Saving cold water loving fish in mountain national parks
Parks Canada is restoring threatened Westslope Cutthroat Trout and aquatic ecosystems in Alberta.
Imagine it’s summertime in the Rockies...
You are a Westslope Cutthroat Trout that’s just hatched in a mountain stream—and you’re hungry! Your ancestors have lived in these waters since the glaciers retreated. And until recently, this environment was the perfect combination of cold, clean, and fresh water that you need.
But as you swim around in search of food, you notice many other kinds of fish are already there, and they’re outcompeting you for precious food. The water also feels warmer than what is comfortable...
If you don’t find a place where only Westslope Cutthroat Trout live, you sense that you won’t be able to compete with these other fish… and you will not survive.
Saving threatened trout
Westslope Cutthroat Trout in mountain national parks are in trouble. So are local Bull Trout. Parks Canada is committed to protecting species at risk. That’s why they’ve stepped in to help save both of these threatened fish—and their habitats—before it’s too late.
Jump ahead to learn how Parks Canada is using cutting-edge science to recover Westslope Cutthroat Trout in the mountain parks!
How we got here
Parks Canada began introducing non-native fish, like Brook Trout, into mountain national parks in the 1940s to enhance the visitor fishing experience. This continued until the 1980s, with lasting negative impacts on the ecosystem.
Westslope Cutthroat Trout are also reproducing with non-native trout, like Rainbow Trout and Yellowstone Cutthroat Trout. This is creating hybrid trout populations that are diluting the Westslope Cutthroat Trout gene pool.
Needed by the ecosystem
The native Westslope Cutthroat Trout are fussy fish when it comes to needing cold, clean and fresh water environments. For this reason, they are considered an indicator species—their presence shows that habitats and ecosystems are healthy.
Bears and osprey also rely on Westslope Cutthroat Trout for food.
The time of year and location that Westslope Cutthroat Trout spawn is ecologically important. They are food for bears when they come out of hibernation and for ospreys that have migrated here. Their eggs are also accessible to Harlequin ducks when they need food to produce their own eggs.
Non-native trout do not replace the important role that Westslope Cutthroat Trout play in an ecosystem. Non-native Brook Trout spawn in the fall—a time when they are less important to the ecosystem. Their eggs are also buried deeper and are not accessible to higher parts of the food chains.
As such, Westslope Cutthroat Trout are important species for transferring energy from aquatic ecosystems to land-based ones.
Where they still swim
Many aquatic habitats located outside of protected areas are being damaged or lost, and climate change is warming waters. Despite this, Westslope Cutthroat Trout still remain in parts of mountain national parks, like:
Banff National Park in Alberta: genetically pure Westslope Cutthroat Trout remain in less than
10% of historic distribution in Alberta, with only a handful of locations in Banff
Kootenay and Yoho National Parks in British Columbia: some isolated streams in these two parks
still have genetically pure populations of Westslope Cutthroat Trout
Parks Canada is an important partner in recovery efforts for this species at risk. They work with other federal and provincial agencies and key stakeholders to restore native trout.
The long road to recovery
Parks Canada has taken a four-part journey to help restore the Westslope Cutthroat Trout. This journey is not over—their efforts are still underway and will continue into the future. To restore Westslope Cutthroat Trout, Parks Canada aims to:
1. Identify habitat refuges
Parks Canada created a long-term headwater refuge to restore Westslope Cutthroat Trout in Hidden Lake and upper Corral Creek in Banff National Park. This area provides a natural refuge that other non-native trout cannot otherwise get into owing to a natural waterfall. Additional refuges will be identified in the future.
2. Remove non-native fish
Parks Canada worked for six years to remove Brook Trout from the refuge using different methods. They tried netting, electrofishing and angling—but the non-native trout continued to thrive.
So, in 2018, Parks Canada worked with fisheries experts from Canada and Montana to use a naturally-occurring compound called Rotenone to remove the remaining Brook Trout.
Rotenone, a fish toxicant made from the roots of the bean plant, has been used safely and successfully by Indigenous peoples, as well as in Eastern Canada and the US—with no effects on the ecosystem or other species like birds, mammals or people.
Same, but different
The aquatic ecosystem conservation team at La Mauricie National Park in Quebec is faced with a similar but different situation when it comes to restoring their native trout.
While considered an invasive species in Western Canada, Brook Trout are in decline in the eastern part of the country. They are being outcompeted by non-native fish and are facing habitat destruction. Learn more about the restoration efforts to save native trout at La Mauricie.
3. Reintroduce native trout
With the non-native trout populations now under control, Parks Canada has started reintroducing Westslope Cutthroat Trout into the habitat refuge. They are restoring the native trout in partnership with fish culture specialists using a technique called remote stream-side incubation.
Parks Canada collects the eggs from native trout populations in two locations in Banff National Park. An Alberta hatchery incubated the eggs to the ‘eyed stage’. The developed eggs were then sent back to the park, where the final weeks of incubation took place in home waters—literally!
No single agency has enough staff and resources to do this work alone. We rely on outside support. We also don’t want to reinvent the wheel. It's been efficient to study what other agencies in the U.S. are doing and implement their methods. We’ve apprenticed on bigger projects in Montana to get hands-on experience and have learned a lot from their leadership.
Since then, Parks Canada has purchased their own incubator to save time and money. This year, and going forward, they raise their own eggs to the eyed stage.
Parks Canada has adapted the Incident Command structure to use as an effective tool for undertaking complex conservation projects on the ground with lots of people.
“It’s a very disciplined and formal technique used by the military and fire personnel during emergencies. It allows us to bring together different agencies and send them to remote areas to work together. It also helps us to be prepared and flexible to troubleshoot when things go wrong.”
Parks Canada will place thousands of eggs into Hidden Basin over the next three years or longer. Their intention is to have fish old enough to spawn every year. Thanks to these efforts, Westslope Cutthroat Trout have begun to swim in Hidden Creek for the first time in 50 years!
“I can’t emphasize enough how helpful it’s been working with Montana Fish, Wildlife & Parks. They’ve been so generous with their time and knowledge on tools, technology and genetics. It's truly inspiring to see what the next five years could look like for us based on their own experience.”
4. Monitor for success
Parks Canada has successfully restored an 11 ha lake and around 4 km of stream. Aquatics staff use environmental DNA (eDNA) to monitor the restoration work (click on Step 2 for information on eDNA). They also monitor the effects of Rotenone on the ecosystem. To date, no negative effects have been reported.
There’s so much success to celebrate with trout! For one, Banff National Park has extremely high quality habitat— it’s even considered a thermal refuge, a place where cold water will still exist in the face of climate change. I think we’re going to have really good success recovering the Westslope Cutthroat Trout. We want people to support this good work, we want to keep the conversation going!
Your support—and actions—can help save native trout in mountain national parks