Do You Know: Coho Salmon?

Quick Facts:

• Scientific name: Oncorhynchus kisutch.
• There are more distinct populations of coho than of any other Pacific salmon species in BC.
• Although coho tend to remain close to the coastline, they have been found as far as 1600 km from shore.
• Juvenile coho defend their territories through a series of maneuvers including a complex shimmy-shake, dubbed by scientists the “wig-wag dance”.

Coho are swift, active fish. These salmon are found in most BC coastal streams and in many streams from California to Alaska, but their major territory lies between the Columbia River and the Cook Inlet in Alaska. Coho spawn in over half of the 1500 streams in BC and Yukon for which records are available.

Young coho generally spend one year in freshwater although in northern populations, high proportions of juveniles spend two or even three years in freshwater before entering the ocean. Juvenile coho favour small streams, sloughs and ponds, but coho populations can also be found in lakes and large rivers. After the eggs hatch in the gravel of stream beds, young coho spend one-two years rearing in freshwater. Migrating as smolts to the oceans, they spend up to 18 months in the sea before returning to their natal streams to spawn. While most coho salmon return to fresh water as mature adults at three years of age, some mature earlier and migrate to their home streams as jacks at only two years.

There is only so much space for territories in streams so the number of young coho is limited and there is intense competition for what space there is. Individuals that can not find or defend a territory do not survive well. A consequence of this territoriality is that a stream tends to produce the same number of smolts year after year regardless of the number of adults that spawn in it.

Unlike other salmon species which generally migrate long distances in the open ocean, coho remain in coastal waters. Their proximity to land, their willingness to take lures and their tendency to jump and dodge makes them a favourite among sport fishers. Coho are also caught in First Nations food fisheries by traditional methods of weirs, nets and gaffs. Commercial troll fisheries have long harvested coho as well, although recent population instability has prompted ongoing restrictions in all fisheries since 1998.

As adults, coho have silvery sides and a metallic blue back with irregular black spots. Spawning males in freshwater exhibit bright red on their sides and bright green on the back and head, with darker colouration on the belly. They also develop a marked hooked jaw with sharp teeth. Female spawners also change colour and develop the hallmark hooked snout, but the alteration is less spectacular.

For further identifying information about coho salmon, please see our Recreational Fishing Salmon Identification pages.
 
Material for this page taken from Underwater World: Pacific Salmon and The Incredible Salmonids (out-of-print), and additionally supplied by the Fisheries and Aquaculture Management Branch of DFO.