Zostera japonica management on commercial clam beds in Willapa Bay General Permit

We issue coverage under this general permit when shellfish growers choose to use an herbicide (imazamox) to control the non-native eelgrass Zostera japonica on their commercial clam beds. Zostera japonica is a class C noxious weed that may be controlled on commercial clam beds, but does not include use for control on geoduck and oyster beds. Physical and mechanical methods of Zostera japonica control are not regulated by this permit. Read our blog to find out more about the Zostera japonica permit.

The current permit went into effect April 4, 2020 and expires on March 3, 2025.

Permit reissuance

The current permit expires on March 3, 2025. The permit reissuance process includes gathering initial input, a formal public comment period on the draft permit, and formal public meetings and hearings. We plan to make a permit reissuance decision at the end of this process in early 2025.


Spring/Summer 2024: Gather early input
Winter 2024: Formal public comment period on the draft permit
February 2025: Decision on reissuance
March 2025: Current permit expires

Permit application, forms, and resources