PRV

Fish farms do not need to test for B.C. strain of virus

Decision follows an eight-month scientific review on the issue of transfer of live fish from land-based hatcheries to open-ocean net pens

By SeaWestNews

The Department of Fisheries and Oceans (DFO) has determined that there is no need for testing of the B.C. strain of the piscine reovirus (PRV) by fish farms, which some eco-activists had claimed could impact wild stocks.

The decision follows an eight-month review by the DFO on the issue of transfer of live fish from land-based hatcheries to open-ocean net pens.

“After thorough consideration and analysis, DFO has determined, at this time, that testing for PRV-1, a B.C. strain, is not required,” Michelle Rainer, DFO Communications Advisor told SeaWestNews.com in an email.

Anti-fish farm activist Alexandra Morton and the Namgis First Nation had claimed in court that salmon smolts being introduced to ocean fish farms needed to be screened for the PRV virus because it is linked to disease in salmon.

Despite overwhelming scientific evidence to the contrary, they had argued that farmed fish with the PRV virus would infect wild salmon passing by the farms and further threaten declining salmon populations.

And they said DFO failed to properly consult with the Namgis First Nation when developing the transfer policy, thereby infringing on their traditional territorial rights.

The court dismissed their science but agreed that DFO needed to consult with the Namgis over the policy and asked DFO to review its rules around transferring baby salmon to the ocean environment.

PRV has long been present in wild salmon in Pacific Northwest waters and the common scientific consensus is that the BC Strain of PRV does not have the same harmful effect on Atlantic salmon farmed in Pacific waters at it does in Norway.

All experimental exposures of the BC strain of PRV to Pacific and Atlantic salmon in B.C. have failed to induce disease or mortality. This suggests PRV in BC has a low ability to cause disease the DFO has concluded.

Fisheries officials also said in February that data shows PRV poses minimal risks to wild sockeye salmon stocks in B.C.’s Fraser River.

“This decision follows a very thorough process with numerous stakeholders, and is aligned with the extensive science done on PRV over the last decade,” said Shawn Hall, spokesperson for the B.C. Salmon Farmers Association (BCSFA).

“The science tells us there are different strains of PRV around the world, and the one in BC is just naturally here, and benign.”

While DFO has said there is no need for testing for the B.C. strain of the PRV virus, it had modified the live fish transfer policy last June to compel fish farm hatcheries in B.C. to test for two foreign strains of PRV.

This change only applied to fish farm hatcheries and not to DFO’s Salmon Enhancement Program (“SEP”), which also release millions of salmon smolts into the marine environment.

At any given time, there are about 60 to 70 ocean-based fish farms operating in B.C. The industry contributes over $1.5 billion annually into B.C.’s economy and occupies 0.05% of the entire B.C. coast.

There are also 132 SEP licences to grow Pacific salmon for release of which 18 are DFO operated hatcheries, 99 are community hatcheries and 15 are classroom facilities.

DFO said it continues to actively work with experts, and further engagement and advice from with stakeholders and First Nations communities, is expected in the coming months. The ‘Framework on the Transfer of Live Fish’ that when finalised “would apply to all fish movements,” DFO said. (DFO image of Inch Creek hatchery in B.C.)

What is PRV?

Piscine reovirus is a virus that can infect Atlantic and Pacific salmonids. Reoviruses get their name because many are respiratory and enteric orphans. They are called “orphans” because many are viruses without an associated disease.

Is PRV found in British Columbia?

Yes. Research published in 2014 suggests PRV has long been present in wild salmon in Pacific Northwest waters.

What impact does PRV have on salmon?

PRV has been detected in healthy fish in healthy populations, showing that its presence does not mean disease occurs.

But isn’t a virus a disease?

No. Not all germ’s in our environment cause disease. There are millions of viruses in every drop of seawater. Viruses are carried by all living things and most never cause disease. Other reoviruses have been found for decades in wild fish and never associated with disease. In British Columbia, there is no link between the presence of PRV and any disease.

Do salmon farmers test for PRV?

Yes. BC salmon farmers provided samples for the 2014 scientific study that documents PRV in BC and Alaska salmon without associated disease. BC salmon farmers are providing samples for other scientific studies that are underway. This is being done even though Fisheries and Oceans Canada (DFO), and the Canadian Food Inspection Agency (CFIA), do not have PRV on the list of reportable diseases/pathogens.

What about the suggested link between PRV and heart and skeletal muscle inflammation (HSMI)?

That link refers only to Norwegian strains of PRV in farmed Atlantic salmon. HSMI is common in Norway, but HSMI has never been identified in any wild fish in the Pacific Northwest. Viruses with the same name often occur as different types in different parts of the world. Some types might cause disease whereas others do not. PRV is a good example.

Is there any human health risk associated with PRV?

No. Viruses found in salmon (including PRV) are not a risk to human health.