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.
Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Sciences, Carleton University, Ottawa, Ontario, Canada;Australian Institute of Marine Science, Townsville, Queensland, Australia;Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada;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;Pacific Salmon Ecology and Conservation Lab, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada;Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Sciences, Carleton University, Ottawa, Ontario, Canada;Institute of Biochemistry, Department of Biology, Carleton University, Ottawa, Ontario, Canada;Department of Natural Resources and Environmental Science, University of Illinois, Urbana, Illinois, United States of America;Pacific Salmon Ecology and Conservation Lab, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada;Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Sciences, Carleton University, Ottawa, Ontario, Canada
Recommended Citation:
Graham D. Raby,Timothy D. Clark,Anthony P. Farrell,et al. Facing the River Gauntlet: Understanding the Effects of Fisheries Capture and Water Temperature on the Physiology of Coho Salmon[J]. PLOS ONE,2015-01-01,10(4)