A conservationist who has worked protecting bull trout says Glacier National Park is “playing God” with Gunsight Lake, a remote lake at the head of the St. Mary River Valley.

But, according to a scientist for the park, it’s a shot at helping bull trout, a native species that’s facing increasing threats downstream.

In August, Glacier National Park announced it had approved a preservation project for Gunsight Lake, a turquoise gem that’s a roughly 6-mile hike from the Jackson Glacier Overlook trailhead on the east side of the park.

The plan takes out non-native rainbow trout from the lake this year, and later, it stocks native fish, bull trout, mountain whitefish and westslope cutthroat trout.

According to a news release from Glacier, an environmental assessment found no significant adverse impacts for the plan, which includes killing the rainbows with an EPA-approved fish poison called rotenone and then restocking the lake with native species.

The plan and environmental review process have drawn criticisms from some members of the conservation community who argue Gunsight Lake should stay fishless, as it was before human interference, and the park should manage the area as wilderness, as it has pledged to do.

A Glacier official, however, said the review process went as planned, and a park scientist said the project is an attempt to preserve native species that are struggling elsewhere, in the throes of a warming climate, by placing them in a cold lake that could be ideal for them to thrive.

ARLENE MONTGOMERY, with Friends of the Wild Swan, said she has many questions about the project at Gunsight Lake, and she hasn’t heard many answers from the park. Friends of the Wild Swan, along with a couple of other groups, petitioned three decades ago to have bull trout listed as an endangered species, she said.

The St. Mary drainage is unique in that it has the only bull trout population in the U.S. on the east side of the Continental Divide, and she wonders what the impacts to those populations will be when fish are removed to populate Gunsight.

Montgomery also said the lake didn’t have fish to begin with, and another generation of people taking one species out and inserting another is a recipe for unintended consequences.

“It’s sort of like they are going to create a new ecosystem, they think,” Montgomery said. “ … Whenever they’ve done ‘playing God’ with fisheries, it never turns out well.”

One prominent example in Montana is the disappearance of kokanee salmon in Flathead Lake after fishery managers introduced mysis shrimp, which should have been a good meal for the salmon.

But the salmon and shrimp had different meals times for another food, zooplankton, and the salmon not only got shorted, they ended up on the dinner plate of lake trout, stout from eating the well-fed shrimp, according to the Flathead Lake Biological Station director in a post from the National Wildlife Federation.

The 2022 post said the story from Flathead Lake is a cautionary tale, and biological station director Jim Elser told the National Wildlife Federation at the time that ecosystems are complex: “We don’t always know what will happen next. Tinker with them at your own peril.”

Montgomery said the rainbows wound up in Gunsight Lake because people were fooling around with nature for their own purposes in the early part of the 20th century: “They put fish in the lakes because it gave the eastern tourists something to do.”

The poison used to kill the fish, rotenone, won’t stay in the lake, either, but will flow downstream, she said.

Scientific journals describe rotenone as a pesticide and insecticide from a natural compound extracted from plant roots; the poison, previously used to kill rats but no longer approved for the task, may be a risk factor for Parkinson’s disease.

Montgomery said the project violates the idea the park will manage the area like true wilderness, and she’d still like to change the trajectory for Gunsight. But that would require reviewing documentation, and she said she’s gotten the runaround.

Montgomery said when she’s asked for the “project file” with analysis, she’s been transferred, placed on hold and had her emails land in spam folders. Eventually, she was sent to a Department of the Interior website to file a Freedom of Information Act request — and she’s filed FOIAs before but thinks public records should be easier to get.

“They have just been, I think, stonewalling in terms of giving the public more information,” Montgomery said.

She is also concerned the park doesn’t have a formal fisheries management plan, and Montgomery said she isn’t alone in her questions.

“I have been contacted by people who are really alarmed about this,” Montgomery said.

CHRISTOPHER DOWNS, aquatic and physical science programs manager for Glacier, said Gunsight Lake has problems, the preservation project already started, and it could address some of the current trouble in the lake and downstream.

First, non-native rainbows hybridize with native westslope cutthroat, and now, the area has no unhybridized westslope cutthroat trout, he said: “They’re in pretty dire, dire condition.”

He said the idea to have no fish in the lake doesn’t meet the intent of the project, which is to conserve native species by taking out rainbows. And he said having a lake with nonnative species at the top of a drainage doesn’t make sense either.

“If we’re going to have fish in there, they should be of some conservation value,” Downs said.

The first part of the project this fall, the rotenone application, went well, he said.

Indigenous people used to swim around with rotenone on their backs to kill fish to collect them for food, and then people started using it to take out undesirable fish from lakes, he said. For example, he said, the rotenone treatment has been used in many lakes in the Bob Marshall Wilderness Complex over the last 10 to 20 years.

“There’s not a ton of unknowns here,” Downs said.

The rotenone affects all gill-breathing animals to one degree or another, he said, but applying it in the late fall gives amphibians a chance to get to their adult stage, and some will be out of the water, and they’ll repopulate. Some streams flowing into the lake aren’t treated, he said, and zooplankton eggs are resistant to rotenone.

“We use it at the minimum amount we need,” he said.

The project is for both bull trout and westslope cutthroat trout, he said, and it’s designed to balance the values in the Wilderness Act, the Endangered Species Act, and other laws and policies. Downs said scientists aren’t doing their work in a vacuum given climate change, invasive species, and other threats to native species.

“We have these populations downstream, and we’re seeing changes in the water temperatures,” he said. “We’re seeing changes in precipitation and runoff patterns. That’s impacting native fish. And nonnative fish often benefit from those conditions, while native fish do not.”

He said Glacier park is looking for actions it can take: “One part of that would be to establish a native fish — for lack of a better word — refuge in a place that’s about the most climate secure place that we’re going to have.”

He said biologists don’t have answers to some of the management challenges downstream, and they shouldn’t be moving fish indiscriminately. But he said the park can give native populations a shot in this northeast-facing lake at a high elevation.

The Gunsight Lake plan is “basically securing them some place to give them a chance in the future to adapt to a changing climate because things are happening really rapidly right now,” Downs said.

The plan is to restock the lake next year. Downs said the park will select fish with a “mix of life histories” to include bull trout that are smaller and stay put versus ones that migrate to maximize the likelihood bull trout will remain in Gunsight Lake.

He said the park does have a fisheries management plan, and it hasn’t been formally adopted, but he said the work is solid, and it’s guiding the current project.

Gina Icenoggle, spokesperson for Glacier, said the public process for the environmental assessment was typical — 30 days of comment for a scoping period last fall and 30 days of comment for the assessment this summer.

She said Glacier posted information about the project on its website, and it considered all comments in its findings, but it cannot respond to all members of the public.

“The park responded to several callers with questions about the project,” Icenoggle said in an email. “However, it is not always practical to respond to calls or emails after the close of the public comment period.”

Keila Szpaller is deputy editor of the Daily Montanan, a nonprofit newsroom. To read the article as originally published, click here.

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