Cultured Salmon Virus Source Amplifies Transmission of Wild Salmon Disease: BC Study-BC

Victoria — A study released Wednesday showed evidence that a debilitating virus found in salmon in British Columbia was removed from storks in the Pacific Ocean and spread from aquaculture in the Pacific to wild fish.

Researchers used genomic sequencing to track fish ortho-reovirus (PRV). They say it was first introduced from Norway to BC waters about 30 years ago at the start of Norwegian open-net pen farming.

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The study, published in the peer-reviewed journal Science Advances, demonstrates that the virus continuously spreads between farmed and wild Pacific salmon and passes through farms.

PRV, which devastated Norwegian salmon farms, is a disease associated with inflammation of the heart and skeletal muscles of farmed salmon and kidney and liver damage in wild BC salmon.

The study was conducted by experts from the University of British Columbia and the Strategic Salmon Health Initiative, a partnership between the Fisheries and Oceans Canada, BC Genome, and the Pacific Salmon Foundation.

“One of the great things about our research is that we can translate this genomic technology developed to investigate viral pathogens in humans and use it to study very important marine resources. “More,” said the viral Dr. Gideon Mordekai. Ecologist at the University School of Medicine.

In an interview, Mordecai said researchers sequenced 86 complete PRV genomes and concluded that the British Columbia viral lineage came from the North Atlantic.

“This coincides with the timing of importing Atlantic salmon eggs from Europe for salmon farms in the northeastern Pacific,” the study said.

According to Mordekai, as BC aquaculture businesses infect wild salmon with the virus and the infection rate increases, there is increasing evidence that wild salmon are closer to storks.

“The virus was brought into the area,” Mordecai said. “It wasn’t naturally here. It was introduced by people, and it continues to be introduced by high infections in stocked net pens, and it works.”

The BC Salmon Farmers Association said on Wednesday that it would like to review the study before responding to it.

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The Federal Ministry of Fisheries and Oceans could not get immediate comments.

The agency has conducted a lot of research on the effects of PRV on farmed Atlantic salmon and wild salmon, but found that the risk to wild resources is minimal.

Indigenous groups who oppose traditional territorial aquaculture, especially near the Discovery Islands in northern Vancouver Island, say the proximity of the farm to the wild salmon migration route increases the risk of illness.

The federal government announced in December last year that it would phase out about 20 open-net fish farms in the Discovery Islands region over the next 18 months.

Mordekai, who holds a PhD in honeybee pathogen research, decided to study salmon health after attending a conference where government scientists were convinced that PRV did not pose a significant risk to wild salmon. He said it had spurred on.

“I thought,’Well, you should ask that question,'” he said. “The government policy is to minimize the threat that the virus poses to salmon. It is low risk. It does not cause illness and the virus is unique to the area.”

However, the results of genome sequencing provide evidence that salmon farms are functioning as a source of virus for wild salmon in British Columbia, Mordecai said.

This study requires increased monitoring and regulation of infectious diseases that threaten wild salmon.

“Infectious diseases are just one of many threats to marine life, but to fully understand the health of at-risk wild populations, management agencies continue to invest in active monitoring of emerging infectious diseases. We need to, “says the study.

“Our study emphasizes the need for strong regulation of aquaculture that may prevent future loss of wild populations, which is exacerbated by PRV-1 and other emerging infectious diseases. There is a possibility.”