Factors Influencing Short-Term Hooking Mortality of Bluegills and the Implications for Restrictive Harvest Regulations

Abstract

Angling can adversely affect populations of bluegill Lepomis macrochirus, and many state agencies have begun to explore restrictive creel and length limits. The fate of released fish can be influenced by a variety of factors, and the success of regulations could be reduced if the mortality of released bluegills is high. We conducted experiments using bluegills caught by the general angling public in Ridge Lake, Illinois, to quantify bluegill hooking mortality and test for the effects of bait type (live versus artificial), season (spring versus summer), retention time in live wells (1, 3, or 5 h), and retention gears (live wells versus fish baskets). Across all seasons and baits, the mortality of caught-and-released bluegills was low; the initial and short-term mortality for fish immediately released was 4.4%. There were significant differences in hooking mortality with respect to bait type, retention gear, and retention time. Bluegills caught on live bait experienced higher mortality (6.6%) than those caught on artificial baits (0%), and wire fish baskets caused higher mortality (34.0%) than live wells (7.6%). The mortality of bluegills held in live wells was higher for the 3- and 5-h retention times than for the 1-h treatment. The probability of dying from catch and release decreased with increasing fish length. We applied our results to a bluegill population under a restrictive harvest regulation consisting of a 203-mm minimum size limit and a 10-fish daily bag limit. Under these restrictive regulations, fish lost from catch and release represented 27.4% of the total kill (harvest and hooking mortality). While catch-and-release angling can cause some mortality, it does not appear from our study that releasing fish will have a deleterious effect on bluegill populations.