Coho Salmon, Oncorhynchus kisutch
Identifying characteristics: (Non-Native Fish) Two dorsal fins including one adipose fin, dark blue to green back with silver sides, white belly, and wide caudal peduncle. Inside of mouth white and gums between teeth gray or white, but tongue may be black. Small dark spots on back, sides and typically on upper lobe of caudal fin. Thirteen or more rays in anal fin.
The average adult Great Lakes coho salmon weighs five pounds. Like Chinook, coho are native to the Pacific coast of North America and parts of Asia. They were successfully introduced into the Great Lakes in 1966, when smolts where stocked in two Lake Michigan tributary streams; Platte River and Bear Creek (Big Manistee River tributary). There was much excitement from anglers and fish managers when coho made their first spawning run in the fall of 1967. Since that time, the coho has become a popular sport fish, and many people come from all over the world to fish Michigan's great coho fishery.
Although coho do spawn in Great Lakes tributaries, present fish stocks are maintained mainly by fish culture and stocking. Depending on the tributary, coho spawning runs occur from early September to November. Females excavate redds, or nests, in tributary stream gravel beds. Coho are semelparous, and both male and female adults die soon after spawning. The next spring the eggs hatch and the young remain in the gravel for two to three weeks. They emerge in the late spring, as fry, and wait until their second spring before descending to the Great Lakes as smolts. Once in the lakes, they may stay near shore for a few months, and then seek deeper waters.
Young coho eat and grow vigorously. Most coho spend about 18 months in the lake feeding, and then return to their parent streams to spawn, although some may stay out for an additional year before making the spawning migration. As soon as they are large enough, young coho begin to eat smaller fish, mostly of other fish species. In the Great Lakes, larger coho feed primarily on smelt and alewives; however they are opportunistic feeders and will feed on a number of species if they are available as forage. They compete primarily with steelhead for food. Coho are preyed upon by predatory fish and birds while they are small, and a residual numbers of sea lampreys also take their toll on coho populations.
For more information on how and where to catch coho salmon see our Michigan Fish and How to Catch Them and Better Fishing Waters.
Coho salmon graphic courtesy of Joseph R. Tomelleri and copyrighted.