Impacts of dissolved oxygen on the behavior and physiology of bonefish: Implications for live-release angling tournaments Aaron D. Shultz a,b, ⁎, Karen J. Murchie b,c , Christine Griffith a , Steven J. Cooke b,c , Andy J. Danylchuk b,d , Tony L. Goldberg b,e , Cory D. Suski a,b a Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 S. Goodwin Ave., MC 047, Urbana, IL 61801, United States b Flats Ecology and Conservation Program, Cape Eleuthera Institute, Eleuthera, The Bahamas c Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Canada, ON K1S 5B6 d Department of Environmental Conservation, University of Massachusetts, 160 Holdsworth Way, Amherst, MA 01003–9285, United States e Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 1656 Linden Drive, Madison, WI 53706, United States abstract article info Article history: Received 1 December 2010 Accepted 17 March 2011 Keywords: Behavior Blood chemistry Bonefish Oxygen Metabolic rate Saltwater tournaments for bonefish (Albula spp.) often retain fish in livewells for up to 8 h to allow fish to recover from the physiological disturbances associated with angling. During livewell confinement, oxygen concentrations may fall due to elevated biomass of fish, coupled with low exchange of water. Some anglers use oxygen infusion systems, potentially exposing fish to water that is supersaturated with oxygen. Currently, the effects of differing levels of oxygen on bonefish recovery are unknown. Because physiological disturbances related to angling can influence the probability of post-release predation in bonefish, livewell conditions that maximize recovery rates without imparting additional negative consequences need to be defined. The objective of this study was to assess the behavior, physiological response (i.e., blood chemistry), and metabolic rates of bonefish recovered in hypoxic, normoxic, or hyperoxic seawater after exercise (i.e., a simulated angling event). Behavioral experiments consisted of placing bonefish in one of three dissolved oxygen concentrations and monitoring gill ventilation rates. For blood sampling and metabolic rates, bonefish were exercised and then recovered in different dissolved oxygen concentrations, replicating an angling event coupled with different livewell holding conditions. Both hypoxic and hyperoxic conditions caused bonefish to experience behavioral and physiological disturbances, compared to fish in the normoxic treatment. In addition, bonefish used more energy when recovered in hyperoxic seawater and fish in the hypoxic treatment were unable remove lactate compared to fish in the normoxic treatment. These results indicate that anglers and tournament organizers should recover angled bonefish in normoxic seawater. To achieve these conditions, dissolved oxygen concentrations should be monitored with a commercially available meter and maintained between 4–8 mg/L by circulating fresh seawater into livewells. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Live-release angling tournaments for saltwater fishes are a popular leisure activity that can have economic benefits for local communities (Schramm et al., 1991; Oh et al., 2006). Indeed, catch-and-release angling and recreational tournaments for bonefish (Albula spp.) are worth a significant amount in Florida (Humston, 2001) and The Bahamas (Fedler, 2010). By releasing fish alive at the conclusion of these events, anglers, managers and organizers hope that fish will survive to reproduce and/or be caught again (Cooke and Schramm, 2007). Nonetheless, angling can result in fish mortality due to a number of different factors that include stress and/or hooking damage (Arlinghaus et al., 2007), and post-release predation of bonefish can occur due to angling-induced disturbances (Danylchuk et al., 2007a,b). Facilitating recovery from angling so that bonefish return to the water with reduced physiological disturbances will maximize survival after release (Cooke and Philipp, 2004, 2008) and ensure minimal impact of angling tournaments on marine communities. A previous study has shown that many of the physiological disturbances induced by angling normalize within approximately 4 h of recovery time if bonefish are placed in ambient seawater (Suski et al., 2007a). However, we currently do not know whether additional practices can be employed that would allow physiological parameters to return to resting values more quickly, thus reducing the duration of the recovery period and further reducing the possibility of predation after release. Past work on trawl-caught Pacific salmon, for example, has demonstrated that recovery times were reduced if fish were forced to swim slowly against a gentle current during recovery rather than remaining in static water (Farrell et al., 2001). Similarly, studies with Journal of Experimental Marine Biology and Ecology 402 (2011) 19–26 ⁎ Corresponding author at: Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 S. Goodwin Ave., MC 047, Urbana, IL 61801, United States. Tel.: +1 609 945 0710; fax: +1 954 337 3799. E-mail address: aaronshultz@ceibahamas.org (A.D. Shultz). 0022-0981/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jembe.2011.03.009 Contents lists available at ScienceDirect Journal of Experimental Marine Biology and Ecology journal homepage: www.elsevier.com/locate/jembe