Coho salmon (Oncorhynchus kisutch), also called silver salmon, are one of the six Pacific salmon species. They are anadromous, spawning in fresh water and growing at sea, and are the backbone of the Alaskan troll fishery.[1]
| Scientific name | Oncorhynchus kisutch |
|---|---|
| Typical size | 20–28 in; 7–11 lb |
| Maximum weight | About 36 lb |
| Return age | 3–4 years |
| Alaska share of salmon harvest | 3.5% by number; 5.9% by weight |
| Smolt migration | Late March through July |
Description
At sea, coho have silver sides and dark-blue backs with spots on the back and upper tail lobe. When spawning in fresh water, they develop bright-red sides, a bluish-green head and back, a dark belly and hooked jaws with teeth. Typical fish are 20 to 28 inches long and weigh 7 to 11 pounds, occasionally up to 36 pounds, and males are slightly larger than females.[1]
Range
The native range covers both sides of the North Pacific, from Hokkaido and eastern Russia around the Bering Sea to mainland Alaska, and south to Monterey Bay, California. Coho have been introduced to the Great Lakes and many U.S. reservoirs, where natural reproduction is generally low.[1]
Life cycle
Adults return to spawn at three to four years old, climbing streams as far as they can. Females dig up to seven nests in gravel, eggs hatch after about six to seven weeks, and the young stay in the gravel for a further six to seven weeks until the yolk sac is absorbed. Juveniles spend one to two years in streams before becoming smolts, migrate to the ocean from late March through July and live at sea one to three years. Some young males, called jacks, return to spawn at age two, and adults die after spawning.[1]
Fishery
The 2010 North Pacific harvest exceeded 6.3 million fish, with 4.5 million in the United States and 1.7 million in Russia. Pink, chum and sockeye yields are about 15 times larger by weight. Most Alaskan coho are caught by net fisheries, and they average 3.5 percent of the annual Alaska salmon harvest by number and 5.9 percent by weight.[1]
FAQs
What is another name for coho salmon? Silver salmon.
How big do coho get? Typically 7 to 11 pounds.
Do coho die after spawning? Yes.
Sources
Key facts
- Typical 7–11 lb
- Dies after spawning
Quick checkHow old are coho when they return to spawn?Show answer
Three to four years
Sources
- Wikipedia. Coho salmon. 2026 (accessed 2026-11-14)
Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 14, 2026Researched and drafted with AI assistanceReport an issue