Experimental study on the approprite breeding density for the production of prawn in closed-recirculating system

A high density closed-recirculating prawn breeding system was constructed and evaluated during an 86-day growing period in which Litopenaeus vannamei were raised from fingerling to market size. The average bogy weight increased from (0.3±0.04)g to (10.40±2.04)g. The average yield was 5.85 kg/m³ and (5~10) times higher than that by pond culture. The food conversion ratio(FCR) was 1.76. The survial rate was 67％. During the experiment, the water quality in the recirculating system was stable. There were little daily variations of main water parameters. The average water temperature was(28.39±1.26)℃. The pH value was stable on 7.9±0.14. The dissolved oxygen was (7.27±1.36)mg/L. The ammonia-N and COD were (0.356±0.180)mg/L, (6.57±0.39)mg/L, respectively. The results demonstrated that the recirculating system could be used for L.vannmei culture and the approprite breeding density for the production of prawn was 1029 ind/m³.