Most of the escaped farmed salmon entering a river during a 5‐year period were infected with one or more viruses

Abstract Disease interactions between farmed and wild populations have been poorly documented for most aquaculture species, in part due to the complexities to study this. Here, we tested 567 farmed Atlantic salmon escapees, captured in a Norwegian river during 2014–2018, for five viral infections th...

Full description

Bibliographic Details
Published in:Journal of Fish Diseases
Main Authors: Madhun, Abdullah S., Karlsbakk, Egil, Skaala, Øystein, Solberg, Monica F., Wennevik, Vidar, Harvey, Alison, Meier, Sonnich, Fjeldheim, Per T., Andersen, Kaja Christine, Glover, Kevin A.
Other Authors: Miljødirektoratet
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2024
Subjects:
Online Access:http://dx.doi.org/10.1111/jfd.13950
https://onlinelibrary.wiley.com/doi/pdf/10.1111/jfd.13950
Description
Summary:Abstract Disease interactions between farmed and wild populations have been poorly documented for most aquaculture species, in part due to the complexities to study this. Here, we tested 567 farmed Atlantic salmon escapees, captured in a Norwegian river during 2014–2018, for five viral infections that are prevalent in global salmonid aquaculture. Over 90% of the escapees were infected with one or more viruses. Overall prevalences were: 75.7% for piscine orthoreovirus (PRV‐1), 43.6% for salmonid alphavirus (SAV), 31.2% for piscine myocarditis virus (PMCV), 1.2% for infectious pancreatic necrosis virus (IPNV) and 0.4% for salmon anaemia virus (ISAV). A significantly higher prevalence of PMCV infection was observed in immature compared to mature individuals. The prevalence of both SAV and PMCV infections was higher in fish determined by fatty acid profiling to be ‘recent’ as opposed to ‘early’ escapees that had been in the wild for a longer period of time. This is the first study to establish a time‐series of viral infection status of escapees entering a river with a native salmon population. Our results demonstrate that farmed escapees represent a continuous source of infectious agents which could potentially be transmitted to wild fish populations.