The Canadian Food Inspection Agency has declared the North Saskatchewan River and its watershed infected with whirling disease.
The declaration includes the river itself upstream from Rocky Mountain House plus all streams, creeks, lakes and rivers feeding into the river and ends at the Saskatchewan border.
Whirling disease was first detected in the North Saskatchewan River in September, but the CFIA did not officially declare the river infected until now because the levels were initially too low, said Peter Giamberardino, Alberta’s whirling disease coordinator, on Friday.
Whirling disease is caused by myxobolus cerebralis, a microscopic parasite of salmonid fish, including trout, salmon and whitefish.
Fish infected with the parasite may swim in a whirling motion due to damage caused to cartilage and the nervous system.
Infected fish may have deformed heads or bodies and discolouration of tails.
In Alberta, rainbow, westslope cutthroat and brook trout, as well as mountain whitefish, are most susceptible to the disease.
The province opened a whirling disease laboratory in Vegreville last summer as part of its plan to tackle the disease. The province is working with University of Alberta researchers to develop non-lethal testing methods for parasite.
Whirling disease is not harmful to humans or other mammals.