A recent study by the Pacific Salmon Foundation has revealed 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 also highlighted the potential for the disease-causing virus, piscine orthoreovirus (PRV), to spread to wild fish in the surrounding waters.
Lead author Emiliano Di Cicco emphasized that the incidence of the disease is higher than previously believed, contrary to earlier assumptions. The study, which involved examining 749 salmon across the farms, found that nearly seven percent showed signs of HSMI. While the role of PRV in causing HSMI was uncertain in the past, recent experiments have established a definitive link between the virus and the disease in salmon.
Di Cicco urged the Department of Fisheries and Oceans (DFO) in British Columbia to reclassify PRV as pathogenic, as current classification labels it as non-pathogenic. He also called for aligning the diagnostic criteria for HSMI with global standards, citing differences in the approach taken by DFO in diagnosing the disease.
The study’s findings are under review by DFO, which emphasized the importance of considering impacts on wild salmon populations beyond detecting viruses in farmed fish. Collaboration with scientific experts led to the establishment of rigorous diagnostic criteria for HSMI, aligning with global standards. The B.C. Salmon Farmers Association has not yet commented on the study’s results.
Collaboration with First Nations communities, including the Mamalilikulla, ʼNa̱mǥis, and Ḵwiḵwa̱sut’inux̱w Ha̱xwa’mis, was integral to the study. Indigenous leaders expressed concerns about the impact of open-net pen salmon farms on salmon populations, highlighting the significance of salmon to their communities and ecosystems.