Chinook salmon (King salmon) (Oncorhynchus)
Chinook salmon have thick, strong bodies and are excellent swimmers. They are olive green on the top and metallic silver mixed with green on the sides. Irregular black spots mark the back. The species is very similar to the Coho salmon, but can be distinguished by the appearance of spots on both the lower and upper lobes of its tail, while Coho salmon only have spots on the upper tail lobe. Also, Chinook salmon have black lower gums while Coho Salmon have white lower gums.
In the ocean, Chinook salmon feed on herring, sand lance, large zooplankton, and a variety of other fish, such as anchovies. They usually feed in deeper waters, but will feed near the surface to access schooling fish. Juvenile Chinook feed on plankton, then, as they grow, on insects.
Chinook salmon range from Monterey Bay of California to Chukchi Sea of Alaska and from Siberia to Hokkaido, Japan. They have been successfully introduced in New Zealand, Australia, and France.
Chinooks, like most salmon, are anadromous, spending part of their life in the ocean and part in freshwater streams, where they are born and return to spawn. They prefer large rivers with deep water during the freshwater segment of their life cycle. Chinook salmon tend to be more abundant in waters that are 45 to 60 F, with the peak feeding temperature being 54 F.
- The building of dams on rivers throughout the Pacific Northwest damaged and even caused extinction of different Chinook salmon populations, mainly because the dams prevented the Chinook salmon from reaching their spawning grounds. At present, some runs are listed as endangered by the National Marine Fisheries Service, including the Sacramento River winter run in California and the Snake River spring-summer and fall runs in Idaho.
- Of the six species of Pacific Salmon, the Chinook salmon are the least abundant but most valued commercial fish. During the 1970s and 80s the world catch was more than four million Chinook salmon annually, but this number has dropped as many fisheries have been closed or shortened due to declining populations.