Shellfish Research and Information
Services for the U.S. West Coast

Our Work

Where We Work


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Internships with PSI

Intern or volunteer on one of PSI's research projects or outreach campaigns.


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The man with a plan

PSI researcher, Andy Suhrbier helps shellfish growers adapt to changing ocean conditions.

Ecosystem Services

Research and outreach to enhance our understanding of the social and ecological impacts of shellfish and shellfish aquaculture.

Citizens and consumers understand and value the economic, social, and ecological benefits of shellfish.


Valuing Ecosystem Services

PSI research and outreach seeks to better understand and communicate the ecosystem services and economic and cultural value of shellfish. Shellfish are integral components of the coastal ecosystem. As ecosystem engineers, shellfish create conditions for other plant and animal species to thrive and they provide valuable ecosystem services to humans. Ecosystem services- the benefits people obtain from ecosystems- can be grouped into four broad categories of services: provisioning, regulating, habitat (formerly termed "supporting", and cultural services. Shellfish have been identified as providing:

Valuing Ecosystem Services

Through a partnership with Northern Economics Inc., PSI contracted the report Valuation of Ecosystem Services from Shellfish Restoration, Enhancement and Management: A Review of the Literature. The document compiles literature related to the ecosystem services of shellfish, and describes economic methods that have been applied to value those services.

Shellfish and Nutrient Mitigation

Shellfish consume nitrogen and phosphorus-containing plankton and detritus, playing an integral role in nutrient cycling of coastal habitats. In marine environments nitrogen is most often the limiting nutrient in phytoplankton productivity, and- although somewhat counterintuitive- over-productive phytoplankton activity causes dissolved oxygen depletion. Low dissolved oxygen conditions (termed "eutrophic," low oxygen, or "hypoxic," no oxygen) result when excessive plankton blooms and eventually decays. (The decay process consumes oxygen in the water column.) By harvesting plankton-consuming shellfish, nitrogen and other elements are removed from the water column. Although more difficult to quantify, shellfish also contribute to nutrient cycling through biogeochemical processes, including production of feces and 'pesudofeces' incorporated in the water column through resuspension or burial in sediment.

Shellfish and Nutrient Mitigation

Recent PSI research examined the potential of nitrogen removal through shellfish harvest and then quantified those services for Puget Sound. A low-end estimate shows Puget Sound commercial shellfish aquaculture removes 62 metric tons of nitrogen per year. Also see the NOAA Fact Sheet: Aquaculture Provides Beneficial Ecosystem Services


West Coast Shellfish Production

Nutrient removal services of shellfish can also be valued though 'replacement cost method', using the cost of traditional waste water treatment processes to remove equivalent nutrients. Estimates result in a range of values, depending on the life-cycle cost of the removal technologies employed at local waste water treatment facilities. A rescent PSI led study found that nitrogen removed through Oakland Bay (south Puget Sound) shellfish harvest is valued at $3-$25 per pound of nitrogen removed, which was valued as a $77,100- $650,863 annual water quality benefit.

In addition to water quality benefits, shellfish aquaculture also provides jobs and revenue for coastal communities. A recent PSI study of the economic contributions of shellfish aquaculture found that the West Coast (AK, WA, OR, and CA) industry generates $228M in revenue each year and provides 3,800 jobs. Using an Input/Output model, PSI and partners at Northern Economics, Inc. also found that each $1.00 spent by the industry generates $1.67 in additional spending in the region.

Recent PSI Research

Comparative Habitat Use Study: Native Seagrass and Cultured Shellfish in West Coast Estuaries

Shellfish Carrying Capacity in Puget Sound

Washington State Shellfish Production & Restoration - Environmental and Economic Benefits & Costs

Budd Inlet Nutrient Bioextraction Phase 1 Report

Shellfish at Work: Mussel Bioextraction

Nutrient Mitigation with Mussels Tacoma's Foss Waterway

West Coast Shellfish Aquaculture - Economic Impacts, Barriers to entry, and Opportunities for Expanded Production

Watch underwater video of the organisms living in and among lines of cultured mussels.

Watch underwater video of the organisms living in and among lines of cultured mussels.

Ecosystem Services Photo

Shellfish at Work: Nutrient Bioextraction

PSI staff harvest mussels to quantify the nutrient (nitrogen and phosphorus) removal capabilities of shellfish and examine the potential to create a marketable compost product from harvested mussels.

Ecosystem Services Photo