loading page

Host-pathogen-environment interactions determine survival outcomes of adult sockeye salmon (Oncorhynchus nerka) released from fisheries
  • +7
  • Amy Teffer,
  • Scott Hinch,
  • Kristina Miller,
  • David Patterson,
  • Arthur Bass,
  • Steven Cooke,
  • Anthony Farrell,
  • Terry Beacham,
  • Jacqueline Chapman,
  • Francis Juanes
Amy Teffer
University of Victoria Department of Biology
Author Profile
Scott Hinch
The University of British Columbia Faculty of Forestry
Author Profile
Kristina Miller
Fisheries and Oceans Canada
Author Profile
David Patterson
Fisheries and Oceans Canada
Author Profile
Arthur Bass
Author Profile
Steven Cooke
Carleton University
Author Profile
Anthony Farrell
The University of British Columbia Department of Zoology
Author Profile
Terry Beacham
Pacific Biological Station
Author Profile
Jacqueline Chapman
Carleton University Department of Biology
Author Profile
Francis Juanes
University of Victoria Department of Biology
Author Profile

Abstract

Incorporating host-pathogen(s)-environment axes into management and conservation planning is critical to preserving species in a warming climate. However, the role pathogens play in host stress resilience remains largely unexplored in wild animal populations. We experimentally characterized how independent and cumulative stressors (fisheries handling, high water temperature) and natural infections affected the health and longevity of released wild adult sockeye salmon (Oncorhynchus nerka) in British Columbia, Canada. Returning adults were collected before and after entering the Fraser River, yielding marine- and river-collected groups, respectively. Fish were exposed to a mild (seine) or severe (gill net) fishery treatment at collection, and then held in circulating freshwater tanks for up to four weeks at historical (14°C) or projected migration temperatures (18°C). Using weekly nonlethal gill biopsies and high-throughput qPCR, we quantified loads of up to 46 pathogens with host stress and immune gene expression. Marine-captured fish had less severe infections than river-captured fish, a short migration distance (100 km, 5-7 d) that produced profound infection differences. At 14°C, river-collected fish survived 1-2 weeks less than marine-collected fish. All fish held at 18°C died within 4 weeks unless they experienced minimal handling. Gene expression correlated with infections in river-collected fish, while marine-collected fish were more stressor-responsive. Cumulative stressors were detrimental regardless of infections or collection location, likely due to extreme physiological disturbance. Because river-derived infections correlated with single stressor responses, river entry likely decreases stressor resilience of adult salmon by altering both physiological status and pathogen burdens, which redirect host responses toward disease resistance.

Peer review status:UNDER REVIEW

04 May 2021Submitted to Molecular Ecology
05 May 2021Assigned to Editor
05 May 2021Submission Checks Completed
13 May 2021Reviewer(s) Assigned