Increasing Efficiency of a Crossbreeding Program for the Pacific Oyster

Shellfish aquaculture occurs in coastal regions, where it is constrained by competition for alternative uses and by onset of the rapid environmental changes expected from global climate change. Commercial breeding programs can improve the yield of Pacific oysters, especially in regions, such as the U.S. West Coast, where farmers depend on seed produced in hatcheries. The Pacific oyster Crassostrea gigas, which has been exported from Japan to all continents but Antarctica and has had the highest production of any aquatic species for the past decade ? 4.2 Mt in 2007 (FAO 2009) ? is an obvious candidate for domestication. Genetic improvement and domestication are proven routes to increasing the efficiency of agricultural production across a range of environments, but research towards these ends in shellfish aquaculture remains in a relatively primitive state. The innovative approach employed in this project will if successful serve to significantly improve the efficiency of a commercial crossbreeding program for increasing the yield of farmed Pacific oysters. The proposal builds on previously published evidence that crossbreeding can improve yield, owing to hybrid vigor, and refines a conceptual framework for commercial crossbreeding. The work plan features the combined application of new culture technologies for replicated larval and seed rearing, molecular-based pedigree confirmation, estimation of specific and general combining abilities of inbred lines for yield, and correlation of performance at different phases of culture to determine the earliest point at which combining ability for yield can be predicted. Inefficiencies in the component processes of the program ? developing inbred lines (at least two generations), testing inbred lines for combining ability, and propagating elite inbred lines for further testing at commercial scales ? have constrained the production and distributing of hybrid oyster seed to farmers. We propose to address and eliminate or reduce several of the inefficiencies that stand in the way of progress in order to provide the basis for a time and cost efficient cross breeding approach to increasing domestication and overall value of the Pacific oyster culture industry in the western United States. Outcomes of this research have the potential to improve production efficiencies in shellfish aquaculture, generally including the potential for use of research results in other commercially important species such as clams, mussels and geoducks.