The stocking of crabs is the first process of adult crab breeding. Preparation for pre-stocking, selection of pure breeds, good-quality and good-quality crabs and scientific stocking are the key to the success and failure of raising crabs, and the stocking of crabs should be noted. Do the following.
First, pay attention to clear pond disinfection.
Clear ponds are best conducted in the winter season by draining the pool water, digging out excess silt, refinishing loopholes, strengthening the stacking, removing weeds, and allowing the bottom of the pond to be filled with water for about 30 cm after several days of freezing, and then disinfected with drugs. To kill bacteria, parasites, and pests. Commonly used drugs are lime, tea seed cake, sodium perchlorate, etc. The dosage per mu (ie 667) is 75-100kg, 30-50kg, 2-3kg respectively. The above drugs may be used alone, or may be multiplexed afterwards, with a single dose selection lower limit and multiplexing amount selection upper limit, and an appropriate amount of “wax water†may be filtered and injected after 10 days of disinfection.
Second, pay attention to create an environment.
Lakes, grasslands, and other excellent natural ecological environments are very beneficial to crab inhabitation, clams, growth, and disease prevention. Therefore, planting plants and fresh snails should be transplanted before and after planting. Before planting, ryegrass and small algae can be sown. Transplanting water plants such as barnyardgrass and water peanuts. It takes about 1 month for the plants to be planted to grow leaves. Therefore, when the seeds are planted, they should be surrounded by bamboo culms and dense meshes in the deepwater area to form a net enclosure area of ​​about 10% of the total area. After the ecological scene is intact, it is removed. The sowing amount of aquatic weeds is generally 50-70g per mu; the coverage of aquatic weeds accounts for about two-thirds of the surface of crabs; the amount of fresh snails is 300-500kg per mu.
Third, pay attention to the quality of crab species.
The quality of crabs is the key to raising crabs. Crab species are divided into natural seedlings and artificial propagation seedlings, as well as differences between the Yangtze River water system, the Gull River water system, and the Liaohe River water system. At present, the best species of crabs cultivated by natural Yangtze River water system seedlings, but the number is very small, normally the crabs cultivated by the artificial breeding of crabs in the Yangtze River water system should be carefully identified during purchase, and they should be prevented from being shoddy and shoddy. It is better to breed crabs or purchase local healthy crabs to ensure the quality of crabs, avoid the long-distance transfer of crabs from other regions, and resolutely stop the purchase of “disease†crabs from diseased areas. At the same time, to identify precocious crab species, the gonads of precocious crab species have been fully developed, and they are susceptible to false mating after stocking. Precocious female crabs covered the abdomen with a round umbilicus, and many sides of the umbilicus were covered with dark hairs. The male crabs covered the abdomen with a triangular umbilicus and the legs were long, thick and dense. In addition to pure products, the selected crabs should be properly sized, with complete limbs, active crawling, good health, and no disease or injury.
Fourth, pay attention to stocking methods.
1, stocking time. Early release can make crab species adapt to the new environment earlier, open foods and shells earlier, extend the growth period, and increase product specifications. Generally, they can be stocked from January to April. When the water temperature is stable at around 10°C, you can select sunny weather and stock up at around 10am.
2. Stocking density: According to the aquaculture water, the source of the bait, the required market specification and the level of feeding and management, etc., the general pond can be placed in 800-1200 pieces of crab per kg (60-240 pieces), lake nets, rice fields, and large Water areas such as surface water should be appropriately reduced.
3, disinfection of crab species. In order to prevent the crabs from entering the parasites, the crabs can be bathed with 2%-5% saline or 5106-10106 potassium permanganate solution for 5-10 minutes before stocking.
4, stocking methods. The crab species that have been transported for a long time before leaving the water should be immersed in the water for 2-3 minutes before they are stocked, placed for about 10 minutes, and then re-infused with water for 2-3 minutes. This is repeated 2-3 times to allow the crabs to climb by themselves. Into the water, so that the distribution of crabs evenly, do not directly pour crabs into the water in order to improve the survival rate.
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