Glacier looks to establish native trout at Gunsight Lake

BY CHRIS PETERSON

Hungry Horse News

Glacier National Park biologists are proposing another native fish restoration project, this one on Gunsight Lake, east of the Divide.

Under the proposed plan, the Park would remove non-native rainbow trout from Gunsight Lake and establish the lake as secure habitat for native westslope cutthroat trout and bull trout.

Bull Trout are listed as threatened under the Endangered Species Act and westslope cutthroats are a species of special concern.

The Park proposes using using a fish toxicant, such as rotenone. While rotenone and other fish toxicants degrade naturally with sunlight and water movement, detoxification would be hastened with a neutralizing agent. The toxicant would be detoxified before it reaches downstream native fish populations.

Native fish, including westslope cutthroat trout and bull trout, are not present in Gunsight Lake, biologists note.

The lake was historically fishless but stocked in 1916 with 35,000 non-native Yellowstone cutthroat trout and again from 1920-1936 with 224,000 rainbow trout. The rainbow trout established a self-sustaining population. These fish are able to migrate downstream and hybridize with native westslope cutthroat trout.

Gunsight Lake by trail is about six miles from the Going-to-the-Sun Road. It is a very popular backcountry camp. It drains into St. Mary Lake. Once biologists rid the lake of non-native trout, they would then re-stock the lake with native westslope cutts and bull trout.

Glacier did a similar project in the Evangeline and Camas Lake drainages, removing non-native Yellowstone cutthroat trout from those waters and then re-stocked with native westslopes and bull trout. That drainage is in its third year of stocking, noted Glacier fisheries biologist Chris Downs.

Biologists have also moved bull trout to Grace Lake, where they have been biologically controlling non-native Yellowstone cutthroat. Bull trout eat cutthroats and other fish.

The difference between Gunsight and Camas is size — Gunsight Lake is much bigger, tucked against the Continental Divide. It's 114 acres and 65 feet deep. The idea, Downs noted, is to not only preserve native species, but to create a wilderness fishing experience with native fish.

The park would continue to allow fishing in the lake after the project is completed. The native fish have both a small inlet to spawn in as well as about a quarter-mile of the outlet to spawn in before the first waterfall, Downs noted.

Helicopter flights would likely be required to transport materials, equipment, and live fish for translocation to Gunsight. If approved, the project may begin in the late summer or fall of 2023.

The project is expected to cost "several hundred thousand" dollars, Downs noted. The bulk of the cost is equipment costs.

The Park has just begun the scoping process on the project. A formal environmental analysis will be released in the coming months.

Comments can be posted on the PEPC site or sent by mail to Superintendent, Glacier National Park, Attn:  Gunsight Lake EA, PO Box 128, West Glacier, MT, 59936. Comments are due by Oct. 26, 2022. People can learn more at : https://parkplanning.nps.gov/GunsightLake