Cascade Creek restoration project helps increase westslope cutthroat trout population

The population of westslope cutthroat trout is being significantly bolstered as a result of the Cascade Creek restoration in Banff National Park, say the project leaders.

The aim of the project, near the Banff townsite, is to completely rehabilitate the stream, according to the federal government's website.

Dan Struthers, project manager of the Cascade Creek restoration project, told CBC News that Parks Canada is using the project to bring back threatened species like the westslope cutthroat trout.

"Adding nine kilometres of stream habitat equates to about a 30 per cent increase in stream habitat found in the park as occupied by pure westslope cutthroat trout," Struthers said.

Nicole Sulewski, resource management officer with Parks Canada, told CBC News the restoration of the stream is not just about reintroducing threatened fish.

"We have looked at the food sources, the invertebrates in the stream, looking at our riparian health, the stream banks, and a lot of it was really washed out during the 2013 flood," Sulewski said. "And so we've done a lot of active work to bring it back."

She says the project team has planted lots of food sources for the bugs that the fish like to eat, adding the bugs live part of their life cycle on the plants and will fall into the water to sustain the trout.

Struthers says a healthy creek has areas with calm water as well as large boulders and wood debris for fish to hide from predators. He adds healthy creeks should also have "splashy water" or what's known as a riffle, a shallow area where water flows rapidly across stones and fish typically find bugs.

The restoration project is sourcing westslope cutthroat trout from places like Marvel Lake and Upper Stoney Creek to reintroduce more fish into Cascade Creek. 

"And then from there we have to test diseases, we have to make sure they were genetically suitable, that they were locally adapted to the Bow River," Struthers said.

Sulewski says it was an undertaking to bring the fish over to the creek.

"We went out … to catch lots of fish while they were preparing to spawn to release their eggs and then we collected eggs as well as milt. We fertilized it on site and then flew it out of the backcountry to an incubation facility, where the eggs were incubated until they were resilient enough to be moved into Cascade Creek," she said.

From there, the fish eggs were moved into in-stream incubator units, where they hatched and swam out into the creek to start their lives. 

"We've made huge gains here," Struthers said. "Some of this habitat downstream of us used to just be dry. There wasn't enough water to connect to the Bow River. Now we're at a place where we've got full connectivity from the top end all the way down to the Bow River.

"We feel really confident that the fish here will develop a self-sustaining population and will be here into the future."