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.
The present status of Great Lakes steelhead is relatively rosy. A lot of work is being done to keep these fisheries healthy.
For example, on Lake Huron and Lake Superior a review of the present regulations is being undertaken, headed by MNR’s Dave Reid, Lake Huron management supervisor, with the goal of streamlining existing regulations, reducing their complexity, while continuing to provide ample angling opportunities. Similarly, a review of steelhead fishing regulations for Lake Ontario is being undertaken jointly with the State of New York.
MNR Senior Operations Specialist Jon George says many steelhead runs in Lake Superior have “never been better.”
He believes the key to good steelheading in Superior streams is to keep annual fishing mortality of adults below 15% and to maintain 55% of the population as repeat spawners.
If angling mortality is minimized, he said it doesn’t take long for a fishery to rebound. A long-term monitoring study of Portage Creek, which George has been involved with, resulted in the spawning run increasing from 400 fish in the early 1990s to a recent high of 1,600, simply by eliminating angling mortality.
On the Canadian side, there is no stocking of rainbows in Lake Superior, and the fishery there is virtually 100% wild fish. In the cold and sterile waters of Lake Superior, the average steelhead caught is in the 5-pound range. A 10-pounder is a big one.
Given the sterility of Lake Superior, I asked George whether the recent introduction of other salmon, notably the chinook, was having an impact on steelhead. He thought that, on the whole, the impact was probably positive, mainly due to the welcome nutrient load the dead and decaying bodies of spawned-out chinook provide nutrient-poor streams.
In Lake Huron, self-sustaining steelhead populations are also the norm, although there is some stocking of specific areas, mainly through the Community Fisheries Involvement Programme(CFIP). In recent years, there has also been a good open-water rainbow fishery in the North Channel of Georgian Bay, the result of fish escapement from local fish farms. In the less hostile and more productive environment of Lake Huron and its feeder streams, the steelhead fishery there can produce more fish in a given area of stream and runs can withstand higher fishing pressure. Fish also grow larger. Steelhead topping 10 pounds are common. Still, fisheries biologists believe that managing for 50 per cent repeat spawners in the tributaries of Lake Huron is necessary to prevent a long-term decline in any given stock. Periodic problems with Lake Huron steelhead fisheries include hot summers, especially when combined with drought. When water volumes drop perilously low, fry mortality can be high.
Lake Erie’s steelhead fishery is also mostly a good news story, in part, said MNR biologist Larry Halyk, due to heavy stocking on the U.S. side. This has resulted in a charterboat fishery that focuses on steelhead in the lake’s central sector. In the absence of stocking, the fishing would be less spectacular, mostly because Erie has few suitable spawning streams. Most of those on the Ontario side of the lake flow through a wide clay belt, which is also a sea of agriculture. Even if agriculture was absent, Halyk believes these streams wouldn’t be suitable for steelhead. However, in the sand plain of Norfolk County, from near Port Stanley and east(where steelhead were first stocked)the fish are doing well. Over the past 10 years, improvements in soil conservation, a result of co-operative efforts with the agricultural industry, and other habitat improvements, like the installation of a fishway on Big Creek, have helped to improve steelhead runs.
Of special note is the Grand River again, where the removal of a dam near Brantford in 1989 provided steelhead access to a huge area of suitable spawning habitat. Halyk believes this run still has a lot of room to grow.
In addition to stocking and improvements to stream spawning habitat, Halyk says Erie is more suitable for steelhead now than it ever used to be. This is largely due to improved water clarity resulting from billions of filter-feeding zebra and quagga mussels. In Lake Ontario, the good news story continues, although recent population estimates suggest steelhead numbers have declined slightly. In part, this could be the result of a rapidly changing fish community in the lake. Even though all of the Great Lakes have been in a state of flux for years, the changes seem to be greatest in Lake Ontario.
Jim Bowlby, assessment biologist with the Lake Ontario Management Unit, said that over the past couple of years successful natural reproduction has also been reported for chinook salmon, coho salmon, lake trout, and lake sturgeon. He believes this indicates “something is going on in the lake.” Bowlby said the lake’s steelhead fishery is made up of about 40% wild fish, mostly of Ontario origin. The emphasis in Lake Ontario, as elsewhere, is on managing wild fish. However, the Ontario government and volunteer groups do stock some steelhead, particularly in areas around Toronto, including the Credit and Rouge Rivers and Bronte Creek.
