Efforts to bring back a threatened native fish in Banff National Park just hit a huge milestone, with westslope cutthroat trout now spawning naturally in Hidden Lake for the first time in generations.
A Huge Milestone
Parks Canada confirmed the win this year after spotting the fish reproducing on their own. It’s a major step toward building a healthy, self-sustaining population.
The fish were first put into the lake as eggs back in 2021 and 2022 after years of prepping the area.
Westslope cutthroat trout used to thrive in Hidden Lake, up in the Skoki area. But over the decades, numbers dropped so low the Alberta population was listed as threatened under the Species at Risk Act.
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How they got here
The trouble started back in the early 1900s when Parks Canada stocked mountain lakes with non-native fish like brook and rainbow trout for sport fishing. Those introduced fish took over, ate up the food supply, and crowded out the native species.
Fixing that meant starting from scratch. Teams spent years trying to remove the invasive brook trout using nets and electric fishing gear, but those didn’t fully work. In 2018 and 2019, they used a natural plant-based fish toxicant called rotenone to clear the lake, making sure the native bug life stayed safe before bringing the cutthroats back.
Hatching in the wild
Instead of using a traditional hatchery, staff parked a special incubation trailer right by the mountain streams. That allowed the eggs to hatch directly in the local water, helping the young fish adapt to the wild right away.
Parks Canada calls these trout a key indicator species because they only thrive in ice-cold, pristine waters. Seeing them reproduce on their own shows the ecosystem is heading in the right direction, and teams will keep an eye on the lake to watch the population grow.