The Swinomish Indian Tribal Community sent a 60-day notice of intent to sue the U.S. Army Corps of Engineers for failing to uphold the Endangered Species Act Sept. 9, citing dwindling Skagit chinook salmon and Southern Resident killer whales populations.

Tribal attorneys and Earthjustice will bring suit in the United States District Court for the Western District of Washington if the Corps granted construction permits to dike districts in the Skagit delta, but did not require hundreds of acres of estuary habitat be restored as mitigation for harm caused to salmon as agreed under the Tidegat...