A recent study by the Pacific Salmon Foundation reveals that viral heart disease is more prevalent in open-net salmon farms in British Columbia than previously acknowledged. The research, published in the Aquaculture journal, identified heart and skeletal muscle inflammation (HSMI) in five out of seven open-net pen salmon farms located in the Broughton Archipelago, situated east of Port McNeill on Vancouver Island. The study also highlights the potential transmission of the disease-causing virus, piscine orthoreovirus (PRV), from farmed fish to wild fish in the surrounding waters.
Lead author Emiliano Di Cicco stated that the incidence of the disease is significantly higher than previously believed. Previous research in 2017 found HSMI in one out of four farms, but it was evident that this was not an isolated case. The study revealed that nearly seven percent of the 749 examined salmon across the farms exhibited signs of HSMI.
While the role of PRV in causing HSMI was uncertain a decade ago, recent experiments by Norwegian researchers in 2017 established a clear link. Di Cicco emphasized that infected Pacific salmon can experience various health issues such as anemia, inflamed hearts, damaged organs, and jaundice due to PRV.
Di Cicco urged the Department of Fisheries and Oceans (DFO) in British Columbia to reclassify PRV as a pathogenic virus, as it is currently considered non-pathogenic. He advocated for aligning the diagnostic criteria for HSMI with international standards, criticizing the current approach used by DFO as inadequate for detecting the chronic, low-level condition of the disease.
In response to the study, DFO stated that it will review the findings and incorporate them into future assessments. The department emphasized that the detection of a virus in farmed fish does not automatically imply negative impacts on wild salmon populations. DFO defended its diagnostic criteria for HSMI, developed in collaboration with scientific experts, ensuring alignment with global standards for scientific rigor.
The B.C. Salmon Farmers Association did not provide immediate comments on the study. The industry group has previously dismissed concerns about PRV as “fearmongering,” asserting that the virus is common, relatively harmless, and widely distributed in marine environments.
Collaborating with the Mamalilikulla, ʼNa̱mǥis, and Ḵwiḵwa̱sut’inux̱w Ha̱xwa’mis First Nations, the study underscores the importance of supporting salmon populations for coastal Indigenous communities in British Columbia. First Nations leaders emphasized the intrinsic connection between salmon and their culture, expressing gratitude for scientific validation of their concerns and advocating for the closure of open-net pen salmon farms.