Chinook Salmon

SCIENTIFIC NAME: Oncorhynchus tshawytscha

STATUS: Endangered/Threatened (different river populations listed separately)

HABITAT: Freshwater streams and rivers at birth; juveniles mature in estuaries before migrating to open ocean

LIFE HISTORY: Ocean salmon have blue-green backs with silver sides; color changes to bright red at spawning, and males develop hooked snout.

THREATS: Loss of freshwater spawning habitat due to dams; pollution; overfishing

RANGE: Pacific Ocean from Kotzebue Sound, Alaska, to Santa Barbara, California

CURRENT POPULATION: Varies by population

The largest of Pacific salmon species, an adult chinook salmon is a monstrous fish, often five feet long and weighing 100 pounds or more. After years at sea, this powerful fish makes an epic journey to spawn in the stream where it was born—and then dies.

Once abundant from Alaska all the way down to Santa Barbara, populations of chinook salmon have been declining steadily. Human modification of natural water flow for dams that produce hydropower or divert water for agriculture has cut into salmon habitat. Dams can also hamper migration to or from salmon spawning grounds. Nine regional subgroups of chinook salmon are listed as threatened or endangered.

NRDC is spearheading a historic effort to restore spring run Chinook salmon to California's San Joaquin River, and is also using the Endangered Species Act as part of its efforts to restore and protect the San Francisco Bay-Delta and its watershed, the most important salmon-producing ecosystem south of the Columbia River.

Photos: Olympic Park © Jeffrey Logan; chinook salmon © Roger Peters, USFWS; marbled murrelet © Gus Van Vliet, USFWS; orca © NOAA/Dept. of Commerce