A River Never Sleeps

The summer, winter and spring runs of steelhead are physiologically different, reflecting their specific adaptations. The milt and eggs in "summer run" steelhead show little development when they first enter the river. The gonads will mature while they overwinter in the river. In contrast, the milt sacs and eggs in spring run steelhead are well-developed, and make up a large proportion of the body weight. Summer run steelhead have a significantly larger amount of fat in their abdominal cavity as compared to their winter and spring counterparts.

Presumably the fat is utilized while the summer run fish overwinter in fresh water. Spring fish do not spend a long time in fresh water before spawning so there is no need for these fish to have a storage of fat.

Spawning summer run steelhead tend to have more pronounced secondary spawning characteristics (darker body color, brighter red-colored gill covers and sides, and greater hooking of the snout). Presumably this reflects the longer stay in freshwater.

Studies done on steelhead in British Columbia streams have shown there are often recognizable, and significant genetic differences between races occupying the same stream. The data suggest that steelhead stream populations typically consist of a large number of semi-isolated populations (races). The genetic differences found between races invariably reflects anatomical, behavioral and
physiological adaptions which have evolved in response to local environmental conditions found at different sites in a stream system.

Studies have found that steelhead from a given race use a number of different strategies in order to minimize the chance individuals will spawn with a steelhead of a different race. The adults of different races return to the river at different times of the year, and they tend to spawn at different sites, and at slightly different times of year. The density of spawning adults is also typically low (20 to 50/km) and dispersal distances of juveniles are also low (less than 1 km).

When the juveniles return as adults they tend to return to same area they were reared. So the various steelhead races in a stream will use both time and space to help keep them apart.

The reported steelhead spawning period in the Bella Coola River is lengthy, from about February to July, with a small peak of activity in June when the water levels are high and fish difficult to count. Presumably the steelhead which entered earliest (summer run and early winter run fish) spawn first.
Tagging studies on Gold River (Vancouver Island) revealed that fish entering in December and January spawned 3 to 7 weeks earlier than their February through April counterparts.

Once at the spawning site, the female steelhead selects a territory in which she will construct a nest or redd. Typically this is in the tail-out of a clear pool. Steelhead have been observed spawning in water 0.7 feet deep and in water more than 5 feet deep. They prefer spawning gravels between 0.5 and 4 inches in diameter, but will accept areas with smaller or larger average gravel size.

The female constructs the nest by turning over on to her side and then strongly flexing her strong tail. Stones are hydraulically lifted from the stream bottom, and there appears a depression 10 to 25 cm deep, and 30 to 60 cm in diameter. While the female is preparing the nest, the males fight vigorously for the right to spawn with her. These often fierce battles may have a lot to do with later survival rates - because far few males will live to make subsequent spawning runs.

The winner of the spawning battles will join the female when she is satisfied with the redd and ready to deposit her eggs. They lie beside each other above the redd. Together they both drop down into the redd, begin to quiver, open their mouths, arch their backs and simultaneously release egg and sperm. The female then moves a short distance upstream, and covers the eggs with gravel by constructing another nest. The gravel she lifts off the stream bottom in the second redd settles downstream, filling the previous nest and covering the eggs.

The male and female will repeat the spawning ritual until all the eggs are deposited. On average 800 to 1,000 eggs are deposited per redd, and the female will deposit eggs in 6 to 7 redds over a few days. Large female steelhead may have as many as 15,000 eggs. Survival of steelhead eggs is low - if just 1 in 1,000 eggs deposited survive to adulthood the spawning pair will have successfully completed its mission.

Flood associated shifting of gravels, smothering sand and silt deposition over redds, predation (by insects, birds and mammals) freezing anchor ice, and/or drying stream beds typically kill over 90% of the eggs deposited. Floods, competition with other juvenile salmon and trout, predation by predatory birds (eg kingfishers, mergansers), mammals, and larger fish typically kills over 90% of the fry. Ocean predators, and poorly understood ocean environmental hazards kill over 90% of the smolts.

