Bangladesh is one of the world’s leading fish-producing country in the world. Fishes and fishery resources play a vital role in improving the socio-economic condition combating malnutrition, earning foreign currency, and creating employment opportunities in Bangladesh. The country ranked 3rd in inland open-water production and 5th in world aquaculture production. Cage culture has been successfully practiced in the open water body of Bangladesh.
The study was conducted over a period of 75 days from August to November 2023 in the Patuakhali district at kalapara upazila of Bangladesh to assess the impact of stocking density on the growth and production performance of Thai pangas in cages. The experiment was designed with three treatments namely T1 (25 fish/m3), T2 (50 fish/m3), and T3 (75 fish/m3) respectively each having three replications. The floating feed contains 30% protein supplied twice a day at the rate of 10% down to 3% of their body weight. Water quality parameters were recorded every fifteen-day interval throughout the culture period.
The water quality parameters range from temperature 26.2 to 31.6 oC, pH 7.5 to 8.7, dissolved oxygen (DO) 4.3 to 5.4 mg/l, ammonia 0.2 to 0.6 mg/l, nitrite 0 to 0.4 mg/l, alkalinity 140 to 172 mg/l, hardness 154 to 176 mg/l and salinity 1 to 5.6 ppt measured during the experimental period. At the end of the culture period higher weight gain of Thai pangas was recorded in T1 (595g) followed by T2 (587g) and T3 (584g). The survival rates were 97.65 % in T1, 96.32% in T2, and 95.89% in T3 which showed there is no significant difference (P>0.05) among treatments. The weight gain, % weight gain, and SGR were found higher in T1 followed by T2 and T3. The FCR was found same at 1.78 among treatments. The BCR was higher in T3 (1.38) followed by T2 (1.32) and T1 (1.16). The result of the study revealed that the culture of Thai pangas in cages is suitable because the growth was appreciable. Besides the stocking density up to 75 fish/m3 is appreciable without any problems in terms of growth and survival and is also economically viable compared to lower stocking density. Salinity did not affect the survivability. So, it is recommended to culture Thai pangas in a cage culture system at hyposaline water.