A recent study by the Pacific Salmon Foundation reveals that viral heart disease, known as heart and skeletal muscle inflammation (HSMI), is more prevalent in open-net salmon farms in British Columbia than previously acknowledged. The research, published in the Aquaculture journal, identified HSMI in five out of seven open-net pen salmon farms located in the Broughton Archipelago near Vancouver Island.
The study highlighted that the disease-causing virus, piscine orthoreovirus (PRV), can spread from farmed fish into the surrounding waters, potentially infecting wild fish populations. Lead author Emiliano Di Cicco emphasized that the incidence of the disease is significantly higher than previously believed, overturning earlier assumptions.
Concerns have long surrounded open-net fish farms off the coast of British Columbia, particularly regarding the potential transfer of diseases from farmed salmon to wild salmon. Previous research by Di Cicco and colleagues in 2017 indicated the presence of HSMI in one out of four farms studied at that time, hinting at a broader issue than initially recognized.
The study revealed that nearly seven percent of the 749 examined salmon showed signs of HSMI, shedding light on the impact of PRV on fish health. While the Department of Fisheries and Oceans (DFO) in British Columbia currently classifies PRV as non-pathogenic, Di Cicco advocates for reclassifying it as pathogenic and aligning diagnostic criteria with global standards to improve disease detection.
DFO has pledged to review the study findings for future considerations. The B.C. Salmon Farmers Association has not responded to requests for comments, but industry groups defend salmon farming, citing its significant contribution to job creation and Canada’s salmon production.
The study was conducted collaboratively with the Mamalilikulla, ʼNa̱mǥis, and Ḵwiḵwa̱sut’inux̱w Ha̱xwa’mis First Nations. Indigenous leaders stress the importance of preserving salmon populations, acknowledging the crucial role salmon play in the ecosystem and Indigenous heritage.