A steelhead might lay 4,000 eggs, of this 400 will emerge as fry from the gravel, of these 40 will reach the estuary as smolts, and of these 4 will return as adults. In good survival years more adults would return, in poor survival years no adults would return from the eggs laid. After spawning, adult steelhead, or kelts, are sorry looking creatures. They typically have frayed fins and their bodies are thin and dark, almost black, with a brick red bands running down their sides. Males typically have more of a hooked jaw, and large teeth, as compared with the females.

After spawning many of these weakened fish drift downstream and die. Male kelts tend to hang around a few weeks in the river system before heading downstream, while the females begin their outmigration shortly after spawning is completed.

Unlike the salmon species, some steelhead kelts will actually make it back to the and survive to spawn another day. Early studies have shown that up to 19% of spawning Bella Coola steelhead have spawned previously.

Female steelhead accounted for 78.2% of these repeat spawning fish. Not surprisingly, the repeat spawners are generally larger than maiden (first-time spawners) steelhead. A few steelhead will actually spawn up to three times and even four times. An eight year old would be an exceptionally old steelhead.

Kelts tend to be ravenous and, unfortunately, are readily taken on a fly. They don't put up much of a fight in their weakened state, and the last thing they need is the stress of being hooked, fought and released. If you catch a kelt, get it in as quickly as possible and release it promptly. Kelts are sometimes called "snakes" because they are so dark and thin.

Those that survive to return to the ocean face an array of dangers. Gillnet fleets that used to work around the central coast of British Columbia in the spring reported killing 4 or 5 "snakes" a night, five days a week for one or two weeks in June and July. BC Packers used to buy the spawned out steelhead for halibut bait; but most of the kelts were thrown over-board or used as crab bait. Probably 3 or 4 thousand steelhead were killed each year this way, contributing to the decline of runs in central coast rivers, because several hundred of those fish probably would have made it back to spawn a second time.

While the kelts are returning to the sea, the pea-sized eggs left behind in gravel nests are incubating, a process that takes about two months, depending on the average water temperature in a given year. From each egg 'hatches' a steelhead alevin - a small fish with recognizable head, tail, plus a large yolk sac. The yolk sac provides nutrients important for further growth in its gravel world. Sometime in early summer, the yolk sac is resorbed, and the young steelhead emerges from the gravel as a 27 mm long free-swimming fry. It is now ready to begin its life in the hostile stream environment.

For the first year, fry spend most of their time along the stream edge, hiding under stones, and feeding on small insects. Juvenile steelhead (and juvenile rainbow trout) are voracious feeders, and they grow rapidly on a diet of small aquatic insects - chironomids, midges, caddis flies, stone flies, and mayflies. As they grow larger, they expand their diet to include fish eggs, smaller fry (especially pink salmon fry), and even small lamprey larvae.

As the juvenile steelhead increase in size, they occupy faster and deeper water in the stream. If all available rearing habitat is taken juveniles are forced to move downstream. If they can establish a rearing territory they may survive, if not they will likely starve and perish. Studies have shown that juvenile steelhead in some stream systems make seasonal migrations depending on the availability of suitable overwintering rearing environments. Seasonal migrations of as much as 16 km have been documented for some juvenile steelhead.

Young steelhead (and young rainbow trout) are an attractive fish. They have 9 to 13 large, dark oval parr marks along lateral line, plus numerous fine black spots on back and upper sides, and on the dorsal fin. A distinct white or pale orange tip is sometimes seen to on the outer edge of the anal fins. Unlike the juvenile cutthroat, no red dashes will be found on the underside of the lower jaw, and there are usually few or no spots on the tail.

Juvenile Bella Coola steelhead will spend 2 to 4 years in the stream before silvering up and going to sea in spring or early summer as smolts. In one study the average length of two, three, and four year old Bella Coola steelhead was 14.9 cm, 16.2 cm, and 18.6 cm in length, respectively. The overall average length of a downstream migrant smolts was 16.4 cm (6.5 in) in length.

