Effect of Stocking Density and Partitioning of Rearing Period on Growth, Feed Utilization and Production of Common Carp Cyprinus carpio Raised in Floating Cages

The effect of stocking density and partitioning of raising period on growth and economic feasibility for common carp Cyprinus carpio was investigated using four wooden floating cages (16 m3 per cage) at Tigris river, Southern Bagdad, Iraq during April to November 2013. Initial weight of fish ranged from 63.7 to 70.9 g. Four different stocking densities (25, 35, 50 and 70 fish/cage) were tried for two raising periods (4 and 8 months). The final weight of 1317.5 gm was obtained by fishes of the lowest density (25 fish/m3). The same group sowed the heights values for food conversion ratio (FCR) of 2.63, food conversion efficiency (FCE) of 0.38, survival rate 94.5%, daily weight gain of 4.99 gm/day and specific growth of 3.57% dayˉ¹. Fish production in the lowest density reached the highest annual return of 54.80% and the best rate of 1.54% among the benefits and costs competition with all other densities.