Efficient Culture Technology of Green Shrimp in Cage

Cage culture of green shrimp is generally carried out in rivers, lakes, reservoirs and other waters with better conditions. Because the big water surface has the advantages of good water quality, sufficient dissolved oxygen and convenient removal of wild miscellaneous fish, it is very beneficial to the growth of green shrimp. Therefore, making full use of the superior natural conditions of large water surface and actively developing cage culture of green shrimp is not only a promising way of culture, but also an important way to develop and utilize the resources of large water surface.

Selection of aquaculture waters

The waters set up for cage shrimp culture should usually choose reservoir bays, lake branches and rivers with fresh water quality, sufficient sunshine, slight slow flow, pH 7-8.5, water depth of more than 2 meters, flat sediment, less sludge and no pollution. Such waters, superior environmental conditions, suitable for the growth of green shrimp, generally can achieve better culture results.

Structure and setting of cages

The bamboo float and polyethylene mesh are used as net clothes, and the ropes are put on around the bottom of the box and tightened and fixed with the bamboo tips and the lower end of the bamboo slices to replace the sunken son. In order to reduce the cost of the cage, increase the exchange of water, improve the wind resistance, and facilitate the selection and capture of the wild, the cage should be built into a rectangle with a specification of 10 meters x 6.67 meters x 1.3 meters. The mesh is the main factor affecting the water quality in the box. The mesh is too dense, the attachment to the box wall is easy to increase and block the mesh, the water inside and outside the box is not easy to exchange, the water quality will deteriorate; the mesh is too large, the water exchange is good, but small miscellaneous fish are easy to get into the cage to prey on shrimp fry, affecting the survival rate and yield of shrimp fry. Therefore, the bottom of the box, box wall mesh mesh should be 24 mesh / cm 2 is better. The depth of the cage sinking into the water, considering that the shrimp head breastplate is difficult to withstand greater water pressure, it is better to take 0.9 meters. If the water layer is too deep, it will oppress its gills and make it difficult to breathe. The height of the anti-escape net should be 0.4 meters. As the second pair of prawns are well developed and have strong climbing ability, it is appropriate to use the mesh size of 196 mesh / cm 2 as a mesh cloth for escape prevention. The cage is installed as an open floating type, which can rise and fall freely with the change of water level. The installation method is as follows: 4 bamboo branches are used and tied into a rectangular bamboo frame of 10 meters × 6.67 meters. A circular hole with a diameter of 5 cm is made in each of the four corners of the bamboo frame, and a 1.4-meter-long bamboo tip is inserted into each hole, 0.9 meters under the hole. A simple pulley is installed at the lower end of the bamboo tip, and the four-corner tie rope at the bottom of the box is tightened by the pulley and fixed on the bamboo frame.

The four corners of the anti-escape net mouth are also tied and fastened to the upper end of the bamboo tip. Every 2-3 meters, a thick piece of bamboo 1.3 meters long is tied on the box bamboo rack. The lower end of the bamboo piece is tied with the bar rope at the bottom of the box, and the upper end is fastened with the anti-escape net bar rope. There is a bamboo pile in each of the four corners of the box, the bottom is in the mud, and the upper end is out of the water. Then the top five bamboo piles fixed on the cage are tied with a rope. Make the cage sink 0.9 meters underwater and 0.4 meters above the surface as an anti-escape net. Cage layout, every 5 cages in a row, box spacing 4-5 meters, row spacing 5-6 meters. As most of the prawns are scattered to look for bait at night, do not set up a fixed bait table. Keep 3-5 square meters of water hyacinth and other water plants in each box. The integrated aquatic plants are arranged in the longitudinal direction of the box, do not stick to the anti-escape net, so as to prevent shrimp from climbing along the box wall with aquatic ladders. The function of raising aquatic plants in the box: first, it can be used as a natural bait table for feeding; second, the underwater root can be used as a habitat for shrimp; third, tender roots can be used as a green feed for shrimp; fourth, leaves can shade the sun and cool down and promote the appetite of shrimp; fifth, aquatic plants are frosty after winter, and sinking to the bottom of the box can be used as a warm place for shrimp to survive the winter.

Shrimp stocking

Cage culture of shrimp can be raised in two batches a year, the first batch is released in summer, usually in March or April, with overwintering shrimp species. The release specifications are 1000-2000 pieces / kg, and 50, 000-60, 000 pieces per mu. After fishing in the middle of July, the shrimp species bred in the same year are generally released from late July to August. The specification of shrimp species is 2000-5000 / kg, and the amount of shrimp per mu is 80-100000. Shrimp species should be weighed, counted and operated with water before entering the box. Shrimp species can not be piled up during the operation, the time away from the water is generally no more than 5 minutes, and can not be exposed in the hot sun. The specifications of shrimp species raised in the same box should be uniform and fully released at one time. The planting time should be selected in the morning and evening on cloudy or sunny days, and the transported shrimp should be reared for 1 day and then put into the box. For natural shrimp species captured by stocking, remove dead seedlings before stocking.

Bait feeding and management system

The feed for shrimp culture in cages is basically the same as that in ponds. However, shrimp culture in cages should appropriately increase the number of daily feeding, usually twice a day, 1max 3 of the daily feed amount at 8: 00 a. M. and 2 max 3 of the daily feed quantity after 5 pm. The powdered bait is thrown on the aquatic plants, and the other baits are sprinkled in the whole box. The daily feeding amount is generally controlled at 5% of the weight of shrimp in the box. 8%. After the bait is put in, the eating situation of the shrimp should be carefully observed. if the bait is eaten quickly, the feeding amount can be increased appropriately on the same day and the next day. In addition, when the weather is cool and the climate is suitable, the amount of bait can also be increased appropriately.

Green prawns are generally cultured with mixed feed, and the feed coefficient is usually between 4.34 and 5.47. The protein content of the compound feed is required to be more than 35%. The loss of powdered feed is serious and the feed coefficient is high. We should actively promote the culture of green shrimp with pellet bait. Raise green prawns in cages. The management of cage shrimp culture is also very important, which requires four diligence, four prevention and wild removal. The four defenses are: diligent patrolling, diligent inspection, diligent brushing boxes, and diligent maintenance; four defenses are: preventing caissons from escaping shrimp, preventing vandalism and theft, preventing gale turning of boxes, and preventing pesticide pollution; and removing wild fish and enemies from dangerous green shrimp. One month after shrimp species are cultured in cages, such as mandarin fish, carp, wheat ear fish, striped fish, eel and river crabs, they will be dangerous to green shrimps and must be strictly prevented from invading. If found, they should be removed in time. The way to get rid of wild fish is to pull up the cage, gather fish and shrimp in a corner of the box, and catch wild fish and harmful fish by hand. It is usually cleared once a semimonthly. Water rats are also very good at eating shrimp, so they should try to catch and kill rats. Waterbirds also often come here and can be killed with shotguns.