Acclimation, thermal tolerance and aerobic metabolism of narrow-clawed crayfish, Pontastacus leptodactylus (Eschscholtz, 1823).

Ectotherms are considered more susceptible to global warming. Variations in ambient temperature are especially alarming as the majority of animals are ectothermic, with temperature seen as a crucial determinant of their ecology, biogeography, behaviour, and physiology. Ectotherms, which depend on external ambient temperatures to regulate their body temperature, exhibit various physiological and metabolic responses to variations in temperature. These responses are essential for comprehending how these species will acclimatise to changing water temperatures and the consequent alterations in oxygen availability. This study assessed the acclimation ability, temperature tolerance, and metabolic rate of narrow-clawed crayfish (Pontastacus leptodactylus) to elucidate the crayfish's responses to potential climate change. Our study showed that the narrowed clawed crayfish is a species that exhibits high thermal tolerance, with an extensive dynamic (1114 °C²), static thermal polygon area (966 °C²), resistance zone of 103 °C² and the ability to withstand extreme temperatures (CT_min-CT_max: 1.60-36.8 °C). The acclimation temperature has minimal impact on the thermal tolerance of the crayfish (P < 0.01). The optimal temperature range for SMR of Pontastacus leptodactylus is 20-25 °C, within which a decline in standard metabolic rate (SMR) occurs as temperature rises.