Out in the ocean, some steelhead undertake very long migrations from their native rivers. One tagged steelhead traveled 2,000 miles in 8 months, and the longest recorded ocean migration was 3,210 (more than halfway to Japan).

Steelhead are voracious eaters and grow rapidly out in the ocean. Predominant food items found in the steelhead stomachs caught in the ocean include fish (eg Greenling, anchovy, herring, and lantern fish), squid, and amphipods. In a number of studies squid were the most important food source consumed by steelhead in the ocean. Crustaceans like euphausiids, branchyurans, anomurans, and copepods have also been found in steelhead but they appear to be less important than they are in the diet of salmon species. Interestingly, feathers have been found in the stomachs of up to 10% of fish sampled in studies. In contrast feathers are almost never found in the stomachs of ocean caught salmon.

In the ocean steelhead appear to feed most often near the surface. The average length after one year in the ocean is 47 cm (18.5 inches), after two years they typically reach 70 cm (27.5 inches), after 3 years they are 81 cm (32.0 inches), and after 4 years at sea are 89 cm (35.0 inches). The majority of Bella Coola steelhead (on average 78.5%) spend 2 years in the ocean and the remainder (21.5%) spend 3 years at sea before returning to spawn. More females (27.7%) than males (15.1%) will spend 3-years in the ocean. The average weight and length of maiden Bella Coola steelhead is 4.3 kg (9.5 lb) and 73.7 cm (29 in), respectively. Male steelhead tend to weigh slightly more and are slightly longer than their female counterparts.

After a growth period in the sea, fish nearing maturity return, or 'home' back to their parental stream to spawn.

In the past, it was generally taught that adult steelhead stop feeding once they entered freshwater. Studies suggest that adult steelhead, particularly summer race steelhead, will feed if food is available and conditions are right. Biologists analyzed the stomach contents of 91 Bella Coola steelhead caught between 1960 and 1963. They found that 14 fish had consumed food items while 77 steelhead had stomachs were empty. Insects were found in one stomach, fish eggs were found in 3 stomachs, and salmon fry were observed in 11 stomachs.

The steelhead containing fry were caught from April 1 to 9, 1961. Their stomachs were usually full, and in three instances, counts equaled or exceeded 100 fry (max 180). Certainly steelhead do not need to feed, as judged by the fact that wild steelhead are frequently held in tanks by hatchery personnel for up to 11 months to mature. They are not fed, the eggs and sperm mature normally, and the fish suffer no apparent ill effects. It is probably a good thing that adult steelhead in freshwater do not feed actively for they would quickly scour the river bottom of food needed by juveniles.

If you believe that steelhead bite a fly because they mistake it for food then it makes sense for the fly fisher to select a fly which mimics a salmon egg, amphipod (shrimp), squid, aquatic insect (eg Pteronarcys californicus), salmon fry, or small lamprey larvae. Though there are thousands of flies to choose from, all the angler really needs is a dark fly pattern (eg Skunk or Black General Practioner), a bright fly pattern (eg Fall Special or Orange General Practioner), a neutral fly pattern (eg Muddler Minnow), an egg-imitation pattern, and a fry imitation pattern. The hooks should be sharp, barbless, and the patterns should be tied in a range of hook sizes (eg 1/0 to 8).

Since steelhead do not actively feed, there is no need to "match the hatch" or think too seriously about what they will be eating on any given day. Instead, the steelhead angler looks for steelhead resting and holding water, and once it is found, attempts to present the fly as close as possible to the fish - hoping the sight of the fly will trigger a feeding response.

When the water is clear, many experts use smaller patterns, when the water is dirty they use larger patterns. Expert steelhead flyfishers recommend a dark fly (eg Black General Practioner) for dark water and dark sky conditions, and a bright colored fly (eg Orange General Practioner) for bright water and bright sky conditions.

What ever fly you choose, fish it with patience, perseverance, concentration and confidence - and when you hook a fish, remember what a remarkable creature it is, and release it unharmed.