Lorenz Hauser, University of Washington, School of Aquatic and Fishery Sciences
Brady Blake, Washington Department of Fish & Wildlife
Jonathan Davis, Pacific Shellfish Institute and Taylor Shellfish Company, Inc.
Brent Vadopalas, University of Washington, School of Aquatic and Fishery Sciences
Washington Sea Grant researchers assessed the population structure of wild purple hinged rock scallops by analyzing genome-wide differentiation among various populations. This project investigated populations’ genetic differentiation, habitat adaptation, and resilience to acidification using several experimental approaches: 1) Gene sequencing to determine genetic diversity within and between populations; 2) Rearing larvae from various Washington, Alaska, and California populations in common conditions at ambient and high carbon dioxide levels; 3) Reciprocally transplanting three different Washington populations to compare the performance of local and non-local scallops; and 4) Integrating all these results to determine the effects of transplantation on local adaptation.The team also investigated the effects of seawater pH on gene expression and conducted transplant experiments to assess whether the rock scallops are locally adapted.
The purple hinged rock scallop, a native West Coast species, holds promise as a new venture in local commercial aquaculture. However, culturing a new species poses challenges, such as potential genetic risks to wild populations. Understanding these challenges requires basic genetic and biological data, including population structure, growth, and the capacity for adaptation among various purple hinged scallop populations. This information is necessary to guide aquaculture operations that are profitable and sustainable.
After analyzing rock scallops collected from California to Alaska, the researchers found little evidence of population structure. This indicates that aquaculture operations would not have to source broodstock locally and that scallop seed could be outplanted over a fairly large area, which would facilitate management and make seed production more efficient. Transcriptome sequence data identified 592 genes of interest that exhibited differential expression in response to the pH treatments. In the transplant experiments, survival was high in scallops outplanted in Totten Inlet and Dabob Bay, but low in Neah Bay—variation that provides some evidence of local adaptation. The researchers also found male scallops matured earlier and at a smaller size than previously assumed, which means that scallops could potentially spawn before being harvested and therefore interbreed with wild populations.