Chinook Salmon

Chinook Salmon is the largest species of Pacific salmon, sometimes called king salmon for both its size and prized status among anglers and commercial fisheries. Native to river systems from California to Alaska and across to Japan and Russia, Chinook are known for undertaking some of the longest and most demanding freshwater migrations of any salmon species, in certain river systems traveling well over a thousand miles upstream to spawn. Individuals can grow to remarkable sizes, with some specimens historically exceeding 100 pounds, though most adults are considerably smaller. Like other Pacific salmon, Chinook are semelparous, meaning they die after spawning just once in their lifetime.

Key field marks:

• Large body size, often the biggest salmon in a given river system
• Black spots on the back and on both the upper and lower lobes of the tail fin
• Black pigment along the base of the teeth and gums (distinguishing feature)
• Bluish-green to blackish back with silvery sides in ocean phase
• Spawning adults darken to deep red, maroon, or olive-brown with hooked jaws in males

Look-alikes: Often confused with coho salmon, which lacks spots on the lower tail lobe and has white (not black) gums; also compared to chum salmon, which lacks distinct spotting altogether.

Chinook Salmon range throughout the North Pacific, spawning in rivers from central California north through British Columbia and Alaska, and west to the Russian Far East and northern Japan. They favor large, cold, well-oxygenated rivers with substantial flow, spawning in coarse gravel beds often in the mainstem of major rivers rather than small tributaries. Juveniles may rear in freshwater for several months to over a year before migrating to estuaries and then the open Pacific Ocean, where they range widely to feed and grow before returning, sometimes after several years at sea, to their natal river to spawn. The species requires unobstructed river access and clean gravel, making it highly sensitive to dams and habitat degradation.

Chinook Salmon exhibit diverse life-history strategies, with some populations, known as 'stream-type,' rearing in freshwater for a year or more before migrating to sea, while 'ocean-type' juveniles migrate to saltwater within months of hatching. At sea, Chinook are voracious predators feeding on smaller fish, squid, and crustaceans, growing rapidly over one to several years before returning to spawn. Spawning runs can occur in different seasons depending on the population, with some rivers seeing distinct spring, summer, fall, and winter runs. After spawning in gravel redds, adults die within days to weeks, and their decomposing bodies contribute significant marine-derived nutrients to river and forest ecosystems.