Glacier National Park has formally released an environmental assessment on a project designed to expand a native fish population in the Park.
Camas and Evangeline lakes, remote lakes at the base of Longfellow Mountain in nearly the middle of the Park, currently have a population of non-native Yellowstone cutthroat trout that were stocked in the 1920s and 1930s.
The high mountain lakes are upstream of Arrow and Trout lakes in the Camas Creek drainage, which snakes its way from its headwaters below Longfellow to the North Fork of the Flathead River.
The lower reaches of Camas Creek wind though broad valleys and are swampy below Rogers Lake. But just above Rogers Lake is Camas Falls, a cascade that keeps non-native species like rainbow and lake trout from migrating up the drainage.
As such, Trout and Arrow lakes are both excellent native trout fisheries.
Conversely, bull trout in Rogers Lake are threatened by non-native invasive lake trout and cutthroat by hybridization with non-native rainbows.
Under this plan, park biologists would kill the non-native Yellowstone cutthroats in Camas and Evangeline using rotenone, a substance toxic to fish. They would also treat Camas Creek above Arrow Lake as well.
Rotenone can be controlled, however, by using potassium permanganate, which in effect, neutralizes the piscicide. Potassium permanganate would be used in Camas Creek to avoid killing fish in Arrow Lake.
Biologists would then gather any fish carcasses that are left onshore and would either sink them in Camas and Evangeline or remove them entirely to avoid attracting bears.
After the two lakes overwinter, they would then be restocked with genetically pure westslope cutthroat trout, sculpins and bull trout gathered from the drainage and other Park waters, like Avalanche Lake. The trout fry will be raised in a hatchery and at about age two, would be stocked back in the lakes via helicopter.
Native sculpin would be collected using methods such as electrofishing or fish traps, transported in containers to the release sites, and directly released into upstream areas.
The translocation of the hatchery-reared fish would not begin until the spring of 2020 at the earliest, the environmental assessment notes, but may begin later depending on the amount of time needed for the hatchery to raise a sufficient number of mature fish. Westslope cutthroat trout would be translocated first, followed by bull trout, possibly beginning in the spring of 2021 at the earliest.
The Park has done similar projects in other waters. For example, in the Logging Lake drainage, theyíve moved native bull trout from Logging up into Grace Lake. Like Camas and Evangeline, Grace is also protected by a waterfall.
Biologists hope to start the project in the late summer and fall of this year ó itís best to remove trout when the water is lowest.
Collection of donor fish would also probably start this year.
Itís estimated the project will require about six to 10 helicopter flights to haul in equipment, boats and gear and about three to six flights to haul gear out. It will take about four additional flights a year for six or seven years to stock the lakes.
The complete environmental assessment is at: http://parkplanning.nps.gov/UpperCamas
Comments will be taken until April 17.