A comparison of claw removal methods on the survival and claw regeneration of stone crab (Menippe mercenaria)

Abstract

Commercial and recreational stone crab (Menippe mercenaria) fisheries primarily occur along the Gulf of Mexico and Atlantic coasts of the southeastern United States and the northeastern Caribbean. The fishery is unique in that only the crabs claws are retained and the animal is returned to the water alive. While the fishery is often regarded as sustainable because it is believed to exploit the crabs natural ability to voluntarily drop (autotomize) and regenerate lost claws, the survival of de-clawed stone crabs is often low, especially when both claws are harvested. In this study, a controlled laboratory experiment was used to compare an induced-autotomy method of claw removal to the typical forced break method currently used in the fishery. For the two different claw removal methods, we compared crab survival and start time to claw regeneration as a function of one or both claws removed. Overall, we found a significant effect of the removal method and number of claws removed on crab survival, but these factors did not influence the time to start claw regeneration. Although the induced-autotomy method was several seconds slower in processing time than the typical forced break method, it resulted in a 29% increase in survival (up to 92% survival throughout the study) compared to the typical forced break method of claw removal (63% survival throughout the study). Overall, these results suggest that the induced-autotomy method of claw removal significantly increases survival of stone crabs.