Lena Lake is 74 acres and is located at the headwaters of the Big Salmon Creek drainage. It is moderately popular with backcountry anglers, who have asked for bag limit waivers prior to previous rotenone treatments to allow more harvest of fish that would otherwise be wasted. Lena Lake is scheduled for rotenone treatment In September 2013. This project is part of the South Fork Cutthroat Conservation Plan.
FWP initiated the South Fork Flathead Cutthroat Conservation Plan to replace nonnative fish with pure westslope cutthroat in 21 lakes in the South Fork Flathead drainage to maintain genetic purity. Replacement involves either chemical treatment or genetic swamping (heavy stocking of pure westslope cutthroat to dilute the nonnative genes). A number of lakes have been successfully treated to date. Lakes are restocked after treatment to restore recreational fishing.