Pond shrimp culture
In recent two years, we have paid attention to the basic construction of shrimp ponds, adhered to the standard of shrimp fry stocking, and boldly invested in intensive cultivation in thin tubes, and achieved good results in single-season output of 750- 1500 kg/ha. The main technical measures are introduced as follows.
(1) Basic conditions and facilities of shrimp ponds
1. 1 Tangkou chose to build a shrimp pond near the fresh and pollution-free water source.
1.2 A shrimp pond with the size of a pond should not be too large. Generally, it should be below 7,000 square meters, preferably1500-3,500 square meters and the water depth 1.5-2 meters.
1.3 clear the pond in winter or before stocking, and clean the mud at the bottom of the pond or expose it to the sun until the sediment forms small cracks. Then the periphery of the pool is leveled to form a gentle slope, and the ridge of the pool is compacted to ensure no leakage. There is a ditch in the center of the bottom of the pond, and a shrimp pond is set at the outlet. The size of the ditch pond can be flexibly controlled according to the pond area, as long as it is conducive to harvesting. If the pool is big, the ditch pool should be bigger. .
1.4 Set up a shrimp nest and plant some submerged plants around the pond, such as Sophora alopecuroides and Haematococcus verticillata, accounting for 1/4- 1/3 of the bottom area of the pond. At the same time, bamboo branches are tied into brooms, and several bundles are arranged in a string in the water layer of the pond. When pulling the net, take it out and dry it, which can be used repeatedly and has a good effect. The use of aquatic plants and bamboo technology plays an important role in increasing shrimp production.
(2) Reasonable stocking
Although it is simple and easy to put the brooding parent shrimp into the pond for direct culture, the yield is low and unstable. The main reason is that the survival rate of larvae is low, many generations are often in the same pond, the density is uncontrollable, the management is blind, the results are uneven, the overall scale is small, and the market rate is low. Therefore, young shrimps should be cultivated in special ponds and then stocked as planned.
Stocking method: Generally, 654.38+052,000 fish are stocked every 667 square meters, and stocking is selected on cloudy days or in the morning. After larval stocking 15-20 days, silver carp and summer flowers are added. You can stock up for two seasons a year. One is to raise 23 cm overwintering young shrimp in February-March in spring, and the other is to raise young shrimp (about 1.5 cm) in June-July in summer.
(3) Cultivation and cultivation of shrimp seedlings
3. 1 Special pond for cultivating young shrimps Choose a pond with an area of 500-2,000 square meters and a water depth of about 1 m, apply sufficient base fertilizer after dredging, put 5-7.5 kilograms of young shrimps every 667 square meters in May, and try to put the parent shrimps with similar egg colors in one pond. Generally, cage incubation method is adopted, and some floating aquatic plants and bamboo technology are installed in the cage, and it is appropriate to place 0.5 kg of egg-bearing shrimp in the cage per square meter. Keep the water fresh and the dissolved oxygen sufficient during incubation. The daily feed amount is determined according to 3% of the shrimp weight to ensure that the parent shrimps are full.
After the larvae hatch, the parent shrimps and cages are removed, and the fattening water is sprayed with soybean milk. When the larvae metamorphose into larvae, add a small amount of rice bran, peanut cake or bean cake powder. Generally, the larvae of Macrobrachium nipponense can reach 1.2- 1.5 cm in about 25 days, and can be used as shrimp larvae in summer, with 400,000-800,000 larvae per 667 square meters.
3.2 Cultivate young shrimps in ponds, release young shrimps in summer and spawn and breed in autumn. At this time, in the management of feeding, pay attention to more feeding and fertilization to keep the water quality fat and cool. At the end of incubation, soybean milk or manure can be poured according to the specific situation, and prawns can be caught at the same time, leaving shrimps, so that adult shrimps that meet the market specifications can be caught and marketed, and the density is reduced, which is beneficial to the growth of young shrimps in the pond. Before winter, these young shrimps generally reach 2-3 cm, which can be wintered in the pond for stocking in the next spring.
3.3 When overwintering, young shrimps and parent shrimps should be divided into pools. Overwintering stocking should be carried out on a sunny day in June 5438+February, and the overwintering pool should be sheltered from the wind and sun, with a water depth of more than 1.5m and more aquatic plants. Parent shrimps entering the pond should be well classified, and the bigger the specifications, the better. The ratio of male to female is 2: 1, and the stocking amount is 20-30 kg per 667 square meters. Put 30-40 kilograms of young shrimp every 667 square meters. During the wintering period, freshwater shrimps are usually fed with concentrated feed once a week. Keep the maximum water depth and pay attention to changing water properly. In severe winter, the pond should be prevented from freezing. In the late winter, the water temperature gradually rises, so the feeding amount should be gradually increased, and the parent shrimp will enter the intensive culture period. When the female shrimps hold eggs, the eggs-holding shrimps are transferred to the shrimp seedling cultivation pool.
(4) scientific breeding
4. 1 feed type The freshwater shrimp is omnivorous, but it is selective to the feed. Shrimp likes peanut cake and bean cake, but not rapeseed cake and cottonseed cake. I like eating earthworms, snails and so on. The utilization rate of animal waste is very low.
4.2 Generally, the daily feeding amount is controlled at 4%-8% of the shrimp weight in the pond. The daily feeding amount of young shrimps is 0. 1-0.3kg/ 10,000 pieces, which is mainly powdery mixture. When feeding, the remaining bait in the pond shall prevail. With the increase of water temperature and the growth of shrimp, it gradually increases to 2-3 kg/10,000 fish.
