Abstract:In order to improve the survival rate of Litopenaeus vannamei during transportation with water after carbon dioxide (CO2) anesthesia, the effects of CO2 flow rates (anesthesia stage), soaking time (soaking stage), water type and salinity (recovery stage) on the survival rate were studied. The experiment set four factors:CO2 flow rates (3 L/min, 5 L/min and 7 L/min), soaking time (0 min, 1 min and 5 min), water type (tap water, supernatant of aquaculture water and aquaculture water) and salinity (3, 7 and 11). The single factor experiment was carried out, and the L9(34) orthogonal experiment and verification experiment were carried out based on the single factor experimental results. The results showed that in the single factor experiment, the best CO2 flow rates was 7 L/min, the best soaking time was 0 min, the best water type was tap water and the best salinity was 7. The results of orthogonal experiment of transportation within 2 hours showed that the primary and secondary relationship of the four factors was:soaking time > water type > salinity > CO2 flow rates, and the best combination was CO2 flow rates of 8 L/min, the water type of tap water, the salinity of 7 and the soaking time of 0 min. The results of orthogonal experiment of transportation within 4 hours showed that the primary and secondary relationship of the four factors was soaking time > CO2 flow rates > water type > salinity, and the best combination was CO2 flow rates of 7 L/min, the water type of tap water, the salinity of 7 and the soaking time of 0 min. The results of orthogonal experiment of transportation within 6 hours showed that the primary and secondary relationship of the four factors was soaking time > CO2 flow rates > salinity > water type, and the best combination was CO2 flow rates of 6 L/min, the water type of tap water, the salinity of 7 and the soaking time of 0 min. The experimental results show that the recovery rate of Litopenaeus vannamei under different transportation time conditions can be improved by adjusting the levels of four factors:CO2 flow rates, soaking time, water type and salinity, which provides a new idea for shrimp keep-alive transportation.