Developing state guidance for commercial marine net pen aquaculture

In 2015, we started leading a science-based planning effort to identify the environmental risks and potential impacts of commercial fin fish aquaculture and improve oversight of net pens operating in state waters.

The process was underway when a commercial net pen off Cypress Island suffered a catastrophic failure in August 2017, releasing at least 240,000 Atlantic salmon to Puget Sound. The incident attracted significant public attention and concern about the industry and potential risks that operations raising non-native salmon might pose to native fish populations.

The project was temporarily put on hold while state agencies responded. On June 1, 2021, the state departments of Agriculture, Ecology, Fish and Wildlife, and Natural Resources released their draft Guidance for Marine Net Pen Aquaculture in Washington State for public review and comments.


The 2018 Washington Legislature adopted House Bill 2957. Part of the bill phases out Atlantic salmon net pens by 2022 and prohibits new aquaculture operations from raising non-native fish in state waters.

The law directed the Washington departments of Agriculture, EcologyFish and Wildlife, and Natural Resources to complete the effort to update guidance and informational resources for planning and permitting net pens.

To produce a new guidance document, the state worked with the National Center for Coastal Ocean Science (NCCOS). However, for a variety of reasons, the collaborative effort to develop a document offering the latest science and updated management recommendations proved challenging.

Instead, NCCOS agreed to complete a state of the science report while the four state agencies began developing a separate guidance document.

Focus area

The focus area includes Puget Sound and the Strait of Juan de Fuca. These water bodies have existing net pens, and the appropriate depth and currents for net pen aquaculture. The agencies have also looked broadly across the body of science to better understand the effects of commercial net pens outside their immediate locations.

How the results will be used

The state’s net pen guidance document is designed to help:

  • Local governments and state agencies identify and address risks from existing and future commercial net pens in Washington’s marine waters.
  • Deliver recommendations for future considerations by state managers and the Legislature.
  • Inform the oversight of Atlantic salmon net pens until they are phased out in 2022. No Atlantic salmon are currently being raised in existing net pens and it is highly unlikely that they will be restocked prior to the phase out.
  • Manage commercial marine net pens rearing native species such as rainbow trout.

The guidance will not address freshwater aquaculture, fisheries enhancement pens, or bait fish rearing pens.

Project schedule