Oncorhynchus tshawytscha

How to identify a Chinook salmon

The most useful field combination is a dark or black gum line plus small black spots on the back and on both lobes of the tail. Chinook are also called king salmon.

Identification checklist

• Ocean-phase adults usually have a blue-green back, silver sides and a white belly.
• Small irregular black spots occur on the upper body and both lobes of the tail.
• The mouth is dark, with black pigment along the gum line—the source of the nickname “blackmouth.”
• Spawning fish can become olive-brown, red or purplish; males may develop a hooked upper jaw.
• Chinook are the largest Pacific salmon, but size alone is not reliable.

Chinook or coho?

Both may have dark mouths and spots, but coho typically show spots mainly on the upper tail lobe and have a lighter or grayish gum line. Chinook commonly show black gums and spotting across both tail lobes. Use multiple features because damage, lighting and life stage can hide individual marks.

Best photographs for confirmation

Capture the full side profile, the open mouth and gum line, and a straight-on photograph of the entire tail. Record the general catch area and whether the fish was in a river, estuary or ocean.

Life cycle and habitat

Chinook hatch in freshwater, migrate to the ocean to feed and grow, and return to freshwater to spawn. In North America their native range extends along the Pacific coast from California through Alaska. Color and body shape change as adults enter freshwater.