title: Species- and sex-specific responses and recovery of wild, mature pacific salmon to an exhaustive exercise and air exposure stressor.
abstract: Despite the common mechanisms that underlie vertebrate responses to exhaustive exercise stress, the magnitude and the timecourse of recovery can be context-specific. Here, we examine how wild, adult male and female pink (Oncorhynchus gorbuscha) and sockeye (Oncorhynchus nerka) salmon respond to and recover from an exhaustive exercise and air exposure stressor, designed to simulate fisheries capture and handling. We follow gill tissue gene expression for genes active in cellular stress, cell maintenance, and apoptosis as well as plasma osmoregulatory, stress, and reproductive indices. The stressor initiated a major stress response as indicated by increased normalised expression of two stress-responsive genes, Transcription Factor JUNB and cytochrome C (pink salmon only). The stressor resulted in increased plasma ion cortisol, lactate, and depressed estradiol (sockeye salmon only). Gene expression and plasma variables showed a general recovery by 24h post-stressor. Species- and sex-specific patterns were observed in stress response and recovery, with pink salmon mounting a higher magnitude stress response for plasma variables and sockeye salmon exhibiting a higher and more variable gene expression profile. These results highlight species- and sex-specific responses of migrating Pacific salmon to simulated fisheries encounters, which contribute new knowledge towards understanding the consequences of fisheries capture-and-release.
authors.affiliation: Pacific Salmon Ecology and Conservation Laboratory, Centre for Applied Conservation Research and Department of Forest Sciences, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: Michael.r.donaldson@gmail.com.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Donaldson
authors.affiliation: Pacific Salmon Ecology and Conservation Laboratory, Centre for Applied Conservation Research and Department of Forest Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Scott G
authors.initials: SG
authors.lastname: Hinch
authors.affiliation: Pacific Salmon Ecology and Conservation Laboratory, Centre for Applied Conservation Research and Department of Forest Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Ken M
authors.initials: KM
authors.lastname: Jeffries
authors.affiliation: Fisheries and Oceans Canada, Freshwater Ecosystems Section, Cooperative Resource Management Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Patterson
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Ottawa-Carleton Institute of Biology, Carleton University, Ottawa, Ontario, Canada.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Cooke
authors.affiliation: Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Farrell
authors.affiliation: Fisheries and Oceans Canada, Molecular Genetics Section, Pacific Biological Station, Nanaimo, British Columbia, Canada.
authors.forename: Kristina M
authors.initials: KM
authors.lastname: Miller
keywords: Cortisol; Gene expression; Lactate; Pink salmon; Recovery; Sockeye salmon; Stress