Whirling disease
Freshwater Fisheries Society of BC
Canada's first recorded case of whirling disease in trout has been documented at Johnson Lake, in Banff National Park. Since many visitors travel back and forth between BC and Alberta, this disease might easily spread. There are several things you can do to help mitigate the risk - here's what you need to know.
The first documented case of trout whirling disease in Canada has been recorded at Johnson Lake, in Banff National Park. The parasite responsible for the disease, Myxobolus cerebralis, is native to Europe, and was introduced to North America in Pennsylvania in 1956. It has subsequently spread westward across the continent. Surveillance is currently being conducted to determine if it has spread further into Canadian waters.
While not a risk to human health, this organism primarily impacts rainbow (steelhead) and cutthroat trout under the age of four months. In a worst-case scenario, the infected fish can die. After a fish reaches four months, it becomes fairly resistant to this microscopic parasite. The various species of anadromous salmon appear to be more resistant to M. cerebralis than these trout species. However, what is vitally important to anglers and recreationists is that – due to the parasite’s miniscule size and complex life stages – whirling disease is extremely difficult to contain and eradicate from water bodies once they are impacted.
Whirling disease is generally transmitted to other water bodies through gear and equipment used for fishing, swimming, paddling, and boating. With many visitors travelling between Alberta and BC, here are important precautions that you can take to help stop the spread of this disease if you’re going to be out on the water:
- There are two recommended methods for cleaning: 1) using very hot water (close to 90° C) or, 2) a solution of one part chlorine (household bleach) to 32 parts water. Preferably, conduct your cleaning at the site before leaving. Be sure to thoroughly clean all sand, mud, and plant material from your boat, trailer, clothing, boots, and any other equipment used in your water activity.
- When cleaning at home, use a solution of one part chlorine (household bleach) to 32 parts water. Do not dispose of the chlorine solution used in the decontamination process into municipal storm drains or water systems; instead, spread it over a nearby lawn or garden. Note, at the suggested dilution level, the solution will not harm lawns or gardens.
- Allow at least 24 hours of drying time in sunlight before entering new waters.
- Remove all water from equipment like waders, boots, live wells, and bilges before transferring.
- Do not transfer live fish from one water body to another. It is illegal to do so in BC
- Do not use fish as bait.
- Dispose of fish, entrails, and other waste in municipal garbage, not in the water body.
Whirling disease
Infected fish can display several physical signs, including a blackened tail, spinal deformities, and erratic swimming (in a whirling pattern). It’s important to note that these physical signs are often not evident, and no outward indication of infection is common. That is why it is critical that you follow the best practices above in all situations. Whirling disease can be deadly – and in other regions of North America, notably Montana and Colorado, it has had devastating effects on wild trout fisheries.
Originally published here.