A molecular assessment of infectious agents carried by Atlantic salmon at sea and in three eastern Canadian rivers, including aquaculture escapees and North American and European origin wild stocks

Infectious agents are key components of animal ecology and drivers of host population dynamics. Knowledge of their diversity and transmission in the wild is necessary for the management and conservation of host species like Atlantic salmon ( Salmo salar). Although pathogen exchange can occur through...

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Bibliographic Details
Published in:	Facets (Ottawa) Vol. 5; no. 1; pp. 234 - 263
Main Authors:	Teffer, Amy K., Carr, Jonathan, Tabata, Amy, Schulze, Angela, Bradbury, Ian, Deschamps, Denise, Gillis, Carole-Anne, Brunsdon, Eric B., Mordecai, Gideon, Miller, Kristina M.
Format:	Journal Article
Language:	English
Published:	Canadian Science Publishing 23-04-2020
Subjects:	atlantic salmon bacteria disease ecology infectious agent qpcr virus
Online Access:	Get full text
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Summary:	Infectious agents are key components of animal ecology and drivers of host population dynamics. Knowledge of their diversity and transmission in the wild is necessary for the management and conservation of host species like Atlantic salmon ( Salmo salar). Although pathogen exchange can occur throughout the salmon life cycle, evidence is lacking to support transmission during population mixing at sea or between farmed and wild salmon due to aquaculture exposure. We tested these hypotheses using a molecular approach that identified infectious agents and transmission potential among sub-adult Atlantic salmon at marine feeding areas and adults in three eastern Canadian rivers with varying aquaculture influence. We used high-throughput qPCR to quantify infection profiles and next generation sequencing to measure genomic variation among viral isolates. We identified 14 agents, including five not yet described as occurring in Eastern Canada. Phylogenetic analysis of piscine orthoreovirus showed homology between isolates from European and North American origin fish at sea, supporting the hypothesis of intercontinental transmission. We found no evidence to support aquaculture influence on wild adult infections, which varied relative to environmental conditions, life stage, and host origin. Our findings identify research opportunities regarding pathogen transmission and biological significance for wild Atlantic salmon populations.
ISSN:	2371-1671 2371-1671
DOI:	10.1139/facets-2019-0048