Abstract Retarded growth

Abstract
Retarded growth, morphological deformities and increased incidence of disease and mortality of hatchery produced carp seeds are found as problems for polyculture promotion in Bangladesh. To address these problems, an experiment was conducted for a period of six months from July to December, 2015 to optimize the stocking density of carp polyculture using wild seeds of Indian major carps (Rui, Labeo rohita, catla, Catla catla and mrigal, Cirrhinus mrigala) and hatchery seeds of exotic carps (silver carp, Hypophthalmichthys molitrix, bighead carp, Aristichthys nobilis, carpio, Cyprinus carpio and grass carp, Ctenophryngodon idella) in farmer managed ponds of Faridpur district, Bangladesh. Three different stocking densities of carps were tested under three treatments as T1: 5,505 fishes/ha; T2: 6,916 fishes/ha and T3: 7,410 fishes/ha, each with four replications. Liming, fertilization and supplementary feeding were same for all the treatments. Water quality parameters were monitored monthly and found within suitable range for fish farming. Significant variation (P