Westslope Cutthroat Trout Evaluations in the Trout Creek and Callum Creek Sub-watersheds, 2024
Final Report
Author(s)
Brad Hurkett, B.Sc.
Kelly Riehl, B.Sc.
Summary
Westslope cutthroat trout (Oncorhynchus lewisi; WSCT) is a Threatened species in Alberta, which has led to a collaborative recovery effort across its range in the province. This effort places a high priority on habitat restoration to help mitigate the impacts of habitat degradation and fragmentation on local WSCT populations. Alberta Conservation Association (ACA) and Freshwater Conservation Canada are collaborating on delivery of WSCT habitat recovery projects in the Trout Creek and Callum Creek sub-watersheds. Freshwater Conservation Canada began fish habitat remediation projects in 2019 using low technology process-based restoration techniques, namely beaver dam analogues, to improve fish habitat in both watersheds.
Alberta Conservation Association conducted fish surveys in both sub-watersheds to update fish community information and establish a baseline to monitor how WSCT respond to ongoing habitat improvements. In 2024, ACA completed watershed-scale backpack electrofishing assessments in both Hydrologic Unit Code 10 sub-watersheds of Trout Creek and Callum Creek. We surveyed 23 sites in Trout Creek, catching 1,308 fish from ten different species. Only two WSCT were captured at a single site in King Bolt Creek, suggesting a sharp decline in WSCT abundance and distribution since the last survey in 2015. Stream temperature monitoring in Trout Creek revealed a warming trend from the headwaters downstream to the confluence with Willow Creek. In the lower half of the sub-watershed, temperatures exceeded the upper incipient lethal temperature for WSCT (≥19.7ºC). King Bolt Creek had the coldest water temperature measurements and was the only stream where we captured WSCT.
In the Callum Creek sub-watershed, we surveyed 21 sites, capturing 1,437 fish from five different species including 156 WSCT. The highest number of WSCT was found in Sharples Creek (n = 114), followed by Playle Creek (n = 32). We also documented for the first time WSCT presence in upper Callum Creek (n = 7) and Burton Creek (n = 9). Stream temperature monitoring showed a warming trend from the headwaters to the lower reaches of both sub-watersheds, with temperatures surpassing the upper incipient lethal temperature for WSCT (≥19.7ºC) in the mainstem channels and tributary streams where riparian vegetation had been degraded or removed. However, locations where WSCT were captured had stream temperatures within the species' thermal tolerance.
Data collected from our fish surveys and stream temperature monitoring will serve as a baseline for assessing WSCT population response to habitat restoration efforts in both sub-watersheds. This information will also help identify priority areas for future restoration projects, ultimately supporting the recovery of WSCT populations.