The Hungry Horse Dam was constructed in 1953, and contributed to the isolation of the fish population. Photo © George Wuerthner
The Bob Marshall Wilderness Complex in northwestern Montana is 1.5 million acres of wilderness bliss. It’s a place where the Continental Divide runs wild like a meandering river for sixty miles. More than a thousand miles of trails lead hikers and packers to places like Gateway Gorge, Curly Bear Mountain and the twenty-two-mile-long vertical wall of rock known as the Chinese Wall. The Bob, as the locals call it, is the destination in the lower forty-eight states for those looking to camp, fish and hunt in a place where noise and man have little presence.
In the far western portion of the Bob, the South Fork Flathead River has its beginnings, fed by more than 350 alpine lakes. Fish species such as rainbow and Yellowstone cutthroat trout, as well as hybrid and pure strains of westslope cutthroat, call these lakes home; some outfitters and their clients call the lakes heaven.
Yet if the U.S. Forest Service accepts a proposed plan to save native westslope cutthroat populations in the South Fork Flathead River, heaven will be in for a change. Through intensive management using helicopters, pack stock and motor boats inside the boundaries of the wilderness, the project would eradicate all fish species in some of those lakes using antimycin—a poison that kills fish and their eggs, but is reportedly not harmful to humans. The lakes would then be restocked with westslope cutthroat.
For this project, officially named the South Fork Flathead Watershed/Westslope Cutthroat Trout Conservation Program, the area slated for treatment has the potential to provide a stronghold for genetically pure strains of westslope cutthroat that are already monitored as species of concern. If the fish populations aren’t restored, some conservationists, anglers and wildlife officials fear that the remaining westslopes will hybridize with nonnatives, eliminating the last pure strains of the species. Others, such as outfitters who depend on those lakes for their livelihood and citizens who have fished the lakes for years, have voiced their objections to both the intent and implementation methods of the project.
Virgil and Barb Burns own the Bob Marshall Wilderness Ranch. They have packed in clients for thirty years to the lakes proposed for treatment and know the plan would put a strain on their business. They take around 100 clients to the lakes every year and say those folks couldn’t care less if the fish they catch are westslope or Yellowstone cutthroat trout.
“If anybody can say what is happening with the fish up there, we can,” says Barb. “They’re big, strong, healthy fish, and they shouldn’t be messed with.” Virgil adds that others already tried a similar plan in Europe during the 1940s. “Hitler wanted a pure strain of people, too, and that didn’t work.”
Most of the public objection to the project stems from the proposed application methods of the poison to the lakes in the wilderness. Montana Fish, Wildlife & Parks officials, who would carry out the treatments, would prefer to use helicopters in some areas of the wilderness to transport supplies, people and powerboats. They say that for some lakes this is the most cost-efficient method to implement the plan, even it isn’t consistent with wilderness values that prohibit any mechanized use.
“Agencies have a tendency not to take processes as seriously as they should,” says John Gatchell, conservation director of the Montana Wilderness Association. “I don’t think there would be as much of a problem if they were going to be on horseback. [They should] start small and see how it goes.”
State officials say that because of the size of the lakes—some exceed 100 acres—it would be difficult to achieve a high fish mortality rate without equipment and methods that would disrupt, if temporarily, the serenity of the Bob.
George Lake, which lies just inside the wilderness boundary, illustrates the difficulties. At 120 acres, it is one of the larger lakes in the area. Even though there isn’t an official trail, the lake receives an estimated 105 angler days—the number of anglers multiplied by the number of days they fish—per year.
Treatment of the lake and almost four miles of George Creek that flows out of it would require more than 10,000 pounds of antimycin. Because of the lack of trail, sixteen helicopter flights would be needed to bring supplies and personnel to the site. The crews would use rafts with outboard motors to distribute the antimycin. According to the Environmental Impact Statement, the poison will naturally detoxify and break down once it hits the lake bottom. The entire process would take about one week.
Once officials could determine that George Lake was devoid of any fish, approximately 11,400 fish from the Washoe Park state hatchery would be dumped in the lake in each of the first three years after treatment.
In the northwestern United States, genetically unaltered westslope cutthroat trout occupy a mere 8 to 20 percent of their original range because of stream siltation, overfishing, and competition and hybridization with introduced species. In Montana, the South Fork Flathead watershed represents half of the statewide range for genetically pure westlopes.
The area proposed for treatment, the high alpine headwater lakes that feed into the South Fork Flathead River, provides a unique opportunity to save some of the last remaining wild populations of westslope cutthroat trout, says Brian Marotz, the fisheries program manager for the state.
With the completion of Hungry Horse Dam on the South Fork Flathead River in 1953, fish populations upstream from the dam in the Bob were cut off from nonnative fish populations below the dam, creating a contained area for local fish populations in the South Fork watershed. Those fish, though, weren’t strictly native.
