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.