Evaluation of the yield performance of freshwater prawns (Macrobrachium rosenbergii) cultured in a biofloc system at various densities

Biofloc technology is beneficial for prawn farming because it saves resources, protects the environment, and uses less energy. This study was conducted to evaluate the yield performance of freshwater prawns (Macrobrachium rosenbergii) cultured in a biofloc system at various densities (T-1 = 50 prawn/m², T-2 = 70 prawn/m², and T-3 = 90 prawn/m²). The experiment, which was conducted over 180 days with three replications, utilized rectangular aquaria with a water volume of 100 liters. Before stocking, post-larvae (12 days old) were nursed in a mother tank for 40 days. Throughout the experiment, water quality parameters, such as temperature, dissolved oxygen, and pH, were monitored daily. Total ammonia nitrogen (TAN) was measured three times a week, whereas nitrite (NO2), alkalinity, and hardness levels were assessed weekly. After the experiment, we evaluated growth performance metrics, including weight gain, specific growth rate (SGR), feed conversion ratio (FCR), and survival rate. The plankton densities in the experimental units were also observed. Except for alkalinity, all water quality variables remained within the optimal range. The maximum weight gain, SGR (%), efficient FCR, and survival (%) were 35.35±8.54, 2.04±0.08, 1.91±0.10, and 74.00±9.57, respectively, in T-1. In contrast, the highest planktonic density (46.8×104 cells/L) was found in T-3. Finally, the results suggest that a stocking density of 50 prawns/m2 yielded better results in a zero water exchange biofloc culture tank and can enhance prawn culture in the farmer’s field.