Effect of low salinity on the survival of postlarvae of the blue shrimp, at different stages

The development of low salinity culture techniques is the major factor that facilitated the wide- spread cultivation of the white shrimp Litopenaeus vannamei in China. Similarly, adaptation to fresh or low salt water is critical for the commercial farming of a related species, the blue shrimp L. stylirostris. To determine the effects of low salinity on L. stylirostris development, the survival of postlarvae was investigated at different levels of salinity at the Haichang Jinhaian Shrimp Breeding Farm and Gulangyu Breeding Farm for Aquatic Animals of the Fisheries Research Institute of Fujian during 2002-2003. Results showed that both salinity and the age of the post- larvae significantly affected survival (p<0.01). The minimum seawater salinity for young postlar- vae was 10-14 ppt and survival rates increased with age. When the post-larvae were 9 days old or older (≥P9), survival did not significantly differ in the low salinity treatments from that of the control (P12). The first hour was the most critical period. If larvae survived the first hour, they usually survived the whole study period (24 h) or longer.