Effects Of Inclusion Of Rohu (Labeo Rohita): At Different Stocking Densitieson Pond Environment and Production in Prawn-Carp-Mola Polyculture

The impacts of inclusion of column feeder rohu (Labeo rohita) on growth and production in freshwater prawn-carp-mola polyculture system were studied in the Fisheries Field Laboratory, Bangladesh Agricultural University, Mymensingh for 172 days culture period between June and December, 2008. Four treatments named as R500, R1000, R1500 and R2000 with inclusion of rohu at different stocking densities (500, 1,000, 1,500 and 2,000 ha-1, respectively) were compared with a control devoid of rohu (R0) each with three replications. All treatments and control ponds each of 120 m2 area were stocked with juvenile freshwater prawn (Macrobrachium rosenbergii), silver carp (Hypophthalmichthys molitrix), catla (Catla catla) and small fish mola (Amblypharyngodon mola) at the fixed stocking densities of 20,000, 1,500, 1,000 and 20,000 ha-1, respectively as well. The study revealed that increasing stocking density of rohu decreased prawn production. However, treatments R0 and R500 fetched higher net profit without significant difference among them. Therefore, inclusion of rohu at a density of 500 ha-1 may be recommended for prawn-carp-mola polyculture.