Parks Canada has made significant progress in reintroducing a threatened fish species to its original habitat in Banff National Park. Following more than ten years of effort, the federal agency reported that westslope cutthroat trout are now starting to spawn naturally and repopulate Hidden Lake near Lake Louise.
Shelley Humphries, an aquatics specialist for Parks Canada’s Lake Louise, Yoho, and Kootenay field unit, expressed satisfaction with the self-sustainability achieved by the fish. She mentioned that the success was anticipated based on similar initiatives in the United States that have resulted in species recovery.
The process to remove brook trout began in 2011 but proved ineffective. Subsequently, rotenone, a natural fish poison, was used in 2018 and 2019 to eliminate brook trout. Starting in 2021, eggs were introduced into Hidden Lake for four consecutive years, leading to successful spawning and the emergence of fully grown fish this year.
Ongoing monitoring is planned with the expectation that the westslope cutthroat trout will expand beyond Hidden Lake to utilize streams and creeks for spawning. Humphries emphasized the importance of observing the fish spawning in streams in addition to the headwater lake to ensure their long-term sustainability.
Westslope cutthroat trout, which once thrived across the northern end of Banff National Park to the southern tip of Alberta, faced habitat challenges due to recreational fishing and the introduction of non-native species like brook trout in the 1900s. This led to westslope cutthroat trout being confined to only about 10% of their traditional waterways.
Humphries highlighted the importance of rectifying past mistakes and expressed optimism in the rescue efforts, underlining the correctability and imminent rescue of the fish. Parks Canada is also working on similar projects in various locations like Helen Lake, Cascade Creek, Katherine Lake, and Corral Creek, with plans to extend similar efforts to protect threatened bull trout.
The initiative is expected to have positive ecological impacts on other species like birds of prey and bears, surpassing the benefits of the removal of brook trout. Humphries emphasized Parks Canada’s commitment to safeguarding at-risk species and preventing their decline through dedicated conservation efforts.