Whirling Towards Disaster

Whirling Towards Disaster

From rockslides to mining explosions, this Southern Alberta trout town is no stranger to catastrophe. Now, a fish epidemic threatens their world-class fishery.

*Article featured in Hooked Magazine, Summer 2022 edition. This is the unedited version I submitted to the editor*

The Crowsnest River drains from the continental divide out of Crowsnest Lake, flowing 40 kilometers east through the municipality of Crowsnest Pass—made up by the communities of Coleman, Blairmore, Frank, Bellevue, and Hillcrest— before emptying into the Oldman Reservoir. In the early 1900’s, settlers came to the region for the wealth and prosperity promised by coal mining. It was immediately clear to the new residents that the river was a sportsman’s delight; small enough to wade, big enough to host large fish, with abundant bug life and endless deep pools.

It didn’t take long for settlers to start tinkering—throughout the 1930’s and 1940’s, rainbow trout were introduced and became well established, displacing the native westslope cutthroat trout. Bull trout were also lost in all areas above Lundbreck Falls due to overfishing and other factors. Brown trout, brook trout, and lake trout have all been introduced to the system and can still be caught today. Despite all this change, the dominant species, rainbow trout, have continued to thrive, due primarily to the excellent trout habitat and abundant insect life in the river. I have many fond memories fishing the Crowsnest, along with some of my personal best rainbow trout. It will always hold a special place in my heart.

Disaster Strikes

This area is familiar with catastrophe. In 1903 Turtle Mountain collapsed, crushing the newly settled town of Frank under the weight of 120 million tonnes of limestone. Aptly named “the mountain that moves” by the indigenous peoples of the region, Turtle Mountain still looms over the pass, the wasteland of rock scattered across the valley providing a constant reminder of the tragedy that took up to 90 lives— the deadliest rockslide in Canadian history. Only ten years later the community suffered its next tragedy, when a pocket of methane gas in the Hillcrest Mine ignited, leading to a catastrophic explosion that tore through the mine killing close to 200 people— the deadliest mining disaster in Canadian history. The misfortunes weren’t done— in 1923 and 1942 large floods damaged infrastructure and property. Throughout these trying years of setbacks, two things remained constant— the resolve of the residents, and the excellent trout fishing in the beautiful waters of the Crowsnest River.

Photo: Kaegan Finn

The boom-and-bust cycle of the mining industry ran its course and eventually fizzled away; but the large, hard fighting rainbows continued to draw people from across the west to the quaint, tragedy ridden municipality. In the years since then, it has gained a lofty reputation as Alberta’s trout town, promising anglers far and wide the opportunity at big, hard fighting rainbows. Revenues from angling support several local guide shops, while indirectly supporting local hotels, gas stations, and restaurants. Fly-fishing is the cornerstone of the regions budding tourism economy. However, a new threat now looms in the future— one that has the potential to change the fishery, and the community, forever. 

A new type of disaster

Enter whirling disease, a condition affecting trout caused by a microscopic parasite. It was first discovered in Alberta in 2016 in the Bow River system. Subsequent investigation revealed that it was present in rivers across the province, including the Crowsnest River. This disease can be devastating to fish populations, as was showcased by the collapse of several fisheries in Montana, Wyoming, and Colorado in the 1990’s.  The parasite that causes the disease, Myxobolus cerebralis, requires two hosts to complete its life cycle— a species of worm known as Tubifex, and trout. While it is relatively harmless in the resilient Tubifex worm, it is highly lethal in trout, causing severe nervous system dysfunction followed by an early death, particularly in young fish. The spores produced inside infected fish are dispersed throughout the system to infect more worms which will perpetuate the cycle— until there are no more fish to spread the spores, in which case recovery may commence. Out of all rivers in Alberta where its presence has been confirmed, the Crowsnest River is being hit the hardest.

How bad is it? A study from 2021 warned that the perfect conditions for a whirling disease outbreak existed in the Crowsnest River, and that there was a high risk of a rainbow trout population collapse. They found infection rates as high as 84 % in the lower river, while 27 % of Tubifex worms were infected. Meanwhile, the density of the parasite in the water was comparable to levels that led to fish collapses in Colorado and Montana. The most troubling sign is the lack of juvenile fish; while some adults can survive with the parasite, it is nearly 100% lethal in juveniles. The big fish are surviving, however almost none of their young are living to adulthood.  This was the first stage of collapse in Colorado and Montana, warning of what is to come on the Crow.

Interestingly, brown trout are not affected by whirling disease like the other species of trout. This might be good or bad depending on the context. They can still carry the parasite and contribute to its spread, yet they have natural immunity to the disease. It is hypothesized that they are the original host of the parasite. It is very possible that a collapse of rainbow trout populations may also lead to brown trout establishing themselves as the dominant species in the stream, which would allow the parasite to remain in the system, indefinitely.

The speed at which the disease has spread should serve as a warning for the rest of the province, and a wake-up call for anglers. These resources are vulnerable, and our activities can have profound effects on their longevity. We need to educate ourselves on the threat posed by whirling disease and do everything in our power to limit its impact and prevent its spread.

Hope Amongst Tragedy

If the collapses in Colorado and Montana are any blueprint, there is many reasons to remain optimistic about the future of the Crow. Many of those populations were able to rebound and gain some natural immunity to the parasite. In recent years, biologists in Colorado have discovered a strain of rainbow trout resistant to whirling disease and have introduced them to their rivers with good success. Furthermore, extensive research is being undertaken to utilize new DNA technologies to disarm the parasite. Fisheries managers in Alberta are working hard to understand the disease and investigating all possible management options. These efforts all provide hope that fishing may remain a central attraction for Crowsnest Pass visitors and residents for years to come. So far, the fishing quality on the river hasn’t faltered and remains excellent— let us hope we can stay ahead of the curve and keep it that way.

 The Crowsnest Pass has had to weather many disasters; whirling disease is just the latest in a history shaped by them.  The landscape is haunted by the ghosts of those who were lost and the remnants of forgotten times. Yet the stories are carried on by those who persevered. Let us hope the river carries this same spirit; it may never be the same, but there is always hope amongst tragedy. Only time will determine the legacy of whirling disease in Alberta— but I remain hopeful that trout will continue to thrive in the perfect trout stream that meanders through Alberta’s trout town.


Whirling disease is spread between waterbodies on the boots and waders of anglers. Mud and debris left on boots can contain both spores and infected Tubifex worms, which can allow the parasite to spread more quickly and establish in new rivers. It is critically important anglers do their part and decontaminate their gear— this includes cleaning boots with a brush between waterbodies to get rid of any mud and debris and subsequently disinfecting by soaking gear in a solution of quat or bleach for 10 minutes. Always dry gear thoroughly and CLEAN, DRAIN, and DRY all watercraft after use. This is particularly important if you spend a lot of time on rivers where whirling disease is prevalent, like the Crowsnest River or the Bow River. Fishing these streams means taking the time to decontaminate before moving elsewhere—you could be preventing the next outbreak.

Photo: Kaegan Finn

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