Photo: DNR

Washington state is phasing out marine farming of Atlantic salmon and other non-native fish by 2022.

Net pens growing Atlantic salmon in state waters have operated for decades but the practice came under heavy criticism after tens of thousands of non-native fish escaped into waterways last summer.

Under legislation signed by Governor Jay Inslee on Thursday, leases and permits for operations that grow non-native finfish in state waters would end when current leases expire.

The legislation targets Canada's Cooke Aquaculture Pacific, the largest producer of farmed Atlantic salmon in the U.S., whose net pens in northwest Washington collapsed in August.