New research finds frequent disease outbreaks in B.C. salmon farms, endangering wild salmon

A new study with unprecedented access to Atlantic salmon farms in British Columbia raises urgent questions about the federal government’s approach to regulating salmon farms and highlights disease risk to wild salmon populations. The Broughton Aquaculture Transition Initiative — a multi-government agreement with the province and the Mamalilikulla, ’Na̱mǥis and Kwikwasut’inux̱w Haxwa’mis First Nations — enabled this rare access to salmon farms for scientists unaffiliated with the aquaculture industry. Read more: Learning from Indigenous knowledge holders on the state and future of wild Pacific salmon Scientists from the Pacific Salmon Foundation, Fisheries and Oceans Canada and the University of British Columbia repeatedly examined the open-net pen salmon farms over more than a year, finding outbreaks of the viral disease heart and skeletal muscle inflammation (HSMI) on most farms sampled. Three independent pathologists confirmed the diagnosis, and the First Nations subsequently removed the farms from their territories. As a viral ecologist at the University of British Columbia and as elected Chief Councillor of the ’Na̱mǥis First Nation, we participated in this research and are co-authors of the publication. Our findings suggest HSMI outbreaks are much more common on farms in B.C. than Fisheries and Oceans Canada reports. They raise questions about the federal government’s policy not to regulate piscine orthoreovirus (PRV) — the virus that causes HSMI — as a “disease agent” or cause of the disease. These findings also echo longstanding warnings about the government’s approach to salmon farming in B.C., which prioritizes industry needs over risks to wild salmon. A history of government denial Heart and skeletal muscle inflammation gained notoriety in B.C. after researchers first documented the disease in farmed Atlantic salmon, and the virus that causes the disease was shown to spill over to wild salmon. Fisheries and Oceans Canada has repeatedly downplayed the significance of these findings, emphasizing uncertainty over whether the disease occurs in the region due to the application of diagnostic criteria more stringent than those applied in other salmon-farming regions. These criteria were developed by Fisheries and Oceans Canada alongside the aquaculture industry itself. The Broughton Aquaculture Transition Initiative program studies the presence of infectious agents in and around open-net fish farms. (Pacific Salmon Foundation) Fish farms heavily infected with pathogens Prior research has documented the consequences of fish farm diseases on wild fish. Farms are frequently infected with pathogens such as piscine orthoreovirus. These pathogens flow freely into the water and are transmitted to wild salmon. They have been associated with decreased survival and population declines in wild salmon. Fisheries and Oceans Canada’s assessment of diseases associated with fish farms deserves renewed scrutiny in light of these findings. The evidence that PRV should be regulated as a disease agent has become overwhelming, yet the department has not updated its policy since 2019, when it concluded that PRV is not an infectious disease agent. ‘Namgis First Nation initiated a judicial review of this policy in 2019, and then put the action on hold in 2021 as it appeared the federal government would follow up on its mandate to remove fish farms from British Columbia. In 2024, the First Nation reactivated the judicial review after losing faith in the government’s commitment to remove the farms. Independent scrutiny is crucial First Nations, independent scientists, non-governmental organizations and even Fisheries and Oceans Canada’s own scientists have repeatedly raised concerns about whether the department’s science advice is sufficiently independent from its policy mandate to promote and regulate aquaculture. Author Gideon Mordecai explains the risks of PRV from B.C. salmon farms to wild salmon. (UBC Faculty of Science) The way PRV is regulated exemplifies these issues and illustrates why independent scrutiny is crucial. Our study, combining Indigenous-led research and independent scientific assessment, has provided an important check on institutional assumptions. It will hopefully ensure that future decisions affecting wild salmon are grounded in transparent, evidence-based assessment of the risks. The federal government is currently stalling on its commitment to remove salmon farms from B.C. Whichever policy option the government ultimately chooses must be weighed against its potential risks and benefits — and that requires accurate information about the risks salmon farms pose to wild salmon. The contrast between the peer-reviewed literature and Fisheries and Oceans Canada’s own science advice demonstrates that the government is currently failing to provide decision-makers with an accurate assessment of those risks.