For most of the year, Hidden Lake is a frozen Rocky Mountain paradise accessible only by foot or helicopter – its most frequent visitors a roaming pack of wolves.
But beneath these sparkling blue-green waters also lurks an invasive but "beautiful villain" – the brook trout. This 13-hectare piece of wilderness, about nine kilometres from world-famous Lake Louise, has become a "baby factory" for brookies. The species is robbing the indigenous westslope cutthroat trout of most of its natural habitat here in Banff National Park, as well as other cold, fresh waterways in Alberta.
Cutthroat – or cutts – are now on the edge of extinction. They were once so plentiful that they were hauled away by the wagonload until overfishing and such industrial development as hydro-electric dams decimated the population. Well-intentioned but imprudent attempts followed to restock the water bodies with non-native species such as brook trout, which gobbled up food and cross-bred with the cutts.
"This is our fault," said Shelley Humphries, an aquatics specialist with Parks Canada. "We caused this. We've monkeyed around. ... but we can fix this one. We can save cutthroat if we just have the will to do it."
She is now on the front lines of a three to five-year project that aims to catch – and kill – every brook trout in Hidden Lake and the creek tied to it.
It's one of two initiatives now underway in Banff to create safe havens for cutthroats, which could be reintroduced within two years.
There is some dispute about how many cutthroats – named for the bright red-orange stripes under their mouths – are left in Alberta. Experts say the numbers are in the thousands, though many are not genetically pure, and they swim and spawn in perhaps 100 kilometres of the province's waterways. That's just 5 per cent of their historic range in a patchwork of creeks, rivers and lakes.
"These populations are so small and fragmented, they need to be tied together," said David Mayhood, an aquatic ecologist at Freshwater Research Ltd., who has written reports on cutthroats.
In 2006, the Committee on the Status of Endangered Wildlife in Canada recommended the Alberta cutthroat be listed as "threatened" under Ottawa's Species at Risk legislation. Under Alberta's Wildlife Act, the species was listed as such in 2009.
Ottawa now has until next April to decide whether it will designate the cutthroat as worthy of protection under federal law – and with it, a potential influx of cash to fuel recovery efforts.
A joint-recovery plan, written by experts from the provincial and federal governments, as well as stakeholders including industry and environmentalists, has already been submitted in anticipation of possible listing, said Shane Petry, a biologist with Fisheries and Oceans Canada.
Meanwhile, the provincial government has its own recovery efforts under way.
Since 1998, when Alberta starting pulling brook trout out of Quirk Creek, southwest of Calgary, more than 9,500 brookies have been caught and killed. Filled with 92 per cent brookies in 1995, now 50 per cent of the fish in Quirk Creek are cutts, explained Jim Stelfox, a senior fisheries biologist with Alberta Environment and Sustainable Resource Development. A special "stewardship licence" pilot project now allows anglers, who have passed a fish identification test, to kill as many brook trout as they can catch in seven creeks, rivers and their tributaries.
By midday at Hidden Lake on Thursday, about 10, mostly tiny, brook trout had been yanked from the gill nets that are dangling in 11 places near the shore. So far, 1,896 have been pulled from the lake, and about another 1,000 were caught within four kilometres of the creek, bound for the mighty Bow River.
Ms. Humphries estimates there may be another 300 still evading the nets, and though it would be impossible to eradicate brookies from Banff, and Alberta, she said that doesn't mean they shouldn't try to help the cutts. Related genetic work is now being done at the University of Calgary to ensure the reintroduced cutts are 100-per-cent pure.
"We don't let species at risk go without a fight," Ms. Humphries said.