Another notable fishing river in Alberta has been infected by whirling disease.
The Canadian Food Inspection Agency has declared the Oldman River watershed infected with the contagious disease. The advisory covers all streams, creeks, lakes and rivers feeding into the Oldman River, including those in Waterton Lakes National Park. The affected zone ends at the confluence of the Oldman River and South Saskatchewan River.
The Oldman is a popular river for anglers with its abundance of bull trout, cut-bows, browns and pike.
Monday's announcement follows a similar declaration of infection in the Bow River watershed in February. But the province says new detections of whirling disease should not be taken as evidence the disease is spreading.
After it was discovered in the Bow watershed, the province has been testing other Alberta rivers and ordered a "precautionary quarantine" of fish farms and hatcheries.
While not a risk to humans eating infected fish, the parasite can kill small, young fish. Mortality rates in vulnerable populations have been as high as 90 per cent.
In Alberta, the most susceptible species are rainbow, westslope, cutthroat and brook trout, as well as mountain whitefish. Symptoms include swimming in a circular pattern, a change in colour and skeletal deformities as the disease eats away at cartilage.
There is no treatment for whirling disease. The province is trying to prevent its spread by inspecting watercraft and asking anglers and boaters to clean, drain and dry their boats and all equipment when moving between bodies of water.
If you suspect a case of whirling disease, call 1-855-336-BOAT (2628).