The populations of both species of salmon are dependent upon stocking. The state also stocks a species of brown trout known as the Seeforellen strain and steelhead trout, which are rainbow trout that live in the lake and spawn in the spring. Another 400,000 chinook are stocked in Lake Superior. Once in the lake, the trout and salmon grow rapidly. Cohos mature in less than two years and begin their fall migration to the streams in which they were planted.
Chinook stay in the lake for three to five years before returning to their home streams.
As a result of these efforts, the Great Lakes sport fishery for trout and salmon has become famous throughout the world, with a Lake Michigan sport catch of up to 300,000 chinook and 200,000 coho a year. And this summer, Lake Michigan surrendered three state-record fish. Seeforellen brown trout was caught by a fisherman out of Algoma in early August. Three weeks later, an angler fishing off the Kewaunee Harbor pier pulled in a brown trout that eclipsed that newly set record by a quarter of an ounce. Then in September, a sport angler out of Milwaukee landed a 26 lb.