Influence of Ice Angler Culling Practices on Bluegill Physiological Stress Responses and Mortality

Abstract

Decreasing bag limits is a management mechanism for enhancing size structure of Bluegill Lepomis macrochirus. However, restrictive bag limits can promote culling, where an angler returns a live fish to the water in exchange for another. Little is known about the effect of culling on ice-angled fishes.Our objective was to compare the effects of Bluegill confinement methods (reference, ice well, and bucket) and holding durations (0, 1, 2, or 5 hours) on changes in water quality parameters (dissolved oxygen, pH, carbon dioxide, and water temperature) and Bluegill stress physiology (blood glucose and plasma cortisol), reflex responses (RAMP scores), and mortality while ice-angling. In February 2018, 182 Bluegill were angled through the ice and randomly assigned a confinement method and holding duration. Bluegill blood glucose levels were higher in both confinement methods than reference fish at 2 and 5-hour holding durations. Bluegill had higher blood glucose levels in buckets than ice wells at 1 and 2 hours, but had higher blood glucose levels in ice wells at 5 hours. Water temperature was warmer in buckets than ice wells at all holding durations, while ice wells were cooler than ambient lake temperature. Bucket pH was higher than the lake at 2 hours and ice well pH was higher than the lake at 1 and 2 hours. Bluegill RAMP scores were similar across all holding durations and confinement methods, but were elevated in individuals held for the 24-hour mortality assessment.Two Bluegill mortalities occurred for fish held in ice wells. Our results suggest confinement method and holding duration while ice-angling can result in altered Bluegill blood glucose concentrations, water temperatures, and pH concentrations but that culling while ice-angling might not result in mortality. Consequently, culling practices may be compatible with and not negate the intended benefits of reduced Bluegill bag limits.Catch-and-release angling is a popular recreational activity driven by changes in angler conservation ethics and more restrictive harvest regulations (Cowx 2002;Cooke and Cowx 2004; Bartholmuw and Bohnsack 2005). Benefits of catch-and-release angling include enhanced recreational quality, increased catch rates, and improved size structure (Hubert and Quist 2010). However, success of catch-and-release practices relies on the assumption that released fish will survive after experiencing stressors associated with capture, handing, and confinement (Arlinghaus et al. 2007). The catch-and- Accepted ArticleThis article is protected by copyright. All rights reserved release process can directly influence changes in fish stress physiology (e.g., changes in blood glucose and plasma cortisol concentrations) via handling practices (e.g., Pottinger 1998;Meka and McCormick 2005) and indirectly via changes associated with confinement water quality (e.g., water temperature, ammonia, carbon dioxide, and dissolved oxygen; Caldwell and Hinshaw 1994;Meka and McCormick 2005). Prolonged exposure to stressors associated with catch-and-release anglin...

An examination of freezing in yellow perch ( Perca flavescens ) following ice fishing using a histological approach

“…Furthermore, one or more of the sampled tissues may have experienced “cold shock”, which is characterized as biological impairments induced by rapid decrease in water temperature (Donaldson et al, 2008). Cold shock results in a suite of physiological changes and in extreme cases, death of the organism (Donaldson et al, 2008), though mortality has rarely been reported in ice fishing studies (e.g., Grausgruber et al, 2021; Logan et al, 2019).…”

“…A potential outcome of this cooling is the slowing of key physiological processes (e.g., enzyme activity, metabolism, hormone production). Past studies on ice fishing have shown that metabolic and stress responses (e.g., glucose, lactate, cortisol) are either absent or lower in caught fish in comparison to fish sampled following fishing in warmer time periods, which has been attributed to a slowing of the enzymatic processes needed for the physiological stress response (Grausgruber et al, 2021; Logan et al, 2019; Louison, Hasler, Fenske, et al, 2017; Louison, Hasler, Raby, et al, 2017). The cooling may also contribute to behavioural and locomotory impairment that has also been noted following ice fishing (Bieber et al, 2019; LaRochelle et al, 2021; Logan et al, 2019; Louison et al, 2017a; Louison, Hasler, Raby, et al, 2017), as neuronal activity and forced swimming performance slow at cooler temperatures (Ward et al, 2002; Van den Burg et al, 2015).…”

“…Furthermore, one or more of the sampled tissues may have experienced "cold shock", which is characterized as biological impairments induced by rapid decrease in water temperature (Donaldson et al, 2008). Cold shock results in a suite of physiological changes and in extreme cases, death of the organism (Donaldson et al, 2008), though mortality has rarely been reported in ice fishing studies (e.g., Grausgruber et al, 2021;Logan et al, 2019). lamellae in the gills of teleost fish is to facilitate ion and gas transfer into the bloodstream (e.g., oxygen uptake and carbon dioxide release; Ferguson & Tufts, 1992), and their delicate structure provides a large surface area for gas and ion transfer to occur (Wilson & Laurent, 2002).…”

“…Fish were haphazardly assigned to either the control or the treatment group. Fish in the treatment group ( n = 8) were measured for total length, weighed to the nearest g, and then placed on the ice for a 3‐min ice and air exposure (ice temperature: −3 ± 0.73°C; a 3‐min exposure duration is a realistic duration to have fish on the ice prior to release; Lawrence et al, 2022; Grausgruber et al, 2021). Fish were laid on the ice freely and were not gripped or held during the 3‐min exposure.…”

“…Landed fish are often held in the air or on ice for a few seconds to several minutes to remove hooks and to take measurements and photos (Lawrence et al, 2022). While fish are frequently harvested, many fish are released back into the water through the hole in the ice for a variety of reasons, including conservation ethics and morals, bycatch, culling, and harvest regulations (Arlinghaus et al, 2007; Cooke & Suski, 2005; Grausgruber et al, 2021). One key assumption of releasing fish after capture is that they continue to survive, reproduce, and are able to be captured again in the future (Brownscombe et al, 2017).…”