The prospects for yellow catfish polyculture are good, and this farming model is worth paying attention to
Yellow catfish, also known as gayazi, huangga, angsi and so on, is an important economic fish in China's freshwater aquaculture. The flesh of yellow catfish is tender, nutritious and delicious, and market demand has continued to grow rapidly in recent years. Because the yield from natural waters and pond culture is very limited, it is difficult to meet the growing market demand, which has kept the market price of yellow catfish high for a long time. Polyculture of yellow catfish in ponds requires little investment and offers high returns, and the farming prospects are generally viewed favorably.
Pond conditions
Ponds for polyculturing yellow catfish should have good water source conditions and be free of any polluted water bodies. The pond should be rectangular in shape, with an area of 3 to 10 mu, and a water depth of 1.5 to 2 m is ideal. The pond should have escape-prevention facilities, and escape-prevention nets should be installed at the water inlet and outlet. The pond water pH should be between 7 and 8.5, and dissolved oxygen should remain above 4 mg/L. Natural food resources in the pond should be abundant, with high levels of organisms such as plankton, water @#@254@#@, small fish and shrimp, and aquatic insects.
Polyculture density
Fingerling ponds, grow-out ponds, broodstock ponds for other fish, and river crab ponds can all be used to polyculture yellow catfish, and the pond should contain abundant small wild fish and shrimp as feed for the yellow catfish. Stocking is done from late April to early May, with 4,500 to 9,000 yellow catfish fingerlings of 3 to 5 g stocked per hectare. Other fierce fish should not be polycultured in the pond, so as to prevent the yellow catfish fingerlings from being preyed upon; when 750 to 3,000 yellow catfish of 15 to 20 g are polycultured per hectare, the yield of yellow catfish can be increased by 75 to 300 kg per hectare. In addition, polyculturing yellow catfish can also significantly reduce the incidence of anchor worm disease in other fish and reduce the amount of medication used. Ponds for polyculturing yellow catfish should mainly raise silver carp, bighead carp, bream, grass carp and so on as the main species, but common carp or crucian carp should not be used as polyculture species, because their feeding habits are basically the same and adverse effects are likely to occur, and they should certainly not be polycultured together with fierce carnivorous fish such as catfish.
Polyculture management
In the feeding management of ponds polyculturing yellow catfish, in addition to carrying out the routine management of pond @#@233@#@, special attention should be paid to doing a good job of water quality management, always keeping dissolved oxygen in the water above 4 mg/L, and frequently adding water. Especially in the high-temperature season from July to September, water should generally be added once every 2 to 3 days, with no less than 15 cm added each time, and at the same time the aerator should be run for 2 to 3 hours every day to ensure sufficient dissolved oxygen and prevent fish from gasping at the surface. If rotational harvesting and restocking techniques can be implemented to always maintain a moderate fish carrying capacity in the pond, the farming results will be even better.
In ponds polyculturing yellow catfish, when preventing and treating diseases in the main cultured species, care should be taken not to affect the normal growth of the yellow catfish. Because yellow catfish is a scaleless fish, drugs can more easily penetrate directly into the body through the skin, so when applying drugs to it, the dosage must be strictly controlled to prevent death from acute and chronic poisoning. Yellow catfish is relatively sensitive to malachite green, copper sulfate, mercurous nitrate, potassium permanganate and trichlorfon, and these must be used with special caution. In addition, in ponds polyculturing yellow catfish, before the yellow catfish has grown to a market size of about 100 g, it is best not to fish there, because yellow catfish is relatively easy to hook.
Related links
Kong Lingjie, a senior engineer at the Heilongjiang Provincial Fisheries Technology Extension Station, offers the following suggestions to farmers:
1. Maintain relatively high dissolved oxygen in the water body. Yellow catfish has relatively high requirements for dissolved oxygen in pond water, so during polyculture the water quality is required to be fresh and the dissolved oxygen sufficient. During the growing season, new water should be added in a timely manner, and during the high-temperature season the water should be changed frequently; maintaining slight water flow is even better.
2. Maintain reasonable stocking density and stocking size. According to the amount of food organisms in the water body, scientifically and reasonably determine the polyculture ratio and stocking size. If the density is too high and the size too small, the market size will not be reached by the end of the year.
3. After yellow catfish is polycultured in a fish pond, it is no longer suitable to polyculture other carnivorous fish, and yellow catfish should not be polycultured in ponds for freshwater prawns or freshwater crayfish.
4. During the farming process, if the yellow catfish is found to be too small, it indicates that the amount of natural food organisms in the pond is insufficient, and small fish and shrimp, summer fingerlings of domestic fish, or artificially prepared special yellow catfish feed can be appropriately added or fed. Yellow catfish has the habit of hiding by day and coming out at night, so feeding should mainly be done at night.
5. Yellow catfish can also be polycultured in crab ponds. Because river crabs and yellow catfish occupy the same water layer ecologically, competition for the same ecological niche between the two is likely to occur. Therefore, crab ponds must maintain sufficient natural food organisms, otherwise the rearing results for yellow catfish will be affected.