Cardiac activity with acute exposure to sub-zero temperatures illustrates the survival mechanism of invasive crayfish

Abstract

The ability to withstand climate and weather extremes can play a key role in survival and establishment of non-native species. We investigated the effect of acute exposure to sub-zero temperature on the heart rate and recovery capacity of invasive crayfish Faxonius limosus, Pacifastacus leniusculus, and Procambarus clarkii. The experiments used non-invasive sensors to assess cardiac activity relative to survival and recovery of crayfish during short (30 min) and prolonged (60 min) exposures to − 18 °C. All P. clarkii specimens survived freezing temperature and rewarming and recovered after the short exposure, and 25% recovered after prolonged exposure. All F. limosus and P. leniusculus died during the recovery period following both exposures. In all tested specimens a heartbeat was measurable several hours after conclusion of exposure, gradually declining in F. limosus and P. leniusculus. The P. clarkii heart rate decreased abruptly upon exposure to sub-zero temperature, and recovery to nearly the pre-exposure rate took longer than for F. limosus and P. leniusculus. Heartbeat decline slopes were as follows: P. clarkii, 80.2° ± 2.1°, > F. limosus, 74.9° ± 4.1°, > P. leniusculus, 70.3° ± 3.7°. During the cooling-warming cycle, F. limosus and P. leniusculus demonstrated more gradual heartbeat decline and more rapid recovery to original levels but ultimately did not survive, most likely due to energy depletion associated with heartbeat fluctuation while cooling. These findings may increase our understanding of the broader distribution of P. clarkii than expected according to its ecological optima and provide insight into the mechanisms of invasive crayfish adaptability.