MANAGING GENETIC RISKS OF NATIVE SHELLFISH AQUACULTURE
Researchers address genetic risks of native shellfish aquaculture by developing genetic risk assessment tools and evaluating risk management strategies.
Lorenz Hauser, School of Aquatic and Fishery Sciences, University of Washington
Brent Vadopalas, School of Aquatic and Fishery Science, University of Washington
Eric Ward, NOAA Northwest Fisheries Science Center
Many local shellfish farms focus on introduced species, but interest in culturing native shellfish species is rising. However, interbreeding captive and wild shellfish raises concerns about potential genetic risks to wild populations. This research will develop genetic risk assessment tools and evaluate management strategies for mitigating these risks.
Three primary genetic risks of aquaculture include: loss of diversity within populations, loss of diversity among populations, and loss of fitness. Measures to minimize risks are possible, but sometimes impose considerable costs to aquaculture operations, and thus need to be scientifically founded and adequately justified to the industry. Management of aquaculture operations has to be specific to the operation, the species and the location, but the framework for such decisions does not exist. This project addresses this gap by developing a decision support tool based on stakeholder input, scientific modeling and management strategy evaluations that can be applied to the management of shellfish aquaculture in general.
The researchers refined a prototype model and ran simulations of shellfish production in a hatchery and farm, as well as gene flow between the farm and wild populations and between a local and a distant wild population. The refinements included incorporating local adaptation, as well as the projected recovery time for wild populations that experienced genetic changes from interbreeding with farmed stocks. The results of the simulated model were in line with what the researchers expected based on population genetics theory, showing that genetic diversity of the local wild populations decreased once the hatchery and farm were introduced, and recovered after farm removal.