Migratory rainbow trout, called steelhead, are highly prized trophies. They’re beautiful fish, leaping titans when hooked and a culinary delight on the plate. For many anglers, steelhead are the ultimate challenge.
Although they’re the same species, steelhead of the Great Lakes and the Pacific Ocean are different from rainbow trout in smaller inland lakes.
The term steelhead describes a rainbow trout that was born in a stream, migrated to the sea, and returned to the stream as an adult to spawn. Such fish are said to be anadromous. Given that the Great Lakes are every bit seas, albeit freshwater ones, a steelhead in Ontario refers specifically to the anadromous rainbow trout found in these lakes and their tributaries. Elsewhere, they’re merely rainbow trout. Or are they?
In 1989, rainbow and cutthroat trout were moved by taxonomists from the genus Salmo, which includes Atlantic salmon and brown trout, to the genus Oncorhynchus, which includes pink, sockeye, chum, Chinook, and coho salmon. Technically, the rainbow trout (oncorhynchus mykiss) isn’t a trout at all, but a salmon. It’s also the same species as the East Asian trout.
While long a fixture of Ontario’s fishery, rainbows are non-native to the province. They were once found only on the West Coast of North America, but humans have widely transplanted this magnificent fish. Today, one of the most important transplanted, self-sustaining populations of steelhead in the world is in the Great Lakes.
The first transplants to the Great Lakes watershed began in the U.S. in 1874, but the first introductions of steelhead to the lakes proper took place when the Aux Sables River was stocked in 1876. On the Ontario side, the first fish were brought in privately sometime in the 1890s to a headwater pond on the Nottawasaga River. The first known recovery of a steelhead in Ontario was a 4-pounder taken near Duck Island, near Manitoulin Island, in 1904.
With an introduction in 1878 in the State of New York, the Lake Ontario watershed was the second Great Lake to receive rainbows. By 1920, they were well established in a number of rivers on the U.S. side. The first seeding on the Ontario side took place in 1922 into a pond in Riverside Park, Toronto.
The Lake Erie-St. Clair watershed was first stocked in 1882, but no fish were recorded in Ontario waters until 1920. The first Ontario stocking was in 1936 in Norfolk County creeks.
Lake Superior was the last of the Great Lakes to receive rainbows, and this time the introduction was initiated by Ontario. Fish were stocked near Sault Ste. Marie in 1883, followed shortly by American releases, also in the eastern basin. By the turn of the century, large numbers of rainbows up to 8 pounds were being taken by commercial netters targeting lake trout.
Not surprisingly, Great Lakes rainbows are not a pure strain. They originate from a long history of stocking both wild and domestic strains on both sides of the border. It’s even possible there was some early hybridization with cutthroat trout, a species known to interbreed with rainbows in the wild. Cutthroats were planted in a number of New York and Michigan tributaries in the late 1800s.
Compared with resident stream rainbows, steelhead of the open lakes are brighter and usually silvery. The clearer the water, the brighter the fish. Some lake fish look almost nickel-plated. Once they return to natal streams, they begin to darken and display a bright red band along the body.
The steelhead doesn’t live to a ripe old age, especially when compared with long-lived Methuselahs like lake trout. Few steelhead live to see their ninth birthday, and generally life expectancy is only 6 to 7 years.