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 located in the Broughton Archipelago near Vancouver Island. The study highlights the potential spread of the disease-causing virus, piscine orthoreovirus (PRV), 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. Previous research conducted in 2017 had identified HSMI in only one of four farms studied, suggesting a more widespread occurrence. The study found that nearly seven percent of the examined salmon across the farms displayed signs of HSMI.
While there had been uncertainty in the past about the role of PRV in causing HSMI, recent experiments by Norwegian researchers established a definitive link in 2017, according to Di Cicco. The research indicates that Pacific salmon can suffer from various health issues when infected by PRV, including anemia, inflamed hearts, damaged livers and kidneys, and jaundice.
Di Cicco is urging the Department of Fisheries and Oceans (DFO) in British Columbia to reclassify PRV as a pathogenic virus and to align the diagnostic criteria for HSMI with global standards. He argues that the current diagnostic standards used by DFO may not effectively detect the disease, as HSMI is considered a chronic, low-level condition globally.
In response to the study, DFO stated that it will review the findings for consideration in future work, emphasizing the importance of scientifically rigorous diagnostic criteria for HSMI. The B.C. Salmon Farmers Association has not yet commented on the study’s findings.
The study was conducted in collaboration with the Mamalilikulla, ʼNa̱mǥis, and Ḵwiḵwa̱sut’inux̱w Ha̱xwa’mis First Nations. Indigenous leaders expressed their concerns about the impact of open-net pen salmon farms on the environment and stressed the importance of supporting salmon populations, which have historically been vital to the coastal Indigenous communities in British Columbia.
