EFFECT OF STOCKING DENSITY OF VIETNAMESE KOI (Anabas testudineus) IN SEASONAL MINIPONDS

Abstract

The current study was conducted to evaluate the effect of stocking density of Vietnamese koi (Anabas testudineus) in farmer’s seasonal mini ponds of Nilphamari and Rangpur district for a period of 120 days. There were three treatments each having three replications. Around 1.3 g weight of Vietnamese koi was stocked at the rate of 300, 400 and 500 individuals per decimal in T1, T2 and T3 respectively. All the experimental fish were fed with a commercial fish feed containing 30% crude protein two times daily at a rate of 5-15% body weight. During the experimental period the water quality parameters were suitable for fish culture. The water temperatures were ranged from 29.33 to 31.81°C; transparency 24.37 to 28.70 cm, pH 7.40 to 7.96, dissolved oxygen 5.17 to 6.28 mg l -1 and total ammonia 0.13 to 0.28 mg l -1 . Higher temperature and NH3 content were detected in the higher stocking density compared to those treatments where the stocking densities were lower. The weight gain (197.36±3.28 g) and specific growth rate (SGR 2.28±0.01% per day) were significantly increased (P<0.05) after 120 days feeding trial in the treatment T1 compared with the other treatment groups. While, a significantly lowest (P<0.05) feed conversion ratio (FCR) was observed in the treatment T1 followed by T2 and T3. Significantly highest (P<0.05) survival was observed in the treatment T1 compared with the remaining two treatments. At the end of the experiment the benefit-cost ratio (BCR) result revealed that best BCR was 1.64±0.03 in T1 which did not differed significantly (P>0.05) when compared with T2. Consequently, the results of this study designated that the lowest stocking density (300 individuals dec-1 ) seems to have a more progressive influence on the development of the growth performance and feed utilization of Vietnamese koi (A. testudineus) in the seasonal mini ponds.