Inadequate seed supply remains a bottleneck for the expansion of the Macrobrachium rosenbergii production industry. Nevertheless, the limitation is not technical, and thus, we presumed that fragile production chains and economic feasibility might be the major issues. Therefore, we investigated the intensification as a way to improve the system's profitability and resilience. We have reported relevant costs and revenues of hypothetical hatcheries stocking 50, 100, and 140 larvae per L in clear water recirculating systems. A Monte Carlo simulation assessed the risks associated with development and management. Data showed that all hatcheries are profitable. Nevertheless, 100 and 140 larvae per L reached better economic results than 50 larvae per L. With less than 40% of the selling price, high‐density hatcheries covered their costs and became profitable. The Monte Carlo simulation demonstrated that high‐density hatcheries are more resilient to production and marketing oscillations. However, the use of 140 larvae per L requires greater investment and is more susceptible to production risks and instabilities. Therefore, 100 larvae per L is the most appropriate stocking density for M. rosenbergii hatchery in clear water recirculating systems. Additionally, the scaled production, the adoption of realistic selling price, diversification of products and markets may strengthen the production chain and hatcheries resilience.

We evaluated the bioconversion of domestic wastewater into protein biomass through duckweed based ponds and fish farming in a pilot recirculating system. The average duckweed wet biomass yield obtained during the experimental period was 4.96 kg/m² (1.3 kg dry matter; 63 g/m²/day), with crude protein and fiber content of 38.03% and 16.17%, respectively. Tilapia final average weight, feed conversion rate, and specific growth rate when fed pelletized duckweed were similar to values with commercial feed. Duckweed production removed 30.8% and 28.7% of ammonia and phosphate, respectively, from stabilized domestic wastewater.

The present research aimed to investigate the stabil¬¬ity of pellets and phosphorus leaching of diets formulated for juveniles of Nile tilapia (Oreochromis niloticus), with different sources of phosphorus and different exposure times in water. Six diets were elaborated by varying the source of phosphorus (1 ‒ dicalcium phosphate (DP); 2 ‒ meat and bone meal (MBM); 3 ‒ poultry meal (PM); 4 ‒ anchovy meal (AM); 5 ‒ tilapia filleting industrial meal (TM); 6 ‒ calcined bone meal (CBM)) and, then, were submitted to four exposure times in water (5, 10, 15 and 20 minutes), with three replicates. Thus, 72 aquariums of 30‒liters were used, each being an experimental unit. All diets were evaluated for electrical conductivity of water, turgidity of pellets, mineral matter leaching, flotation of pellets, and total phosphorus leaching. Only turgidity and flotation of pellets varied with the different sources of phosphorus in the diets. The MBM diet had the highest turgidity of pellets. The PM, AM, and CBM diets had the highest flotation of pellets. The total phosphorus leaching had a linear effect with the increase of the exposure time, showing a greater release of phosphorus in the water with increase of exposure time. Data showed that PM, AM, and CBM diets had less potential impact on the aquatic environment. Conversely, the TM diet has greater polluting potential. These results showed that diets formulated with different sources of phosphorus exhibit distinct actions in the water, providing different effects on the fish culture environment.