What about PRV? - Mowi - Canada West

What about PRV?

May 16, 2024

Despite the marine piscine reovirus (PRV) not being a health concern to wild or farm-raised salmon in British Columbia, salmon farmers test their salmon regularly to ensure salmon populations transferred to sea from freshwater hatcheries are PRV free.

There are millions of viruses found in a single drop of seawater and most are considered harmless and do not cause disease.

One particular virus – piscine reovirus (PRV) – has been much studied in the last decade. The results of this research can be summarized as this: PRV is a common virus found in many marine fish in the Pacific Northwest, is genetically different when compared to PRV from the Atlantic Ocean, and following exposure studies has not caused disease.

Regulatory approval for farmed fish transfers in BC requires confirmation from a veterinarian or fish health professional that the population of fish is healthy and is free of disease or disease agents that may be harmful to the protection and conservation of wild fish.

As a precautionary approach, salmon raised in British Columbia[1] are screened for the prevalence of PRV in freshwater hatcheries prior to transfer to seawater by licensed veterinarians. Only PRV-negative populations are transferred to seawater farms.

During the past five years, veterinarians at Mowi Canada West has tested 7831 hatchery salmon for PRV. The results have been negative.

To learn more about piscine reovirus research, visit the Department of Fisheries and Oceans Canada website at: Piscine Orthoreovirus (PRV) and Heart and Skeletal Muscle Inflammation (HSMI) (dfo-mpo.gc.ca)


[1] PRV screening is specific to commercial salmon farms only, and does not include hatcheries releasing salmon to supplement sport and/or commercial fishing.

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