Evaluating the Ability of Tiger Muskellunge to Eradicate Brook Trout in Idaho Alpine Lakes

AbstractIn western North America, nonnative Brook Trout Salvelinus fontinalis in alpine lakes threaten the persistence of native trout and often offer limited sport fishing opportunity as they are prone to stunting. Stocking tiger muskellunge (Northern Pike Esox lucius × Muskellunge E. masquinongy), which are reproductively sterile, may be an option to eradicate Brook Trout in some alpine lakes. We used floating gill nets to survey 17 alpine lake Brook Trout populations, then stocked 13 lakes with tiger muskellunge, with four additional lakes serving as controls. Tiger muskellunge were stocked at a mean TL of 317 mm and a density of 40 fish/ha. Brook Trout were resampled for 4 or 5 years after stocking to evaluate changes in Brook Trout TL and CPUE (fish/net-night). Declines in CPUE were substantial for both treatment and control lakes but were significantly greater in treatment lakes. Mean Brook Trout CPUE in treatment lakes declined from 23.1 fish/net-night to 2.3 fish/net-night 5 years after stocking t...