The Behavioral Responses of Koi Carp (Cyprinus carpio) to Different Temperatures: Which Is Better, Infrared or Quadrupole Technology?

Based on the homemade Physiological and Ecological Comprehensive Analysis System for Aquatic Animals (PECA-BES01), this study compared the behavioral responses of koi carp (<i>Cyprinus carpio</i>) at three temperature gradients using two behavioral monitoring techniques as follows: infrared tracking and quadrupole impedance. The experiment employed comprehensive behavioral strength monitoring and infrared tracking (with tracked coordinates converted to swimming velocity data) to reflect behavioral changes. Within a certain temperature range, the behavioral strength and swimming velocity of carp increased with increasing temperature, which indicated heightened activity. The average behavioral strength and swimming velocity during light conditions (over three temperature gradients) were greater than during dark conditions. The circadian rhythm of carp becomes unstable at high temperatures, which shows abnormal periodicity with earlier occurrences of diurnal time points. Results from the system's two behavioral monitoring methods were largely consistent and confirmed the reliability of PECA-BES01 in monitoring aquatic organism behavior. Simultaneously, each of the two technologies has its own characteristics. Quadrupole impedance can be used to monitor the behavioral response of fish to different water depths, whereas infrared tracking can be used to monitor the behavioral response of fish to different flow velocities. Therefore, both behavioral strength monitoring and infrared tracking monitoring are effective techniques for monitoring fish behavior and can be widely applied. This study provides scientific support for koi carp cultivation and other aquatic species aquaculture, while also aiming to deliver high-quality methodology for online monitoring of aquatic organisms.