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 potential spread of the disease-causing virus, piscine orthoreovirus (PRV), from farmed fish into the surrounding waters, posing a risk to wild fish populations.
Lead author Emiliano Di Cicco emphasized that the incidence of HSMI is significantly higher than previously believed, challenging earlier assumptions. This finding builds upon a 2017 study by Di Cicco and colleagues, which initially identified the disease in one out of four farms investigated, indicating a more widespread issue.
The Department of Fisheries and Oceans (DFO) in British Columbia currently classifies PRV as non-pathogenic, despite research linking it to HSMI. Di Cicco urges the government to reclassify the virus as pathogenic and align diagnostic criteria with international standards. He argues that the current diagnostic approach employed by DFO may overlook cases of the disease, as HSMI is considered a chronic, low-level condition globally.
The study, which involved examining 749 salmon across various farms, revealed that nearly seven percent exhibited signs of HSMI. While DFO acknowledges the study’s findings, it emphasizes the need for comprehensive scientific evaluation to determine the impact on wild salmon populations.
Collaborating with First Nations communities, including the Mamalilikulla, ʼNa̱mǥis, and Ḵwiḵwa̱sut’inux̱w Ha̱xwa’mis, the study underscores the importance of protecting salmon populations that have historically supported Indigenous communities in the region. Leaders from these communities, such as Rick Johnson and Don Svanik, emphasize the cultural and ecological significance of salmon and advocate for stronger conservation efforts.
The study’s revelations highlight the ongoing debate surrounding open-net fish farms in British Columbia, emphasizing the need for further research, collaboration, and policy adjustments to safeguard the health of wild salmon populations and the ecosystem.