Compensatory growth response of freshwater prawn(Macrobrachium rosenbergii) polycultured with Indian major carp, Catla (Catla catla)

Abstract

With a view to evaluate the compensatory growth response, production and survival of prawn (Macrobrachium rosenbergii) and catla (Catla catla) under polyculture system, an experiment was conducted at the Faculty of Fisheries Field Laboratory in Bangladesh Agricultural University campus from 20 March 2006 to 20 June 2006. The experiment was consisted of three treatments with three replications for each. The three treatments were: fed to satiation twice a day (T1), fed every alternate day (T2) and fed every two days of interval (T3). SABINCO prawn feed was used as supplementary diet for the experiment. The stocking densities for prawn and catla were 40/dec. and12/dec., respectively. The initial weights at stocking were: 50 g for catla in all the treatments, and 5.8, 6.4 and 6.2 g for prawn in T1, T2 and T3, respectively. The water quality parameters were almost similar in all treatments and also were within an acceptable range of fish culture. The survival rate for catla was 100.0% in T1, 91.6% in T2 and 83.3 % in T3, while for prawn was 85.0% in T1, 71.0% in T2 and 69.0% in T3, respectively. The average weight of prawn was much lower in T3 and T2 than those in T1. The best FCR value was found in T2 (1.80) followed by T3 (1.85) and T1 (1.98) in this order. The average highest gross yield was obtained from T1 (1656kg/ha) followed by T2 (1077kg/ha) and T3 (1127kg/ha), while the production of prawn was T1 (791kg/ha), T2 (517kg/ha) and T3 (429kg/ha), respectively. However, no significant differences were found in the total yield in T2 and T3. The total costs of production for the three treatments were: T1 (125.93Tk/kg), T2 (143.21Tk/kg) and T3 (146.71Tk/kg), while the profits were: T1 (104.07Tk/kg), T2 (55.86Tk/kg) and T3 (24.60Tk/kg) in which the benefit cost ratio were found to be 1:0.83, 1:0.39 and 1:0.17, respectively. The results indicate that every day feeding had provided good growth and economic returns and thus seemed to be most practicable and viable feeding options for prawn-fish polyculture. Therefore, prawn-fish polyculture with regular feeding provides satisfactory growth and production.