Suppression of invasive lake trout in an isolated backcountry lake in Glacier National Park
- Fredenberg, C. R. [ U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT, USA ]
- Muhlfeld, C. C. [ U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT, USA ] [ Flathead Lake Biological Station, University of Montana, Polson, MT, USA ]
- Guy, C. S. [ Montana State University: Ecology ] [ U.S. Geological Survey, Montana Cooperative Fishery Research Unit, Montana State University, Bozeman, MT, USA ]
- D'Angelo, V. S. [ U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT, USA ]
- Downs, C. C. [ National Park Service, Glacier National Park, West Glacier, MT, USA ]
- Syslo, John M. [ Montana State University: Ecology ]
Fisheries managers have implemented suppression programmes to control non-native lake trout, Salvelinus namaycush (Walbaum), in several lakes throughout the western United States. This study determined the feasibility of experimentally suppressing lake trout using gillnets in an isolated backcountry lake in Glacier National Park, Montana, USA, for the conservation of threatened bull trout, Salvelinus confluentus (Suckley). The demographics of the lake trout population during suppression (2009–2013) were described, and those data were used to assess the effects of suppression scenarios on population growth rate (λ) using an age-structured population model. Model simulations indicated that the population was growing exponentially (λ = 1.23, 95% CI: 1.16–1.28) prior to suppression. However, suppression resulted in declining λ (0.61–0.79) for lake trout, which was concomitant with stable bull trout adult abundances. Continued suppression at or above observed exploitation levels is needed to ensure continued population declines.