Temporary Retention in Cold Water Reduces Postrelease Behavioral Impairment in Angled Rainbow Trout

Abstract

The effectiveness of catch and release as a conservation practice assumes minimal impacts to released fish. In most cases, angling-related stressors can be mitigated via changes to angler behavior that reduce fight duration, handling, and air exposure. In some cases, stressors may significantly impact the ability of fish to engage in normal swimming behavior upon release. In these scenarios, it may be beneficial for anglers to assist recovery or retain fish until they are adequately recovered. We investigated the effectiveness of two assisted-recovery devices at facilitating behavioral recovery in angled Rainbow Trout Oncorhynchus mykiss: (1) retention in a flow box, or (2) retention in a water-filled cooler. Additionally, we compared the effects of assisted recovery in surface water (24-27°C) or cool water pumped from the hypolimnion (17-19°C). From July to mid-September 2020, 169 fish were angled from five stocked lakes at Kenauk Nature (Montebello, Quebec). Fish were air exposed for 30 s, for 15 s, or not at all (0 s) and were held in a flow box or a water-filled cooler for 3 min, while fish in a control group were immediately released. Triaxial acceleration and temperature biologgers were temporarily fixed around the trunk of the fish with Velcro to observe postrelease swimming behavior for 10 min. Rainbow Trout that were held in assisted-recovery devices regained equilibrium significantly more quickly than those that were immediately released, and fish that were held in 17-19°C water regained equilibrium the most rapidly. In fish that were air exposed for 30 s, individuals that were held in recovery devices exhibited greater swimming activity compared to those that were immediately released. Our study demonstrates that for Rainbow Trout, assisted-recovery devices can reduce equilibrium impairment, especially when water in the recovery devices is significantly cooler than the relatively warm surface water temperature. Global water temperatures are expected to rise as a result of

Effect of climate change on fillet quality and shelf‐life of Oncorhynchus mykiss under controlled conditions

“…11,12 High temperatures in summer months have become the biggest threat to rainbow trout farming. 11,13 For this species, the optimal growth temperature us 12-18 °C, and temperatures exceeding 25 °C can be fatal. Global warming, increases in seasonal water temperature, and an increase in the frequency of extreme heatwave events have been reported to affect the worldwide distribution and survival of cold-water fish.…”

“…The rainbow trout ( Oncorhynchus mykiss ) is an economically important cold‐water fish worldwide and is highly sensitive to temperature changes 11,12 . High temperatures in summer months have become the biggest threat to rainbow trout farming 11,13 . For this species, the optimal growth temperature us 12–18 °C, and temperatures exceeding 25 °C can be fatal.…”

hysiological and Behavioural Responses of Lake Trout to Catch-And-Release Angling

“…In the present study, fish were held at low densities in a large, covered stock tank and water was frequently exchanged. Thus, holding conditions were not expected to greatly influence stress responses or behaviour (Portz et al 2006;Chhor et al 2022b). Therefore, either surface water temperature inhibited sufficient metabolic recovery or the angling itself induced a larger effect than what has been seen in other studies.…”

“…Harness attachment took no longer than 30s and Velcro straps were attached as to not inhibit the normal range of motion in order to reduce the impact of the harness on fish behaviour. The accelerometer harness was connected to a rod and reel spooled with 13.61 kg braided line using a snap swivel clipped through a reinforced hole in the Velcro tape (see Chhor et al 2022a;Chhor et al 2022b). Fish were released by hand at the side of the boat and allowed to swim without resistance for 15 min on a "free-spool" before I retrieved the accelerometer harness by tugging the line, which released the Velcro.…”

On Physiological Exhaustion in Fish Arising from Catch-and-release Angling: Mechanisms and Potential Solutions

“…Following fixation, fish were exposed to a treatment protocol before accelerometers were turned on and set to record a 15-minute period for each trial. That duration is rather typical of previous studies of black bass following C&R interactions using acceleration biologgers (LaRochelle et al 2021;Chhor et al 2022b). At the end of the 15-minute trial period, tension was applied to the tethered line to break the Velcro connection and dislodge the accelerometer package for retrieval and downloading of information.…”