Inclusion of Monosex Tilapia (Oreochromis niloticus) with Freshwater Prawn (Macrobrachium rosenbergii) in Polyculture Systems in the Ponds of Coastal Region: Impact of Stocking Density of Tilapia on Production and Profitability

摘要

Experiment was carried out to ascertain the impact of stocking density of monosex tilapia ( Oreochromis niloticus ) on production and profitability in freshwater prawn ( Macrobrachium rosenbergii ) farming system over a period of 150 days at farmers’ shrimp ponds, Madrasha village, Bamorta union, Bagerhat district. There were three treatments viz. T₁, T₂ and T₃ with tilapia of 10,000, 15,000 and 20,000/ha, respectively and each having three replicates. Density of prawn at 20,000/ha was maintained in all the treatments. Ponds were stocked with monosex tilapia and all male prawn juvenile. On average, 25 genera of phytoplankton and 6 genera of zooplankton were identified from pond water. Water quality parameters were within suitable ranges for tilapia and prawn in all the treatments. Mean weight of tilapia decreased significantly (p1 (950.4 kg/ha) followed by T₂ (923.0 kg/ha) and T₃ (805.2 kg/ha). On the contrary, production of tilapia was significantly higher in T₃ (1,686.60 kg/ha) and T₂ (1,587.60 kg/ha) than in T₁ (1,310.0 kg/ha). However, the overall total production of tilapia and prawn was significantly (p2 (2,510.60 kg/ha) and T₃ (2,491.80 kg/ha) compared to T₁ (2,260.40 kg/ha). Higher profit was also found in T₂ (BDT 238,923.00/ha) followed by T₁ (BDT 222,557.00/ha) and T₃ (147,819.00/ha). Therefore, the results of the study implied that inclusion of tilapia at a density at 15,000/ha enhanced the total production and contributed greatly to earn higher profit.