Aerial view of a fish farm off the coast of northern Vancouver Island. File photo

Farmed Atlantic salmon in B.C. unaffected by virus, researchers find

Effects of piscine orthoreovirus, or PRV, under increased scrutiny following Federal Court decision

Newly published research says that piscine orthoreovirus (PRV) doesn’t cause severe heart inflammations in farmed Atlantic salmon in B.C., and their respiratory fitness is unaffected by the virus.

The two DFO-funded studies published online by peer-reviewed journals on Wednesday represent the latest developments in the controversy surrounding PRV.

The research suggests that PRV is less of a threat for Atlantic salmon in B.C. than in Norway, where it causes a deadly condition known as heart and skeletal muscle inflammation (HSMI).

“The PRV here, at least in our B.C. salmon, seems to have a lower capacity to cause disease than it does in Norway,” says Mark Polinski, co-author of the two studies and research scientist with Fisheries and Oceans Canada (DFO).

The virus infects Atlantic salmon throughout B.C. and is also found among wild Pacific salmon.

PRV-infected Atlantic salmon with severe heart inflammations turned up during audits on B.C. fish farms in recent years, and researchers wanted to know whether the virus was causing that HSMI-like condition.

One of the studies, this one by scientists from DFO and the B.C. Ministry of Agriculture, was published in the journal Scientific Reports.

READ MORE: Federal fisheries minister calls for precautionary approach to fish farming

Researchers injected Atlantic salmon with the virus, and compared those fish with a virus-free control group. They found the virus didn’t cause severe heart inflammations, although cases of minor inflammations increased, Polinski said.

The other study – written by scientists from DFO and the University of British Columbia and published online by the journal Frontiers in Physiology – found that PRV didn’t affect the cardiovascular and respiratory fitness of farmed Atlantic salmon.

READ MORE: Dissenter says effects of fish farm virus ‘extremely uncertain’

For the experiment, PRV-infected farmed B.C. Atlantic salmon were placed in a testing chamber with an oxygen sensor that measured the efficiency of their respiratory systems compared to virus-free fish.

“We get a new measure every ten minutes, and we do that for five days,” Polinski said.

Various indicators were measured, including recovery from exertion. The experiments showed no significant differences between infected and non-infected fish, Polinski explained.

While these tests involved Atlantic salmon, he added that tests on wild sockeye showed similar results, although those findings haven’t yet been published.

READ MORE: Ottawa won’t appeal Federal Court ruling on farmed salmon virus

Previous research indicates a connection between PRV and anemia in chinook salmon in B.C. The new studies don’t have any bearing on that research, Polinski said.

Asked why the two peer-reviewed articles were released on the same day, he said the Frontiers in Physiology article relied on research in the Scientific Reports article, so the former was held until the latter’s publication. Both studies were funded through grants from DFO.

This follows a series of events that have renewed scrutiny on the virus and its effects.

On Feb. 4, a Federal Court judge struck down a DFO policy allowing fish farm companies to transfer young Atlantic salmon into open-net pens without first screening them for PRV, saying the threshold for harm to wild stock was too high and the precautionary principle wasn’t met.

The court also ruled that Ottawa breached its duty to consult ‘Namgis First Nation about PRV policy.

READ MORE: Alexandra Morton, ‘Namgis First Nation win Federal Court ruling

The decision came in response to lawsuits brought forward by ‘Namgis First Nation and marine biologist Alexandra Morton, a prominent critic of the fish farm industry.

DFO said on Tuesday that it won’t appeal the decision. DFO’s court-ordered review of PRV policy is ongoing.

On the heels of the Feb. 4 ruling, DFO announced that participants in an expert peer-review process had reached a consensus that PRV poses minimal risk to Fraser River sockeye salmon.

That led to controversy when someone involved in that process – John Werring of the David Suzuki Foundation – said that no consensus exists, and that too much uncertainty remains about the pathogen and how it spreads.

PRV is just one bugbear for B.C.’s controversial aquaculture industry.

Opponents of open-net fish farming have long argued that salmon farms discharge harmful materials and contaminate the environment, spread sea lice and diseases among wild fish, and allow Atlantic salmon to escape, posing a variety of risks to wild stocks sacred to First Nations.

Industry critics have called for the removed of fish farms from B.C. waters. Alaska has banned open-net fish farms, while Washington State has begun phasing out its Atlantic salmon facilities, leaving B.C. as the hold-out in the Pacific Northwest.

Industry officials and other proponents say that concerns about fish farms are overblown and that open-net aquaculture provides a relatively green source of food, lowers pressure on wild stocks and provides economic benefits to B.C.

According to a study commissioned by the BC Salmon Farmers Association – which represents the fish farm industry – more than 2,900 people were employed directly in salmon farming by 2016.

Another 3,600 workers were either employed indirectly – that is, by industry suppliers – or due to spending by workers in the industry, according to the study.

@davidgordonkoch
david.koch@campbellrivermirror.com

Like us on Facebook and follow us on Twitter

Just Posted

West Shore residents report finding anti-SOGI 123 flyers in mailboxes

SD62 trustee Ravi Parmar says the flyers are ‘garbage’

Saanich woman runs marathons to make dreams come true

Hempler gutted her way through 122 kms with minimal breaks, to support Help Fill a Dream Foundation

Tsartlip canoe team pulls for international glory in Australia

Geronimo Canoe Club paddles to Victoria to kick-start fundraising

Colwood resident cycles for 12.5 hours to raise money for hospice

Graham Hales will participate in the Cycle of Life tour in July

What’s bugging you? Exterminator talks pests in Victoria

Dealing with pests in the home this summer and beyond

Victoria Weekender: What’s happening this weekend, June 15-16

Car Free YYJ, a barber battle and an Outdoor Discovery Day

Homalco tour gives glimpse into area’s ‘People, Land, Water’

First Nation business mixes cultural components with wildlife excursions

B.C. university to offer mentorship program for former youth in care

Students using the provincial tuition waiver program will soon be able to form a community at KPU

Cyclists competing in one of the toughest bike races on the planet pass through Fernie

Divide riders looking strong as they finish first leg of 4160 km race

You might not know these B.C. records are public

Hired a lawyer to file a civil claim? Those are published online

B.C. bus driver loses case to get job back after texting while driving full bus

An arbitator ruled that Tim Wesman’s phone usage was a “a reckless disregard for public safety”

Revamped B.C. Lions set to battle veteran Winnipeg Blue Bombers

The Lions’ first test of the season will be a big one

No business case for Trans Mountain expansion, says former environment minister

Cabinet is expected to announce its decision on the expansion of the Alberta-to-B.C. pipeline by Tuesday

LETTER: British Columbia’s forest industry crisis being made worse

Andrew Wilkinson warns of regulatory overload by John Horgan’s NDP

Most Read