Pre-cooling effect on live transport of the Southern king crab, Lithodes santolla

Abstract

Live transportation of subtidal crustaceans is mostly done in dry conditions. Lowered body temperatures optimizes survival since it reduces standard metabolism. In this study, we evaluated whether lowering water temperature in recirculating aquaria (pre-cooling protocol) would lower the stress accumulated during the transport of Southern king crab (Lithodes santolla). Animals were sorted into three treatments: i. pre-cooling (animals cooled to 2 °C, then dry-stored for 24 h and re-immersed at 8 °C for recovery); ii. no pre-cooling (animals dry-stored for 24 h at 8 °C and then re-immersed); and iii. control (animals without air exposure kept at 8 °C). The crab hemolymph was sampled before and after air exposure and at different intervals of the recovery period. We measured animal vigor and hemolymph parameters such as pH, total protein, oxy-hemocyanin, glucose and l-lactate. The pre-cooling protocol enhances the crab recovery and lowers its metabolic stress, as it attenuates the hyperglycemic response to emersion. Pre-cooling also stimulates animals to reach maximum vigor during the recovery period. We conclude that lowering the body temperature of Southern king crab before transport lowers the metabolic rate, and thus animals are less susceptible to emersion damage. Also, pre-cooling enhances metabolic recovery, as crabs experience less stress. Pre-cooling could be of importance for improving crustacean welfare and reducing mortality during long-haul transportation.