Everything you wanted to know: bull trout
Big, beautiful and bold, the magnificent bull trout is one of North America’s most interesting — and sometimes misunderstood — salmonids.
In fact, it wasn’t until 1980 that bull trout were formally recognized as a distinct species. Until then, what we now know as Salvelinus confluentus were considered Dolly Varden.
Found in several Northwest states and Canadian provinces, bull trout are prized as gamefish, but that position is complicated by their rarity. In the Lower 48, bull trout are listed as threatened under the Endangered Species Act. That status has prompted states to implement strict regulations, including no-take rules in every state where they are found and widespread prohibitions against even targeting bull trout.
Anglers fortunate to be able to legally put their hands on a bull trout have accomplished one of the rarest feats in trout fishing.
Everything you need to know about bull trout: species, location, size, and diet
Like Dolly Varden and brook trout, bull trout are actually members of the char family, and the three species share many visual characteristics.
The flanks of a bull trout feature small, pale yellow-to-crimson spots on a darker background that ranges from olive to brown, fading to a white belly. Fins are edged in white.
During much of the year, a bull trout’s coloration can actually be quite drab.
But spawning season brings out the best in coloration, with fish developing red and orange highlights along their flanks and bellies.
Bull trout were once found throughout the Columbia River Basin, east to western Montana, south to northern Nevada, west to California and possibly as far north as southeastern Alaska.
The main populations remaining in the lower 48 states are in Montana, Idaho, Oregon, and Washington, with a small population in northern Nevada.
When able to access interconnected habitats, bull trout are migratory, moving throughout large river systems and lakes. Some bull trout even move back and forth between the ocean and coastal rivers, exhibiting behavior shared with salter brook trout. Resident bull trout, on the other hand, live their entire lives in a single stream.
Migratory bull trout tend to be much larger than resident fish, with the largest sometimes topping 30 pounds.
Bull trout require relatively cold water and spawn in the fall after water temperatures drop below 48 degrees Fahrenheit. Their spawning habitat features clean gravel and cobble substrate with gentle slope. Incubation takes four to five months, which is long compared to other salmonids.
Fry emerge in the spring, feeding on zooplankton and moving on to small aquatic macroinvertebrates as they grow before becoming largely piscivorous (feeding on other fish). Even larger bull trout that primarily eat other fish can be opportunistic feeders—for example, feeding heavily on salmon eggs when available.
Bull trout by the numbers
States in which it is legal to keep bull trout
States with known bull trout populations
River miles identified as critical habitat in the Fish and Wildlife Service’s Bull Trout Recovery Plan
Year that bull trout were recognized as a distinct species
Challenges and opportunities
Though bull trout are distributed over a relatively large geographic area, overall population numbers and distribution have been significantly impacted by human activities as our nation has grown and developed.
Dams and barriers such as undersized and perched culverts have fragmented habitat, harming bull trout by reducing access to areas needed for spawning, feeding and refuge from high temperatures, flow extremes, and fire. Isolation of local populations has reduced genetic variability and impacted migratory behavior.
Development to support growing human populations has encroached on bull trout habitat. Industrial scale resource extraction, such as logging and mining and the road build-out to support these, has further reduced and fragmented suitable habitat.
Competition from non-native species, including brook trout, brown trout and lake trout, has further squeezed imperiled bull trout populations. Hybridization with the closely related brook trout has also weakened bull trout numbers.
Wildfires, which are becoming more common and severe across the West, can be detrimental to river ecosystems. Many river systems are also seeing increases in stream temperatures and impacts on stream flows as the planet’s climate becomes warmer; these changes are a likely cause of bull trout declines to date and will continue to threaten the species in the future.
Trout Unlimited is committed to bull trout recovery, supporting actions outlined in the Fish and Wildlife Service’s formal Bull Trout Recovery Plan.
TU and partners have undertaken extensive restoration projects to help restore bull trout streams, for example, increasing watershed connectivity by addressing barriers such as dams and poorly functioning culverts. TU has fiercely advocated for important landscape protection, including fighting proposed rollbacks of important conservation tools such as the Roadless Rule.
TU and its members also have supported regulations to protect particularly vulnerable bull trout populations, including strict no-targeting angling regulations that exist throughout a significant portion of bull trout habitat.
How to fish for bull trout
Although fishing opportunities for bull trout are extremely limited, there are a few areas where they may be legally targeted. Consult state or provincial fisheries agencies to identify fishable waters, and pay attention to local stream temperature and flow conditions to ensure angling is not exacerbating these stressors.
Anglers who specifically pursue bull trout are not undertaking the game to catch small juveniles. They are seeking big fish. So, of course, that dictates the approach.
Fly anglers will want to use relatively heavy gear, similar to what they would use for chasing steelhead or coho salmon.
That means a 7- or 8-weight rod outfitted with a quality reel with a stout drag. A heavier rod can handle fish that commonly top 10 pounds, and is critical for efficiently casting large flies.
Big bull trout generally target big prey, so many fly anglers opt for large streamers in the 4- to 6-inch-long range. Effective colors depend on the local forage, which can include smaller trout, whitefish and suckers. White, brown, and olive streamers are all good bets.
Bull trout tend to be bottom huggers, so using a sink tip line can help flies get to the strike zone. Swinging flies, sometimes with a few twitches, is a popular approach, but bull trout will also chase fast-stripped streamers.
If salmon are spawning, egg patterns and beads fished under an indicator can work well. Even giant bull trout will eat salmon eggs when they are plentiful.
Spinners, spoons and minnow-shaped plugs are all effective lures for those who fish with gear.
Because of their limited numbers, strict regulations and the often-rugged landscapes where they live, bull trout are among the most challenging targets for anglers. And, therefore, they are among the most cherished catches when it all comes together.
All data compiled from:
Western Native Trout Initiative
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