‘Zombie trout’ are troubling Montana, which has long been a fly-fishing mecca
Wise River, Mont. – Since the Velen family founded Big Hole Lodge in the 1980s to take people fishing the Big Hole River, they have seen big changes in the pebbly and rock-studded trout stream.
For as long as anyone can remember, this river that rises high above the Beaverhead Range has been clogged with ice and deep snow every winter, preventing the fishing season from starting until June. The river is now ice-free by April or May, and the lodge opens early to welcome anglers eager to cast a fly.
Signs of a changing river ecosystem are hard to miss. Clouds of insects no longer hover in such large swarms, and some key species, such as salmon flies, which are vital sources of food for fish, have become less abundant.
These shifts are occurring at the same time that state biologists report that the river’s brown and rainbow trout populations have declined over the past seven years to historic levels, with strange diseases affecting some of the most sought-after fish.
In addition to their declining numbers, “we’ve seen swirling diseases, red sores and lesions on fish and brown trout with cauliflower fungus,” Wade Felin said over coffee in the dining room of the country inn that serves the business his father started. Father Craig in 1984.
“The brown trout is blind, and it’s still alive,” he said, and is referred to as the zombie trout.
The rainbow and brown species are the quarry of many anglers, and were introduced to the area in the 1800s. Twenty years ago, fish biologists counted about 3,000 fish per mile along the Big Hole River. This number has dropped dramatically to hundreds in some areas.
In May, the number of trout per mile dropped so low in some sections that the Felins, other guides, outfitters and business owners formed a nonprofit called Save Wild Trout and urged Gov. Greg Gianforte to create a task force in hopes of eliminating the problem. . And deepening losses.
“We have an emergency in the rivers of southwest Montana, and we must act immediately to avoid a complete collapse of trout fisheries,” they wrote. “It’s a moment of togetherness.”
For businesses and enthusiasts alike, the 155-mile-long Big Hole River isn’t the only waterway in the state raising such concerns. Other rivers in the Jefferson Basin — including parts of the Beaverhead and Ruby rivers, both of which are top trout streams — have seen similar declines, as has the upper Clark Fork River, although some experts suggest the latter may be related in part to runoff. Surface from previous mining.
Unlike many states, Montana does not stock its rivers with hatchery-raised fish, relying instead on wild populations to sustain themselves. If these populations collapse, it could be a long time before they recover.
Environmental groups also recently filed a lawsuit to list the Arctic grayfish, a distinctive-looking native fish, as endangered due to its dwindling numbers. The Big Hole is the only river with it in the lower 48 states.
All of this adds uncertainty to the future of fly fishing in Montana, where catching trout with artificial insects gently rising on the surface of cold, flowing water is not just a pastime but part of the state’s identity.
Despite the alarming conditions, the large hole was still recently teeming with rafts and floating boats. As summer ends, streams cool, which can give fish a break.
The large crater has long been exposed to warm temperatures and low summer flows. In 1995, Craig Filene was one of the founders of the Big Hole Watershed Committee, a group of valley residents formed to volunteer ways to relieve pressure from irrigation and fishing.
But things have gotten worse recently, with tensions rising between the competing forces of fishing enthusiasts, the businesses that cater to them, and the state’s residents. Some blame the processing industry, which targets company cars and drills holes in their gas tanks.
Wade Velen, who studied water law and is the resort’s manager and guide, said the state’s fly fishing industry should bear some responsibility for helping the fish survive.
The sport has spread along the state’s rivers, where many fear the trout are becoming “loved to death.” For example, the number of anglers’ days — or the portion of a person’s day spent fishing on a given day — in the Big Hole rose to more than 118,000 days in 2020, up from 71,553 in 2011.
The situation has become so urgent that the state has imposed a number of restrictions, including an unusually large number of river closures and “screech owl” limits — which end fishing in the afternoon when the water temperature warms. To protect spawning brown trout, Montana officials decided to stop fishing two weeks earlier than usual, on Sept. 30, for portions of the Big Hole, Ruby and Beaverhead rivers.
