CALGARY—When anglers in the early 1900s fished, they would turn their noses up at Alberta’s native bull trout species — the top predator in the waters — and considered them a “garbage” fish.

They’d deliberately pluck the critters out of the water and leave them to dry up on the banks, making room in the river for more favourable trout species that were introduced from eastern North America and Europe.

This took a toll on their population and despite being more prized in recent decades, the province’s official fish, the bull trout, is in trouble.

Late this summer, the species “finally” found itself covered by Canada’s Species at Risk Act, a move University of Calgary biologist John Post said was recommended seven years ago.

Now Post, who sits on the Committee on the Status of Endangered Wildlife in Canada (an independent advisory panel of scientists and experts who identify at-risk species), along with other conservationists, is sounding the alarm for the indicative fish species or, as Post puts it, the “canaries in a coal mine.” If they’re not doing well, it’s a sign that other organisms in the waters might not be doing too well, either.

“If we lose them, it’s not just those fish species (affected), it’s other organisms — either other fishes or invertebrates, insects, native fauna — in these rivers (that) are at risk as well,” he said.

“It’s not just a fish story, it’s an ecosystem sustainability issue, really.”

The species, which are technically not true trout but char, mostly inhabit cold and pristine snow-melt-fed waters that flow into some of Alberta’s larger rivers, including the Bow, the Oldman and the Red Deer. Decades ago, the bull trout used to be found farther downstream in those areas, but now they’re mostly seen in the Eastern Slopes watersheds of the Rocky Mountains and the foothills of southern Alberta.

Dams and culverts are partly to blame for the bull tout population drop because they impede its migratory routes. Logging and oil and gas activity, as well as the development of trails and road crossings, also play a part, like muddying the normally clear waters the species depend on.

Meanwhile, in the rivers, the species are competing with non-native trout that have been hybridizing with them.

Changes to climate over time will also have a dramatic effect on the water cycles, which, in turn, impacts stream flows and temperatures, says Ryan MacDonald, an adjunct professor at the University of Lethbridge. He’s also a hydrologist (a scientist who studies the quality of water and its cycles) and does work with Alberta WaterPortal, a non-profit that aims to educate people on the province’s water systems.

These climate changes can impact bull trout, which rely on cooler water temperatures. If the rivers warm up, it can also increase the likelihood of disease in the waters that will affect cold-blooded critters, like trout.

Other human impacts on the fish include fishing for the critters, despite the catch-and-release policy for bull trout. Post said about one or two out of every 20 bull trout caught are not going to survive the release. And when many of these populations have been pushed to low densities, those deaths could be sufficient to push the species “over the edge,” he said.

“Anglers who fish for them have to decide, in fact, whether they want to go and catch 30 or 40 fish in a day and release them, realizing that maybe four or five or six of them might not survive,” Post said.

“They might have to at least consider the option of reducing the number of fish that they catch.”

Similar fish species in Alberta aren’t doing well, either, including the cutthroat trout and the Athabasca rainbow trout, which was listed as endangered in August.

Predictions by the Committee on the Status of Endangered Wildlife in Canada point to a population decrease in the three trout species of 50 to 70 per cent over the next 12 to 20 years unless there’s immediate actions in the field to protect them.

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The province says it has been working on the problem, including the creation of a native trout recovery initiative, which focuses on priority locations with help from partners, regulators and industry, according to John Muir, spokesperson for Alberta Environment and Parks.

On top of that, the province said it has initiatives to help mitigate environmental impacts along the Eastern Slopes that affect native species, like the bull trout, including programs that look at water crossings and recreation management. Last year, the province completed two remediation projects for bull trout in Fall Creek and Rocky Creek near Rocky Mountain House.

But it’s strongly up to the federal government now, said Joanna Skrajny with the Alberta Wilderness Association, since there are less “legal levers” under the provincial Wildlife Act.

Within two years, the federal government has to come up with a recovery strategy and then begin protecting the species habitat six months after that, Skrajny said.

“They’re incredibly valuable. They’re basically Alberta’s salmon,” Skrajny said, noting the bull trout face similar issues as British Columbia’s salmon population.

“We should definitely do everything we can to protect them now and to recover them back to what they were.”

But Post worries bigger changes aren’t happening quick enough. And if a top predator’s population — such as the bull trout — continues to dwindle or is lost, he said, the whole ecosystem could be thrown off.

“What often happens in these situations is you see a super abundance of organisms lower in the food chain that changes the whole structure,” Post said.

And those changes can weaken the ecosystem’s resilience to issues like floods and climate change, he said.

“I think the pressure is on to just take this seriously,” Post said.

As of now, it isn’t enough for the fish to be placed on species-at-risk lists, Post said, adding there needs to be further efforts to protect their habitats — and quickly.

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