Bangladesh is one of the world’s leading fish-producing country in the world . Cage aquaculture has grown rapidly during the past decades in different countries to mitigate the worldwide global demand for aquatic products. Cage culture has been successfully practiced in the open water body of Bangladesh . Pabda (Ompok pabda) is an indigenous commercially important fish that is highly demanding for cage culture.
The study was conducted over 90 days from July to October 2022 in an earthen pond of Patuakhali Science and Technology University to assess the species suitability for polyculture of Pabda (Ompok pabda) in a cage culture system where Gulsha (Mystus cavasius) and S tinging catfish (Heteropnuestes fossilis ) practiced as co-species with Pabda. Stinging catfish is locally known as shing. The experiment was designed with three treatments namely T1 (only Pabda- 100%), T2 (Pabda -50% and Gulsha-50%), and T3 (Pabda-40%, Gulsha-30% and S tinging catfish -30%) respectively each having three replications. The stocking density was 300/m3 . Firstly they are fed with starter powder feed which was then replaced with floating feed containing 30% protein supplied twice a day. Water quality parameters were recorded every fifteen-day interval throughout the culture period.
Water quality parameters were within the suitable range for fish culture. At the end of the culture period higher weight gain of Pabda (13.81g) was observed in T2 followed by (13.59g) in T1 and (12.53g) in T3 and Gulsha showed higher weight gain (12.08g) in T2 followed by (11.87g) in T3, lowest weight gain observed for S tinging catfish (8.54g) in T3. The survival rate of Pabda ranges from 73.53 to 75.52 % and Gulsha from 95.78 to 95.89 %. The lowest FCR value was obtained from T2 (2.42) followed by T 1 (2.5) and T 3 (3.0). Higher production of fish (kg/m3) was recorded in T2 (3.59 kg) followed by T1 (3.48 kg) and T3 (2.86 kg). However, a short economic analysis of the present experiment revealed that the maximum profit obtained from T2 followed by T3 due to the combination of three different species commanding a higher market price and than T1. The BCR was higher in T2 (1.65), followed by T3 (1.36) and T1 (1.30). The result of the study revealed that the culture of Pabda with Gulsha in the cage is more suitable than with Gulsha and S tinging catfish (both) because the growth performance and survivability of Stinging catfish were very poor. Overall Pabda in T1 showed averagely good performance but in terms of profitability Pabda with other species (Poly culture) was more profitable than single species (monoculture) and these studies recommended Gulsha (M ystus cavasius) to culture with Pabda in terms of production and profitability. So, it is not recommended to culture Shing with Pabda in the cage culture system.