Lakes in Yoho, Kootenay National Parks closed due to suspected whirling disease

Whirling disease found in B.C. Parks Canada says whirling disease has been discovered in Emerald Lake in Yoho National Park.

Parks Canada has closed lakes in Yoho and Kootenay National Parks, in an attempt to limit the spread of a suspected case of whirling disease.

All waterbodies and shorelines in the parks will be closed until March 31, 2024, effective Thursday, according to a Parks Canada news release.

Parks officials reported a suspected case of whirling disease in Emerald Lake, located in Yoho National Park, on Sept. 20.

Whirling disease is a parasitic disease that affects some fish, but does not present health risks for people or other mammals. Parks Canada officials are concerned about helping protect populations of westslope cutthroat trout and kokanee salmon.

“Whirling disease has the potential to decimate fish populations, with mortality rates up to 90 per cent in some cases,” Francois Masse, Parks Canada’s Lake Louise, Yoho and Kootenay superintendent, said during a press conference Friday.

At the time, Emerald Lake, Peaceful Pond, Lone Duck Pond and the Emerald River shorelines, water bodies, and tributaries were closed until further notice.

After further investigation, officials discovered suspected cases of whirling disease in Kicking Horse River, Wapta Lake, Finn Creek, Monarch Creek and the confluence of Emerald River and the Kicking Horse River.

“Aquatic invasive species pose a significant threat to the health of national parks and vital aquatic ecosystems,” Parks Canada said in a news release.

“These species disrupt and irreversibly damage aquatic ecosystems, affecting vulnerable species at risk.”

SPRING, SUMMER UP IN THE AIR

While the restrictions are scheduled to expire in the spring, officials say that date could be flexible depending on what steps they decide to take.

“Once the water has frozen and there’s very little activity in the parasite, and really little exposure to actual liquid water or the mud that contains the parasite, then the risk becomes incredibly low,” Megan Goudie, a Parks Canada spokesperson, said.

“We’ll be taking this time to investigate management activities that will dictate what the spring will look like.”

The possibility remains that these bodies of water could stay closed into the spring and summer.

“All the options are on the table at this stage,” Masse said.

“Right now the focus is on understanding the spread and taking protection actions, and then we’re going to start really thinking about how can we make sure that we have a regime next summer that’s going to be working well.”

FIRST DETECTION IN B.C.

Whirling disease was previously detected in Banff National Park’s Johnson Lake in 2016, however, this is the first case in British Columbia parks.

With the parks having separate watersheds located on opposite sides of the Continental Divide, officials suspect the parasites were likely transported from Alberta by human activity.

“Although it is present in the Bow River in Alberta and Banff National Park, it has not yet been detected in Yoho or Kootenay National Parks, which are on the British Columbia side of the continental divide,” Goudie said.

“That’s why it’s so important for us to be taking these management actions at this time to protect further spread throughout the west side of the continental divide in Yoho and Kootenay national parks.”

RESTRICTED ACTIVITY

Parks Canada said the risk factors for spreading the disease include the movement of fish, mud/sediment, aquatic vegetation, and water, according to a bulletin posted Oct. 26.

As a result, all in-water and shoreline activities are prohibited in the affected bodies of water.

Prohibited activities include, but are not limited to:

People must remain at least three metres away from any affected water body.

Some exceptions apply, including:

Use of rental canoes at Emerald Lake is permitted and Radium Hot Springs remains open.

“The boat rentals at Emerald Lake stay at the lake, they do not move between water bodies, and so this is a very low risk for spreading the parasite that causes whirling disease,” Goudie said.

“These boats staying in place pose no threat to transferring those parasites across the watersheds.”

Anyone violating these restrictions could be charged under the Canada National Parks Act, with a maximum penalty of $25,000.