Meeting Abstract
Red drum (Sciaenops ocellatus) is a highly targeted recreational species, with 95% of captured individuals released alive. However, it is uncertain how many of these released fish survive, as many experience barotrauma as part of capture. Thus, we replicated recreational practices to (1) estimate post-release survival and sub-lethal impacts of capture on red drum and (2) experimentally test the effect of common release practices on survival and behavior. To do so, captured individuals (n=54, TL = 93 ± 7.3 cm) had an acceleration data logger(monitoring duration 39 ± 24 hr) affixed to their dorsal musculature and their physiological status was assessed using an iStat blood gas analyzer in the field. Individuals were then released by one of three treatments: a descending device (SeaQualizer, n=13), venting their swim bladder (n=18), or a control of no treatment (n=23). Of the 46 recovered data loggers, only two fish experienced mortality events; a gut-hooked fish that received no treatment (moribund: 102min PR) and a descended fish that likely was predated upon 124 minutes after release. However, recreational capture was stressful for fish, as longer fight times were associated with higher lactate concentrations (p=0.01) and lower blood pH (p=0.022). Upon release individuals had 60% higher activity levels (p=0.001) and displayed twice as much vertical displacement (p=0.001) compared to 24 hours after release. Both vertical displacement and activity level displayed similar patterns, decreasing over the first 10 hours after release before reaching a baseline level. Release treatment also had no apparent sublethal effects on fish, as activity level (p = 0.17) or vertical displacement (p = 0.14) remained the same between treatments.
