To successfully cultivate broodstock, it's essential to start by selecting the right pond. The ideal location should be quiet, with easy access and proximity to both water sources and a urine production pool. The pond bottom should be flat and leak-proof, with an area of 1.5 to 2 acres and a water depth of about 2 meters, making it suitable for broodstock rearing.
Next, proper stocking is crucial. The average stocking rate should be between 100 kg to 150 kg per acre. However, this may vary depending on the species—grass carp might require slightly higher stocking, while white catfish should be kept at lower densities to avoid overcrowding.
Fertilization should be moderate, especially during the spring when fish gonads are developing and their food intake increases. Organic fertilizers like manure are preferred, with cow dung being the main choice, accounting for around 70%, and other livestock manures making up the remaining 30%. In carp ponds, powdered compound feed or bean cake can also be used. Fertilize once a week, applying approximately 200 kg per mu. The water clarity should be maintained between 35 cm and 45 cm, with the water color ideally yellow-green or oil blue. Avoid heavy fertilization in the first half of the month before spawning.
Controlling water temperature is another key factor. During sunny days, lowering the water level by about 30 cm helps increase the temperature. However, if rain or cold weather approaches, refill the pond in advance to slow down the cooling process.
Feeding should be adjusted based on water temperature. Once the temperature reaches 10°C, broodstock begin feeding, and the amount should gradually increase as the temperature rises. Transition from concentrated feeds to green feeds, adjusting the quantity based on feeding behavior and water conditions.
Water quality must be carefully managed. Maintain a balance between richness, vitality, and coolness. Before spring feeding and fertilizing, replace half the old water with fresh water to keep the depth around 1 meter. This helps raise the water temperature and improve energy conversion, supporting broodstock development. Spring flushing is an effective method to stimulate gonad growth, typically done twice a month, adding 5–10 cm of water each time. A week before spawning, flush daily for 2–3 hours, especially for grass carp. Throughout the breeding season, maintain clear water with transparency above 35 cm.
During flushing, ensure the water flow is moderate—not too fast to tire the fish, nor too slow to reduce effectiveness. If water supply is limited, reuse existing pond water or exchange with adjacent ponds. Starting in late April, implement a daily 3-hour pre-spawning water stimulation routine.
Lastly, regular pond inspections are vital for disease prevention. Check the pond twice a day—at dawn and dusk—to monitor feeding activity and water clarity, adjusting feed and fertilizer accordingly. If signs of illness or floating fish are observed, immediately add fresh water or use an aerator to improve conditions.
Handheld Dry Chemistry Analyzer
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