Evaluation of the physiology, behaviour, and survival of adult muskellunge (Esox masquinongy) captured and released by specialized anglers

Angling for muskellunge (Esox masquinongy) is a specialized endeavor involving species-specific equipment and handling procedures. The latter were developed by anglers with little influence from fisheries managers or the scientific community. Today, release rates approach 100% for specialized anglers; therefore, a formal evaluation of these procedures was warranted. Using two handling treatments – one to mimic current handling procedures with a period of air exposure and another gentler alternative without a period of air exposure – we assessed the physiological and behavioural disturbances as well as mortality associated with the catch-and-release process. Seventy-seven muskellunge were angled and blood sampled during the 2009 and 2010 muskellunge angling seasons. An additional 18 muskellunge were electrofished and immediately blood sampled to obtain baseline physiology data. A subsample (N = 30, 15 per treatment) of the 77 angled individuals was fitted with external radio transmitters to assess behaviour and survival. Glucose and lactate concentrations were found to be significantly lower for controls, and glucose and potassium concentrations increased significantly with increasing surface water temperatures. No differences in physiology were noted between angling treatments. Muskellunge treated with normal and alternative handling procedures exhibited similar post-release behaviour, and no angling related mortalities were observed across a range of water temperatures (17.5–26.0 °C) This study demonstrates the effectiveness of current handling procedures at minimizing physiological and behavioural disturbances, particularly when compared with a gentler alternative. A fishery in which no angling mortality exists is not possible, but our study provides support for the notion that angling related mortality for muskellunge captured and released by specialized anglers using handling procedures evaluated in this study may indeed be negligible.

► We evaluate the effects of specialized catch-and-release angling on muskellunge.
► Physiological and behavioural disturbances as well as mortality are evaluated.
► Air exposure had no affect on physiological or behavioural disturbances.
► Regardless of air exposure, no mortality was observed.
► Current handling practices maximize survival and should be advocated.