Discard Fate: Using Cooperative Research and Acoustic Telemetry to Assess Efficacy of Barotrauma Mitigation Techniques and Long-Term Survival of Gag Grouper after Recreational Catch and Release

Gag grouper Mycteroperca microlepis are regularly targeted by marine anglers in the southeastern United States. Seasonal and size restrictions contribute to recreational discard, and the associated release mortality is an important consideration during stock assessments. There is much uncertainty regarding current discard mortality estimates, and the effectiveness of barotrauma mitigation techniques is unclear. Using a cooperative team of recreational and commercial anglers, Gag (n = 66; 473–803 mm TL) were caught on hook and line and monitored via acoustic telemetry at reef habitats on the west Florida shelf. Capture depths ranged 10 – 40 m and fish were tagged during all seasons of the year. After tagging, individuals were either placed back into the water without barotrauma mitigation (n = 15), were returned to the bottom using a descending device (n = 22), or were vented to assist descent (n = 29). Research is ongoing, but to date, Gag have been tracked for periods of 1–293 days (mean = 105 d) and have demonstrated small core areas of use. Although chronic effects of catch and release remain unclear, acoustic telemetry indicates that acute mortality after discard on the west Florida shelf (for depths to 40 m) is < 10%.