The Use of Acoustic Telemetry and Conditional Reasoning to Estimate the Discard Mortality of Atlantic Cod in the Gulf of Maine Recreational Rod-and-Reel Fishery

The recreational contribution to total catch of Atlantic cod (Gadus morhua) in the Gulf of Maine (GOM) has increased in recent years. However, recreational discards have outnumbered landings by 2:1 due to increasingly strict regulatory measures in this region, where discard mortality (DM) for cod remains poorly understood. Therefore, the current project estimated cod DM in the GOM recreational rod-and-reel fishery in order to address uncertainty in stock assessments and fishery management plans. Atlantic cod (n=640; 26-72cm) were angled with specific tackle setups from June-October 2013 on southern Jeffreys Ledge. Alongside other variables, all cod were visually assessed for capture injuries according to a four-level injury score index. Injury-dependent mortality was validated through the use of acoustic telemetry on a subset (n=136) which allowed for scaling DM estimates to the fishery level. Additional analyses of remaining capture variables produced “best capture and handling” practices to reduce mortality. Mean tackle-specific DM rates of 15.4% and 21.2% were estimated for bait- and jig-captured cod, respectively, with an overall 16.5% mean DM rate for the 2013 GOM recreational cod fishery. Results will continue to assist future management decisions and reduce mortality through dissemination of “best capture and handing” recommendations to fishery stakeholders.