Evaluation of Stone Crab (Menippe mercenaria) fisheries practices using simulated fishery scenarios in the laboratory

Menippe mercenaria (Stone Crab) fisheries primarily occur along the Gulf of Mexico and Atlantic coasts of the southeastern US. Crabs are generally captured in baited traps during the commercial and recreational claw-only fisheries. Fishing regulations differ by region and country, but often dictate that harvested claws must be legal size, with ovigerous females and crabs with sub-legal sized claws returned to the water. However, despite traps remaining close to the site of capture, repeat captures of claw-harvested crabs are relatively low, suggesting either low survival of crabs following release, learned behavior towards avoiding traps, or a physiological or anatomical impairment preventing trap reentry. Using a combination of laboratory simulations of the Stone Crab fishery practices including trapping experiments, post-release feeding experiments, and respirometry to measure energetic cost, we examined: (1) the relative role and repeatability of physiological and behavioral traits in the capture process, and how this may change following claw removal and release; (2) the effect of claw removal on the immediate behavior (shelter use, exploration, and feeding) of crabs following release; and (3) the immediate physiological cost associated with the practice of removing claws. Results suggest that claw removal had a negligible effect on trapping behavior. However, crabs with claws removed spent less time feeding and had a higher relative standard metabolic rate (SMR) and relative routine metabolic rate (RMR) compared to crabs with no claws removed. Lastly among the intact crabs, individuals with higher relative SMR and relative RMR took significantly less time to enter the trap, suggesting these individuals were more catchable. Given the results, we suggest Stone Crab fisheries practices may have the potential to cause significant behavioral and physiological changes at both the individual and population level that may transcend to ecosystem and potentially wider evolutionary changes to populations.