The cannibal of mountain streams: Salvelinus confluentus
The Bull Trout is a threatened species of special concern primarily found in the Northwest United States. It ranges from Northern Nevada, through Oregon, Idaho, Western Montana and Washington, through British Columbia and southern Alberta in Canada all the way up to Alaska.
This fish is often confused with the Dolly Varden (Salvelinus malma) trout as it should be. The two fish are virtually identical in appearance. They have a yellow to light grey to olive body with a white belly. The belly of the fish often blushes to an orange hue during the mating season in early autumn. It has pale yellow spots on the back with red and orange spots on the side. None of these spots has a halo like some of the other “true trout” species. The leading edge of fins is white and the dorsal fin is clear with no spots.
Modern science has made the distinction of the species, though taxidermists would be strained to determine the difference. The confusion starts here, as neither of these trout are “true trout” rather they are chars, like the Lake Trout and Arctic Char. Chars differ from true trout in that they have a dark colored body with light colored spots where as trout have light colored bodies with dark spots. Chars also lack teeth on the upper roof of their mouths. Dolly Varden and Bull Trout do inhabit the same waters, but it is unknown if there are hybrids and if the offspring are able to reproduce which adds further confusion to the distinction of these fish in overlap waters. As often with many of the trout, genetic differences occur in different geographies. The greatest distinction is that the Dolly Varden is mainly a coastal fish and the Bull Trout primarily inhabits inland waters. Lake trout differentiation is fairly simple, the lake trout has a severe angled tail and the Bull has a moderate angle.
Bull trout like cold, clean water. They are highly susceptible to water conditions, which is one of the reasons they are a threatened species. They are all born in small streams but may move to other waters as they mature. Resident adults live in the same stream or tributaries in which they were born, fluvial adults move to larger streams and migrate back to their birth stream to reproduce, adfluvial adults migrate to large lakes and return to their native stream every other year to breed and anadromous adults move to marine environments. Adfluvial Bull trouts from Montana’s Flathead lake migrate one hundred and fifty miles to spawn.
In the Autumn from late August to early October when the temperature of the water reaches forty eight degrees Fahrenheit, adult Bull trout of five to nine years migrate to the small streams and spawn. They prefer clear, clean streams with gravel bottoms, with abundant ground water and a swift current that will keep sediment off the eggs.
The female will choose a site called a “redd”and dig by turning on her side and will vigorously beat the gravel away with her tail. This redd can be up to the size of meter long and five to eight inches deep. When the site is all set, the male will nudge the female over the nest and do a dance of sorts around her quivering and moving from side to side, while she continues to dig. This goes on for about a half hour until the pair is ready to spawn. The female will remain upright and sweep the redd with her tail as the male quivers around her and then she will release eggs and he will release his milt. This sequence occurs a few times and then the male will return to deeper water. Sometimes, juvenile males will milt on the eggs after the dominant male has departed. The female will then do a post spawning dig in the gravel above the redd and the displaced gravel will cover the eggs, then she too will return to deeper water. In some streams, the male Bull trout will remain to guard the nest for a few weeks.
The eggs have an incubation of four to five months and hatch in late winter to early spring. They will stay by the redd for about three weeks and in their little stream for one to three years, and some for their entire life.
The world record Bull trout was caught in Idaho and weighed thirty two pounds. They get this big by eating other fish, including their own. Back in the day they were considered a predatory species and many were destroyed for killing salmon fry and eggs. They also ate other, more desirable species that were introduced to their native streams. Bull trout usually grow to be about fourteen to eighteen inches with the marine and lake run migratory species a bit bigger on average. They typically live for twelve to twenty years, but with current pollution and other variables, the Bull trout existence is threatened.
Pollution in the form of sediment from logging, development and farming techniques harm the development of the Bull Trout eggs. The sediment clogs gravel blocking the flow of oxygen to the eggs. Damns and culverts block migratory Bull trout from reaching their spawn streams. Misidentification by anglers also deplete the species. Trout anglers often are able to keep as many as twenty or thirty of the brook trout or brown trout which live in the same streams as the Bull. By improper identification, many of these kept fish could be Bulls. These same fish that share water with the bull trout also compete for food and feed on the fry and eggs of the Bull, the brook trout also can breed with the Bull trout and the offspring hybrids are sterile, which depletes the breeding population.
Fly fishermen are unlikely to hook into one, as they are deep feeders. The action packed cutthroat, brookie or brown trout are much better to fish for. The Bulls prefer to eat other fish over insects which is why anglers fishing in streams they inhabit should resort to using small lures and flies to avoid catching the big breeding fish. A good motto to follow is “If no black, put it back”. This refers to the lack of dark spots on the Bull as opposed to the other trout in the stream which often have numerous spots on the back and dorsal fin.
I came of interest of the Bull trout from my fish monger who I trade ceramic fish for chucked fish. I use the fish they give me to make molds out of and my deal is, that any fish they give me, I’ll provide them a replica. With trout, the basic form is the same with minor alterations I am able to make any most variations when I take the clay out of the mold or in the coloration in the glazing process. I’ve received trout of various size from them on a number of occasions. I do extensive research on fish to try to make my replica ceramic fish as realistic as possible as a result, I have discovered an almost endless variety of trout and their markings.
Recently, Pat the monger went on a fishing trip to Montana and suggested that he would like a Bull trout for himself. I went to work and this is the result. Learning is an awesome means of empowerment and education can make the soul rejoice, even if it is just about some fish.