Decades before the dam was constructed, agency officials and sportsmen alike stocked some lakes in the watershed with rainbow and Yellowstone cutthroat trout. Some lakes were previously barren of fish, while others contained native populations of westslopes. In the late 1950s, fish managers recognized the impact that stocking the lakes with nonnative fish was having on native populations and began stocking the lakes only with native westslopes. But the damage had been done. Eventually, the westslopes began to interbreed with rainbows and Yellowstone cutthroats, creating hybrids.
The area of the South Fork drainage above the dam is home to 355 lakes, fifty of which have fish. Of those fifty, a little more than half have been determined to contain genetically pure westslopes. Officials fear that the hybrids in the remaining lakes will eventually migrate out of these headwater lakes, use the South Fork as a highway and breed with existing pure westslope populations.
The Bonneville Power Authority, which owns the Hungry Horse Dam, is responsible for providing mitigation money to projects like this one that will help fish and wildlife affected by the dam. In the case of this project, the mitigation money is intended to combat losses to fisheries incurred by construction and operation of the dam, which includes the elimination of some bull trout and westslope cutthroat trout spawning runs.
While the proposed plan is going to cost the Authority an estimated $2.5 to 3 million, the entire process to treat all of the lakes will span a decade. The plan is to treat two to three lakes per year at a cost of around $300,000 annually.
The fear that current populations of Yellowstone cutthroat and rainbow trout will eliminate pure strains of westslope cutthroats in the South Fork is at the core of this project. While some couldn’t care less about a fish’s heritage, others, such as Bruce Farling, executive director of the Montana Council of Trout Unlimited, say hybrids are a problem.
“Hybrid fish will eventually take over,” Farling says. “We’re making assumptions that the natural disposition of wild fish to adapt to climate of the area, drought, fire, geology, predators and a fairly sterile food system will do better than hatchery-raised fish. Any fish like Yellowstone cutthroat or rainbow are not going to be as fit to adapt to the aquatic ecosystem up there as the fish that are ancestral to the area.”
Farling and Trout Unlimited have also recognized other areas of concern in regard to the proposed fish poisoning. Some environmental groups, such as Wilderness Watch, have suggested that certain lakes should be left barren, as they were in the time before Lewis and Clark. Farling feels that it would be a “wonderful opportunity to see how a lake recovers once that predator is taken away.” But he realizes that many anglers don’t see it that way.
“We’ve figured out an approach and made some suggestions to where 80 to 90 percent of people would get what they want,” he says.
But those not getting their way, mainly outfitters, have been outspoken in their opposition to the plan. Farling admits that not everyone is happy about the proposal, but he says annually, the lakes only receive a combined 2,000 to 3,000 angler days.
“It’s not like we’re going in and nuking the Madison River [near Bozeman] and 100,000 angler days a year. There are plenty of other angling opportunities for cutthroat in that area. There’s the whole South Fork,” he says.
Farling suggests agencies should use pack stock where they can, but he says that in his experience, using a motor on lakes is necessary for a successful fish-kill. He adds that one of the biggest risks is that the project simply won’t work. The antimycin that would be used in the Bob is effective often, but not every time. After a lake is treated in the fall, it would then be monitored the following spring and summer. If it is determined that fish remain, a second application of poison could follow. Even so, Farling says the project should go on. “It’s not 100 percent perfect,” he says. “It’s not risk-free, but man, conservation of these fish is not a risk-free business anymore.”
One of the biggest bones of contention in the project is the use of poison to kill the fish. When many people hear the words poison, water and agency used in the same sentence it makes them cringe—and for good reason. In 1997, California’s Department of Fish and Game treated Lake Davis, the drinking water supply for the town of Portola, with rotenone, a poison similar to antimycin. The result was a catastrophe.
The chemical was supposed to break down in two months and destroy all of the introduced pike in the lake. Instead, the rotenone lingered for ten months, contaminated Portola’s water supply and didn’t kill all of the pike. In the end, the Department of Fish and Game was fined $250,000 by the regional water quality board, and Portola, Plumas County and affected businesses were paid $9 million in reparation by the state.
The antimycin proposed for the lakes in the Bob breaks down in a matter of hours, and studies have shown that its threat to humans in diluted doses is low to none. It kills both gill-breathing organisms and their eggs, but there is some concern about the poison’s effect on non-vertebrate populations and amphibians. Recent studies have shown that antimycin would have short-term impacts on amphibians and aquatic insects, yet almost all of the studies cited in the plan’s environmental impact statement are more than thirty years old.
Even with antiquated studies, incomplete science and a public that isn’t overwhelmingly supportive of the plan, the lakes above the Hungry Horse Reservoir provide a unique, fairly controlled environment to restore westslope cutthroat trout populations. It’s a tradeoff. If the Forest Service decides to go ahead with the plan, the solace provided by the Bob Marshall Wilderness could be suspended for a decade, beginning as soon as fall 2006. Water could be contaminated and fish, native and nonnative alike, will be killed. In exchange, westslope cutthroat trout populations could have a safe haven to live without the fear of hybridization. If the project works, it will be a victory for the trout. If the plan fails or gets rejected, it will be one more blow to a species already on the verge of extinction.