S. Stoyanova*, Y. Staykov

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. Optimisation of stocking density of reared fish is one of the essential factors for high yields from aquaproduction. The purpose of the present study was to evaluate the effect of different stocking densities in a superintensive system on growth performance and feed conversion of common carp fingerlings (CyprinuscaprioL.).Fishwithsimilarbodyweight(g)weredistributedinnet cagessized3.0x3.0x2.5m3intoonecontrolgroup(CG)atstockingdensityof 450 individuals/m3 and two experimental groups (CG- 450 individuals/m3; EG1 – 650 individuals/m3 and ЕG2 – 850 individuals/m3), each of them in four replications. The experiment lasted for 60 days. The highest stocking density did not have a negative impact on growth performance of fingerlings and they attained an average body weight of 84.40 g, which was higher than that of fish from CG by 6.36% (p≤ 0.01). Feed conversion ratio of carps decreased proportionally to increasing the stocking density. Specific growth rate showed that it was the lowest in carp fingerlings from the control group – (450 individuals/m3).