Results show virus could pose risk to wild salmon
“The results of this study are significant because they show—for the first time—strong evidence that the same strain of PRV (Piscine orthoreovirus) that causes heart and skeletal muscle inflammation disease in Atlantic salmon is likely to cause disease in at least one species of Pacific salmon,” the Chinook, wrote Dr. Brian Riddell, president of the PSF, in the report. “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.”
PSF, which worked on the report as part of a joint initiative with Fisheries and Oceans Canada (DFO), took the unusual step last week of releasing the study ahead of its upcoming publication in the scientific journal, FACETS. Stan Proboszcz, science advisor for the Watershed Watch Salmon Society, called the results “shocking.”
“This is some pretty definitive research that shows that a virus that is very common in salmon farms can be found in about 75 per cent of farmed fish in B.C.,” he added.
Heart and skeletal muscle inflammation disease (HSMI) has been shown to be a “significant cause of mortality and economic loss” in the salmon-farming industry, and has also been reported in Norway, the U.K., Scotland and Chile. The PRV-1 strain that causes HSMI had, until now, not been “directly affiliated” with disease in Pacific salmon, according to the PSF. The findings suggest that the virus affects Chinook differently than their Atlantic counterparts, causing red blood cells to rupture, eventually leading to jaundice and anemia.
Given the prevalence of PRV in net pen salmon, estimated to affect between 65 and 75 per cent of farmed salmon, the debate among marine biologists centres around just how big a risk the virus poses to B.C.’s migratory salmon—and exactly how it got here.
“PRV-1 is the only (strain) in B.C.,” Proboszcz noted. “The kicker is that this is the European strain, so that suggests that the industry may have transported it here. We already know that the industry has transported other viruses to South America, so that would be quite shocking if that’s what happened here.”
Pam Goldsmith-Jones, MP for the Sea to Sky, is hopeful the findings will lead Ottawa to reconsider its position on open-net farming.
“I think we will be able to now take action and to transition the industry to closed containment (farming),” she said.
For his part, Proboszcz said Watershed Watch doesn’t oppose the aquaculture industry “if it’s done right,” but he would personally like to see a shift away from open-net fish farming to closed-containment or land-based farming.
The PRV virus sits at the crux of a federal court case that found the DFO had illegally allowed aquaculture companies to transfer young salmon infected with PRV and other diseases from hatcheries to open net farms—another example of the federal agency’s seemingly conflicting mandate of protecting wild salmon while actively promoting fish farming, according to DFO critics.
In 2015, the courts ordered the DFO to begin testing hatchery fish and barred them from being transferred to the ocean if infected with PRV—a ruling the federal agency has flouted so far, prompting another lawsuit that is still being heard.
Last month, a report by Julie Gelfand, Canada’s Commissioner of the Environment and Sustainable Development, found that the DFO did not “adequately manage the risks associated with salmon aquaculture,” and has not made “sufficient progress” to control the spread of infectious diseases and parasites in B.C.’s wild fish.
Even amidst the criticisms, Sea to Sky Fisheries Roundtable member Dave Brown believes the PRV report might be a sign that times are changing at the DFO.
“Having this published and out in the open … and now having the government allowing scientists to speak, I think it’s huge,” he said, referring to “the muzzling” of DFO scientists during the Stephen Harper years.
Original article: http://bit.ly/2rShbs7