Bull trout are Montana’s largest salmonids and are highly migratory. Since the removal of Milltown Dam in 2008, tagged bull trout have moved back and forth from the Blackfoot River into Rock Creek via the Clark Fork. And Lake Koocanusa bulls migrate from Montana into British Columbia to find their natal spawning grounds. (Joel Sartore, National Geographic, with Wade Fredenberg photo)
October 29, 2021
By Jess McGlothlin
This article was originally titled "A Long Way to Go" in the Migration column of the Oct-Dec 2015 issue of Fly Fisherman magazine.
In the past decade, bull trout have gained a rather mystical status. True predators, large bull trout have been known to munch on a smaller trout caught on the end of a line, providing high entertainment and often inadvertently hooking themselves in the process. While the species cannot be actively targeted—with a few permitted exceptions in the northwest corner of Montana—fly fishers eagerly recount tales of their interactions with the species. Yet while some anglers actively—and illegally—target the fish, too few appreciate or understand the bull trout’s daily struggle for survival, a struggle that, some days, the species seems to be losing.
“Bull trout are a much different species than cutthroat for a number of reasons, chiefly among them that they’re highly mobile and migratory,” explains U.S. Fish & Wildlife Service (USFWS) fisheries biologist Wade Fredenberg. “Fundamentally, they’re a migratory critter for spawning and pursuing food sources . . . they evolved that way.” He adds the fish have been known to travel more than 150 miles from the Flathead Valley in northwestern Montana all the way to British Columbia to return to their natal spawning grounds.
The bull trout’s battle for survival isn’t a new one. In 1998 the species was listed as threatened under the Endangered Species Act with provision for a Section 4(d) rule, allowing the USFWS flexibility to develop specific protections for the species. It was determined that in certain locales, angling was not detrimental to the bull trout populations, and a carefully managed harvest was allowed in two northwestern Montana lakes: Lake Koocanusa and Hungry Horse Reservoir. Fredenberg explains there was a tactical reason beyond the obvious that encouraged USFWS to enact the Section 4(d) ruling.
“Allowing anglers to participate is really important to keeping bull trout front and center,” he explained. If a species is listed, anglers have a tendency to forget about it—there’s something about sport fishing viability that keeps certain fish forefront on our mind. The permit-only harvest brought two benefits: it kept anglers engaged while also generating annual surveys to determine catch.
Fredenberg says Hungry Horse Reservoir—habitat shown by modeling to be some of the best suited for the species on the planet—is the sanctuary of bull trout, but a number of problems are threatening the species in lower watersheds, including the popular Clark Fork. He’s quick to identify three main reasons the species isn’t flourishing: dams, nonnative species, and warming water temperatures.
The poster child for bull trout aiding has been the removal of Milltown Dam. The massive restoration project allowed the Clark Fork and Blackfoot Rivers above the Thompson Falls Dam in 2008 to flow freely for the first time in over 100 years. While the physical, full removal of the dam and restoration of a naturalized river channel in the old reservoir took a few years more, the benefits are evident.
“We’ve seen an overall redistribution of all fish [in response to dam removal],” says Pat Saffel, Region 2 Fisheries Manager with Montana Fish, Wildlife & Parks. He reports an uptick in bull trout redd counts in the North Fork of the Blackfoot, and notes how important the varied environment is to the species. “We need different habitats at different life stages. Cold water refuge in the summer, winter refuge, spawning and rearing . . .” The list goes on and on. It’s not all bad news—while his team used to count bull trout in pike stomachs in Milltown Reservoir, they now count fish in the river. It’s a small victory; while the removal of Milltown has undoubtedly been a positive step, there is still a long way to go.
Saffel sees bull trout as far more than a sport fish. For the fisheries manager, the species is an important sign of a healthy system.
“They are certainly an indicator of high-quality water; of cold, clean water,” he shared. “If you have bull trout in the headwaters, you know you have cold, clean water feeding the entire system. It’s an indicator of a healthy lower system. They’re an integral part of the ecosystem.”
