Burrowing Shrimp are Threatening Washington's Shellfish Farming Industry
Oysters are the oldest agricultural crop in Washington State, first gathered by Native Americans for centuries before settler-contact.
Today, the industry is the lifeblood for small towns along Willapa Bay and Grays Harbor, where multi-generational families have been farming nearly 12,000 acres of privately owned tidelands, many since before Washington statehood.
Shellfish aquaculture continues to be a critical economic driver for the state economy, especially in the rural communities of Southwest Washington.
Washington State shellfish exports are worth hundreds of millions of dollars each year and the industry is the cornerstone of employment in many rural areas where jobs are often hard to come by.
In Willapa Bay and Grays Harbor, shellfish farmers face an existential threat from a persistent infestation of burrowing shrimp, which can render productive shellfish beds into desolate mud flats in a single season.
High population densities of burrowing shrimp soften the tide flats and cause shellfish to sink and suffocate. In the past, growers used pesticides to manage the burrowing shrimp populations but public concern about use of the chemicals forced changes.
Numerous techniques including alternative pesticides, mechanical control, electricity, and even microwave blasts have been tested, but growers still lack an effective management program and farms are rapidly losing productive acreage; some have gone out of business. The search for a solution continues with research trials of other alternative products and techniques.
In 2019, Willapa Grays Harbor Oyster Growers Association (WGHOGA) and the Department of Ecology (Ecology) agreed to work together to identify an integrated approach to control the burrowing shrimp infestation that is devastating oyster beds in Willapa Bay and Grays Harbor.
The Working Group is developing the framework for identifying “treatments to reduce populations of burrowing shrimp to below established thresholds using biological, cultural, mechanical, and chemical control methods,” and “evaluating the environmental effects and efficacy of burrowing shrimp treatments.”
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