EFFECT OF STOCKING DENSITY ON THE GROWTH PERFORMANCES OF SHING (Heteropneustes fossilis) UNDER POLYCULTURE SYSTEM IN SEASONAL MINI PONDS OF NORTHERN REGION OF BANGLADESH

Abstract

The present study was carried out to evaluate the effect of stocking density on the growth performance and water quality parameters of shing (Heteropneustes fossilis) polyculture system at Saidpur and Dimla Upazila of Nilphamari district and Taragonj Upazila of Rangpur district, for a period of 150 days from 30 March 2016 to 30 August 2016. H. fossilis with an average weight of around 3 g were stocked in nine uniform earthen ponds (around 10 decimal) at three different stocking densities of 500 (T1), 600 (T2) and 700 dec-1 (T3) together with Clarias batratus, Oreochromis niloticus and Barbodes gonionotus at a ratio of 5:2:1. All the experimental fish were fed with a commercial feed (Lily fish feed) containing 35.53% protein twice daily at 5-10% body weight of H. fossilis. During the study period, the water quality parameters were evaluated and the results revealed that significantly lowest (P<0.05) total alkalinity, hardness and ammonia content were noted in the lowest stocking density (T1) compared to those that were stocked at highest stocking density (T3). At the end of the feeding trial, weight gain (62.15±0.64g), percent weight gain (2135.46±5.05 %), average daily gain (0.41±0.01 % day-1 ) and SGR (2.04±0.01 % day-1 ) were significantly improved (P<0.05) in the treatment of T1 compared with the other treatment groups. Significantly highest (P<0.05) survival (%) of shing was also found in the treatment of T1 (77.93±0.94%) compared to the remaining treatments. Considering the survival highest gross production (kg dec-1 ) was observed in T2 (26.50±0.65) followed by T1 (25.38±0.55) and T3 (24.43±0.26). The benefit-cost ratio (BCR) result revealed that the best BCR was obtained in the treatment of T1. Therefore, the results of this study indicated that the lowest stocking density (500 fingerlings dec-1 ) seems to have more positive effect on the growth performances of shing (H. fossilis) polyculture in the seasonal farmer’s mini ponds.