‘We don’t let species go without a fight’: Parks Canada works to protect threatened fish species | CBC News

Parks Canada works to protect threatened westslope cutthroat trout

'Their populations and distributions have been pretty decimated on the landscape,' says fish aquatics expert

Parks Canada adding threatened fish species to several Banff lakes

A black milk crate is carefully placed into the fast flowing waters of Helen Creek in the back country of Banff National Park.

The crate is stacked with red blocks that look like Lego — known as Jordan-Scotty incubators — which are full of thousands of westslope cutthroat trout eggs.

The crate is engulfed by the glacier-fed water. The trout need cold mountain water to survive and thrive.

Not all of the eggs will become fully grown adult fish, but those that do will be part of Parks Canada’s long-term project to restore the threatened species to the national park’s ecosystem.

Once a mainstay in the Canadian Rockies, now they only live in about 10 per cent of their traditional territory.

“Their populations and distributions have been pretty decimated on the landscape,” said Brad Stitt, the native trout restoration project manager for Parks Canada's Lake Louise, Yoho and Kootenay field unit. “These fish are imperilled.”

Project showing success in helping threatened fish

In the first half of the 20th century, non-native fish like brook trout, rainbow trout and Yellowstone cutthroat trout were introduced to areas of the national park for fishing.

The non-native fish competed with westslope cutthroat trout for food, leading to its population decline and the species being listed as threatened under the Species at Risk Act.

Parks Canada began working on plans in 2011 to revive the trout species. It began removing non-native fish using rotenone — a natural fish poison — over a multi-year period starting with Hidden Lake in 2018.

Shelley Humphries, an aquatic specialist with the field unit, said Hidden Lake is seeing a successful return of westslope cutthroat trout.

“If you go up there now, you can see fish all over the lake. … You can see them in the streams and it’s been excellent. We’re expecting to have that same situation here [Helen Creek] in a few years,” said Humphries.

After confirming non-native fish were removed, Parks Canada staff began a four-year process of adding westslope cutthroat trout eggs each year to get different age classes for a “smooth continuous flow of eggs and adult fish reaching maturity,” said Stitt.

This year, Parks Canada placed about 10,000 eggs in multiple locations in Helen Creek, with similar numbers planned for Margaret Lake this summer. They join other areas like Cascade Creek, Katherine Lake and Little Herbert Lake.

Humphries said it’s Parks Canada’s mandate to protect ecological integrity, and “we don’t let species go without a fight.”

Reviving, protecting local ecosystems

Grizzly bears, wolves and cougars may get more publicity, but fish are equally critical to maintaining the area’s ecosystem.

Westslope cutthroat trout can be food for bears and birds. They also eat bugs and other fish.

Stitt said westslope cutthroat trout are also an “indicator species” that allows Parks Canada to monitor if there’s changes to the water.

Preliminary work is ongoing by Parks Canada to do similar projects for bull trout in the area of Moraine Lake.

Parks Canada has two options for returning fish to their natural habitat.

They can take adult fish from other water bodies to the new areas; or they can collect eggs, fertilize them on-site, use a mobile hatchery that looks like a large cooler and incubate the eggs.

The latter is the more successful option, though it takes considerably more work.

The project will be about two decades from start to finish to help the trout species return to its territorial waters.

If westslope cutthroat trout grow to one day be removed from the threatened species list, Stitt was clear about his plans.

“If it happened in my lifetime, it’d be so rewarding. I’d definitely crack some champagne and shed some tears,” he said with a laugh.

Greg Colgan is a journalist for CBC in the Bow Valley. He was previously the editor of the Rocky Mountain Outlook in Banff and Canmore. He has also worked for media outlets in Ontario and has experience covering topics such as sports, politics, housing and development, courts and arts and entertainment. He joined CBC in 2025. He can be reached at greg.colgan@cbc.ca.