Bioscience Evidence 2026, Vol.16, No.4, 264-276 http://bioscipublisher.com/index.php/be 272 important factor affecting water pollution. By regulating the carbon-to-nitrogen ratio, microorganisms can better utilize residual organic matter and nitrogen-containing substances, thereby reducing pollution loads and improving feed conversion efficiency. In a zero-water-exchange biofloc nursery system, different C/N ratios significantly affected production performance and water quality. The treatment with a C/N ratio of 20 achieved better overall performance, with a feed conversion ratio of 2.65, while total ammonia nitrogen and nitrite concentrations were significantly lower than those in the clear-water control group (Hosain et al., 2021). Proper regulation of water nutrient structure can therefore achieve simultaneous improvement of water quality and production efficiency. In addition to water quality regulation technologies, long-term environmental optimization can also improve economic returns from aquaculture. A full production-cycle probiotic application experiment showed that continuous probiotic use improved growth performance, protein utilization, production output, and net income of M. rosenbergii. The continuous probiotic treatment group showed better growth patterns and economic performance (Azad et al., 2023). In a M. rosenbergii farming system in the mountainous region of India, optimized feed management combined with suitable water environmental conditions improved production and economic returns. The benefit-cost ratio of the formulated feed group reached 1.62, higher than the 1.23 observed in the conventional feed group, with production levels of 865 kg/ha and 637 kg/ha, respectively (Khemundu and Banerjee, 2019). Water environment management not only reduces aquaculture risks but also directly improves the economic benefits of family farms and large-scale aquaculture systems by reducing pollution, improving feed utilization efficiency, and stabilizing production. 6 Sustainable Water Quality Management and Future Development Directions 6.1 Water quality management system based on culture stages For prawn farms, establishing a stable water quality monitoring system is the foundation for reducing aquaculture risks. The pond environment of Macrobrachium rosenbergii changes rapidly, and relying only on visual observation of water color or experience-based judgment often makes it difficult to detect potential problems such as oxygen deficiency and increasing ammonia nitrogen levels in time. Therefore, aquaculture management should establish a hierarchical monitoring system based on risk levels. In daily management, temperature, pH, and dissolved oxygen are the basic indicators requiring the most attention and should be monitored according to daily variations. Transparency, ammonia nitrogen, nitrite, and turbidity can be measured regularly according to stocking density and feeding amount to evaluate organic matter accumulation and algal changes. During high-temperature seasons, feed transition periods, and late culture stages, additional attention should be paid to total nitrogen, total phosphorus, and chlorophyll a to assess the overall nutrient status of ponds. Even when monitoring systems do not have automatic control functions, using water quality data to guide manual aeration and management decisions can effectively reduce oxygen deficiency risks (Vaughan and Ankumah, 2018). Water quality management should also be adjusted according to different growth stages of M. rosenbergii. During the seedling and juvenile stages, temperature, pH, and ammonia nitrogen levels should be carefully controlled because early-stage individuals are more sensitive to environmental changes. During adult prawn culture, increasing feed input requires greater attention to dissolved oxygen, organic matter accumulation, and algal community stability. For small-scale farms, it is not necessary to establish complex automated systems at the beginning. Instead, priority should be given to developing a management process of “regular monitoring, timely evaluation, and rapid adjustment.” Aeration time can be adjusted according to dissolved oxygen changes, feeding amount can be modified according to transparency and water color, and water exchange, microbial regulation, or feed reduction can be applied according to ammonia nitrogen changes. This basic management approach is essential for achieving stable production. 6.2 Low-cost ecological regulation and digital management technologies For most prawn farms, water quality improvement should first consider cost and operational feasibility. Low-cost and easily applicable ecological regulation measures remain the most practical approaches. Supplementary aeration, reasonable feed reduction, plant co-culture, and polyculture systems can all reduce environmental pressure in ponds. Diversified farming systems can improve resource utilization efficiency in small-scale
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