Department of Ecology News Release - April 16, 2015

Permit issued to help coastal shellfish growers
Burrowing shrimp threatening shellfish operations in Willapa, Grays Harbor

OLYMPIA – At the request of shellfish growers, the Washington Department of Ecology has issued a permit for use of imidacloprid, a common household pesticide, to combat a growing population of burrowing shrimp in Willapa Bay and Grays Harbor.

Burrowing shrimp are a native species that burrow into shellfish beds, making them too soft for shellfish cultivation. While other control methods have been permitted since the 1960s, Ecology has been studying the environmental impacts, and has selected imidacloprid as a preferred, less-toxic alternative.

“We worked with shellfish growers and other stakeholders to find an effective method to control burrowing shrimp, and identified safeguards that will reduce and minimize the environmental impact of pesticide use,” said Rich Doenges, water quality section manager for Ecology’s Southwest region.

The permit requires the applicants, the Willapa–Grays Harbor Oyster Growers Association, to submit an annual operations plan for Ecology’s approval before any use of the pesticide. The permit allows growers to use the pesticide on up to 1,500 acres of commercial tidelands in Willapa Bay and 500 acres in Grays Harbor, and directs that it be applied no more than once a year and only in low-wind conditions to minimize impact to other species.

“The shellfish industry is a key economic contributor in Washington’s coastal areas and, by issuing this permit, we can help protect the economic vitality of these family businesses for years to come,” said Sally Toteff, director for Ecology’s Southwest Region.

Ecology staff will monitor applications, and the growers are required to conduct intensive water and sediment monitoring throughout the five-year term of the permit through a partnership with the Washington State University Long Beach extension research facility.

Shellfish growers are expected to finalize their operations and monitoring plans in May and, upon approval by Ecology, the shellfish beds can be treated.

More information



Chase Gallagher, communications, 360-407-6239, @ECYSW

Sandy Howard, communications, 360-407-6408