Mohammad Hossien khanjani

The effects of Banana shrimp Fenneropenaeus merguiensis stocking density on water quality, growth performance, survival rate and body composition was assessed in a biofloc system with limited water exchange. The study was conducted for 32 days with an average larvae weight of 10 ± 0.85 mg in fiberglass tanks containing 120 L of water at four stocking densities. Five experimental treatments consisted of a control (density 1000 shrimps/ m3 ) with 50% daily water exchange and four biofloc treatments with limited water exchange (0.5% daily) at four stocking levels (1000 shrimps, T1; 2000 shrimps, T2, 3000 shrimps, T3 and 4000 shrimps, T4/ m3 ) were considered. According to the results, total ammonia nitrogen (0.99 mg /L) and nitrite levels showed higher amounts in the control compared with the other treatments (P<0.05). Growth performance and survival rate (95.55%) in the biofloc treatment with a density of 1000 shrimps/ m3 were higher than the other treatments (P<0.05). The proximate composition of shrimp body and biofloc produced in rearing tanks depended on the stocking density, so the shrimp body ash increased along with the enhancement of stocking density. The lowest amount of ash (31.53± 0.81%) and protein (26.38± 1.26) of bioflocs was observed in T1 treatment. The present study showed that stocking density affects the water quality, growth performance, survival rate and body composition of Banana shrimp larvae in a biofloc system. More improved indices of water quality, growth performance and survival rate were observed with the least stocking density of 1000 shrimps / m3 in the limited water exchange system.