The study, titled Piscine reovirus in wild and farmed salmonids in British Columbia, Canada:1974-2013 (G. Marty, D. Morrison, J. Bidulka, T. Joseph, A. Siah, 2014), reports on the results of thousands of fresh and historical salmon tissue samples tested to understand more about the presence of piscine reovirus (PRV) in the Pacific Northwest.
The study concludes that PRV is present in many species of wild-sourced and farm-raised salmon. The earliest positive result, identified in a wild-source steelhead trout from British Columbia, was from 1977 and predates the start of salmon farming in British Columbia.
Importantly, the study confirms that the fish that carry PRV did not show any signs of disease, such as heart and skeletal muscle inflammation.
The 2013 research follows a legal challenge launched by salmon farming critic Alexandra Morton. It was alleged by Ms Morton that PRV was very recently introduced to B.C. by the salmon farming industry, and that the virus was the causative agent of heart and skeletal muscle inflammation (HSMI). Despite extensive testing, HSMI has not been found in any fish (farm-raised or wild-caught) in the Pacific Northwest.
"We are happy to see that in B.C. piscine reovirus appears to be a harmless virus that's commonly found in fish in the Pacific Northwest," says Clare Backman, a biologist at Marine Harvest Canada.
"While the serious allegations by Ms Morton were without factual basis, we felt it was important to acquire greater knowledge about piscine reovirus."
The collaborative study includes researchers from the Ministry of Agriculture, Centre for Aquatic Health Sciences, and Marine Harvest Canada.
