First, method

1. Pond preparation

220 acres of breeding bases were selected for breeding bases, and the original large ponds were converted into 65 ponds ranging from 2 to 5 acres according to the characteristics and requirements of the cultivation of crab species. A 40-mesh grate net is laid around the pool floor, and the bottom of the pool is covered with tiles. Artificial caves are created to prevent crabs from appearing during the cultivation process of crabs. The crabs are of uniform specifications and good physique. Properly set up the water peanuts and plant the Elodea, so that each pond forms a cultivating environment that fully simulates the natural ecological conditions. specific methods:

(1) The pond area is 2 to 5 mu, the water depth is about 1.5 meters, and the drainage and drainage systems are matched to install anti-escape mesh at the inlet and outlet.

(2) Clear pond disinfection. Before the end of March, carry out the exposure of the pond, use bleaching powder to disinfect, kill pests, the water depth of 0.5 meters is 10 to 15 kg/mu, 7 to 10 days after the drainage, and then use quicklime 100 to 150 kg/mu clear pond.

(3) Planted aquatic plants in April. After 15 days of clear ponds, Elodea was released, accounting for 30% of the area for hiding inhabiting young crabs.

(4) Small ponds are laid at the bottom of ponds in the ponds, which account for 10% to 15% of the floor area.

2. Bigeye larvae stocking

(1) Large-eyed larval parent selection. In the Yangcheng Lake area, the pure Chinese mitten crab in the Yangtze River water system was selected as the parent. The male parents were between 150 and 175 g/body, and the female individuals were around 125 g/body. Each parent was required to have appendages that were sound and free from disease. With strong activity, special personnel are sent to the Tupai nursery in coastal areas to cultivate crab seedlings, and special personnel are assigned to supervise the whole process of seedling raising in the soil pool.

(2) Seed stocking. In order to ensure the survival rate, 15 tons of organic fertilizer is applied per acre five days prior to planting, and water quality is cultivated so as to provide sufficient biological feed for the big eye larvae of the lower pond.

(3) Stocking density. One kilogram of crab seedlings with an average of one mu of healthy and high-quality stocking is sized to about 140,000 eggs per kilogram.

3. Feed the feed

According to the growth of juvenile crabs, eating and weather conditions determine the amount of feed each day. At the stage of bigeye larvae, feeding was performed 4 times a day, which was mainly composed of egg yolk and larval compound feed, supplemented with soymilk (mainly cultivated biological bait). After the metamorphosis, it was fed twice a day. The feed is mainly composed of artificial compound feed, and attention should be paid to the addition of aquatic plants. In the later period, some fresh fish are properly fed to provide necessary animal nutrition for wintering. A total of 65,000 kilograms of pellet feed and 0.8 million kilograms of fresh fish were fed throughout the year.

4. Water Quality Management

In the earlier period, the main fertilizer was weight gain, and no water was changed. In the medium term, fertilizer-maintaining water is mainly used, and a small amount of water is changed. In the later period, improved water quality is mainly used to change water frequently. During the hot season, change the water every 3 to 5 days. Change the water volume every time and hold 15 to 20 centimeters. Adjust the pool water to “fat, live, cool and tender”. The transparency is maintained at 30 to 40 cm. The pH is maintained at Between 7.5 and 8, dissolved oxygen is kept above 5 mg/l, and quicklime is regularly applied.

5. Disease prevention and treatment

In the breeding process, the principles of disease-free early prevention, disease early treatment and prevention and control combination shall be implemented. Use pesticides and water disinfection once every month. The drugs used are highly irritating, non-lesional and highly effective drugs with low toxicity.

6. Daily management

Strictly implement management and management in the end, and formulate a series of corresponding management measures based on the characteristics of the cultivation of crab species. Implement the group management system and arrive at people. We will be able to observe the ponds 2 times in the morning and in the evening, and solve problems in time to ensure production. Smooth progress.

Second, the results

According to the market conditions, they will be captured from December and sold to growers for stocking. The end of the dry pool at the end of February the following year. In 2003, the aquaculture experimental area was 220 mu and the production of 20500 mu of crabs was in production. In the year, a total of 4.5 million crab species were sold, with an output value of 2.25 million yuan, netting a cost of 1.15 million yuan, a net income of 1.1 million yuan and a net revenue of 5977 yuan.

Third, the summary

Through a year of trials, we have achieved initial success in raising the survival rate, specifications, and quality of crab species, and we have explored some good experiences in the cultivation of crab species.

1. The transformation of crab ponds, the laying of sieves, and the setting of tiles have improved the survival rate of crab species, and the uniformity of farming specifications has played a significant role. The phenomenon of lazy crabs has basically been eliminated. The specifications for crabs are basically the same, and the listing rate is high.

2. Formulated feeds are good for normal growth of crab species. Many farmers in order to prevent the emergence of "small green crabs", with less or no food, or only cast green feed, but make the crab growth and development is poor, poor health, easy to die during the winter, the survival rate in adult crab breeding , high incidence, inconsistent size, slow growth and so on.

3. The choice of parents, soil pond nursery, and fertilizer pond are the key to the survival rate of big-eyed larvae to the five young crabs.

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