Effect of stocking densities on growth, production and survival rate of red tilapia in hapa at fish hatchery Chilya Thatta, Sindh, Pakistan

Effect of stocking density on growth, production and survival of red tilapia ( Oreochromis mossambicus × O. niloticus ) were conducted in hapa for 60 days at Chilya Thatta. Tilapia fry (4.5±0.02 cm, 2.0±0.01 g) were stocked into hapa (4.5x2.4x1 m). Three treatments with two replicates were used: T 1 -200; T 2 -250 and T 3 -300 fry/ hapa . Fry were fed twice a daily with pelleted feed containing 35% protein, 5% of total biomass. After 60 days, the highest growth were determined in T 1 (49.8±0.0 g) while in T 3 lowest growth (29.09±0.0 g) was recorded. Production (9.56, 10.13 and 8.12 kg/m 3 /60days) in T 1 , T 2 and T 3 respectively were significantly different ( P 0.05). Survival was significantly different among treatments ( P <0.01). Highest survival (100%) was attained in T 1 with lower stocking density, followed by T 2 (98%) and T 3 (95%). Water quality parameters recorded throughout the study period were found within the ranges for fish culture such as temperature 27.2 to 28.5 °C, dissolved oxygen 5.8 to 6.4 mg/l, pH 6.9 to 7.6, ammonia from 0.45 to 0.51 mg/l, hardness 106 to 110 ppm and nitrite 0.151 to 0.162 mg/l.