Chinook Salmon, Oncorhynchus tshawytscha
Identifying characteristics: (Non-Native Fish) Two dorsal fins including one adipose fin, inside the mouth and gums, black, small spots on upper back and tail, 15 to 17 rays in anal fin.
The Chinook or King Salmon is a member of the Salmonidae family, which includes the salmon, trout and whitefishes. All are characterized by an adipose fin (the small dorsal skin flap just in front of the tail), and have a preference for cold water with high oxygen content, making the Great Lakes an ideal habitat.
Chinook Salmon were first introduced into the Great Lakes in the 1870s, but these attempts were not successful. In the 1950s and early 1960s, an undesirable exotic species, the Alewife, had proliferated in the Great Lakes to the point where they were dying off by the millions and fouling popular beaches. In an attempt to control the Alewives (and hopefully create an exciting new sportfishery!), Coho Salmon were stocked into select Lake Michigan tributaries in 1966, and Chinook Salmon were stocked into Lake Michigan and Lake Superior tributaries in 1967.
The stockings were wildly successful. The Alewife population was reduced, and anglers flocked to Lake Michigan to catch the salmon. In Lake Michigan, stockings from 1967 to 1970 yielded exceptional angler returns of about 13% of the stocking rate. As a result, Chinook Salmon stocking programs spread to lakes Huron (1968), Ontario (1969) and Erie (1970). Since then, a multi-billion dollar sportfishery developed, particularly on lakes Michigan and Huron.
In addition to being stocked, Michigan's streams offer excellent habitat for Chinook Salmon natural reproduction. For example, rivers like the Pere Marquette and Betsie have never been stocked with Chinook Salmon, yet they host outstanding runs of naturally reproduced fish each year. Chinook Salmon egg-takes for hatchery rearing are conducted on the Little Manistee River near Manistee and the Swan River near Rogers City. In recent years the Lake Huron fishery has diminished, due to a lack of prey fish for the salmon to eat. As Alewife levels have dropped in Lake Michigan as well, stocking numbers have been reduced in both lakes.
Chinook Salmon reproduce by spawning in Great Lakes tributary streams varying in size from small tributaries to large-connecting waters. During the fall months (mainly September and October), Chinook spawn ascend the streams from the big lakes, and then spawn over beds of gravel, typically on riffles. Within a few weeks after spawning, adult Chinook die. The following spring, Chinook Salmon eggs will hatch and the young usually remain in the river for a few months before out-migrating to the lake. In some cases, Chinook smolts have been reported to spend up to 1.5 years in the stream before they migrate. Young Chinook smolts in rivers eat insects, insect larvae and crustaceans; whereas adults in the open lake eat fish almost exclusively. In the Great Lakes, Alewives make up the majority of their diet.
Once in the lake, males tend to remain for 1 to 2 years and females for 2 to 4 years before returning to spawn. Adult Chinook Salmon average approximately 15 pounds, but can reach 20 to 25 pounds or even upwards of 30 pounds. Chinook Salmon live in the open waters, also termed the pelagic zone, during the majority of their life span. In the late fall to early winter, they move into the southern reaches of each of the lakes traveling many miles offshore as they go. In the spring they first move up the coast line, then they move offshore depending on prey fish patterns and lake temperatures, but by fall, mature Chinook Salmon will congregate at the mouth of their natal stream and began their journey upstream to spawn.
Anglers prize Chinook because of their large size and the challenge they present for fishing, and because they make a delicious meal. Chinook Salmon are heavily targeted by trollers in the Great Lakes. At times they can be caught by shorebound anglers fishing Great Lakes piers. Small-boat anglers often catch them in the harbors or "drowned rivermouth lakes" along the coast of Lake Michigan. River anglers also heavily target the Chinook Salmon.
For more information on how and where to catch Chinook Salmon see our Michigan Fish and How to Catch Them and Better Fishing Waters.
Chinook Salmon graphic courtesy of Joseph R. Tomelleri and copyrighted.