Breeding technique of Shrimp in Crab Tangli River

River shrimp is the scientific name of Macrobrachium rosenbergii, also known as green shrimp. The artificial cultivation techniques of river shrimp seedlings are as follows:

1. The selection and storage of parent shrimp should be selected as artificial breeding parent shrimp, which requires standard body shape, pure body color, fat and strong, disease-free and injury-free, better gonadal development, female shrimp with a body length of more than 6 cm, and male shrimp with larger size. It can be selected from naturally caught prawns or from farmed ponds. The selected parent shrimp should be kept in a special pond. The area of parent shrimp pond is 1-3 mu and the water depth is about 1 meter. Parent shrimp should be strictly cleaned and disinfected before stocking, and the water inlet should be sealed with a tight mesh to prevent wild fish and other enemies from entering. Generally 1 mu of water surface can store 5-10 kilograms of parent shrimp. After the parent shrimp enters the pond, it is necessary to strengthen the feeding management and feed concentrate once every 2 days, so as to make the river shrimp accumulate a large amount of nutrients, promote gonadal development and ovulate earlier, so as to lay a good foundation for the smooth progress of artificial reproduction.

2. Spawning and hatching of river shrimp can be carried out in a cage (incubator), and shrimp seedlings can also be cultured in the same cage. The cage material can be made of polyethylene mesh cloth, which is stitched into a net cage with a mesh of 196 mesh / cm 2, and a polyethylene lever rope of 3X15 specification is installed in the bottom of the box and in the upper mouth of the box. The box is rectangular, with specifications of 10 meters x 6.67 meters x 1.7 meters. It is installed as an open floating type, so that the cage is 0.3 meters out of the water as an anti-escape net. Put 2-3 square meters of water plants in the box, and put 1-2 small net cages with wooden frame for hatching. the size of the incubator is 1.7 meters x 1 meters x 0.5 meters, and the mesh is 12 mesh / cm 2. The four corners of the incubator are hung with a brick to make the box out of the water about 5 centimeters. At the beginning of March, the overwintering parent shrimp began to be bait. The bait increased with the increase of water temperature. At the beginning of April, the daily feed intake can be increased to 4% of the weight of parent shrimp. Let the river shrimp fattening, mating and laying eggs in the overwintering pond (box). The egg-holding female shrimp used for cage reproduction requires that the eggs begin to have compound eyes. Each cage holds 700-1000 female shrimps. After hatching in the incubator for 6-7 days, the larvae can break the membrane and break away from their parents. At this point, the incubator can be taken out of the incubator together with the hatched female shrimp.

Spawning and hatching can also be carried out in the spawning pool. The spawning pond should have an area of 1-3 mu and a water depth of about 1 meter, which requires no weeds on the pond slope, good ventilation, flat bottom and convenient drainage, and the drug disinfection of shrimp pond cleaning should be done in advance.

3. From the day when the larvae are put into the incubator, 0.5-1 kg of soybeans should be used for the cultivation of shrimp seedlings in cages. After soaking, grind the juice, remove the bean dregs, feed it once in the morning and afternoon, and pour it in the incubator. When the young shrimp grows to about 2 cm, a small amount of wheat flour or bran should be added while splashing soybean milk. The water quality in the box should be fat and cool, and the transparency can be controlled at 25-35 cm. After 25 days of cultivation, the young shrimp can reach the stocking specification.

4. Cultivating shrimp seedlings in cement ponds and soil ponds, using indoor tilapia overwintering cement ponds as hatching ponds for river shrimps, the water source is fresh and unpolluted river water, with a depth of 80-100cm and a water temperature of more than 20 ℃. The parent shrimp retained last year (shrimp with eggs) were concentrated in the cage (100 cm × 50 cm × 50 cm) in the hatching pond with a stocking density of 300-400 pieces per box. A small amount of bean cake was fed regularly every day, and water and sewage were added once a day. When the water temperature was 20-26 ℃, shrimp seedlings could be hatched after 6-7 days.

The cultivation of shrimp seedlings in soil ponds is carried out in outdoor land ponds. When the light is good in the morning during the day, the larvae are fished out with 80-mesh cages and moved to the outdoor dirt pool. The stocking density is 400000-600000 tails / mu. If the natural bait is insufficient after the larva is in the pond, in addition to cultivating good water quality, some fine soybean milk must be fed every day. After more than one month of culture, when the body length reaches 1.5-2 cm, it can be caught and divided into ponds for adult shrimp culture.

The mixed culture of river shrimp and river crab can release river crab and green shrimp seedlings in March every year. 550,600 Yangtze River crab buckle crabs (150,200 crabs / kg) and 18 kilograms of green shrimp fry (1600-1800 crabs / kg) are released per mu. During the small-size growth period of river crabs in spring, we mainly catch green shrimp culture to ensure that more than 35 kilograms of commercial shrimp can be caught per mu in June. at the same time, river crabs also have enough water space and their growth will not be affected.