A recent study by the Pacific Salmon Foundation reveals that viral heart disease, specifically 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 in the Broughton Archipelago, situated east of Port McNeill on Vancouver Island.
Researchers highlighted the potential spread of the disease-causing virus, piscine orthoreovirus (PRV), from farmed fish to wild fish in the surrounding waters. Lead author Emiliano Di Cicco emphasized that the prevalence of the disease is significantly higher than previously believed.
In the past, open-net fish farms off the British Columbia coast have been a topic of debate due to concerns about disease transmission to wild salmon. The study’s findings, based on the examination of 749 salmon by three independent pathologists, showed that nearly seven percent exhibited signs of HSMI.
While the role of PRV in causing HSMI was uncertain a decade ago, recent experiments by Norwegian researchers established a connection. The study also noted that Pacific salmon infected with PRV can experience anemia, heart inflammation, liver and kidney damage, and jaundice.
Di Cicco urged the Department of Fisheries and Oceans (DFO) to reclassify PRV as a pathogenic virus and align diagnostic criteria with international standards. He emphasized that the current classification of PRV as non-pathogenic by the DFO may not accurately reflect the virus’s impact.
DFO responded by stating that it will review the study’s findings and incorporate them into future assessments. The department defended its diagnostic criteria for HSMI, which were developed in collaboration with scientific experts to meet global standards.
The study was conducted in collaboration with the Mamalilikulla, ʼNa̱mǥis, and Ḵwiḵwa̱sut’inux̱w Ha̱xwa’mis First Nations. Indigenous leaders highlighted the significance of salmon to their communities and expressed support for scientific evidence confirming long-held concerns about the impact of open-net pen salmon farms on wild salmon populations.