A recent study by the Pacific Salmon Foundation revealed 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 in the Broughton Archipelago, located east of Port McNeill on Vancouver Island. The study highlighted the potential of the disease-causing virus, piscine orthoreovirus (PRV), to spread from farmed fish to wild populations in the surrounding waters.
Lead author Emiliano Di Cicco emphasized that the occurrence of HSMI is significantly higher than previously believed, contradicting earlier assumptions. The study, which involved examining 749 salmon across the farms, found that nearly seven percent exhibited signs of HSMI. While the role of PRV in causing HSMI was uncertain a decade ago, subsequent experiments have established a clear link between the virus and the disease.
Di Cicco urged the Department of Fisheries and Oceans (DFO) to reconsider the classification of PRV as non-pathogenic and align diagnostic criteria for HSMI with international standards. He noted discrepancies in how HSMI is diagnosed, emphasizing the need to recognize the disease as a chronic, low-level condition rather than requiring specific observable symptoms or mortality spikes for diagnosis.
In response to the study, the DFO committed to reviewing the findings and incorporating them into future assessments. The agency emphasized the importance of rigorous scientific standards in diagnosing HSMI, based on collaboration with leading experts in the field. The B.C. Salmon Farmers Association, while yet to comment on the study, has previously dismissed concerns about PRV as fearmongering, asserting that the virus is benign and widely distributed.
The study was conducted in cooperation with the Mamalilikulla, ʼNa̱mǥis, and Ḵwiḵwa̱sut’inux̱w Ha̱xwa’mis First Nations. Indigenous leaders expressed gratitude for the scientific validation of longstanding concerns about the impact of open-net pen salmon farms on wild salmon populations and the marine ecosystem. Chief Rick Johnson and Chief Councillor Don Svanik emphasized the cultural and ecological significance of salmon to their communities, advocating for the closure of open-net pen farms to protect the vital marine resources.