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Macrobrachium rosenbergii, commonly known as the giant freshwater prawn, plays a vital role in China's aquaculture industry. Ensuring the proper retention and wintering of broodstock is essential for achieving high yields and stable production in the following year. Below are the key technical aspects involved in the process: **I. Selection of Broodstock** The broodstock used for artificial breeding is typically sourced from shrimp culture ponds. The selection criteria include: 1. **Size and Weight**: Female prawns should be over 10 cm in length with a body weight of at least 25–30 grams. Males should be larger than females, as smaller individuals tend to produce fewer eggs with lower quality larvae. Larger individuals are preferred to ensure better genetic traits and higher survival rates. 2. **Health and Disease-Free Status**: Select healthy shrimp with bright coloration, normal movement, and no signs of disease. Healthy broodstock contribute to better egg viability and larval development. 3. **Intact Appendages**: Ensure that the shrimp have all their appendages, especially the walking legs and antennae, intact. During handling, care must be taken to avoid injury or detachment of these structures, which can affect mating and overall performance. 4. **Age Consideration**: It is best to select first- or second-year shrimp, preferably those that have survived one winter. These individuals exhibit faster gonad development and shorter spawning intervals. 5. **Sex Ratio**: The recommended male-to-female ratio is 4:1 to 5:1 to maximize fertilization rates. However, since males often die after mating, it’s advisable to slightly increase the proportion of males. A 3:1 ratio is usually effective. The number of broodstock to retain depends on factors such as individual size, breeding goals, survival rate during wintering, and management capabilities. Under normal conditions, about 2000 pounds of female shrimp can be expected, assuming an average weight of 35 grams per female and an 80% survival rate during winter. **II. Wintering Management of Broodstock** Wintering is crucial for maintaining broodstock health and preparing them for the next breeding season. Common methods include using plastic greenhouses or deep well water insulation in freshwater environments. A pond area of 50–100 square meters is suitable. Before entering the wintering pond, the broodstock should be disinfected with 15 ppm bleach or 100 ppm potassium permanganate. The stocking density should be around 25 prawns per square meter. The wintering period typically lasts from November to April. Key management practices during this time include: 1. **Water Temperature Control**: In early winter, maintain the temperature between 20–22°C, with a minimum of 18°C. As the season progresses, gradually raise the temperature to around 26°C. Avoid rapid temperature changes—no more than 1°C per hour and 3°C per day. 2. **Feeding Strategy**: In early winter, feed with artificial diets at 1–2% of body weight, split into morning and evening feedings, with 70% given at night. In late winter, increase feeding to 6–7% of body weight, incorporating fresh animal feeds like fish, cockroaches, and silkworms to support gonad development and improve spawning success. 3. **Water Quality Maintenance**: Ensure good aeration and oxygen levels (above 3 mg/L). Remove leftover food daily and change water regularly. Water changes should occur every 7 days, replacing 1/3 to 1/2 of the pond volume. Maintain a water depth of around 80 cm. 4. **Disease Prevention**: Disinfect both the pond and the shrimp before wintering. Monitor shrimp behavior and feeding regularly. Use antibiotics like oxytetracycline (1 ppm) or chloramphenicol (0.5 ppm) every 15 days to prevent disease outbreaks. By carefully managing broodstock selection and wintering conditions, aquaculturists can significantly improve the quality and quantity of offspring, ensuring long-term productivity and sustainability in Macrobrachium rosenbergii farming.

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