Lake trout find bad news for pristine Glacier fishery

Hungry Horse News

GLACIER NATIONAL PARK - On July 13 biologists Bill Michels and Wade Fredenberg made a discovery that was a dagger to their hearts.

Michels went out on 900-acre Quartz Lake to fish. He brought back a 14-inch lake trout.

Fredenberg was heartbroken.

See, lake trout are a non-native species on Glacier's west side. Quartz Lake was considered one of the last bastions for native bull and cutthroat trout. A pristine lake that's also home to bald eagles, loons and otters as well.

Fredenberg, with the U.S. Fish and Wildlife Service and Michels, with Glacier Park, had worked hard the previous fall on a fish barrier in Quartz Creek. The barrier was designed to keep non-natives like lake trout out of Quartz Lake.

But the effort may have been too late.

The trout Michels caught, Fredenberg noted, was of the age class that had been in the lake for sometime. It was a product of other adult fish who had already spawned in the lake - a second generation trout.

The fish is probably five, six years old.

"If there aren't a lot (of lake trout) in there now, there will be before long," Fredenberg said Tuesday.

Lake trout are an insidious species to native fish populations. Biologists aren't sure how, exactly, they do it. But once lake trout establish themselves in a lake, they literally take it over.

Bull trout vanish. Cutthroat trout numbers drop as well.

One might say, so what, they're just fish.

But it's deeper than that, Fredenberg noted. Lake trout also have an impact on mammals and birds. Unlike bull trout and cutthroat trout, which spawn in streams, lake trout spawn in lakes. They spend most of their time in deep water - away from predators like bald eagles and otters and loons.

An infestation of lake trout could potentially have severe consequences for those species as well.

They have the potential to disrupt the entire ecosystem, not just the fishery.

Fredenberg said biologists were also counting on Quartz being lake trout free so it could be used as a baseline to gauge other lakes by. Biologists are looking at ways at controlling lake trout where infestations have already occurred - like Lake McDonald and Swan Lake.

On those lakes, biologists hope they can get at lake trout and put a dent in the populations through some sort of control, such as netting the fish.

But in Quartz, which is six miles from the road, it would be nearly impossible to do something like that.

Now the lake is compromised and the number of large lakes in Glacier that haven't been completely taken over by lake trout grows smaller and smaller.

So far, lake trout have infested Lake McDonald, Kintla Lake, Bowman Lake, Harrison and Logging Lakes, he noted.

None have fared well.

"It's frustrating," Fredenberg said.