Environmental DNA from multiple pathogens is elevated near active Atlanic salmon farms
Date
2020
Authors
Shea, Dylan
Bateman, Andrew
Li, Shaorong
Tabata, Amy
Schulze, Angela D.
Mordecai, Gideon J.
Ogston, Lindsey
Volpe, John P.
Frazer, L. Neil
Connors, Brendan
Journal Title
Journal ISSN
Volume Title
Publisher
Proceedings of the Royal Society B: Biological Sciences
Abstract
The spread of infection from reservoir host populations is a key mechanism for disease emergence and extinction risk and is a management concern for salmon aquaculture and fisheries. Using a quantitative environmental DNA methodology, we assessed pathogen environmental DNA in relation to salmon farms in coastal British Columbia, Canada, by testing for 39 species of salmon pathogens (viral, bacterial, and eukaryotic) in 134 marine environmental samples at 58 salmon farm sites (both active and inactive) over 3 years. Environmental DNA from 22 pathogen species was detected 496 times and species varied in their occurrence among years and sites, likely reflecting variation in environmental factors, other native host species, and strength of association with domesticated Atlantic salmon. Overall, we found that the probability of detecting pathogen environmental DNA (eDNA) was 2.72 (95% CI: 1.48, 5.02) times higher at active versus inactive salmon farm sites and 1.76 (95% CI: 1.28, 2.42) times higher per standard deviation increase in domesticated Atlantic salmon eDNA concentration at a site. If the distribution of pathogen eDNA accurately reflects the distribution of viable pathogens, our findings suggest that salmon farms serve as a potential reservoir for a number of infectious agents; thereby elevating the risk of exposure for wild salmon and other fish species that share the marine environment.
Description
Keywords
aquaculture, infectious disease, disease spillover, wild salmon, microparasites
Citation
Shea, D., Bateman, A., Li, S., Tabata, A., Schulze, A., Mordecai, G., Ogston, L., Volpe, J. P., Frazer, L. N., Connors, B., Miller, K. M., Short, S., & Krkošek, M. (2020). Environmental DNA from multiple pathogens is elevated near active Atlantic salmon farms. Proceedings of the Royal Society B: Biological Sciences, 287(1937), 20202010. https://doi.org/10.1098/rspb.2020.2010