Monday August 15, 2022
Flathead Beacon —
State fisheries managers are asking for the public’s feedback on a proposed conservation project aimed at restoring native westslope cutthroat trout populations in Rainbow Lake, an alpine jewel situated on a drainage of the Wigwam River near Eureka, where hybridization with nonnative fish has imperiled the prized species in a region considered their last best stronghold.
The proposed project is in Lincoln County, approximately 11 miles northeast of Eureka, and calls for stocking the mountain lake with genetically pure strains of the native trout species. However, the architects of the project must first remove non-native Yellowstone cutthroat trout that have infested the drainage by using a fish toxicant called rotenone, which is extracted from the roots of several plant species in the legume family and is lethal to gill-breathing creatures.
According to a draft environmental assessment submitted by Montana Fish, Wildlife and Parks (FWP), the chemical treatment of Rainbow Lake would have “short-term, minor effects on wildlife, recreation and vegetation,” and would be limited to the lake and approximately one mile of tributary downstream from its outlet. If the project moves forward, public access to Rainbow Lake would be temporarily closed during the period of rotenone treatment, which FWP expects to take no more than four days to one week. FWP would coordinate all access closures with the U.S. Forest Service Rexford Ranger District at least one week prior to the project’s implementation, according to officials.