Overwintering fattening techniques of commercial hairy crabs

After October every year, most of the cultured crabs are on the market. In exchange for the seasonal price difference, the river crabs can be warmed and fattened in plastic greenhouses to New Year's Day and sold around the Spring Festival, and the benefits can be significantly increased. The main points of the technology are introduced as follows.

Conditions for hoarding and fattening

1. Cement pool: with an area of 50 square meters to 100 square meters, it can store water more than 1.2 meters, and it is convenient for entry and drainage. Spread 10cm ~ 15cm fine sand on the bottom of the pool, after disinfection, soak in water for about 10 days before use, and then build a plastic greenhouse according to the above requirements.

2. The earth pond: the area is 5 mu ~ 10 mu, which can keep the water level above 1.5 m without leakage, and the mud depth is not more than 15 cm. 10 days before the crab enters the pond, the pond is cleaned with quicklime and a week later, the plastic greenhouse can still be installed according to the aforementioned method.

3, indoor: indoor do not need to build plastic greenhouse insulation facilities, directly use idle houses to build smooth walls, floor non-leakage cement pool, can also be short-term hoarding, the general area of 10 square meters to 30 square meters.

4, hoarding density: cement pond, 1.5 kg ~ 2 kg per square meter. Before river crabs enter the ground, aquatic plants such as water peanuts must be put into the pond. Soil ponds, 500 kg to 700 kg per mu, should also be filled with aquatic plants that occupy an area of 1, 3, 2 and 5 of the water area, so that crabs can safely avoid enemies and feed. Indoor is 3 kg ~ 5 kg per square meter.

5. Bait feeding: the plastic greenhouse is used in winter, which can keep the water temperature above 15 ℃ in most of the winter, and ensure that the river crab can grow normally under the suitable water temperature. In the previous stage of feeding, the bait should be mainly plant-based food. Such as soaked or cooked wheat, soybeans, sweet potatoes, vegetables and so on. The daily feeding amount accounts for about 5% ~ 8% of the crab weight, once in the morning and once in the afternoon, from 10:00 to 11:00, 3 parts of feed, and 7 parts from 4 pm to 5 pm. In the later stage of feeding, the animal protein content in the food should be increased appropriately, and the small miscellaneous fish and shrimp, snail clam meat, formula feed and so on can be fed appropriately, but when the cost is reduced or the animal feed is not easy to be obtained, it can still be fed according to the above-mentioned method. the effect is also good.

Daily management

1. Water quality regulation: River crabs like a relatively fresh water environment, so the amount of water should be changed according to the inlet and drainage capacity of the pool. The general reference standard is that the pool water must maintain 5 milliliters of dissolved oxygen with a transparency of about 40 centimeters.

2. Greenhouse management: in order to maintain the water temperature, we must pay attention to the sealing of the plastic film and the edge of the pool, do not open the greenhouse door for a long time or open the door frequently, and repair the agricultural film if it is damaged. The feeding condition of river crab should be observed every day and the feeding amount should be adjusted at any time. At the same time, according to the water quality, every 1 ~ 3 days, when the weather is warm in the afternoon, replace the water in the pool with 1 pound. As for indoor hoarding, in addition to maintaining ventilation, fish pond water is sprayed three or four times a day to maintain a certain degree of humidity.

3. Disease prevention: in order to prevent disease, an appropriate amount of sulfonamides should be mixed in the feed every 1 to 2 weeks. The feed can be soaked in a solution prepared with a specified dose of medicine and fed together with a small amount of leftover liquid. If the disease occurs, the disease should be treated in time, and the dead crab should be fished out. It is also necessary to prevent pests such as rats and snakes from entering the greenhouse.