Low Salinity Rearing of the Pacific White Shrimp Litopenaeus vannamei: Acclimation, Survival and Growth of Postlarvae and Juveniles

Low salinity rearing of Litopenaeus vannamei requires the transfer of postlarvae (PL) from high salinity hatchery systems to low salinity conditions. In order to determine effective transfer methods, fifteen-day-old postlarvae (PL 15) were acclimated front a salinity of 30 ppt to endpoint salinities of 1 and 5 ppt using single-step and gradual salinity reduction procedures. Higher survival rates were obtained with gradual acclimation than with single-step acclimation. Survival of PL15 acclimated to 5 ppt was better than that of PL15 acclimated to 1 ppt. Survival of PL15 and juvenile stages in various low salinity treatments ranging front 0-5 ppt was also compared. In the PL stage, survival rates were good (>85%) in salinities over 1.5 ppt. Tolerance to low salinities increased with age and survival rate of juveniles (65%) was higher than that of PL (2%) in freshwater. In our long-term growth trials of juvenile shrimp maintained in different salinities, optimal growth comparable to that in normal seawater was observed in animals reared in a salinity of 5 ppt, demonstrating that L. vannamei can be successfully cultured in low-salinity inland systems.