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Abstract : |
An experiment was conducted to evaluate the water quality, growth and production of fishes at different species compositions in polyculture using tilapia (Oreochromis niloticus), pangas (Pangasius hypophthalmus), mrigal (Cirrhinus mrigala) and silver carp (Hypophthalmichthys molitrix). The experiment was conducted for a period of 90 days from September 8, to December 7, 2002 at the Fisheries Faculty Field Laboratory of Bangladesh Agricultural University, Mymensingh. There were three treatments each with three replications. In all the treatments, the stocking density was 100 fish/decimal at different species compositions. All the ponds were subjected to same regime of feeding and fertilization. Fortnightly random sampling was done to adjust the feeding rate. In this experiment, mrigal showed the highest SGR (% per day) value (3.74) in T2. Tilapia showed the second highest (3.65) SGR (% per day) in T1. Specific growth rate (% per day) of pangas was comparatively lower in all treatments. Mean survival rates of various species ranged from 90.63 to 91.10%. Comparatively, tilapia showed the highest survival rate where pangas showed the lowest. T1 showed the highest survival rate but there was no significant variation among the treatments. Weight gain (g) of tilapia, pangas, mrigal and silver carp were 89.18, 30.61, 85.75 and 91.71 g in T1, 63.95, 37.24, 86.86 and 65.63 g in T2 and 70.84, 47.65, 70.42 and 72.87 g in T3, respectively. The highest and the lowest weight gain were found in T1. Silver carp attained maximum weight gain (91.71 g) in T1 where pangas showed the lowest (30.61g) in the same treatment. Among the treatments, the highest production was found in T1 (1974.02 kg/ha/90 days) which was significantly higher than other treatments. The production in T2 and T3 were 1405.59 and 1522.01 kg/ha/90 days but there was no significant variation between T2 and T3. Considering the above, pangas showed the lowest growth performance and production in all treatments compare with other species. From the findings of the present study, it can be said that polyculture of pangas with tilapia is not suitable, but it may be suitable with carps and for this further research is necessary. , An experiment was conducted to evaluate the water quality, growth and production of fishes at different species compositions in polyculture using tilapia (Oreochromis niloticus), pangas (Pangasius hypophthalmus), mrigal (Cirrhinus mrigala) and silver carp (Hypophthalmichthys molitrix). The experiment was conducted for a period of 90 days from September 8, to December 7, 2002 at the Fisheries Faculty Field Laboratory of Bangladesh Agricultural University, Mymensingh. There were three treatments each with three replications. In all the treatments, the stocking density was 100 fish/decimal at different species compositions. All the ponds were subjected to same regime of feeding and fertilization. Fortnightly random sampling was done to adjust the feeding rate. In this experiment, mrigal showed the highest SGR (% per day) value (3.74) in T2. Tilapia showed the second highest (3.65) SGR (% per day) in T1. Specific growth rate (% per day) of pangas was comparatively lower in all treatments. Mean survival rates of various species ranged from 90.63 to 91.10%. Comparatively, tilapia showed the highest survival rate where pangas showed the lowest. T1 showed the highest survival rate but there was no significant variation among the treatments. Weight gain (g) of tilapia, pangas, mrigal and silver carp were 89.18, 30.61, 85.75 and 91.71 g in T1, 63.95, 37.24, 86.86 and 65.63 g in T2 and 70.84, 47.65, 70.42 and 72.87 g in T3, respectively. The highest and the lowest weight gain were found in T1. Silver carp attained maximum weight gain (91.71 g) in T1 where pangas showed the lowest (30.61g) in the same treatment. Among the treatments, the highest production was found in T1 (1974.02 kg/ha/90 days) which was significantly higher than other treatments. The production in T2 and T3 were 1405.59 and 1522.01 kg/ha/90 days but there was no significant variation between T2 and T3. Considering the above, pangas showed the lowest growth performance and production in all treatments compare with other species. From the findings of the present study, it can be said that polyculture of pangas with tilapia is not suitable, but it may be suitable with carps and for this further research is necessary., |
