Climate change and past overharvesting have reduced Washington’s native Olympia oyster, a species that filters water, builds habitat for fish and invertebrate species, and holds cultural significance for Tribes and coastal communities. As waters warm, acidify, and swing between heat and cold extremes, managers need practical guidance to ensure restoration and hatchery practices strengthen — not erode — the genetic diversity that helps oysters adapt. Yet there is limited, easy-to-use information on how local environmental conditions shape genetic differences among oyster populations or how common hatchery introduction strategies might affect long-term resilience, leaving questions for those working to restore and manage Olympia oysters. For example, which site conditions matter most for maintaining potential local adaptations? How many hatchery oysters can be released at a site without diluting the traits that help populations cope with future stress?

In this project, University of Washington researcher Zachary Bengtsson will partner with the Washington Department of Fish and Wildlife (WDFW) to co-develop simple, transparent tools that answer these questions and enable climate-smart oyster restoration in Puget Sound. He will combine existing DNA datasets with regional water monitoring data (e.g., temperature, pH, oxygen) to identify which environmental factors are most closely linked to genetic differences among populations. He will also upgrade an existing computer model that tracks individual oysters over time to test how different broodstock sourcing — collecting wild adults for hatchery breeding — and hatchery-reared oyster introduction strategies perform under scenarios such as warming, acidification and marine heatwaves. The outcomes — maps and summaries that highlight climate-resilient sites; clear guardrails for hatchery releases; and a public code repository with step-by-step guides WDFW can run in-house; will directly support management decisions. These products will help agencies choose broodstock and sites that preserve population specific genetic variation, set release limits that protect diversity, prioritize monitoring and refugia, and update restoration plans so Puget Sound’s oyster beds continue to provide ecological services and sustain cultural values under a changing climate.