title: Facing the river gauntlet: understanding the effects of fisheries capture and water temperature on the physiology of coho salmon.
abstract: An improved understanding of bycatch mortality can be achieved by complementing field studies with laboratory experiments that use physiological assessments. This study examined the effects of water temperature and the duration of net entanglement on physiological disturbance and recovery in coho salmon (Oncorhynchus kisutch) after release from a simulated beach seine capture. Heart rate was monitored using implanted electrocardiogram biologgers that allowed fish to swim freely before and after release. A subset of fish was recovered in respirometers to monitor metabolic recovery, and separate groups of fish were sacrificed at different times to assess blood and white muscle biochemistry. One hour after release, fish had elevated lactate in muscle and blood plasma, depleted tissue energy stores, and altered osmoregulatory status, particularly in warmer (15 vs. 10°C) and longer (15 vs. 2 min) capture treatments. A significant effect of entanglement duration on blood and muscle metabolites remained after 4 h. Oxygen consumption rate recovered to baseline within 7-10 h. However, recovery of heart rate to routine levels was longer and more variable, with most fish taking over 10 h, and 33% of fish failing to recover within 24 h. There were no significant treatment effects on either oxygen consumption or heart rate recovery. Our results indicate that fishers should minimize handling time for bycatch and maximize oxygen supply during crowding, especially when temperatures are elevated. Physiological data, such as those presented here, can be used to understand mechanisms that underlie bycatch impairment and mortality, and thus inform best practices that ensure the welfare and conservation of affected species.
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Sciences, Carleton University, Ottawa, Ontario, Canada.
authors.forename: Graham D
authors.initials: GD
authors.lastname: Raby
authors.affiliation: Australian Institute of Marine Science, Townsville, Queensland, Australia.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Clark
authors.affiliation: Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Farrell
authors.affiliation: Fisheries and Oceans Canada, Science Branch, Pacific Region, 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: Pacific Salmon Ecology and Conservation Lab, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Nolan N
authors.initials: NN
authors.lastname: Bett
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Sciences, Carleton University, Ottawa, Ontario, Canada.
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Wilson
authors.affiliation: Institute of Biochemistry, Department of Biology, Carleton University, Ottawa, Ontario, Canada.
authors.forename: William G
authors.initials: WG
authors.lastname: Willmore
authors.affiliation: Department of Natural Resources and Environmental Science, University of Illinois, Urbana, Illinois, United States of America.
authors.forename: Cory D
authors.initials: CD
authors.lastname: Suski
authors.affiliation: Pacific Salmon Ecology and Conservation Lab, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Scott G
authors.initials: SG
authors.lastname: Hinch
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Sciences, Carleton University, Ottawa, Ontario, Canada.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Cooke
mesh_terms: D000818:Animals; D003247:Conservation of Natural Resources; D004562:Electrocardiography; D005260:Female; D005398:Fisheries / Q000941:ethics*; D006339:Heart Rate / Q000502:physiology*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D017684:Oncorhynchus kisutch / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D045483:Rivers; D013312:Stress, Physiological; D013696:Temperature; D013997:Time Factors
chemical_list: D019344:Lactic Acid