The National Marine Fisheries Service proposes to designate almost 1,200 square miles of Puget Sound as critical habitat for three species of endangered rockfish.
The habitat protection follows the 2010 decision to list yelloweye, canary and bocaccio rockfish under the Endangered Species Act.
The Fisheries Service says the rockfish are vulnerable to overfishing because they have long lives and mature slowly with sporadic reproduction.
Tuesday's designation will require federal agencies to make sure their actions don't harm rockfish habitat. The protected area in Puget Sound overlaps existing critical habitat for Puget Sound Chinook and Hood Canal summer-run chum, bull trout and Southern Resident killer whales.