By Steve Hubrecht

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The Pioneer reported earlier this month that the parasite causing whirling disease in certain fish has prompted the closure of all waterbodies in Kootenay National Park and Yoho National Park. 

Parks Canada adopted the measures and sounded alarm bells after discovering several cases of the debilitating disease in Yoho this fall. These were the first confirmed cases in B.C, which has staggering mortality rates in fish species, such as Kokanee salmon and westslope cutthroat trout in the Columbia Valley.

Last week the Pioneer talked with Parks Canada Lake Louise, Yoho and Kootenay field unit aquatic ecologist Shelley Humphries, who gave more details on the situation. The bottom line? When it comes to dealing with whirling disease, an ounce of prevention is better than a pound of cure. In other words, stopping the spread of the parasite that causes the disease is by far the most effective approach. That could — depending on test results — be good news for Kootenay National Park. Although whirling disease is definitely present in Yoho, it may not yet be in Kootenay. Parks Canada is awaiting word from a laboratory to find out.

“This (the closures in Kootenay) are a precaution. We are doing it because we don’t want the parasite to spread while we try to figure this out,” said Humphries.

After finding whirling disease in Yoho earlier this fall, Parks Canada took multiple water samples in several locations in Kootenay National Park — near the confluence of the Simpson and Kootenay River, at Kootenay Crossing, and the Kootenay River day use area. In total, about 60 or 70 samples were taken. Those were shipped off to a specialized lab for testing and Parks is now waiting to hear back if whirling disease is in Kootenay National Park or not.

“Kootenay (National Park) is ecologically a bit different than Yoho,” outlined Humphries. For one thing, Kootenay National Park is home to several of the fish species – Kokanee salmon, westslope cutthroat, and mountain whitefish — that are most susceptible to whirling disease (with mortality rates of up to 90 per cent), whereas Yoho does not have all these species within its park boundaries (they are blocked from migrating that far upstream by Wapta Falls).

Kootenay National Park abuts Yoho National Park, and although they are both part of the larger Columbia River watershed, it would be physically impossible for fish to take the disease from Yoho into Kootenay National Park.

If fish did carry the disease down the Kicking Horse River to the Columbia, then downstream along the Columbia River to where the Columbia joins the Kootenay River, they couldn’t then carry whirling disease from there up to the headwaters of the Kootenay River in Kootenay National Park. That’s because of several large dams on the Kootenay River, including near Nelson, just upstream from the Kootenay-Columbia confluence, which block the fish.

Kokanee salmon are susceptible to whirling disease that Parks Canada is taking a serious look at.
(Photo by MariuszBlach/Getty Images)

But recreating people, such as those fishing or standup paddle boarding, could very easily move whirling disease from Yoho National Park to Kootenay National Park, or from the Bow Valley (where whirling disease has been present for several years) into Kootenay National Park.

“That’s the most likely method of transfer — people and recreational activities, especially if people don’t handle their equipment properly or clean it well,” Humphries told the Pioneer. 

To make sure fishing equipment and standup paddleboards are truly whirling disease free, all water, mud and plant matter must be thoroughly removed and the equipment then left to dry for a minimum of 48 hours before it is used in a different water body. 

“You need to do a good job, not like my 19-year old would do,” emphasized Humphries.

She noted that it can be annoying, especially for people who want to paddle on one lake on a Saturday and another on a Sunday. But it’s necessary. Humphries loves to fish herself, and she has two pairs of waders. If she fishes at two different spots on the weekend, after fishing at the first spot, she removes the waders and then puts on the second pair before going to the second spot.

In the summer, the provincial government has designated cleaning stations set up in the Columbia Valley — one on the Radium Hill on Highway 93/95 and another in Golden. Parks Canada has one near the Lake Louise overflow parking lot and another near Lake Minnewanka. It is mandatory for anyone carrying aquatic recreation equipment to stop at these stations.

Humphries added that, unfortunately, staff at these cleaning stations often encounter people who are clueless about aquatic invasive species (such as the parasite causing whirling disease, as well as zebra and quagga mussels), much less about how to properly clean their fishing gear and paddleboards to prevent the spread.

Over the coming weeks Parks Canada will be talking to counterpart agencies in Alberta and parts of the U.S. where whirling disease is already present, and working with the Canada Food Inspection Agency (which deals with fish infections) to gain insight into what kind of action it should take to deal with whirling disease. 

And, despite whirling disease having a very high mortality rate and being very difficult to eradicate, there are, in fact, some options to deal with it.

One option is to completely remove all fish from affected water bodies.

“That can’t be done on a large scale in open population, but on a small scale it does work,” explained Humphries. In fact it has already been done by Parks Canada in two locations in Alberta’s Banff National Park – Johnson Lake and Little Herbert Lake.

Another option, which has been tried in the U.S., is to look at fish populations that have already been hit hard by whirling disease, take the surviving fish (which have developed some immunity to the disease) and then try to propagate these resistant fish elsewhere.

Unfortunately both of these options “are very expensive, very difficult, and don’t work everywhere,” noted Humphries. “The best thing we can do right now is minimize the spread as much as possible.”