Effect of Species Composition of Carps in Penculture System in Bauysona River of Narail District

Abstract

An experiment was conducted from April to December 2008 to determine suitable species composition in poly culture of carps Labeo rohita (ruhu), Cirrhinus mrigala (mrigal) , Catla catla (catla) and Hypophthalmichthys molitrix (silver carp) in pen enclosures at dead Bauysona river jalmahal of Kalia upazilla under the district of Narail. Three treatments were taken with same stocking density (20,000pcs/ha) but the species compositions were varied. The species composition ratio of ruhu, mrigal, catla and silver carp were 6:2:1:1; 4:2:1:1 and 4:3:1.5:1.5 for T1, T2 and T3 respectively. The initial average body weight of ruhu, mrigal, catla and silver carp were 80.23, 70.41, 90.16 and 85.03g respectively and these were same for all the treatments. Same management technology was used for all the treatments. After stocking supplementary feed like rice polish (RP) and mustered oil cake (MOC) mixture (1:1) was used initially at a rate of 5% body weight of the stocked fish and the doses of feed was reduced up to 2% when average body weight became about 500g. After 8 months of culture period all the experimental species were harvested and recorded. The total production of all the experimental species in T1, T2 and T3 were 8033, 8589 and 7793 kg/ha respectively. Net profit in T1, T2 and T3 were 1, 32,740; 1,36,760 and 1,14,960 Tk/ha respectively. The cost benefit ratio was calculated as 1.31, 1.30, and 1.27 for T1, T2 and T3 respectively. From this study it was found that T1 had the best species composition.