Effect of stocking density on water quality, plankton community structure, and growth performance of Litopenaeus vannamei post-larvae cultured in low-salinity biofloc system.

This study aimed to investigate the effects of stocking density on Litopenaeus vannamei at the nursery phase in low-salinity biofloc system. Post-larvae of L. vannmei were cultured for 28 days at 2000, 4000 and 6000 shrimp m-3, and the water quality, plankton composition and growth performance were evaluated. The water quality variables remained within the ideal range for the shrimp culture, and only total suspended solids showed a significant difference between treatments -- the highest stocking density has increased the levels of total suspended solids. In regarding to zooplankton structure, the Protozoa group had the greatest diversity regardless of treatment, and also the greatest abundance (> 66%). For phytoplankton structure, Bacillariophyta (Navicula sp. and Cyclotella sp.) was the dominant class in phytoplankton structure throughout the culture, although a Cyanobacteria bloom has reported at the end of the cultivation at 2000 shrimp m-3. At the end of cultivation, the shrimp yield (0.133 ± 0.028 kg m^-3) was significantly higher in the 6,000 shrimp m^-3. In contrast, the shrimp survival was significantly higher in the lowest stocking density (71.66 ± 10.36%). Our findings suggest that a density of 6,000 shrimp m^-3 should be used under these conditions, but an economic feasibility study should be considered in the future. [ABSTRACT FROM AUTHOR]