Eighth wilderness lake slated for fish treatment

A trail in the Bob Marshall Wilderness will be closed from Sept. 9-14 as Montana Fish, Wildlife and Parks biologists continue efforts to restore native westslope cutthroat trout in the headwaters of the South Fork of the Flathead River.

Trail No. 291 will be closed from the junction of Gordon Creek Trail No. 35 while biologists treat Lick Lake with rotenone to kill the fish in the remote 19-acre lake. Lick Lake is southeast of Holland Lake, tucked below Ptarmigan Mountain and Wolverine Peak on the edge of the wilderness.

After treatment, the lake will be re-stocked with native westslope cutthroat trout. Lick Lake was stocked long ago with nonnative Yellowstone cutthroat trout.

FWP maintains that removal of these fish is necessary to eliminate the hybridization risk they pose to the remaining populations of westslope cutthroat trout in the South Fork drainage. Lick Lake is the eighth lake that has been treated since the project began in 2007.

The South Fork drainage, particularly in the wilderness, is considered a last stronghold of native westslope cutthroat trout. The trout are susceptible to hybridization from non-native species, like Yellowstone cutthroats and rainbow trout.

All told, the project aims to preserve the genetic integrity of the watershed intact and remove nonnative species in 21 lakes. Not all lakes were treated to kill the fish. Biologists utilized a technique known as genetic swamping in several lakes over the years, where large numbers of westslope cutthroat trout are stocked in a lake. Over time, in theory, their numbers are large enough to breed out recessive genes from nonnative fish in a lake.

The project is projected to continue until 2016, when the largest lake in the project, the 148-acre Sunburst Lake, is scheduled to be treated with rotenone, a compound that specifically kills fish.

For more information on this project, visit online at http://fwp.mt.gov/regions/r1/wctproject.