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Three ways of carp pond culture
Mandarin fish, also known as dragon fish, bream, eel fish, sweet-scented osmanthus fish, flower carp, and many other local names, has long been a popular species in aquaculture due to its high market value. Historically, it was mainly caught from natural water bodies, which could not meet the growing demand, leading to high prices and unstable supply. To address this, farming techniques have been developed, focusing on maintaining clean, well-oxygenated water, and providing fresh live bait with sufficient nutritional content.
In one common method, ponds with a depth of 1.5 to 2.0 meters are prepared by clearing the bottom and adding fish seedlings. The water is kept flowing to maintain oxygen levels. A stocking density of 750,000 fish per 1,000 square meters is used, along with additional water areas for raising bait fish. These areas typically hold 10 million fish per 1,000 square meters, and soybean milk is fed daily. After about 10 to 15 days, when the fish reach 1.5 cm in length, salmon fry are introduced at a rate of 3,000 to 4,500 per 1,000 square meters. As the pond fills, the fish grow in sync, and their size is carefully controlled to be 50% to 60% of the catfish's length. If bait fish become scarce, they are replenished every five days, depending on the fish population and satiation levels. Weekly water changes and two fresh water injections are performed, with lime added to keep the water clear and transparent (around 40 cm). An aerator is used during hot summer days, running for about an hour midday and two hours in the morning to improve feeding efficiency. After three months, survival rates can reach up to 64%.
Another approach involves a two-tier stocking system, where 3 cm larvae are directly raised. This method often uses large-sized, one-day-old fish or a secondary stocking technique. In the latter, fry are raised for 20 days to grow into 10 cm fingerlings before being transferred to larger pools for commercial production. This includes using small cages near the pond for intensive breeding, cultivating bait fish, and gradually introducing carp seedlings once the bait reaches 1.5 cm. Stocking density is usually 1 fish per square meter, and management focuses on oxygen levels, water quality, feeding, and disease prevention. Survival rates can reach 85% to 90%, with about 60% to 80% of 0.5 kg fish harvested by year-end. Smaller fish like trout can also be collected.
In adult fish ponds, broodstock ponds, and river ditches, polyculture systems are used to raise mandarin fish. This helps control wild fish populations and convert low-value species into high-value ones, supporting better gonadal development in broodstock. Fish stocking depends on pond conditions, including existing wild fish, bait availability, and water quality. Typically, around 3 cm fish are stocked at 40–60 per 1,000 square meters, or 25–30 fish per 25 g. In smaller rivers, numbers can be slightly increased.
Key considerations in polyculture include avoiding overgrown domestic fish that might be eaten by carp, not stocking carnivorous species together, separating broodstock from adult ponds, reducing domestic fish production to prevent overcrowding, and ensuring regular water and oxygen flow. To boost yield, carp, tilapia, and highly fertile broodstock should be included to increase food supply and economic returns.
The valve stem is an important part of the valve.
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