EFFECTS OF FISH POPULATION DENSITIES ON GROWTH AND PRODUCTION OF FISHES

The experiment was carried out under three treatments each with two replications. Fish population density was 80 fish per decimal (silver carp 32, tilapia 32 and mrigal 16) under treatment-1, 120 fish per decimal (silver carp 48, tilapia 48 and mrigal 24) under treatment-2 and 160 fish per decimal (silver carp 64, tilapia 64 and mrigal 32) under treatment-3. The average initial length and weight of the fingerlings of silver carp, tilapia and mrigal were 7.49, 5.12, and 5.56 cm and 8.00, 2.00 and 1.50 g respectively. The ponds were fertilized fortnightly with cowdung, urea and TSP (triple super phosphate) at the rates of 5 kg, 60 g, and 90 g per decimal, respectively. During the experimental period, the range of water temperature (30.20 to 32.900C), transparency (28 to 38 cm), dissolved oxygen (8.20 to 10.60 mg/L), pH (6.90 to 7.90), total alkalinity (92.00 to 127.00 mg/L), free CO2 (1.00 to 1.60 mg/L), phosphate-phosphorus (1.00 to 1.90 mg/L), and nitrate-nitrogen (1.90 to 3.90 mg/L) were within the productive range and more or less similar in all the ponds under three treatments. Ther