"That's a pretty tough place to have to work all summer, but somebody has to do it," said Christopher Guy, Meeuwig's advisor and assistant leader of the Montana Cooperative Fishery Research Unit based at Montana State University.
From June through September, Meeuwig, a doctoral student in ecology, and two technicians hiked trails to Akokala Lake, Arrow Lake, Lake Isabel and Lincoln Lake and bushwhacked their way to Cerulean Lake to find out how far lake trout have invaded Glacier National Park. All the lakes are west of the Continental Divide. So are the other 10 lakes Meeuwig will visit over the next two years in a study funded by the U.S. Geological Survey.
"These lakes haven't been surveyed systematically in a number of years, and some of them never," said Guy who heads the project with Wade Fredenberg of the Creston Fish and Wildlife Center near Kalispell.
Nonnative 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 the native bull trout population in Glacier National Park. Now back at MSU, Meeuwig said he and his technicians were happy to find bull trout and no lake trout in the five lakes they surveyed this year.
Meeuwig and two undergraduate students -- Chris Penne from Iowa and Destin Pewitt from Michigan -- hiked between four and 14 miles to reach those lakes. After setting up camp, they used gill nets, angling and electrofishing to determine the number and type of fish in the lakes. They sorted and counted the fish by species. Then they weighed and measured the fish and took genetic and muscle samples before returning the fish to water. Fortunately, the scientists had mules to carry their equipment, because the container of liquid nitrogen that held muscle samples weighed about 25 pounds, Meeuwig said.
He plans to use his findings to develop recommendations for a park management plan, Meeuwig said. One suggestion might be to place barriers in streams to keep lake trout from swimming into additional lakes. Another goal is to figure out what causes bull trout to decline when lake trout are present.
"Recent research has identified dramatic recent declines of bull trout over the last 25 years in the four largest lakes on the west side of Glacier National Park (Lake McDonald, Kintla Lake, Bowman Lake and Logging Lake," Meeuwig wrote in his latest quarterly report for the National Park Service. "... Over the past four years, the invasion of Harrison and Lower Quartz lakes by lake trout has been verified."
Quartz Lake, Upper Kintla Lake and Trout Lake in Glacier National Park, along with Big Salmon Lake in the Bob Marshall Wilderness are the four largest lakes remaining in the Columbia River basin that contain native bull trout populations uncompromised by lake trout, Meeuwig wrote. As a result, he said, the protection of those waters is a priority for the U.S. Fish and Wildlife Service.
"It is critical that we understand the population ecology of bull trout and potential threats of invasion by lake trout in these areas if we want to develop a functional action plan and effective recovery effort," Meeuwig said.
Evelyn Boswell, (406) 994-5135 or firstname.lastname@example.org