Angler Experience and Seasonal Effects on the Response of the Lake Sturgeon to Catch‐and‐Release Angling

Abstract

AbstractLake Sturgeon Acipenser fulvescens, once widespread throughout North America, are now considered endangered in much of their natural range. However, recreational catch‐and‐release (C&R) fisheries targeting the Lake Sturgeon have developed in areas with strong populations. Here, we evaluated physiological and behavioral impairment of Lake Sturgeon after C&R angling. Fish were angled from the Winnipeg River and transferred to a holding pen to recover and facilitate serial sampling after angling. Measured physiological traits included blood osmolality, pH, glucose, and cortisol concentration. Behavioral impairment was measured as a binary score using reflex action mortality predictors in addition to ventilation rate. The effects of season and angler experience on these measured variables were assessed. Catch‐and‐release angling resulted in an immediate physiological stress response and behavioral impairment in all Lake Sturgeon regardless of treatment. Generally, we observed a recovery in acid–base balance, ion balance, and reflex impairment by 24 h; however, cortisol and glucose were elevated throughout the recovery period, possibly indicating interactive stressors of holding and repeat sampling. Angling in the summer period caused increased ventilation rate and decreased osmolality at all timepoints compared to angling in the spring. In comparison with experienced anglers, novice anglers caused higher reflex impairment in Lake Sturgeon immediately after capture. This is the first study to examine the response of wild Lake Sturgeon to C&R angling. Data show an apparent resilience of Lake Sturgeon to C&R and can be used to assess the validity of C&R as a management strategy in the conservation of Lake Sturgeon.