Types of fish
Chinook Salmon
Many chinook salmon end their days as trophies mounted on tavern and game room walls. In tribute to their size and character, they are also known as "king salmon."
Chinook were the first Pacific salmon to be transplanted to other parts of the world, but the only notable success in creating self-sustaining stocks has been in New Zealand. A key factor in this general failure was that, like other Pacific salmon, chinook salmon seek the stream of their birth to spawn and die. They have apparently failed to find the right kind of spawning streams along Lake Michigan, so continuous stocking is necessary to maintain the chinook as one of the lake's most prized game fish.
Chinook are generally caught by trolling. For several reasons, this salmon species is especially popular with fish management agencies. They can be released five to six months after hatching and therefore are cheaper to hatch and stock than cohos, which require 14 to 16 months.
Coho Salmon
Commonly called "silver salmon," this Pacific import has been planted in lakes Michigan and Superior annually since 1966 and is now an integral part of the lake's "put-and-take" sport fishing industry.
Mature cohos gorge themselves on alewives, smelt, and other forage fish. In Lake Michigan, cohos attain an average weight of five to six pounds but often top out at 10 pounds or more.
There is some concern that this aggressive fish might disrupt the spawning of other valued species, such as brook, brown and rainbow trout.
Coho salmon ordinarily return in their third year to the streams where they were planted to spawn and die. They reproduce naturally in many streams on the eastern side of Lake Michigan, but their general population must be sustained with hatchery-reared fish. Continual stocking has helped to improve the lake's predator-prey balance and given satisfaction to thousands of sport fishermen as well.
Brown Trout
Brown trout, a European relative of the Atlantic salmon, arrived in North America as early as 1883 and were introduced to Wisconsin waters four years later. These resourceful fish managed well in degraded habitats no longer suitable for brook and other trout.
At the same time, the browns proved they could grow faster and live longer than the other kinds of trout.Their reputation as a wary fish that tends to feed at dusk or night may account in part for their durability.
Brown trout have adjusted well to life in Lake Michigan. They spawn in late autumn, sometimes on rocky reefs along shore though they generally prefer the gravelly headwaters of streams. Wisconsin now stocks about 1.5 million brown trout in the lake each year, with lesser numbers stocked by Michigan and Illinois.
This has brought more variety to the lake's ecosystem and to the lives of many anglers. Brown trout are among the wariest of fish, feeding usually at dusk or at night, so fishermen are the adult brown's chief predator.
Lake Trout
These swift, torpedo-shaped fish inhabit the cold waters of an area extending from Wisconsin and Upper Michigan to the northernmost reaches of the North American continent. For more than half a century, lake trout were the most valuable commercial fish in the Upper Great Lakes. Then overfishing and the onslaught of the sea lamprey from the late 1930s and into the 1950s effectively eliminated this fish from Lake Michigan.
Thanks to sea lamprey control and continuous stocking, lake trout now live seven or more years in the lake, thriving on a diet of chubs and sculpins (their traditional prey), smelt and alewives. As a result, the return of this preeminent native, along with the introduction of Pacific salmon, has created a thriving world-class sport fishery in Lake Michigan.
Lake trout are long-lived and do not reach sexual maturity until 6-8 years of age. While the average lake trout in Lake Michigan today weighs around seven pounds, some of the larger trophy fish are three feet long and weigh as much as 25 pounds.
Rainbow Trout
These attractive game fish strike aggressively, fight valiantly and are an angler's joy. The first rainbow trout planted in the Great Lakes were probably "steelheads." This is a strain of rainbow trout that migrates into the ocean before returning to spawn in their freshwater home streams.
Rainbows have adapted well, moving in and out of the Great Lakes much as they would the ocean. As might be expected, they range widely throughout Lake Michigan and Lake Huron. Tagging has revealed that some migrate as far north as the Canadian tributaries of Lake Superior.
Rainbow trout seldom swim deeper than 35 feet along the Great Lakes shores and are easily located. In forage-rich Lake Michigan, they grow 30-32 inches long and may reach 16 pounds by the time they are five years old.
Rainbow trout reproduce naturally in Lake Superior's tributaries and in some Lake Michigan tributaries as well. Unlike Pacific salmon, the rainbow survives after spawning and may spawn two or three times during its life.