For the first time in Canada, officials have confirmed a case of whirling disease. The aquatic parasite has been found in fish in Johnson Lake in Banff National Park.
Although the parasite is not a health concern for humans or other mammals, it is for fish, particularly salmon and trout.
Parks Canada has restricted access to Johnson Lake to reduce the risk of further spreading it. The fear is that it will be spread by swimming, boating and fishing gear so water-based recreation at the lake has been prohibited.
Sampling and testing of fish from other water bodies in Banff National Park is underway, and fish downstream of Banff are also being sampled.