Last month, Gianforte visited Big Hole Valley, appearing in Wise River to a packed house of people affected by hunting concerns. He did not say, as the group had hoped, that he would appoint a task force, but instead delegated the work to state fisheries experts. Save Wild Trout has contracted its own scientists to assess water quality and study possible causes of the sharp decline. The research will be conducted over the next few years.
Experts believe that a combination of factors caused the collapse. Climate is at the top of the suspect list: Montana has warmed an average of 2.7 degrees Fahrenheit since 1950, and the pace is accelerating, especially in the winter and spring. These seasons are crucial for replenishing rivers with cool, clear water in which trout thrive. Temperatures in the high mountain valleys of the Rocky Mountains are increasing at a rate two or more times faster than temperatures nationally.
“There is an ongoing drought in the West,” said Stephen W. Ranning, professor emeritus of environmental and conservation sciences at the University of Montana. “As the air temperature increases, evaporation increases, precipitation does not increase, and the snow melts earlier. Once that snowpack melts, there is nothing to cool that water.
“We’re not getting the high flows that flush sediment out of the river” and help maintain healthy fish habitat, added Brian Wheeler, executive director of the Big Hole River Foundation, a nonprofit in Dillon, Montana, that monitors water quality. .
Warm water has lower levels of dissolved oxygen for fish, “which is what really stresses them out,” Renning noted.
State officials agree that climate plays a major role. “Fish are constantly stressed during the summer due to drought conditions and enter another stressful situation in the fall when they spawn,” said Eileen Rice, chief of the fisheries office for the Montana Department of Fish, Wildlife and Parks. “All of this is hard on the survival of the fish. On top of that, you add hunting and handling of the fish.
Many trout are caught and released, but anglers’ handling of them can remove a layer of protective slime, and playing with a fish hooked at the end of the line can weaken it.
The fish can then become susceptible to pathogens. A common fungus that appears on fish is saprolinia, but it appears with alarming frequency, Rice said.
Researchers have not determined the cause of the lesions, and no new pathogens have been found, she said. The state has opened a web portal where people can submit descriptions or photos of sick trout.
Other potential contributors to the trout’s disappearance include competition for resources from agricultural practices, some say. Ranchers along the river divert water from the river into their fields to grow alfalfa for hay. While the irrigation method is legal, it significantly reduces flows in the summer months and exacerbates damage to fish.
Manure from livestock grazing in fields along the river seeps into the riverbed, causing algae blooms. “They flood-irrigate those fields, so we make tea from the manure,” Filin said.
Some ranchers have made changes to ensure the health of Big Hole, which is located in a county with more cattle than any other county in the state.
“We work hard to fence the riparian areas,” said J.M. Beck, who owns and operates Trapper Creek Ranch, near Melrose, with others in his family. “We work hard to restore water in difficult times. It is a shared sacrifice.”
Research into insect populations is also being conducted, with a focus on salmon flies.
Jackson Birrell, director of the Salmonfly Project, which studies the decline of aquatic insects across the West, warned that the so-called insect apocalypse is real and that it could significantly impact trout populations. One study on the Colorado River found that salmon accounted for just over half of trout’s diet.
He has just begun a study on the insect ecology of the Big Hole, although there is not enough historical data on the river to compare the past with this year. So far, he said, the numbers of salmon flies and other insects in the area appear to be high. “The decline in trout has nothing to do with food,” he said.
However, he noted that salmon flies are less prevalent throughout the West than they used to be, having disappeared from Utah’s Logan River and parts of the Provo River. They have receded or disappeared along 500 miles of the Montana River.
Another climate-related threat to fly fishing in Montana is the emergence in some rivers of invasive smallmouth bass, a warm-water species that feeds on trout. State officials have proposed emergency regulations for the Bitterroot River, for example, that would require anglers to kill and report any small fish they catch.
Some other potential impacts on trout have been talked about. Some fish developed proliferative kidney disease. Runoff from fighting wildfires over the years with flame retardants containing ammonium phosphate can be a highly toxic ingredient.
As the search has continued, Vilen said his family and his fishing guides have changed their practices to adapt to the river’s changes, in an effort to help recover both the big hole and its trout.
“The state says 73, but we stop fishing at 68 degrees, pinch off the spines and leave the spawning fish alone,” he said. “We are indebted to the resources that enable us to keep these wild animals alive.”