Telemetry reveals the movement, fate, and lure-shedding of northern pike (Esox lucius) that break the line and escape recreational fisheries capture

Abstract

Although many fish are captured and released following hook removal by recreational anglers, some fish break the line and are confronted by the potential impediment of a lure lodged in the jaw, buccal cavity, or throat. We simulated break-off events by releasing northern pike (Esox lucius) into Lake Opinicon, Canada with custom-built lures that were manufactured to contain radio transmitters. Treatment groups combined hook placements (lower jaw, upper and lower jaw, throat) and hook types (barbed and barbless) to investigate the effects on pike survival, movement, and lure shedding. Fifty-one pike were released (522 ± 64 mm), three of which died (6%; 95% CI = 2–16%). Data were analysed by dummy variable regression to investigate the main effects of hook placements and hook type in pike. Cumulative distance swam after release was significantly reduced by deep hooking and lower jaw hooking. All fish except for one shed the lures within 14 d of release, and barbed hooks and lures lodged in the lower jaw significantly increased the time required for pike to shed lures. In light with previous work, we documented significant short-term behavioural consequences of lure break-off for pike (i.e. hyperactivity) but the experimental fish rapidly and naturally shed the hooks within days in nearly every instance. Given our findings, for pike (and likely related species such as muskellunge), anglers can be reasonably confident that long-term damage to individuals is limited even when a lure is retained by an animal following a break off event. Nonetheless, use of barbless hooks facilitates lure shedding, and all efforts should be taken to avoid break off events in the first instance using appropriate gear (e.g., wire leader, heavy line) especially when angling for fish with sharp dentition.