Estimating the Nanobubble Aerated System and Stocking Density Effects on Oxygen Consumption and Survival of Litopenaeus vannamei (Boone, 1931) Postlarvae 8 Using Receiver Operating Characteristic (ROC) Analysis

Litopenaeus vannamei postlarvae (PL) 8 were usually stocked at high densities, affecting the shrimp and water quality. This condition makes stocking density becomes a challenge in shrimp cultures, and one of the solutions for this is using a nanobubble aerated system. Meanwhile, there is a lack of robust studies estimating the nanobubble and stocking density effects on shrimp survival and water quality. This study used different stocking densities of 200, 400, and 600 postlarvae/L under nanobubble treatment and control (without nanobubble) to culture L. vannamei PL 8 and were assessed using Receiver Operating Characteristic (ROC) analysis. The ROC showed that the values of area Under the Curve (AUC) for dissolved oxygen (DO), survival rates, and oxygen consumption were 0.826 (95%CI: 0.598-1.000), 0.722 (95%CI: 0.47-0.794), and 0.576 (95%CI: 0.28-0.873), respectively. Considering these AUC values, it can be concluded that nanobubble treatment has the possibility to affect DO and shrimp survival, although it is not the same for shrimp oxygen consumption because it has the lowest AUC values. The optimum values for DO, survival rates, and oxygen consumption of shrimp under nanobubble treatment were observed at densities of 400 postlarvae/L. The survival and oxygen consumption of L. vannamei PL 8 at this density were 96.83% (95%CI: 95.2-98.4) and 0.52 mg/g/h (95%CI: 0.46-0.57). Meanwhile, water DO, temperature, and EC were 4.08 mg/L (95%CI: 2.84-5.32), 27.27°C (95%CI: 27.30-27.40), and 1.43 mS/cm (95%CI: 1.40-1.46), respectively. Nanobubble has maintained DO and temperature in the suitable range for L. vannamei PL8 survival.