Estimating and Mitigating Post-Release Mortality of Atlantic Cod in the Gulf of Maine's Recreational Hook-and-Line Fishery

Recreational hook-and-line angling for Atlantic cod, Gadus morhua, in the Gulf of Maine (GOM) has increased over the past decade and recreational discards are approximately double the recreational landings in this region. However, the discard mortality of cod remains poorly understood, creating uncertainty in recent GOM cod stock assessments. The current project aims to examine the capture-related factors most detrimental to post-release survival of cod in the recreational hook-and-line fishery. Both sublegal and just legal cod (n = 637; 25 – 71cm) were angled using Norwegian-style jigs (48%) or baited J-hooks (52%) at depths ranging from 44.5 – 83.0m on southern Jeffreys Ledge from July – October 2013. All cod were visually inspected for injuries sustained during capture and ranked based on a condition index. A subset (n = 136) were also tagged with ultrasonic transmitters before being released into a fixed acoustic receiver array deployed to monitor survival over a 30d period. A mixed-effects logistic regression model was applied to the capture-related data to determine their effectiveness as post-release mortality predictors. Results can robustly estimate cod discard mortality and enhance survival through “best practice guides” that will be disseminated to stakeholders.