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Coho Fish in water Coho (Silver) Salmon
Oncorhynchus kisutch

Other names: silver
Average size: 6-12 lbs, up to 31 lbs

Coho salmon are a very popular sport fish in the Puget Sound. The species uses coastal streams and tributaries; often being present in small neighborhood streams. They can even be found in urban settings if their need for cold, clean, year-round water is met.


Coho spawn in small coastal streams and the tributaries of larger rivers. They prefer areas of mid-velocity water with small to medium sized gravel. Because they use small streams with limited space, they must use many streams to successfully reproduce. As a result, coho can be found in virtually every small coastal stream with a year-round flow.

Returning coho frequently gather at the mouths of streams and wait for the water flow to rise, often after a rainstorm, before heading upstream. The higher flows and deeper water enable the fish to pass obstacles such as logs or beaver dams that would otherwise be impassable.


Coho have a very regular life history. It takes them about 18 months to go from egg to smolt. In the fall they are deposited in gravel as eggs, emerge from the gravel the next spring, and then rear in the stream for a year before making their way to the ocean.


Coho Picture
  • Mouth is light with a white gum line
  • Medium size, sharp teeth
  • Spots only on upper lobe of tail
  • Spots on back
  • Wide caudal peduncle


Coho Head The mouth is white and the gum line is almost white, but the tongue may be black. The teeth are sharp and strong.


Coho Tail The coho tail has just a few scattered spots, usually on the upper lobe, with silver streaks. It has a wide caudal peduncle.


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.

Coho Populations List
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Fun Facts
Did you know?
Coho and sockeye are found in freshwater year-round; coho in small coastal streams and sockeye in lakes. These fish are very susceptible to poor water quality, such as high temperatures and pollution.

Fun Facts
Did you know?
Salmon species have adapted to use virtually every part of every stream in the northwest.

Fun Facts
Did you know?
Big rivers are used by pink salmon in the lower reaches, chinook in the mainstem and larger tributaries, coho in small tribs, and steelhead in the uppermost tributaries.

Fun Facts
Did you know?
Small streams are used by chum in the lower reaches, coho next, and cutthroat in the headwaters.

Fun Facts
Did you know?
A moving fry is much easier to see than a motionless one. This is why salmon tend to spawn in parts of the stream that their offspring use for rearing; the emerging fry do not have to travel far to find rearing areas.
Fun Facts
Did you know?
The size of a salmon is usually related to its age. Pink salmon are the smallest fall-spawning salmon and are also the youngest, at two years. Chinook can live up to nine years, the longest, which is why some chinook can grow to over 100 pounds. Cutthroat, which live longer than pinks, are typically smaller because they spend less or no time feeding in productive marine waters of the north Pacific.
Fun Facts
Did you know?
There is a sixth fall-spawning salmon, the masu, or cherry salmon, which is found only in Asia. This fish occupies the same niche that the sea-run cutthroat trout occupies in North America.
Fun Facts
Did you know?
Steelhead and rainbow trout are the same species of fish; rainbow are the freshwater form, and steelhead the anadromous form.
Fun Facts
Did you know?
Steelhead and cutthroat trout were recently added to the salmon genus, Oncorhynchus, from the trout genus, Salmo. Also, the scientific name of steelhead changed from Salmo gairdneri to Oncorhynchus mykiss.