Effect of low salinity on growth and survival of postlarvae and juvenile Litopenaeus vannamei

The effect of low salinity on survival and growth of the Pacific white shrimp Litopenaeus vannamei was examined in the laboratory due to the interest of raising shrimp inland at low salinities. In three separate experiments, individual L. vannamei postlarvae (similar to 0.1 g) were cultured at salinities of either 0.5, 1, 1.5, 2, or 3 ppt (N = 5 or 10/treatment) for 18 to 40 d at 30 C in individual 360-mL containers. In each experiment controls of 0 and 30 ppt were run. There was no postlarval survival at salinities < 2 ppt. Survival was significantly different (P < 0.01) at 2 ppt (20%) compared to 30 ppt (80%). Growth was also significantly different (P < 0.01) at 2 and 3 ppt compared to 30 ppt (416%, 475%, and 670%, respectively). A Fourth experiment compared juveniles (similar to 8 g) and postlarvae (similar to 0.05 and 0.35 g). Shrimp were cultured at salinities of 0, 2, 4, and 30 ppt for 40 d at 25 C, in individual 360-mL and 6-L containers (N = 7/treatment). There was no postlarval survival at < 2 ppt. Postlarval survival at 4 ppt (86%) was not significantly different (P > 0.05) from 30 ppt (10090). Juveniles exhibited better survival at lower salinities (10090 at 2 ppt) than 0.05 and 0.35 g postlarvae (2990 and 14% respectively, at 2 ppt). The effects of salinity on growth varied with size/age. Final growth of 0.05 g postlarvae at 2 ppt (69390) was significantly less (P < 0.01) than at 4 ppt (1085%) and 30 ppt (106490). Growth of 0.35 g postlarvae was significantly less (P < 0.01) for 4 ppt (175%) than for 30 ppt (264%). There was no growth data for juveniles (8 g). It appears from these experiments that the culture of L. vannamei poses risks when performed in salinities less than 2 ppt.