New research has shown that a virus known to cause disease in farmed Atlantic and Pacific salmon may cause a related disease in wild B.C. chinook salmon.
The results of a study by the Pacific Salmon Foundation show strong evidence that wild chinook is at risk of being exposed to high levels of picscine orthoreovirus (PRV), a virus causing heart and skeletal muscle inflammation disease (HSMI) in farmed Atlantic salmon.
“These findings add to the existing concerns about the potential impacts of open net salmon farming on wild Pacific salmon off the coast of B.C.,” said Dr. Brian Riddell, president and CEO of the Pacific Salmon Foundation, in a press release.
Decline in wild salmon stocks on the West Coast of Canada has lead to commercial and recreational fishing closures. On May 8, the Department of Fisheries and Oceans closed fishing to recreational anglers on the Skeena and Nass rivers on the North Coast. More restrictions or possible closures are expected to be announced in June for the commercial industry, and for First Nations food, ceremonial and social fishing.
The Pacific Salmon Foundation estimates a high prevalence of PRV — up to 75 per cent — in net pen salmon. Some strains of the virus have been associated with jaundice-related diseases in Pacific salmon, but for the first time new research shows the PRV strain that causes HSMI has been found in B.C. wild salmon. The study found this particular strain of PRV was related to the development of jaundice and anemia in chinook salmon.
“This research confirms our worries that migrating juvenile wild Pacific salmon are vulnerable to diseases transmitted from open net-pen fish farms. Disease transmission could be the additional stressor that tips the scales for some wild salmon populations,” said Jay Ritchlin, David Suzuki Foundation director-general for B.C. and Western Canada.