He notes high hopes for the ongoing Superfund cleanup of the Clark Fork, another step in fostering friendly habitat for bull trout and other species. It’s an ongoing attempt to reclaim the river from decades of extremely high heavy metals saturation; a project that will likely continue for 15 or more years. Saffel reports extremely high mortality of cutthroat and brown trout in the section currently, due to both a “very inhospitable” river filled with heavy metals and to warming water. And while the primary project is to restore a healthy sport fishery largely based on brown trout, without much of a likely bump in native cutthroat and bull trout numbers, the project is one of many designed to help foster healthier fisheries in the future.
Will McDowell, stream restoration director for the Clark Fork Coalition, is up front with his concerns. “Bull trout are the most sensitive native fish in western Montana to habitat degradation. Their eggs and larvae require the coldest water of any Montana trout to survive. They migrate long distances, require pristine spawning streams in headwaters which are cold and clean, and they need at least 30 miles of well-connected, quality stream habitat to maintain a population because they naturally are found at low densities.”
Almost all human economic activities, McDowell adds, have potential negative effects on water temperature, water quality, riparian habitat, or migration. Roads, culverts, dams, and forest harvest—the list goes on and on. It’s a constant balancing act.
Invasive species pose another significant threat to the fragile bull trout population. Lake trout in Flathead Lake, for example, have taken a significant chunk out of the adfluvial (lake-dwelling) bull trout population.
“Large lakes are sinks for any species people want to throw in there,” Fredenberg shares with a grimace. “Frankly, lake trout are just eating our lunch right now; they’re so prolific.”
Recent population estimates by the Confederated Salish and Kootenai Tribes assess Flathead Lake now holds in the neighborhood of 3,000 adult bull trout, battling against a population of between 600,000 and 1.1 million lake trout. “Have you seen the movie 300 ?” Fredenberg asks. “That’s about the correct analogy.”
Saffel notes brown trout are also making incursions into bull trout habitat, likely seeking colder water as water temperatures continue their upward slide. Efforts are continually underway to improve riparian habitats and bring more cold water in, but some days more than others it’s a sobering battle. “It’s not all recovery,” he shares. “Some smaller populations are blinking out, especially at lower elevations.” He cites Rock Creek as “in a downward trend, and we really can’t put a finger on why.”
All hope is not abandoned, however. Saffel notes the Blackfoot River bull trout population is slowly showing an upward trend, largely due to habitat restoration efforts. A community approach—uniting conservation groups and federal agencies with local ranchers and anglers—seems to be working, and it offers hope. But the battle still has a long way to go.
“They’re kind of a glacial fish,” he says as our conversation wraps up. The respect and awe for the species is obvious in his voice. “This is the southern end of their range. Bull trout grow to 30 inches; you don’t see other species getting that big. And it’s a native fish, one clearly of value to people.” He laughs at the number of stories he’s heard of anglers getting the “thrill of a lifetime” watching a bull trout chase down and eat other fish. They are truly unique, a highly mobile, migratory fish that thrives in the coldest and cleanest Western waters.
And it’s partly that predatory instinct that makes the species vulnerable. “They’re big, vicious predators that are going to attack anything available,” Fredenberg says. The tendency to chase after hooked gamefish often isn’t in the bull trout’s best interests. “Anglers need to be conscientious and careful.” It’s human nature to get excited and try to interact with something new, but intentional stalking and baiting of bull trout does nothing to help conservation efforts, and interactions can stress fish unnecessarily.
“We need to manage bull trout as our heritage,” Fredenberg reiterates. He understands. I understand. We’ve both grown up in that northwestern corner of Montana, surrounded by glacial waters and the fish that love them. “A lot of people don’t really recognize bull trout, but from a northwest Montana and northern Idaho standpoint, these are our trout and salmon. We need to make sure bull trout in Flathead and Koocanusa never become so scarce people can’t experience them.”
Writer/photographer Jess McGlothlin spends her time chasing stories around the globe. She can usually be found with a camera, notebook, and fly rod close at hand. Visit jessmcglothlinmedia.com for more information.