With respect to the river runs, Bowlby believes a high angler exploitation rate has contributed to the recent decline of the fishery, although he was quick to add that the fishing quality is still good. He attributed the highest exploitation to the extended all-year season in the lake and in some lower stream sections.
Bowlby said there’s a correlation between catch rates in the lake and the weather. If April is warm, fishing tends to be good on the Canadian side of the lake, but poor on the U.S. side. The reverse is true if April is cold. Whatever happens in April tends to carry through the rest of the year. April 2003 was the coldest since 1985, and fishing on the Canadian side of the lake was poor. Bowlby attributes this phenomenon to thermal bars. When April is warm, steelhead encounter – and like – the warm water and stay near shore. If the lake is cold, the habitat is not to their liking, and they disperse.
Steelhead lifecycle and patterns
Unlike most other Pacific salmon, all steelhead don’t die after spawning, and some individuals may spawn three or four times before they finally expire. The oldest fish are usually the biggest.
The rainbow trout modifies behaviour and survival strategies to suit its surroundings. For example, although most steelhead spawn in spring, the exact timing varies considerably. There is also great variation as to when adults return to a spawning stream. While individual fish might return during any month of the year, most spawning runs in the steelhead’s native West Coast streams are categorized as winter runs or summer runs.
Winter-run fish normally spawn during April and May of the year they return, but summer-run fish do not spawn until spring of the following year. Many of Ontario’s steelhead are spring spawners. They enter streams in fall and again in early spring.
Steelhead exhibit strong homing instincts, although fish stocked into new waters will readily colonize suitable new habitats. In the upper Great Lakes, about 2% of the spawning population in any given stream, in any given year, spawn in a stream they weren’t born in. This is referred to as the stray rate.
Females dig and spawn in several redds, depositing as many as 1,000 eggs in each one. Because the eggs are large (.117 to .195 inches/3 to 5 mm in diameter), the maximum number in a female is relatively small, usually less than 10,000.
The eggs hatch four to seven weeks later, depending on temperature. Three to seven days after hatching the alevins become free-swimming fry that start eating. Growth patterns of young steelhead parr in rivers, before they smolt and enter one of the Great Lakes, has been described as “bewildering.” Preferred foods, chosen habitats, growth rates, and time spent in-stream, vary tremendously between flows.
According to Dave Gonder, management biologist with the Lake Huron office of the MNR’s Upper Great Lakes Management Unit, insects and other in- vertebrates form the bulk of the diet of a young steelhead, augmented with sculpins, minnows, crayfish, and other foodstuffs.
While the average stay in a stream is two years, it can be as little as one or as much as five years. The cold, sterile streams on the north shore of Lake Superior tend to hold young fish longer than the more productive streams to the south, but it’s by no means a hard-and-fast rule.
On the other hand, there’s no doubt the highly productive feeder streams flowing into Lake Ontario produce more fish than streams elsewhere. Surveys show streams flowing into Lake Ontario can have from three to five parr per 1.196 square yards(1 square m)of stream bottom, compared with one parr per 2.39 square yards(2 square m)in Superior’s streams.
Once in a lake or the ocean, steelhead grow rapidly. Invertebrates, both airborne insects and aquatic varieties, remain the mainstay of their diet, which, according to Gonder, they exploit efficiently by keying in on scum lines and thermobars where they abound. As the fish put on the pounds, baitfish like smelt and alewife become an increasingly larger part of the steelhead’s food intake. Generally, after about two years roaming open water, steelhead are ready to return to their birthplace to spawn.
For the record
The biggest steelhead taken from Ontario’s water weighed 29.12 lbs. Russell Kenwell caught it on May 13, 1975, from the mouth of the Nottawasaga River in Georgian Bay. Fittingly, this is the same river where the fish made its first appearance in the province.
First published in the April 2004 issue of Ontario OUT OF DOORS. Subscribe.