Incorporation of Golda (M. rosenbergii) in the Carp Polyculture System

Abstract

The investigation was conducted to evaluate the economic performance of polyculture of prawn (M. rosenbergii) with carps in the three ponds at the village named Kharshanga under Dumuria upazila in Khulna over a period of 12 months (June, 2002 to May, 2003). The experiments were designed as T1 and T2 and each treatment was conducted with three replications. The treatment T1 was stocked with M. rosenbergii juveniles at stocking density of 10,000/ha along with silver carp (Hypophthalmichthys molitrix), rohu (Labeo rohita), catla (Catla catla), mrigal (Cirrhinus cirrhosus) and grass carp (Ctenopharyngodon idella) at 5060 fingerling/ha at the ratio of 29.17: 25.0: 12.5: 16.67: 1.0 (silver carp: rohu: catla: mrigal: grass carp). On the other hand, the treatment T2 comprised of only the above carps having the same stocking density and species ratio. Supplementary feed consisting of mustard oil cake and rice bran (1:3) was applied in ponds once daily in the morning at 4% of the body weight. Water quality parameters of ponds such as temperature, dissolved oxygen and pH were inspected and monitored monthly. After twelve months of rearing, the gross productions of 358.13 kg/ha and 2592.91 kg/ha of golda and fish respectively were obtained from the T1. The gross production (2400.18 kg/ha) of fish was achieved from the T2. The initial weight was positively correlated with the final weight in the treatments and there is significant variation between initial weight and final weight. The variation between survival rate and net production was significant. Among the treatments, T1 shows better performance in terms of survivability (90.61%) and benefit cost ratio (1.24). The results of T1 indicate that the polyculture of prawn with carps is more economic than only carp culture.