Production and profitability of Macrobrachium rosenbergii (de Man) using over-wintered juveniles under polyculture system

Production performance and economic viability of over-wintered juveniles of freshwater prawn, Macrobrachium rosenbergii, with Indian major carps Labeo rohita, Catla catla, Hypophthalmichthys molitrix, and Ctenopharyngodon idella were examined in a pond polyculture system for a six-month period from January to June in four sites, namely; Fulpur, Tarakanda, Gafforgaon, and Nandail upazilla under the Mymensingh district of Bangladesh. Four upazillas (sub districts) were considered as treatments, having three ponds in each treatment as replications. The stocking density of M. rosenbergii, L. rohita, C. catla, H. molitrix, and C. idella was 40, 4, 4, 10, and 2 per decimal, respectively. Prawn and fish were fed with farm-made supplementary feed @ 3% body weight twice daily. The ponds were fertilized fortnightly with urea and TSP. The water quality parameters were within the optimum ranges, and suitable for prawn-carp polyculture. The ranges of survival rate of prawn and carps were higher in all treatments (78.33-95.56%) with no significant differences. The yield of prawn was considerably higher (638.38 kgha-1) in Fulpur, followed by 629.66, 592.23, and 558.59 kgha-1 in Tarakanda, Gafforgaon, and Nandail, respectively, while that of carps was the significantly higher in Nandail upazilla (1917.49 kgha-1). A simple economic analysis showed that total expenditure was Tk. 176886 ha-1, gross income was Tk. 366 760 ha-1 with a benefit cost ratio of 2.07. The results of the study revealed the high potentiality and profitability of producing prawn using over-wintered juveniles of prawn with carps under a polyculture system in the northeast region of Bangladesh.