Once considered a pest, Alberta's official fish is now under threat

For decadesbull trout would be removed from a fishing line and left to rot in the sun.

Alberta anglers considered the once-abundantfish as unwanted predators, feeding on more favoured trout species such as brook trout and brown trout.

"At the time, they saw the bull trout as a predator on the species they were more interested in fishing," said John Post, a biologist at the University of Calgary.

"They would catch them and throw them up on the bank," Post said in an interview with CBC Radio'sEdmonton AM.

"They saw them as a pest."

Populations have never recovered from overharvesting in spite of nearly two decades of protection, he said.

The bull trout, Alberta's official fish, is in trouble, Post said. And if the bull trout is in trouble, other species will soon follow suit.

'A top predator'

"The bull trout is a top predator," Post said "It's a grizzly bear-like animal, but of streams and rivers.

"They're an important part of the structure of aquatic food webs in streams and rivers. And if they're not doing well in these systems it's an indicator of the poor health of our streams and rivers."

The bull trout technically a large char species has been listed for years as threatened under Alberta's Wildlife Act.

This August, the federal government classified the bull trout as threatened under Canada's Species At Risk Act.

If we don't manage it effectively, it will become endangered.- John Post

The federal designation is something Post has been asking for since 2012 in his role as co-chair of Freshwater Fishes Species Specialist Committee on the Status of Endangered Wildlife in Canada.

Populations have declined between 30 and 50 per cent over the past 25 years, Post said.

"That's quite worrisome," he said. "If we don't manage it effectively, it will become endangered and then potentially, locally extinct."

Giving the fish federal, not just territorial protection, will force governments to preserve habitat. The designation may also signal the end of the current catch and release regulations for bull trout, Post said.

"In the short term, it forces all the stakeholders to get together and develop recovery plans for the species and this has to happen within a year of the listing which happened in August," Post said.

"They will meet and work very hard at trying to figure out how to eliminate some of the threats so the species can recover ... This is required legally nowas a process and that's useful."

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The species, slow-growing and late to spawn, thrives in the coldest, cleanest and most secluded waters. It's found in all river systems with headwaters in the mountains in Alberta and B.C., but its habitat continues to shrink.

Any mining development that contaminates rivers or streams with sediment hurts the trout's ability to spawn. The bull trout must compete with non-native species for the habitat that remains.

Relying on cold water makes the bull trout especially vulnerable to climate change, Post said. The few remaining healthy populations left are found in protected areas such as provincial parks.

Post is hopeful, with additional protections, the species could once again thrive in the mountain headwaters.

"It's an iconic species in the east slopes of the Rocky Mountains in Alberta," he said. "In many ways, it's Alberta's equivalent to B.C. salmon."