Crab incubation technique

At present, most crab farmers are still adopting the rapid crab cultivation method that was cultivated in the year of early seedling production in the current year. This has resulted in the small size, poor quality, low price, and weak marketability of crabs. In view of this, the author advocates the idea of ​​“climbing crabs and raising crabs”. During the operation, we concluded that the key to nurturing crabs is to control their growth speed. Due to the slow growth of the crabs, specifications of 1000 to 1500/kg, will promote the advantages of crabs to develop crabs; fast growth, specifications of 30 to 50 / kg, you can easily lead to precocious puberty. The quality of crab standard: 1 specifications are neat, with 120 ~ 300 / kg is appropriate; 2 the second year crab size, female crabs up to about 125 grams, about 150 grams of male crabs; 3 the ratio of sexual precocity does not exceed 10 %; 4 The survival rate of culture is about 50%; 5 The body is robust, the activity is powerful, the reaction is sensitive, there is no injury, there is no residual limb, no parasites such as crab slaves, polyhelminthes, etc.; 6 The authentic Chinese mitten crab of the Yangtze River system. For this reason, the author will introduce the relevant technical points of cultivating deduction crabs as follows:

1. Pond conditions The pond area is 667~1334m2 (1~2 mu), suitable for water supply, water drainage (consisting of two sets of channel facilities), water quality is fresh and pollution-free, water plants in the pool should remain abundant, if lacking, Grab, transplant water peanuts, and bitter herbs, etc., in time, and control the area of ​​aquatic plants to about 40% to 60% of the total area of ​​the pond.

2. Anti-escape facilities As juvenile crabs have strong turbulence and phototaxis, the water inlet and outlet are tightly sealed with a dense mesh to prevent crabs from running. The pond is surrounded with a 60-cm calcium plastic plate to prevent escape, and is inclined at an angle of 5 degrees.

3, crab seedling selection and transportation time to buy seedlings should be in mid-May, too early or too late are difficult to achieve the desired results. The selection of high-quality crab seedlings can be performed using the "see two questions and three investigations" method. A look at the appearance of crab seedlings: complete limbs, uniform size, active and powerful; the second question finger asks the origin of the pro-crab, and the second asks the desalination time. Generally, after 5 to 6 days of desalination, the Yangtze River water-based crabs can be cultured; The investigation refers to the investigation of the original records of the nursery, the status of the parent crabs in the second pool and the parents in the pool, and the investigation of the medication in the field. When crab seedlings are transported, the bottom of the crab seedlings is placed on the bottom of the box, and the crabs are placed on the top of the crabs for dry transport. Each box can hold 0.5 to 0.75 kg of seedlings. After 24 hours, no damage is caused.

4, v young crab cultivation In order to improve the utilization rate of crab seedlings, the crab will be cultivated into the middle of the v period of young crab cultivation process, and then divided into pools to develop into crabs. That is, 2 to 40 thousand young crabs per 667 m2. After the middle cultivation, the survival rate was increased by about 10% compared with direct investment seedling cultivation.

5, control of precocious puberty and strengthen management to prevent precocious puberty is the key to cultivating deduction crab. Therefore, in the whole process of cultivating crabs should be: 1 control density. Overstocking is too dense, and the size of buttoned crabs is too small. When stocking is too thin, the proportion of precocious puberty is high. The appropriate density is 2 to 40 thousand, ie 1 to 2 kilograms, per 667 m2 of v larvae that are bred in the middle. 2 water quality supervision. Generally, change the water once every half month, splash lime 1 time, strengthen the water quality management in high temperature season, change the water when the shell is forbidden. 3 Reduce accumulated temperature. In the summer season, increasing water depth can control the accumulation of effective accumulated temperature of young crabs. 4 Reasonable feeding. When the crabs first entered the pond, they were fed a small amount of animal feed, which accounted for 20% of the body weight of the crabs. Afterwards, the amount of bait was reduced step by step and was generally controlled at about 8% to 10%. At the same time, the ratio of animal feeds was decreased, and the vegetality was increased. Food. 5 winter management. Before the winter, the pond level is increased to 1.2~1.5 meters, and at the same time, every 667 meters 2 farmhouse manure 100 kilograms, regular inspection of water quality. 6 disease prevention and control. It is mainly prevention, focusing on the prevention of hydromycosis, ciliate disease, rotten limb disease, etc. We must also prevent ferocious fish and rat snakes from predators. 7 for sale. Before and after the Spring Festival, the time of arrest was used to stimulate the water, catch cages, and catch dry ponds.

As long as the cultivation techniques are in place and properly handled, generally about 10,000 crabs can be cultivated per 667 m2, and the high-yielding ones can reach 1.3 to 15,000. The economic benefits are obvious.

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