Effect of temperature on the swimming ability of mantis shrimp, Oratosquilla oratoria

This study investigated the effects of temperature on the swimming performance of the mantis shrimp (Oratosquilla oratoria). Swimming endurance, pleopod beat frequency, and maximum pleopod beat amplitude were measured across a range of temperatures (12, 16, 20, 24, and 28 °C) and flow velocities (0, 25, 29, 33, 37, and 41 cm·s^-1) in a flume tank. The critical swimming speed (U_crit) and swimming ability index (SAI) were also assessed at the same temperature range. All measured indicators exhibited sexual dimorphism, with females and males showing quantitatively different values but consistent response trends. Temperature significantly influenced swimming endurance, SAI, U_crit, pleopod beat frequency, and maximum pleopod beat amplitude. Swimming endurance decreased with increasing flow velocity at all temperatures. SAI showed a unimodal response to temperature, initially increasing and then decreasing. The fitted curves for SAI against temperature show that males attained a maximum SAI of 5.44 cm at 22.6 °C, females reached a maximum SAI of 5.76 cm at 22.5 °C. Both U_crit and relative U_crit (U_crit') increased with rising temperature, a relationship best described by quadratic models (all P < 0.01). Pleopod beat frequency increased with swimming speed at all temperatures. Maximum pleopod beat amplitude increased significantly only when speed rose from 0 to 25 cm·s^-1, remaining stable at higher velocities. These results improved the theoretical understanding of crustacean locomotor physiology and provided foundational data to support the sustainable aquaculture of O. oratoria.