WHITEFISH – Glacier National Park officials want to build a fish barrier on Quartz Creek in the North Fork region of the park as part of a plan to prevent non-native lake trout from entering an area favored by native and threatened bull trout.
Park officials started building a fish barrier in 2004 but discovered lake trout in Quartz Lake in 2005 and work on the barrier was suspended. But an experimental program to remove lake trout from Quartz Lake and suppress the population is showing promising results, and officials now want to complete the barrier to prevent additional lake trout from entering the upper Quartz Drainage.
“I believe there is hope,” said Clint Muhlfeld, an aquatic ecologist with the U.S. Geological Survey’s Glacier Field Station.
The park is taking public comments on the fish barrier plan through Sept. 6.
Nine of the 17 lakes on the west side of the park that support bull trout have been invaded by lake trout, and a 10th lake is being threatened by non-native brook trout. Officials say lake trout populations are increasing while bull trout populations are on the decline.
Since 2005, the National Park Service has worked with the U.S. Geological Survey to remove lake trout from Quartz Lake, where officials say lake trout are still in the early stages of taking over the lake.
Researchers at the lake have netted and removed nearly 1,200 lake trout while also discovering the locations of the prime spawning areas. Muhlfeld said monitoring last year showed a decline in the number of juvenile lake trout.
So Glacier National Park officials want to prevent the lake trout population from being bolstered by additional fish entering through Quartz Creek. That means improving the partially completed barrier.
Bull trout were listed as threatened by the U.S. Fish and Wildlife Service in 1998 because of their declining numbers. Besides non-native lake trout, bull trout face other challenges. Montana fisheries officials say bull trout can still be found throughout their historic range, mainly the Clark Fork and Flathead drainages, but are a sensitive species that do not tolerate high sediment levels in their spawning streams.