Statistics

Chinook
Oncorhynchus tshawytscha

Other names: king, tyee, blackmouth (immature)
Average size: 10-15 lbs, up to 135 lbs

Chinook salmon are the largest of the Pacific salmon, with some individuals growing to more than 100 pounds. These huge fish are rare; most mature chinook are less than 50 pounds.

Spawning

Most chinook spawn in large rivers, such as the Columbia or Snake, although they will also use smaller streams with sufficient water flow. They tend to spawn in the mainstem of streams where the water flow is high. Because of their size they are able to spawn in larger gravel than most salmon.

Chinook spawn on both sides of the Cascade Range, some traveling hundreds of miles upstream to reach their spawning grounds. As a result of the distance needed to travel, these fish enter streams early and comprise the spring and summer runs. Fall runs spawn closer to the ocean and tend to use small coastal streams. All chinook reach their spawning grounds by fall, in time to spawn.

Rearing

Depending on the race of chinook and the location, chinook fry rear in freshwater for three months to a year. Spring chinook tend to stay in streams for a full year; fish in northern areas tend to stay in the stream longer as well, primarily because the streams are less productive and growth is slower. Rearing chinook fry use mainstems of rivers as well as their tributaries.

Terminology

Alevin - The lifestage of a salmonid between egg and fry. An alevin looks like a fish with a huge pot belly, which is the remaining egg sac. Alevin remain protected in the gravel riverbed, obtaining nutrition from the egg sac until they are large enough to fend for themselves in the stream.

Anadromous - Fish that live part or the majority of their lives in saltwater, but return to freshwater to spawn.

Emergence - The act of salmon fry leaving the gravel nest.

Fry - A juvenile salmonid that has absorbed its egg sac and is rearing in the stream; the stage of development between an alevin and a parr.

Kype - The hooked jaw many male salmon develop during spawning.

Parr - Also known as fingerling. A large juvenile salmonid, one between a fry and a smolt.

Smolt - A juvenile salmonid which has reared in-stream and is preparing to enter the ocean. Smolts exchange the spotted camouflage of the stream for the chrome of the ocean.

Substrate - The material which comprises a stream bottom.

Body

• Mouth is dark with a black gum line
• Large, sharp teeth
• Spots on both lobes of tail
• Large spots on back

Jaw

The chinook has a dark mouth and black gums at the base of its teeth. Immature chinook are known as a "blackmouth".

Tail

Both the upper and lower lobes of the tail are covered with spots and silver is prominent.