Comparison of the Growth Potential of Macrobrachium rosenbergii in Mono and Polyculture Conditions in Earthen Culture Ponds of Jammu, India

The study was conducted to assess the growth and survival of Macrobrachium rosenbergii in earthen culture ponds in order to know about the growth potential of M. rosenbergii in mono as well as polyculture conditions in Jammu. Polyculture experiments of prawn with some selected carps Indian Major Carps (Cirrhinus mrigala and Labeo rohita) and Exotic Carps (Cyprinus carpio) were undertaken in 3 freshwater ponds for duration of 4 months. Under the monoculture conditions, prawns attained an average size of 10.40 ± 0.17 cm weighing 23.84 ± 0.32 g in 4 months and the survival rate was found to be more than 75%. The growth rate of prawns was found to increase steadily during the first half (upto mid-October) after which a decline in the growth rate was evident as the mean temperature reached below 18°C. In the polyculture ponds the prawns attained an average size of 10.10 ± 0.03 cm weighing 18.39 ± 0.89g (without C. carpio) and 8.4 ± 0.36 cm weighing 15.23 ± 0.36 g (with C. carpio) in 4 months and their survival rate was less than 70%. Prawns being benthic feeders utilized the leftover food (of the fishes) that settled at the bottom, therefore, saving the feed cost. It was observed that mean size of the fish attained in the polyculture practice was almost similar to that obtained in the monoculture. The ideal prawn polyculture should be practiced with fast growing compatible carps such as Rohu and grass carp. Bottom feeder carps such as Mrigal (C. mrigala) should be avoided in prawn polyculture practice as they compete with prawns in feeding.