Capture Is Predicted by Behavior and Size, Not Metabolism, in Muskellunge

Abstract

Fish that strike angling lures often have a set of characteristics that predispose them to capture. Vulnerable fish may then be removed from a population, either through harvest or incidental mortality, and in turn leave individuals in a population that are less vulnerable to angling. Over time, the removal of vulnerable individuals can erode capture rates, possibly resulting in evolutionary changes if traits that result in capture correlate with characteristics such as fecundity or growth. We sought to define the mechanisms driving individual angling vulnerability in Muskellunge Esox masquinongy, with the intent of informing management activities to conserve populations. The behavior of individually identified Muskellunge (n = 68; mean TL = 310.2 mm; range = 229–350 mm) was assessed using standard open‐field tests; the fish were then stocked into earthen‐bottom ponds to assess angling vulnerability. After angling, all captured fish and a subset of uncaptured fish were assessed for metabolic parameters. Results indicated that larger Muskellunge displaying low levels of exploration and aggression were preferentially captured. Behaviors such as boldness and activity did not influence capture, and metabolic parameters did not differ between captured and uncaptured fish.

Food availability influences angling vulnerability in muskellunge

“…Acclimation and angling time resulted in 14‐days of food deprivation to minimize the likelihood of food deprivation impacting angling or fish behavior (Gingerich et al, 2010). A variety of gears and techniques commonly used by muskellunge anglers were used, sized appropriately for fish in ponds, including spinner baits, “twister” baits, tube lures, plastic flukes, and minnow lures (colored white, pink, yellow, orange, or navy) fished at a variety of depths, speeds, and angles (Bieber et al, 2023). An effort was made to cast to all areas of ponds with the same combination of lures and angling strategies in all ponds.…”

“…In open‐field behavioral assays (Réale et al, 2007), twenty‐three different muskellunge were used to define how behaviors previously shown to influence angling vulnerability in muskellunge [aggression and exploration (Bieber et al, 2023)] might change as a result of food deprivation. On October 8, 2022, initial behavioral assays that used all twenty‐three muskellunge to generate baseline behavior data consisted of a 15‐min trial broken into three 5‐min segments (Bieber et al, 2023).…”

“…In open‐field behavioral assays (Réale et al, 2007), twenty‐three different muskellunge were used to define how behaviors previously shown to influence angling vulnerability in muskellunge [aggression and exploration (Bieber et al, 2023)] might change as a result of food deprivation. On October 8, 2022, initial behavioral assays that used all twenty‐three muskellunge to generate baseline behavior data consisted of a 15‐min trial broken into three 5‐min segments (Bieber et al, 2023). Behavioral assays were conducted between 0730 and 1800 within one of four identical indoor arenas composed of a 565 L (181 cm long × 65 cm wide) rectangular polyethylene stock tank filled with water to a depth of 15 cm that was isolated on all four sides with blackout curtains to eliminate external stimuli (Bieber et al, 2023).…”

“…On October 8, 2022, initial behavioral assays that used all twenty‐three muskellunge to generate baseline behavior data consisted of a 15‐min trial broken into three 5‐min segments (Bieber et al, 2023). Behavioral assays were conducted between 0730 and 1800 within one of four identical indoor arenas composed of a 565 L (181 cm long × 65 cm wide) rectangular polyethylene stock tank filled with water to a depth of 15 cm that was isolated on all four sides with blackout curtains to eliminate external stimuli (Bieber et al, 2023). Arenas were divided into a refuge zone and an open zone.…”

“…In many cases, the motivation for a fish to strike a lure is driven by feeding (Baur et al, 1976;Raat, 1991;Ware, 1972), which can be influenced by internal factors such as hormones that regulate metabolism or external factors such as food or temperature (Einen et al, 1998;Fry, 1971). Lure striking can also result from factors other than food or feeding, including territory or brood defense (Suski & Philipp, 2004) or repeatable behavioral characteristics that motivate lure striking in fish, with behaviors such as aggression, activity, boldness, or hormone responsiveness influencing capture (Bieber et al, 2023;Klefoth et al, 2017;Louison et al, 2017Louison et al, , 2018. Last, a lure must be presented in a way that induces striking behavior (i.e., fish must be receptive to the lure), which can be influenced by factors such as size of the lure relative to size of the fish, novelty, habituation, lure behavior, or lure type (Gaeta et al, 2018;Lennox et al, 2017;Nieman et al, 2020;Stålhammar et al, 2014).…”