Effects of temperature, salinity, body length, and starvation on the critical swimming speed of whiteleg shrimp, Litopenaeus vannamei

The critical swimming speed (Ucrit, cm s− 1) of whiteleg shrimp, Litopenaeus vannamei, exposed to various temperatures (17, 20, 25, and 29 °C), salinities (20, 25, 30, 35, and 40), and starvation days (1, 4, and 8 d), was determined in a flume tank. Body length (5.5, 6.6, 7.3, 9.4, and 10.0 cm) was also studied in relation to the Ucrit. Temperature, salinity, body length and starvation significantly affected the Ucrit of whiteleg shrimp. The Ucrit increased as temperature increased from 17 to 29 °C. The relationship between temperature (t, °C) and Ucrit can be described by the linear model as Ucrit = 1.5916t + 0.8892, R2 = 0.9992 (P < 0.01). The Ucrit increased and then decreased as salinity increased from 20 to 40. The optimum salinity and the corresponding maximum Ucrit are 36.17 and 42.87 cm s− 1, respectively. The relationship between salinity (s) and Ucrit can be described by the quadratic model as Ucrit = − 0.0171 s2 + 1.2371 s + 20.497, R2 = 0.7667 (P = 0.234). The Ucrit increased as body length increased from 5.5 to 10.0 cm, whereas relative critical swimming speed (Ucrit′, BL s− 1) decreased. The relationship between body length (l, cm) and Ucrit or Ucrit′ can be described by the quadratic model as Ucrit = − 0.6233 l2 + 12.302 l − 20.264, R2 = 0.9942 (P < 0.01) or Ucrit′ = − 0.0514 l2 + 0.5351 l + 3.8132, R2 = 0.9862 (P < 0.05). The Ucrit decreased as starvation days increased from 1 to 8 d. The relationship between starvation day (d, d) and Ucrit can be described by the quadratic model as Ucrit = − 0.1262d2 − 0.0395d + 40.979, R2 = 1. Low temperatures and salinity and starvation can reduce the swimming speed of whiteleg shrimp. Results can be of value in evaluating the locomotive ability, understanding ecological processes, and improving the capture and stock enhancement of whiteleg shrimp.