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 the presence of HSMI in five out of seven open-net pen salmon farms located in the Broughton Archipelago near Vancouver Island.
The study highlights the potential risk posed by the disease-causing virus, piscine orthoreovirus (PRV), which can spread from farmed salmon into the surrounding waters, potentially infecting wild fish populations. Lead author Emiliano Di Cicco emphasized that the occurrence of the disease is significantly higher than previously believed, challenging earlier assumptions.
The debate surrounding open-net fish farms off the B.C. coast has long centered on the transfer of diseases from farmed fish to wild salmon. Previous research conducted by Di Cicco and colleagues in 2017 found HSMI in one out of four farms studied at that time, indicating a broader issue than initially recognized.
The study observed signs of HSMI in nearly seven percent of the 749 salmon examined across the farms, underscoring the impact of PRV on Pacific salmon health. Despite past uncertainties about the role of PRV in causing HSMI, recent experiments by Norwegian researchers have established a definitive link, prompting calls for reclassification of PRV as a pathogenic virus.
Di Cicco urges the Department of Fisheries and Oceans (DFO) in B.C. to align its diagnostic criteria for HSMI with global standards and recognize the chronic nature of the disease. The DFO has committed to reviewing the study findings, emphasizing the need for scientific rigor in assessing the impact of diseases on wild salmon populations.
The collaboration with First Nations communities in the study underscores the importance of supporting salmon conservation efforts. Indigenous leaders stress the cultural and ecological significance of salmon, advocating for the closure of open-net pen salmon farms to protect the ecosystem and traditional practices.
Industry groups argue that salmon farming in B.C. sustains high-paying jobs and plays a crucial role in Canada’s salmon production. However, the study’s findings raise concerns about the potential impact of viral diseases on both farmed and wild salmon populations, prompting calls for enhanced monitoring and regulatory measures.