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

Strathcona Gardens shuffles ice time to accommodate BCHL game ousted by ammonia leak at Port Alberni rink

Campbell River’s Rod Brind’Amour Arena will host a British Columbia Hockey League… Continue reading

Local salon raises $5,300 for Ovarian Cancer Canada

Affected team member catalyst for fundraiser

BCHL’s Alberni Valley Bulldogs set to play in Campbell River after ice rink closure

City of Port Alberni waiting on Technical Safety BC approval to re-open multiplex

Campbell River RCMP investigating after two stabbing incidents Tuesday night

Police are treating each case separately and have one person in custody

Campbell River celebrates National Child Day on Friday

Annual event at Community Centre recognizes the rights of children and lets them let loose for a day

VIDEO: Canadian allergists’ group wants Benadryl behind the counter due to side effects

Some doctors say the medication is over-used because of its easy availability

Yelling at your dog might hurt its long-term mental health: study

Researchers find dogs trained using negative reinforcement are more ‘pessimistic’

Vancouver Island soap company releases Lucky Lager beer soap

Beer-infused olive oil soap comes out just in time for holiday shopping

Jagmeet Singh says he’ll vote against throne speech if NDP requests not met

Singh is to meet with Prime Minister Justin Trudeau on Thursday

Community uses loophole to paint 16 rainbow crosswalks after B.C. council says no

So far 11 rainbows are painted and five planned, all since council denied the first proposal in September

Workers’ camp at LNG facility in Kitimat takes shape

Extensive worker camp now being assembled

Former B.C. youth pastor guilty on one of five sexual assault allegations

Judge cites reasonable doubt in finding Cloverdale couple not guilty of majority of charges

238 and counting: Vancouver gelato shop sets Guinness World record for most flavours

Vince Misceo has come up with 588 different flavours over the decades

Killer who fled to Taiwan day after shooting B.C. man over $80 sentenced 13 years later

The sentence comes 13 years after Shaoxin Zhang, 19, was killed in a Burnaby parking lot

Most Read