Depth-based barotrauma severity, reflex impairment and stress response in two species of ice-angled fish

Barotrauma is a frequent event in fish captured from depth, and anglers often attempt to remedy this problem by venting fish. Barotrauma has been frequently assessed in fish during the warm water season, but no work has been done during winter ice angling, and the need and/or effectiveness of venting for ice-angled fish has not been quantified. To answer these questions, bluegill Lepomis macrochirus Rafinesque and black crappie Pomoxis nigromaculatus (Lesueur) were angled through the ice, barotrauma assessed, and the effect of venting on reflex responsiveness and blood glucose levels after 1 or 2.5 h of holding were determined. Greater capture depths resulted in more severe barotrauma, with bluegill experiencing symptoms at shallower depths than black crappie. Bluegill reflex action mortality predictor (RAMP) scores improved more than black crappie scores following venting. These results suggest barotrauma impacts fish in winter fisheries in a similar fashion to fish in warmer conditions, with species-specific differences in their susceptibility to barotrauma and their response to venting.