their resistance to variants of oyster herpes virus. Research to address these problems will use approaches described in the project plan for 2072-31000-005-00D. Researchers will use the data collected on the pedigrees of selected individual oysters from these experiments and information on gene expression to quantify and determine trait heritability and design new breeding experiments. Conduct quantitative analysis of data from on-going projects designed to determine heritabilities of larval and adult traits of Pacific oysters exposed to hatchery conditions including early exposure to high pCO2. Use genetic markers to determine heritabilities and/or markers for larval and adult traits (growth, survival, meat content, shell shape) of three mixed family populations (MBP, MBP hybrid crosses between inbred lines, and Willapa wild) subjected to high or low OA seawater. Initiate and collect data from initial Oyster herpes disease trials. Use a quantitative, genetic mixed-model to calculate heritabilities and genetic correlations for families exposed to the two different herpes strains (Tomales and French), as well as genetic correlations of responses to the Tomales Bay OsHV-1 strain. Develop analytical approaches to use quantitative and molecular data from these projects, the MBP program and other data sources including years that span the onset of OA conditions on the west coast, and initial results of OSHv-1 exposure trials to develop and optimal breeding scheme for the US West Coast oyster aquaculture industry.