Salmon Species of the Columbia Basin

Chinook

Oncorhynchus tshawytscha

Chinook usually mature in their third or fourth year. However, it can be as early as the second year or as late as the eighth. The fish return to the Columbia in the fall, spring, and summer. Some types of chinook linger in deep pools in the river until the water is just right for moving on to their spawning grounds. Chinook are known as long-distance swimmers and will travel to the farthest reaches of the Columbia to spawn.

Females can dig and deposit eggs in several gravel nests (called redds). They can release 3,000 - 7,000 eggs. Five thousand eggs is the average. Some young chinook - most typically, fall chinook - will go to seas in their first year. Others will remain in the stream one more year before migrating.

Coho

Oncorhynchus kisutch

Coho spawners return to the Columbia in the fall of their third year. Almost all spawn in Washington and Oregon. Rarely are coho seen in Idaho. The female may dig several redds and will deposit a total of 3,000 - 4,000 eggs.

After hatching, the young fish gather in schools in shallow areas near the stream bank. As they grow older, they disperse and become very aggressive, even towards each other. Most make the journey to seas when they are in the spring of their second year but can migrate anytime between one and three years of age.

Sockeye

Oncorhynchus nerka

Sockeye will return to the river between their third and eighth year of life, but most of them return as four-year olds. All require a lake at the headwaters of their chosen stream to spawn. The adults pass through the lake to smaller, tributary streams where the females dig their redds. The female releases an average of 3,500 eggs. After hatching in early spring, the young fish move immediately into the lake. Most will spend a full year there before migrating to the ocean.

Steelhead

Oncorhynchus mykiss

Steelhead migrate to the sea throughout the year. Some migrate after their first year, but most wait until after two years. As the young go downstream, they pass adults moving upstream to spawn. Most steelhead return after two years at sea. More return in the summer than in the winter.

Winter fish spawn within one or two months. Summer fish may wait as long as six months. The female digs a huge redd, covering an area of up to 60 square feet. She will bury the eggs in up to a foot of gravel. The female will release from 200 - 9,000 eggs. It depends on her size and type of stock.

Unlike other salmon species, steelhead don't die after spawning. They can swim back to sea and return to spawn again. But only 10 to 15 percent survive the trip. Steelhead of up to nine years old have been caught.