Westslope Cutthroat Trout Range Expansion
Recovery of westslope cutthroat trout (WSCT) in Alberta requires recolonization and expansion of their range, which is currently 5% of the historical distribution. Since 2018, we have been adapting a framework originally developed for bull trout into a framework for WSCT range expansion feasibility in Alberta, into watersheds that are secure from invasion, above barriers. Across the WSCT range, many watersheds are fed directly or indirectly by headwater lakes, where thermal habitat is promising for WSCT survival, but overwintering and spawning potential remain key uncertainties. Since WSCT are almost exclusively stream spawners, we assessed lake outlets for suitable spawning substrates, and performed littoral habitat surveys to investigate rare shoal spawning potential at over 20 high mountain lakes. Since upwellings are thought to create stable winter refuge areas by inhibiting below-ice freezing, we also tested new methods to evaluate overwintering and spawning potential using thermal infrared drones to detect upwellings. We used remote camera surveys to estimate angler use at high mountain lakes containing WSCT. Of the 14 high mountain lakes we assessed for angler effort, total observed anglers and total estimated angler effort were highest at Rawson Lake, whereas estimated angler effort by lake area was the highest at Picklejar Lake 4. Conversely, Commonwealth Lake had the lowest number of observed anglers, total estimated angler effort, and estimated angler effort by lake area. In 2023, we will complete estimates of angler use at the four remaining lakes, complete analyses, and catalogue lake suitability information including outlet and littoral survey data, drone survey footage for detecting upwellings, outlet and lake profile temperature data, and environmental DNA results.
Partnerships
Alberta Environment and Protected Areas, Alberta Native Trout Collaborative, Fisheries and Oceans Canada through the Canada Nature Fund
Annual Summaries
| Title | Year | Category |
|---|---|---|
| Westslope Cutthroat Trout Range Expansion Feasibility | 2018-2019 | 1 |
| Westslope Cutthroat Trout Range Expansion Feasibility | 2019-2020 | 1 |
| Westslope Cutthroat Trout Range Expansion Feasibility | 2020-2021 | 1 |
| Westslope Cutthroat Trout Population Monitoring in the Upper Oldman River Core Area Range Expansion | 2021-2022 | 1 |
| Westslope Cutthroat Trout Range Expansion | 2022-2023 | 1 |