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ARS Home » Northeast Area » Orono, Maine » National Cold Water Marine Aquaculture Center » Research » Publications at this Location » Publication #399223
Research Project: Genetic Improvement of North American Atlantic Salmon and the Eastern Oyster for Aquaculture Production

Location: National Cold Water Marine Aquaculture Center

Title: British Columbia freshwater salmon hatcheries demonstrate minimal contribution to piscine orthoreovirus (PRV) regional occurrence with no evidence for non-endemic

Author
item Polinski, Mark
item HADDAD, COLLEEN - Department Of Fisheries And Oceans Canada
item SIAH, AHMED - Bc Center For Aquatic Health Sciences
item FULLER, CHAD - Okanagan Nation Alliance
item HIGGINS, MARK - Department Of Fisheries And Oceans Canada
item PARSONS, JAY - Fisheries & Oceans

Submitted to: Agriculture Canada Policy Branch
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2023
Publication Date: 5/22/2023
Citation: Polinski, M.P., Haddad, C.A., Siah, A., Fuller, C., Higgins, M. 2023. British Columbia freshwater salmon hatcheries demonstrate minimal contribution to piscine orthoreovirus (PRV) regional occurrence with no evidence for non-endemic. Aquaculture Research. https://doi.org/10.1139/facets-2022-0218.
DOI: https://doi.org/10.1139/facets-2022-0218

Interpretive Summary: Piscine orthoreovirus (PRV) is a common virus of salmon where variations in virulence have been observed for which host, virus, and environmental factors all likely play a role. Considerable scientific and public attention have been placed on understanding risks associated with PRV. Current gaps in knowledge have been the source of much speculation and controversy. In this study, we identify that PRV is rarely found in either commercial production or public enhancement hatcheries that grow salmon in western Canada, and that no presumptive non-native strains of PRV have been introduced into these systems. This is the first comprehensive evaluation of PRV prevalence in hatchery reared salmon in the Americas and provides critical insight into identifying regional reservoirs and likely transmission pathways for this virus.

Technical Abstract: Piscine orthoreovirus genotype 1 (PRV-1) is a common virus to farmed and wild salmon in the northeastern Pacific Ocean. Regional occurrence in freshwater is far less clear. From 2019 to 2021, tissues of 5,619 juvenile anadromous salmon (primarily Atlantic, Chinook and coho) sampled from 12 commercial and 27 enhancement British Columbia hatcheries during 83 sampling events were screened for PRV-1 prior to seawater entry. More than 2,200 (~40%) were also screened using a Pan-PRV assay targeting all known PRV genotypes. PRV-1 was detected in 4 coho salmon at 2 freshwater enhancement facilities and in 1 Chinook salmon at a commercial facility. Whole genome sequencing identified detections to be of the PRV-1 sub-genotype endemic to the northeastern Pacific. PRV-1 was not detected (5,611 individuals; 99.9%) or test results were inconclusive (3 individuals; 0.05%) for all remaining samples screened for PRV-1. PRV-2 and PRV-3 were not detected using the Pan-PRV assay. It is concluded that commercial and enhancement freshwater hatcheries of British Columbia contribute minimally to the prevalence and persistence of PRV-1 in anadromous salmon of the northeastern Pacific, and these hatcheries appear not to have contracted or participated in the distribution of non-endemic forms of PRV in recent years.