The chinook is the largest fish in the salmon family. Within Washington State, there are 7 distinct populations (also called ecologically significant units or ESUs), all of which are declining. In 1999, the Puget Sound chinook salmon (one of the 7 ESUs in Washington state) was designated as threatened under the U.S. Federal Endangered Species Act. It is also a candidate for listing by Washington state. For more information, see the US Fish and Wildlife Service's chinook salmon species profile, the Pacific Biodiversity Institute website, and NOAA Fisheries website on Puget Sound chinook salmon.