Whirling disease has been detected in fish in the Crowsnest River, according to the Canadian Food Inspection Agency (CFIA).
The infectious disease deforms and cripples young fish by penetrating the heads and spines of salmanoids like salmon, trout, whitefish and char.
The microscopic parasite eats away at cartilage in fish skulls, causing fish to swim erratically — or whirl. The whirling makes it difficult for the fish to feed and avoid predators. The fish also usually die prematurely.
The disease isn’t harmful to humans or other animals that consume infected fish.
The CFIA says whirling disease was detected on April 4 at three locations within the Crowsnest River — at the confluence of Crowsnest River and Todd Creek, downstream from the Highway 3 bridge near Lundbreck and upstream from the confluence of Crowsnest River and Rock Creek.
The first Canadian case of whirling disease was found in fish in Banff National Park’s Johnson Lake in August 2016.
In February of this year, the CFIA confirmed fish in the Bow River, a renowned Alberta trout stream, had also been infected by the disease.
The disease is spread between waterways by fish themselves, or recreational equipment used in the rivers and lakes for fishing, boating, paddling and swimming.
The CFIA says the confirmation of the disease in the Crowsnest River don’t necessarily mean it’s spreading, saying it could have been in the waterway undetected for many years.