It’s spring, but frost covers nearly half the boat ferrying Clint Muhlfeld and his crew across Quartz Lake, high in the mountains of Montana’s Glacier National Park. They hiked 6 miles to meet the flat-bottomed skiff — which was strapped to the bottom of a helicopter and flown in — and carried nets, food, gear and gas because mules couldn’t cross the streams swollen with snowmelt. They’re here to tag an invasive species.
The arduous trip is one of many biologists have made to the park’s lakes in recent years, part of an ongoing search-and-destroy mission to rein in one of the most pernicious aquatic threats in the West: lake trout. The sport fish, introduced in lakes over the past 100 years, have outcompeted native bull trout in many of them. In Glacier, Muhlfeld is determined to put an end to this slow-moving catastrophe. Over the years, lake trout have invaded eight of the park’s 12 connected glacial lakes west of the Continental Divide.
Quartz Lake was number nine.
“And that’s where we drew the line,” says Muhlfeld, an aquatic research ecologist with the U.S. Geological Survey and the University of Montana. “We have to stop this ecological catastrophe, or Glacier’s native fishes will be lost for future generations.”
Biologists have tried various ways to rid Western lakes of these invaders, such as electrocuting their eggs or encouraging anglers to take as many of the fish as they can catch. But on Quartz Lake, Muhlfeld and his team worked with the National Park Service to deploy a weapon they believe will greatly improve the bull trout’s odds: the Judas fish.
