Rutilus kutum is one of the most important economic fish species of Iranian costal of Caspian Sea. This species conducted more than 60% of fish caught in Caspian Sea annually, and more than 10 thousands fisherman engaged to its fishery. In present study, kutum fingerlings reared in two different densities include of 25 and 40 fish/m^2 with mean weight of 17.5±5.87 g. The period of test being planned 10 weeks and the test organism housed in circular concrete pools of 3 m^3 capacity with flowing water and aeration in pools are supplied. The fishes feed by extrude food with 45% crude protein and 14% crude fat. After termination of the experiment, the result showed that weight gain performance, specific growth rate, condition factor, food efficiency rate and protein efficiency rate decreased, while food conversion ratio increased with rising of density, as their different was significance in two experimental treatments (p〈0.05). The kutum reared in low density showed significantly higher survival rate (SVR) (with 88.8%) than high density (with 76.9%) (p〈0.05). Based on the different observed effects of the density on growth and survival, it is recommended the use of a 25 kutum/m^2 density for rearing by Caspian Sea water.
Monograph or Serial Issue