Short‐Term Physiological Disruption and Reflex Impairment in Shortnose Sturgeon Exposed to Catch‐and‐Release Angling

Abstract

AbstractSturgeons (Acipenseridae) are the most imperilled group of fishes globally. Yet, many species remain important targets of recreational anglers. In the Saint John River, New Brunswick, Shortnose Sturgeon Acipenser brevirostrum is a popular species targeted by recreational anglers. The International Union for the Conservation of Nature has placed Shortnose Sturgeon on the Red List as “Vulnerable,” and therefore this species is afforded protection from harvest in Canada by the federal Species at Risk Act. Here, we evaluated physiological stress using two principal components axes, RC1 and RC2, generated from blood lactate, glucose, and pH, hematocrit, and reflex impairment of sturgeon exposed to exhaustive chase experiments at a hatchery and angled sturgeon that were captured during an annual fall competitive angling event. Physiological indicators of stress increased with holding time for Shortnose Sturgeon transferred into a tank and for sturgeon exposed to chase trials. Circulating metabolite concentrations were not associated with reflex impairment. The odds of reflex impairment increased as a function of air exposure, with a 1‐min increase in air exposure increasing the odds of impairment by 1.78. All sturgeon survived hatchery experiments. Most of the wild Shortnose Sturgeon captured in the fishing derby (71%) exhibited reflex impairment, and 38% had superficial injuries such as cuts or wounds. None of these factors were associated with physiological disturbance, although ordinated stress physiology axes were elevated both 1 and 2 h after initial sampling, which was predictive by the holding time prior to weigh‐in and measuring fish size. All fish were hooked in the mouth and each was released alive from the derby. Taken together the evidence suggests that Shortnose Sturgeon are resilient to recreational angling interactions, yet managers could use this information to improve best practices of catch‐and‐release angling.