Willard National Fish Hatchery
Pacific Region
 

Coho Salmon

salmon eggsSilver in the ocean, coho undergo an amazing spawning transformation. Males get bright red flanks, dark green backs, and dark gray bellies and heads; females sport a paler version of the same colors. Males' jaws become grotesquely hooked. The gums are white–very noticeable when the fish are in their dark spawning colors.

Most coho spend 1 ½ years at sea, although about 10 percent of males, called "jacks," stay only 6 months. They are not long-distance migrants; Columbia River coho range only from northern California to Vancouver Island, and stay close to shore. Coho migrate upriver in late summer and fall and spawn from October through December.

Coho fry stay in fresh water for 18 months before heading out to sea. Unlike other salmon fry, young coho are colorful, with orange bellies and black-and-white bordered fins. Their colors aid them in territorial displays; they are the most aggressive of all salmon fry, both to their own and other species.

Unlike chinook, coho will spawn in small coastal streams that have been less affected by development. However, wild coho in the Columbia Basin have been hard hit by loss of stream habitat, and continue to decline. Ninety percent of Columbia River coho are now hatchery-raised.

Spring Chinook Salmon

When they first arrive in fresh water, spring chinook are greenish with paler flanks. As spawning approaches they become grayer and darker; spawning males can almost be black. Their bodies are slender and rounded in cross-section, whereas fall chinook are more slab-sided; this allows spring chinook to swim more easily in turbulent, fast-flowing water.

Spring chinook spend 1-5 years at sea. They migrate upriver from March to May and stay in fresh water for weeks or months before they are ready to spawn. Unlike fall chinook, spring chinook prefer to spawn in smaller rivers and side streams. Spring chinook fry spend over a year living in fresh water, and are aggressive to others of their kind.
Spring chinook used to outnumber fall chinook in Columbia River catches 2 to 1, but this is no longer the case. Because their fry spend a long time living in streams, spring chinook have been especially hard-hit by pollution and siltation of stream habitat. Upriver stocks–those that have to pass through several dams–are very low. Lower river stocks have increased since the 1950s, mainly due to hatchery production.

 

Last updated: February 21, 2012
Willard National Fish Hatchery
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