About 400 arctic grayling and nearly 300 native cutthroat trout have a new home in Handkerchief Lake. The lake sits about four miles above the Hungry Horse Reservoir. In the fall of 2016 the lake was treated with the fish poison Rotenone to kill off the non-native rainbow-cutthroat trout hybrids in the lake, as part of a large project by Montana Fish, Wildlife and Parks to preserve the genetic integrity of the South Fork of the Flathead’s native westslope cutthroat trout.
The cutthroat in the South Fork are one of the last genetically pure populations in the nation.
The effort worked, but it also killed off the grayling population in Handkerchief.
Grayling are a species of special concern and FWP wanted to re-establish a population in the lake because they did well previously, so they brought in 400 three-year-old grayling from Red Rocks Lakes in the Centennial Valley, reared at the U.S. Fish and Wildlife Service Bozeman Technical Center.
After an eight hour or so ride in a truck specially designed with tanks to haul fish, a crew of Youth Conservation Corps teens hauled the fish from the truck bucket by bucket down the slope to the lake, where FWP biologists gently released them.
The grayling should spawn next spring, noted Toby Taylor, a fish culture specialist with FWP. Handkerchief has a clean cold spawning stream at its inlet.
Grayling from Red Rocks Lake National Wildlife Refuge are struggling. At Red Rocks they’re in the southern end of their range and water quality and competition from non-native fish, particularly brown trout, are putting a dent in their population.
Handkerchief will provide another habitat to preserve the gene pool of the Red Rocks grayling, noted FWP Region 1 fisheries manager Mark Deleray. The cutthroat trout that were stocked also are native to the drainage, reared from stock taken from Youngs Creek in the headwaters of the South Fork.
In addition to the 400 grayling released last week, FWP will add another 3,000 one-year-old grayling in a few weeks from eggs collected directly from Red Rocks tributaries. Those grayling were then raised at the hatchery in Somers.
Those fish will likely be stocked by helicopter.
Grayling are a beautiful fish. They have a fan-like dorsal fin that shines with a rainbow of colors, particularly when they spawn.
Only Michigan and Montana had native populations of arctic grayling in the lower 48. Michigan’s population went extinct in the 1930s.
Grayling used to be abundant in the upper Missouri River as far south as Great Falls — Lewis and Clark mention the fish in their journals. But today, fluvial populations — fish that live exclusively in rivers — are scarce, with a population in the Big Hole and Ruby Rivers.
Adfluvial populations are far more common and doing much better. Locally, Elizabeth Lake in Glacier National Park has a good population of grayling, as does Rogers Lake west of Kalispell.
Given a few years, Handkerchief promises to once again be an excellent grayling fishery. For now, FWP plans on implementing a catch-and-release only regulation for grayling at Handkerchief until the population is established, Deleray said. FWP commissioners were expected to vote on the regulation this week. Cutthroat trout regulations at Handkerchief would remain the same as other nearby waters — three fish per day.
FWP will wrap up its 10-year South Fork cutthroat conservation project this fall with the treatment of Sunburst Lake. All told, 21 lakes were treated to kill off non-native trout and hybrids in the South Fork drainage, while restoring native westslope cutthroat populations.
In coming years, Glacier National Park is expected to embark on a similar effort to restore native trout populations in its waters as it completes its fisheries management plan.