The entire Bow River Watershed has been infected with whirling disease, the Canadian Food Inspection Agency (CFIA) has declared, prompting new province-wide measures to try to contain the spread. The disease can cause infected fish — predominantly trout and whitefish — to swim in a whirling pattern and die prematurely. Inside the buffer zone, provincial acquaculture facilities and Class A fish farms will have to test fish for whirling disease. This map shows the area of Alberta declared infected with whirling disease. Since then, cases of the disease have been detected at a number of additional locations in the Bow River in southern Alberta.

Source: CBC News February 10, 2017 21:11 UTC