The Steelhead Trout

Until quite recently scientists classified the steelhead trout Salmo gairdneri separately from the freshwater rainbow trout of the Pacific coastal region of North America, which they named Salmo irideus. However, the steelhead is now regarded simply as a rainbow trout that spends part of its life cycle at sea. Thus, the steelhead and the freshwater rainbow trout are clumped together as the species Salmo gairdneri. However, those who have angled for both freshwater rainbows and steelheads will attest that the two varieties are quite different in appearance and behaviour.

The adult steelheads spawn in late winter and spring, when high water in the river systems, following the first snowmelts, enables the fish to reach the headwaters quickly and easily. During the winter these streams are often iced-up; in summer, the flow may be too small for the fish to complete their upstream migration. The fertilized eggs, hidden deep in gravel redds, are assured a good supply of oxygen-rich cold water as the snow melt continues during spring and early summer. And by the time the steelhead fry begin to seek food in the summer and early autumn, the river is at its most productive as far as insects are concerned.

Young steelhead trout grow rapidly. By, the end of the year they may have reached five inches in length, and by their second birthday seven inches or more. At this stage, the steelhead parr are indistinguishable from the parr of freshwater rainbow trout that will never go to sea. But the following year, when they are seven to ten inches long, the steelhead parr become smolts. They lose their lavender-pink hue and attain a more silvery attire; quickly they move downstream to saltwater.

While sea-run cutthroat trout tend to remain in tidal waters close to the estuaries of their natal rivers, steelhead shoals will frequently travel a few hundred miles from their home river in search of marine foods. Some steelheads tagged as smolts in rivers in British Columbia have been reported from the seas around Kodiak Island in Alaska, and others have been reported by commercial fishing boats in mid-Pacific up to 2,500 miles away from their natal rivers.

Some rivers have a reputation for producing big steelheads, others produce smaller fish. Even though they are all steelheads, the pattern does suggest that each river system has its own variety of steelhead. In his large work Trout (1979), Ernest Schweibert noted that the steelhead smolts from 'big fish rivers' made the longest migrations and spent an extra year feeding out at sea. Hence the greater size of these fish. However he also argued that the ecology of rivers such as the Columbia and Skeena influenced trout size, because the heavy flow of these rough rivers and the very large stones of the river bed meant that smaller steelheads could not breed there successfully. Only the older and much larger steelheads could mate, cut redds and spawn in these torrent-like conditions.

Because of their size and the spectacular rivers they inhabit, steelheads are possibly the most exciting trout to catch. However, this has to some extent been their undoing. During the 20th century the rivers of Oregon, Washington State, British Columbia and Alaska have attracted anglers from across the USA and Canada, and from Europe and the Far East. Steelheads have been a popular quarry: huge numbers have been taken with little recognition that the populations might one day suffer from over-fishing.

The outcome is that the steelhead stocks of many rivers are now supplemented with fish raised in hatcheries. Bill Luch, author of Steelhead Drift Fishing (1976) put it this way: 'There are very few "wild" runs of steelhead trout left in the United States. Due mostly to the insane depredations of man, it has become necessary to artificially propagate these fish in order to preserve the runs. In other words, most steelheads today are not wild fish, but the product of the hatchery.'

A far better solution to the problem of over-fishing is to reduce fishing pressure. Measures to achieve this are now in force on many river systems: some areas are catch-and release; elsewhere the angler is restricted to the number of fish that may be taken; and on some rivers (for example, the Dean River system of British Columbia) the number of fishing permits available to visiting anglers is severely restricted. Surely this is the answer to conserving wild trout populations: to keep the angling pressure at a level the trout stocks can sustain.