Performances of wild sourced Indian major carps and hatchery produced exotic carps under different stocking combinations in polyculture ponds

Performances of wild sourced Indian major carps and hatchery produced exotic carps were studied during July to December 2014 in polyculture ponds of Faridpur district, Bangladesh. Three different combinations of species (surface: catla, Catla catla, silver carp, Hypophthalmichthys molitrix and bighead carp, Aristichthys nobilis + column: rui, Labeo rohita + bottom: mrigel, Cirrhinus mrigala and carpio, Cyprinus carpio + all layer: grass carp, Ctenophryngodon idella) were tested under three treatments as T1 (30% + 40% + 29% + 1%), T2 (30% +30% + 39% + 1%) and T3 (40% + 30% + 29% + 1%), each with four replications. As surface feeder, silver carp was dominant in treatment T1 and that of catla in treatments T2 and T3. Semi intensive carp polyculture was followed for all the treatments. Water quality for the treatments was found within the suitable range. Fish yield and net return varied more significantly (P