Evaluation of freshwater prawn‐small fish culture concurrently with rice in Bangladesh

An integrated aquaculture of freshwater prawn ( Macrobrachium rosenbergii ) and self‐recruiting small fish mola ( Amblypharyngodon mola ) was conducted in farmers' rice fields at Mymensingh, Bangladesh. There were four treatments with three replications. Four stocking densities, 10 000, 15 000, 20 000 and 25 000 ha −1 , of freshwater prawn were applied. The stocking density of mola was the same (20 000 ha −1 ) in all treatments. During land preparation, triple super phosphate (TSP) and murate of potash (MP) were applied at the rate of 150 and 75 kg ha −1 respectively. Urea was applied at the rate of 200 kg ha −1 in equally distributed three installments after 16, 45 and 65 days of rice plantation. Prawns were fed with commercial pelleted feed at 3–8% body weight. All water quality parameters were found to be within the suitable range for freshwater prawn culture. There was a homogenous abundance of plankton communities in all treatments. The results of a 4‐month culture period showed that the average production of prawn ranged from 222 to 388 kg ha −1 , mola 51 to 68 kg ha −1 and rice 2 880 to 3 710 kg ha −1 . Significantly higher production of both prawn and mola was recorded in the plots where the freshwater prawn stocking density was 15 000 ha −1 . This treatment resulted in a net profit of USD 1100 ha −1 .