I have been engaged in artificial breeding of crabs since the early 1990s. In particular, in recent years, a set of techniques for low-cost, high-yield, superior-quality, and economically-efficient pond culture crabs have been summarized and widely promoted. A very good effect. 1. Aquaculture ponds should be selected for cultivation in areas suitable for crab production. At the same time, it is required to have sufficient water sources, no pollution, and convenient drainage and drainage. 2. Select high-quality crab species. Select the reliable, moderately sized Chinese mitten crabs in the Yangtze River water system. Use the coastal nursery facilities to transport the high-quality crabs that have been bred back to the local area and cultivate crabs. This will not only ensure quality, but also improve the survival rate. The spread of pathogens is conducive to the cultivation of large-size, high-quality commercial crabs. 3, reasonable stocking density when stocking, select specifications and tidy, physically strong individuals, specifications in 100--300 per kilogram, 600-800 acres to put; specifications in 2000-4000 per kilogram, 1500--2000 acres only. Restocking time is appropriate from the end of February to the end of March in early spring. 4. Creating a good environment To create a water environment suitable for the growth and development of crabs, the key is to cultivate aquatic animals and plants, so that the biological communities and the environment in the water area together constitute a natural whole. (1) Cultivation of aquatic plants Aquatic plants suitable for cultivation in crab ponds include black-leaf algae, Elodea, and Vallisneria. During planting, the alfalfa of aquatic species is formulated according to each growth stage of the crabs to form a combination of high-grade water and submerged water. The aquatic grass community always maintains the 1/3--2/3 water grass cover rate in the pool, which can provide habitat for crabs, avoiding enemies and shelling sites, and delicious feeds. It can also increase dissolved oxygen in water and purify water quality. . (2) Putting a certain amount of fresh snail shellfish into the pool of snails is a natural bait for crabs, and it also eliminates leftover bait for bottom debris. Every year, from April to April, 400--500 kg of live snails are placed per acre to allow them to reproduce naturally, and according to the growth conditions, fresh snails are replenished from time to time to keep live snails at a certain density in the crab pond. (3) Filter-feeding fish, squid, and green prawn are nested in crab ponds, and appropriate feeding of oysters, squid, and green prawns, as well as fish, shrimp, and crabs, can fully utilize the potential of pond production. In general, 20- to 30-kilograms of tadpoles are reared, 5 to 10 mackerel, and 1.5-3 kilograms of juveniles. (4) Probiotics such as photosynthetic bacteria are regularly introduced into crab ponds. 5, regulate the quality of pond water is mainly to adjust the pool of water, increase the pool of dissolved oxygen. The first is to spit lime regularly, usually about 10 kg per mu. After spraying a quick lime for 7 to 10 days, some soluble phosphates, such as calcium dihydrogen phosphate, should be applied. Generally about 1 kg per mu, in order to maintain the balance of calcium and phosphorus in water. Promotes normal shelling of crabs. The second is to constantly change new water. Usually 7 to 10 days, new water is added once, each time water is injected by 5 to 10 centimeters, and once in half a month, the water exchange volume accounts for about 1/4 of the total pool water. 6, science feeding through the cultivation and transplantation of aquatic plants, increase the type and density of natural food, in the basic meet the nutritional needs of river crabs, timely and appropriate amount of fresh small fish feeding. Feed feeding follows the principle of "two fine, medium thick, and meaty ingredients matching". In the early stage, "reclamation and husk removal" was used. In the later stage, the goal of "fattening, strong breeding, and gaining weight" was taken. Plants were planted from July onwards. The main feed is: In the later stage of growth, 60% of animal feed is fed and 40% of plant feed is fed; sticking to “Four Ding†feeding improves quality and maintains a good ecological environment. 7. Actively prevent diseases and adhere to the principle of "prevention first, prevention and control combined", mainly ecological control, supplemented by drug control, disinfection of good clear ponds, disinfection of seedlings, etc. to cut off pathogenic transmission routes; actively planting plants, Self-developed crab seedlings, scientific feeding, water quality regulation, probiotics and other technical measures to achieve no or less medication, not sick or less sick. The use of drugs, but also according to the different symptoms of crab disease, the use of high efficiency, low toxicity, non-residue drugs, symptomatic use, and do pest control and sterilization combined, combined with oral and external use, Western medicine and Chinese medicine combined.
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