Shellfish in Washington

Washington is the nation’s lead producer of farmed clams, oysters, and geoducks, with an estimated annual harvest worth more than $107 million. Nowhere else in the country can you find the abundance and variety of shellfish that we enjoy.

Shellfish have been a subsistence and ceremonial food for Native Americans in the Pacific Northwest for millennia and commercial shellfish farming has been active in Washington waters for more than 160 years. Washington Sea Grant (WSG) works closely with NOAA, West Coast shellfish farmers, state agencies, and tribes to support sustainable Northwest aquaculture and wild fisheries. 


Photo: Tara Schmidt

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    Filter Feeders

    Clams, oysters, mussels, and other bivalve shellfish take in seawater and feed on the phytoplankton it contains. This filtering process improves light penetration in the water column, reducing overall turbidity and benefiting larger aquatic plants such as eelgrass, which provides habitat for juvenile salmon and other species. Bivalve shellfish help control the overabundance of phytoplankton that arises when nitrogen from terrestrial sources has led to over fertilization of marine waters.

    Bivalve economics

    The 2011 Washington Shellfish Initiative estimated that state shellfish growers directly and indirectly employ more than 3,200 people and provide an estimated total economic contribution of $270 million. The industry includes hatcheries, nurseries, and farms, as well as processing, distribution, and wholesale and retail operations. WSG’s pioneering research on the Manila clam helped establish a major new shellfish market with an annual production of 8 million pounds per year. Today, Manila clam farming generates retail sales of about $32 million annually and accounts for more than 100 jobs in the state.

    Emerging Threats

    Shellfish are an important component of marine ecosystems, and environmental changes and stressors can affect production. The Washington coast is especially vulnerable to ocean acidification, a change in ocean chemistry that could affect species and marine food-web dynamics. Aquatic invasive species and toxic algal blooms also continue to pose serious threats to shellfish resources and seafood product safety. And growing human populations have affected coastal water quality, putting additional pressure on regional shellfish resources. This increase in human populations has also increased the desire for locally grown seafood.

Community Engagement

WSG has been involved with shellfish research and aquaculture for more than four decades, helping waterfront property owners and communities maintain sanitary shorelines, educating consumers about shellfish safety, and participating in the Pacific Rim Shellfish Sanitation Association and the California Current Acidification Network (C-CAN). Outreach efforts include ongoing community conferences, seminars, and events, as well as a range of publications.

  • WSG has partnered with local shellfish farmers to provide safe shellfish to award-winning Seattle restaurants. To get a taste of this work, the Farm to Table Aquaculture Experience Self-Guided Field Trip gives directions to three of these oyster bars, with some background on their history with WSG.
  • WSG’s Marine Water Quality Specialist provides technical assistance for tideland owners, including shoreline assessments and shellfish recruitment techniques. The Bivalves for Clean Water program teaches waterfront residents how to ensure the water that runs off their property and into marine waters is as clean as possible.

WSG aquaculture specialist shares information at a community outreach event.

  • Through WSG’s State of the Oyster study, King encourages Puget Sound waterfront property owners to collect oyster and clam samples from their beaches during summer months. WSG arranges for laboratory testing of the samples, which are analyzed for the presence of contamination. WSG then helps participants interpret their test results and, if needed, works with them to identify and remedy the sources of the contamination.
  •  A partnership of tribes, government entities, educational institutions, and citizens. This monitoring program provides early warning of harmful algal bloom events to minimize both human health risks and economic losses. Observations from SoundToxins volunteers are used by the Washington State Department of Health, NOAA, and researchers.
  • WSG’s Marine Ecologist Jeff Adams conducts special events to educate Puget Sound residents about shellfish and the importance of water quality: Kids’ Day at Oysterfest, tideflat tours at Hama Hama Oyster Rama, a touch-tank at the Geoduck Festival, and beach walks.

Research Projects

WSG supports research to address the concerns of the shellfish industry, regulators, policy makers, and consumers. Funded projects focus on issues specific to Pacific Northwest wild and farmed shellfish.


Learn about our State Shellfish Research Program

Other WSG research projects include:



In the News


Online Library

WSG’s publications about shellfish cover a variety of topics, including marine water quality, safe consumption, and economic impacts. In addition to the publications listed here, you can find more at on our Publications webpages.