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, located east of Port McNeill on Vancouver Island.
The study highlights the presence of the disease-causing virus, piscine orthoreovirus (PRV), which has the potential to spread to wild fish in the surrounding waters. Lead author Emiliano Di Cicco emphasized that the incidence of the disease is significantly higher than previously believed, challenging previous assumptions.
The study examined 749 salmon across the farms, with nearly seven percent showing signs of HSMI according to three independent pathologists. While the role of PRV in causing HSMI was once uncertain, recent experiments by Norwegian researchers in 2017 established the link, indicating the potential detrimental effects on Pacific salmon.
Di Cicco advocates for the reclassification of PRV as a pathogenic virus by the Department of Fisheries and Oceans (DFO) in British Columbia. He urges alignment of diagnostic criteria for the disease with global standards, emphasizing the chronic nature of HSMI as a low-level condition.
The DFO has stated its intent to review the study findings for future considerations. The department asserts that diagnosing a virus in farmed fish does not inherently imply adverse impacts on wild salmon populations, citing collaborative efforts with scientific experts to establish rigorous diagnostic criteria for HSMI.
The collaboration between the Pacific Salmon Foundation and local First Nations communities underscores the significance of salmon to Indigenous coastal populations. Leaders from the First Nations expressed support for the study’s findings, emphasizing the critical role of salmon in their cultural heritage and ecosystem balance.