Montana State researchers study spread of lake trout in Glacier Nat...( BOZEMAN Mont. -- Natural barriers li...)

BOZEMAN, Mont. -- Natural barriers like waterfalls play an important role in preventing lake trout from spreading through Glacier National Park, so maintaining those barriers should be a priority, Montana State University researchers said after conducting a four-year study in the park.

Park workers might have to remove ice, logs or debris to keep the water from rising behind those barriers, said graduate student Michael Meeuwig and his adviser Christopher Guy. If they don't, lake trout will have an easier time swimming up the rivers and invading new lakes.

Monitoring and maintaining natural barriers are easier than trying to get rid of lake trout after they've entered a lake, Guy said. He pointed to the expense and effort spent at Yellowstone National Park where lake trout prey on native cutthroat trout in Yellowstone Lake. In Glacier National Park, lake trout compete with native bull trout.

Guy, assistant unit leader for the Montana Cooperative Fishery Research Unit at MSU, heads the Glacier research project with Wade Fredenberg of the Creston Fish and Wildlife Center near Kalispell, Mont. The U.S. Geological Survey funds the research.

Non-native lake trout were introduced into Flathead Lake about 100 years ago and are believed to be the source of the lake trout that are threatening Glacier's native bull trout population. Meeuwig's and Fredenberg's work have found that lake trout have since invaded eight lakes on the west side of the park: Bowman Lake, Harrison Lake, Kintla Lake, Lake McDonald, Logging Lake, Lower Quartz Lake, Quartz Lake and Rogers Lake.

"Quartz Lake was one of the last big lakes on the west side of the park that had intact native species assemblages," Meeuwig said. "That was a little bit of a surprise to find lake trout there."

Guy said visitors can be awed by Glacier National Park's scenery without realizing the unfolding drama within its lakes.

"What's going on in those lakes
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