Meeting Abstract

P1.92  Tuesday, Jan. 4  Hexapedal locomotion and reproductive ability after fatigue in the Atlantic Blue Crab, Callinectes sapidus (Rathbun) STOVER, K.K.*; BURNETT, L.E.; MCELROY, E.J.; BURNETT, K.G.; College of Charleston; College of Charleston; College of Charleston; College of Charleston stokris@gmail.com

The Atlantic blue crab, Callinectes sapidus (Rathbun), is an important commercial and recreational fishing species that resides in the estuarine waters of the Atlantic Ocean and Gulf of Mexico. These highly mobile crustaceans must locomote when finding food, evading predators, avoiding adverse conditions such as hypoxia and even finding a mate. In effect, maintaining continuous activity and resisting fatigue for extended periods of time may be necessary for daily survival of blue crabs. Previous studies on hexapod locomotion have focused on forward- moving cockroaches while work on crab locomotion has concentrated on terrestrial species utilizing 8 limbs. This study characterizes the walking parameters of the blue crab and examines the effect of fatigue on both locomotion and grip strength. Sideways hexapedal locomotion in C. sapidus has not yet been described; therefore this study serves as a baseline from which changes due to stress can eventually be distinguished. Performance was evaluated on a treadmill where crabs could move freely while walking at 8 m min^-1 while high speed cameras captured video at each hour time point until fatigue. Fatigue was assessed by pulling male crabs off a force transducer to simulate strength required to hold onto a female while mate guarding. A decrease to 66.6% of maximum force was considered fatigued. Grip force is significantly correlated with body mass, scaling with body mass^0.90, which is positively allometric. Locomotor endurance was also assessed with time to fatigue and changes in the 3D kinematics. Crab holding force decreased with a slope of -0.208 over 5 hours until fatigue was reached. Supported by NSF IOS-0725245.