Efficacy of suppressing non-native lake trout in an isolated backcountry lake in Glacier National Park
Fredenberg CR. 2014. Efficacy of suppressing non-native lake trout in an isolated backcountry lake in Glacier National Park. Montana State University
Graduate thesis describing the program of removing non-native lake trout from Quartz Lake in Glacier NP in support of bull trout conservation and management. The USGS and NPS began suppressing non-native lake trout (Salvelinus namaycush) in Quartz Lake (352 ha) in 2009 to reduce impacts to native bull trout (Salvelinus confluentus). Lake trout exhibited slower growth, lower condition, and lower fecundity relative to other populations. Spawning locations were identified on cobble and boulder substrates (depths 2-20 m) near the base of two avalanche chutes where adults began aggregating between prior to thermal destratification. Catch rates of spawning (ripe) adults were highest 12-25 October when temperatures declined to below 10 C°. Gill nets with 0.1 mm twine thickness and green color increased catchability of juvenile lake trout. Although density dependent parameters were not included, population simulation models indicated the population was growing exponentially and would likely reach carrying capacity within ten years without suppression. Suppression resulted in declining population growth rates. Bull trout redd abundances remained stable throughout the suppression period. Targeted suppression successfully reduced lake trout abundance and that continued suppression at or above observed exploitation levels is needed to ensure continued
- Type
- Academic
- Authors
- Fredenberg, Carter
- Date of Issue
- 2014-11
- Publisher
- Montana State University
- Units
- CRCO , GLAC
- Keywords
- Aquatic Studies, Bull Trout, Fisheries, Lake Trout, lake trout suppression, Non-Native Fish, Quartz Lake, Salvelinus confluentus, Salvelinus namaycush, species conservations, thesis
- Subjects
- Ecological Framework: Biological Integrity | Invasive Species | Invasive/Exotic animals , Ecological Framework: Biological Integrity | Focal Species or Communities | Freshwater Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Fishes