One of Canada’s most famous natural landmarks has fallen victim to a new aquatic invasive species, prompting a new level of restrictions in Banff National Park.
Parks Canada workers have identified a presence of whirling disease in Lake Louise, Alta.
“Whirling disease is an infectious disease that affects fish populations. It is not harmful to humans or other mammals, but it can have a significant effect upon trout, whitefish and salmon,” Parks Canada says.
“It’s unlikely that whirling disease was spread to Lake Louise through natural fish movement, because there’s a natural fish barrier between (the lake) and the Bow River,” explained Francois Masse, superintendent of the Lake Louise, Yoho and Kootenay field unit.
“It’s most likely whirling disease was introduced by mud or water on a watercraft or angling equipment.”
As a result — effective spring 2026 — paddling and the use of large inflatables, along with the use of waders or wading boots while fishing, will be banned at Lake Minnewanka, Bow Lake and Moraine Lake.
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Visitors will still be able to use those devices at Lake Louise, as well as several other area lakes and the Bow River, downstream of Hector Lake.
“We understand the disappointment that visitors would like to continue recreating on these water bodies, but we are trying to find a balance between protection of our sensitive ecosystems as well as finding locations and opportunities for visitors to continue water activity recreation in the parks,” said Marie Veillard, the aquatic invasive species project co-ordinator for Lake Louise, Yoho and Kootenay field unit.
Anyone bringing equipment is asked to clean, drain and dry their waders, inflatables or watercraft and fill out a self-certification form before use.
Parks Canada says its aquatic invasive species prevention strategy is an evidence-based approach that uses data and lessons learned from similar situations and that more components of the strategy will be rolled out over the next two years.
The implementation of restrictions and specific permitting requirements may vary by park and officials encourage visitors to plan ahead and check which zone a waterbody is in to ensure their planned water-based activity is permitted.
Parks Canada says there’s no end date for the restrictions right now, but it will be evaluated on an ongoing basis.
It comes after the group has spent the past several months testing Banff, Kootenay and Yoho national parks for aquatic invasive species.
Lake Louise was last tested for whirling disease in 2016 and officials say this is the first time the disease has ever been found in the lake.
Aquatic invasive species can also spread downstream beyond park boundaries through interconnected river systems, according to Parks Canada.
“Once established, aquatic invasive species may never go away.”
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