of the Rocky Mountain states (Colorado, Wyoming, Utah, Montana, Idaho, New Mexico), where it is causing heavy mortalities in several sportfishing rivers. Some streams in the western United States have lost 90% of their trout. In addition, whirling disease threatens recreational fishing, which is important for the tourism industry, a key component of the economies of some U.S. western states. For example, "the Montana Whirling Disease Task Force estimated trout fishing generated US $300,000,000 in recreational expenditures in Montana alone". Making matters worse, some of the fish species that M. cerebralis infects (bull trout, cutthroat trout, and steelhead) are already threatened or endangered, and the parasite could worsen their already precarious situations. For reasons that are poorly understood, but probably have to do with environmental conditions, the impact on infected fish has been greatest in Colorado and Montana, and least in California, Michigan, and New York. Impact in Canada Whirling disease was first detected in fish in Johnson Lake in Banff National Park in May, 2016. CFIA Labs confirmed in August and Parks Canada announced the outbreak August 23, 2016. Although it was first discovered in Banff, it is not necessarily where the disease originated and spread. The Government of Alberta is currently sampling and testing fish in 6 different watersheds (Peace River, Athabasca, North Saskatchewan, Red Deer, Bow and Oldman) to see where the disease has spread. Initial sample fish were collected in 2016, and are currently being processed by the Government of Alberta and CFIA labs. Since testing began, it has been detected in the Upper Bow River, and in May 2017 it was confirmed that whirling disease had also been detected in the Oldman River Basin. The declaration does not mean that every susceptible finfish population within the Bow and Oldman River watersheds are infected with the disease. As a result of the new declaration, a domestic movement permit will be required from the CFIA for susceptible species and end uses identified in the Domestic Movement Control Program, the vector Tubifex tubifex, the disease causing agent Myxobolus cerebralis, and/or related things out of the infected and buffer areas of Alberta. Recreational and sport fishing, including fishing led by a professional guide, will not require a CFIA permit. Prevention and control Some biologists have attempted to disarm triactinomyxon spores by making them fire prematurely. In the laboratory, only extreme acidity or basicity, moderate to high concentrations of salts,