Fisheries Research 108 (2011) 133–141 Contents lists available at ScienceDirect Fisheries Research journal homepage: www.elsevier.com/locate/fishres The consequences of angling, beach seining, and confinement on the physiology, post-release behaviour and survival of adult sockeye salmon during upriver migration Michael R. Donaldson a,∗ , Scott G. Hinch a , David A. Patterson b , Jayme Hills b , Jim O. Thomas c , Steven J. Cooke d , Graham D. Raby d , Lisa A. Thompson b , David Robichaud e , Karl K. English e , Anthony P. Farrell f a Pacific Salmon Ecology and Conservation Laboratory, Centre for Applied Conservation Research and Department of Forest Sciences, University of British Columbia, Vancouver, British Columbia, Canada b 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 c J.O. Thomas and Associates, Vancouver, British Columbia, Canada d Fish Ecology and Conservation Physiology Laboratory, Ottawa-Carleton Institute of Biology and Institute of Environmental Science, Carleton University, Ottawa, Ontario, Canada e LGL Limited, Sydney, British Columbia, Canada f Department of Zoology, and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada article info Article history: Received 27 August 2010 Received in revised form 4 December 2010 Accepted 6 December 2010 Keywords: Capture Migration Pacific salmon Stress Salmonid Temperature abstract Few studies have examined the effects of fisheries capture on wild fish, particularly in the context of evaluating the sustainability of capture and release methods for Pacific salmon (Oncorhynchus spp.) during upriver migration. This study examined the physiological condition, post-release behaviour and survival of adult migrating sockeye salmon (O. nerka) in the Fraser River, British Columbia, Canada. Fish were captured by either beach seine or angling and released immediately, or were captured by angling and released following a 24-h recovery period in a net pen. Before release, all salmon were biopsied or tagged with radio telemetry transmitters. Capture by either angling or beach seine with immediate release resulted in >95% survival 24 h after release, whereas net pen recovery after angling resulted in ∼80% survival. This differential in survival was similarly expressed in the percentage of released fish reaching natal sub-watersheds, with 52.2% and 36.3% of fish immediately released by beach seine and angling reaching natal sub-watersheds, respectively, compared with 2.9% of fish released after angling and net pen recovery. Blood plasma stress indices reflected the 10-fold difference in survival, with a ∼4-fold higher plasma cortisol, a ∼2-fold higher plasma glucose and significantly depressed plasma ions and osmolality relative to fish sampled upon capture. Plasma lactate did not differ among groups. Collectively, these results suggest that a 24 h recovery in net pen following angling failed to promote post-release survival experienced with immediate release after angling or beach seining. © 2010 Elsevier B.V. All rights reserved. 1. Introduction The anadromous reproductive migrations of Pacific salmon are some of the most challenging life history stages of any organ- ism (Dingle, 1996; Dingle and Drake, 2007). The transition into freshwater requires a series of changes in osmoregulatory and ∗ Corresponding author at: Centre for Applied Conservation Research, Forest Sci- ences Centre, 2424 Main Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4. Tel.: +1 604 822 1969. E-mail addresses: mdonald@interchange.ubc.ca, michael.r.donaldson@gmail.com (M.R. Donaldson). ionoregulatory systems (Shrimpton et al., 2005) and physiologi- cal and morphological changes associated with the development of secondary sexual characteristics (Brett, 1995; Hendry and Berg, 1999). Environmental conditions in freshwater, particularly high river temperatures, can result in a number of physiological costs, including elevated indices of stress (Macdonald, 2000) and stock- specific collapse of aerobic scope (Farrell et al., 2008). Fisheries interactions are overlaid on these inherent migration-related chal- lenges. As Pacific salmon enter freshwater, they are targeted by recreational (e.g., hook and line), commercial (e.g., gill net) and First Nations (e.g., gill net, beach seine) fisheries. In the Fraser River, British Columbia, Canada, the sockeye salmon recreational fishery has traditionally been regulated as a 0165-7836/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.fishres.2010.12.011