Performance of Litopenaeus vannamei postlarvae reared in indoor nursery tanks under biofloc conditions at different salinities and zero-water exchange

摘要

Shrimp farming at low salinity is a trend that will continue to grow globally. Performance of Litopenaeus vannamei postlarvae in the nursery at different salinities with a biofloc technology (BFT) system needs to be explored further, as the nursery is currently used as a transitional stage between the hatchery and grow-out ponds. Hence, this study evaluated the effect of seven salinity levels (2, 4, 8, 12, 16, 25, and 35 aEuro degrees) on the performance of L. vannamei postlarvae reared with a BFT system and zero-water exchange at 2000 org/m(3). Additionally, this study evaluated the water quality of all salinity treatments. After 28 days of culture, the findings showed that, under biofloc conditions, salinity affected the performance of some variables of water quality in some cases, but only the combination of a high nitrite-N concentration (> 4 mg/l) and low salinity (2 and 4 aEuro degrees) caused up to 100 % shrimp mortality in the first 2 weeks. In the rest of the treatments (8, 12, 16, 25, and 35 aEuro degrees), shrimp survival was > 72 %. Shrimp mortality was affected by salinity, especially when it decreased from 35-25-16 to 12 and 8 aEuro degrees. The organisms reared at low salinities presented lower final weights and specific growth rate than those reared at higher salinities. An inverse relationship was shown between the ion concentration and the final weight of shrimp.