4.3 Feeding methods adhere to the four principles. Generally, feed it once a day in the morning, once at night, one-third in the morning and two-thirds in the evening. It is not appropriate to feed a single bait, and attention should be paid to the collocation of meat and vegetables. Generally, animal feed accounts for about 20%. When feeding snails, break the shells and cut the miscellaneous fish into pieces. It is not suitable to beat them with a beater, because it is easy to form slurry, which not only has low utilization rate, but also easily deteriorates water quality. Attention should also be paid to the combination of splashing water and beach water phase when feeding, which is beneficial to the domestication and fixed-point feeding of prawns.
(5) Strengthen daily management.
The key to daily management is to patrol the pond frequently, observe carefully, and solve problems in time when they are found. Management content has the following aspects.
5. 1 water quality adjustment The water in the shrimp pond should be rich, but the shrimp can't be raised well in clean water. Preventing hypoxia is the most important thing in high-yield shrimp ponds, and changing water frequently can prevent the water quality from deteriorating due to hypoxia. Flush as much as possible in the early morning and evening of hot season. When the water quality is light, it should be fertilized in time. Usually, fermented fertilizer or fertilizer with fast fertilizer effect is applied to keep the water quality fat and tender, and fertilization cannot be applied in rainy weather.
5.2 Prevent injury and escape into the water, and filter with dense mesh every day to prevent wild miscellaneous fish and fierce fish from entering. These fish not only compete for food, but also are enemies of freshwater shrimp. Drain pipes should also be blocked with dense mesh. If the shrimps grow up or the shrimps in the pond breed too much, you can change the mesh of the blocking net a little to control the density. If it is difficult to prevent wild fish in the pond, we can take advantage of the fact that mandarin fish don't like shrimp, and put some large-scale mandarin fish species to control wild fish, but we should be careful not to over-stock them.
5.3 Pay attention to the growth and development of shrimp. The purpose of observing growth and development is to implement targeted management. Firstly, the size and composition of individuals are considered to determine the size and quantity of feeding particles; The second is to see if the growth is normal. If slow growth or cannibalism is found, it is necessary to check the feed quality, shrimp density and water quality and take timely measures; The third is to look at the breeding period, such as parent shrimp holding eggs and hatching young, so as to take corresponding management measures. The observation method is to copy the net, measure the body length with a ruler and make records. Check every two weeks during the peak growth period, and the results are compared with the last time. It can also be observed by visual inspection combined with daily inspection of the pond.
Pond culture of freshwater shrimp is the most widely used culture method at present, whether it is single culture or mixed culture with fish species. Its main operating points are:
1. Shrimp pond conditions The freshwater shrimps in qingtang are zoobenthos and spend most of their time in the bottom and wall of the pond. Shrimp has high oxygen consumption. Not tolerant of low oxygen environment. Therefore, the pond for cultivating freshwater shrimps is required to be close to the water source, with fresh water quality, no pollution and convenient water intake and drainage. The shrimp pond covers an area of 2-6 mu, with a water depth of 1- 1.5 m, a steep slope and a large beach foot, which is convenient for freshwater shrimp to eat. The bottom of the pool is relatively flat, and there is not too much silt; The shape of the pool should be a regular rectangle, which is convenient for pulling the net. Some submerged plants can be properly planted in the pond, generally not exceeding 1/4 of the pond water surface. Shrimp ponds can be built or rebuilt by using existing fish ponds.
Generally, shrimp ponds are cleaned in early March. Drain the pond water, remove excess silt, complete the pond ridge, and maintain the water inlet and drainage system to expose the bottom of the pond, promote the decomposition of organic matter at the bottom of the pond and improve the fertility of the shrimp pond.
Croton is the most ideal medicine for cleaning shrimp ponds. Because croton contains a kind of croton, which can make the blood of fish coagulate and die. It can effectively kill wild fish in the shrimp pond, so there is a saying that croton cleans the pond. The clearer the shrimp, the more shrimp there are. General water depth 10 cm, 5-7.5kg croton is used for each mu of shrimp pond. When cleaning the pool with croton, first grind croton into paste, put it into a jar, add100g of soju or 0.75kg of salt, and seal it for 3-4 days. Pump the pond water until the remaining water at the bottom of the pond is about 10 cm. After croton is diluted with pond water, the pond is filled with residue and juice. Clear pond 10- 15 days, water storage 1 m. After the medicinal properties completely disappear, shrimp species can be released. Cleaning the pond with tea residue can also get the same effect. When used, the water depth per mu is generally 1m, 40-50 kg, so that the concentration of the medicine in the pool water can reach 60-75 mg/L. It can kill all kinds of wild fish, frog eggs, tadpoles and grasshoppers. However, cleaning the pond with tea residue has no killing effect on aquatic plants.
2. The freshwater shrimp is raised in the pond, and the nutrients of the shrimp are released in summer and autumn. From March to April, summer stocking began, mainly wintering shrimp species, with the specification of 1 0,000-3,000/kg, and each acre of shrimp pond was stocked with1.5-20,000. In autumn, it is generally stocked from June to July, with the shrimp species cultured in that year as the main species, with the specification of 2,000-5,000/kg and 30,000-40,000 per mu of water surface. Macrobrachium nipponense is polycultured in ponds, mainly for shrimp culture, with150,000-200,000 larvae per mu. No matter which stocking method is adopted, the average yield of freshwater shrimp per mu can reach 50- 100 kg. Attention should also be paid to the following matters when raising shrimp species: (1) The shrimp species put in the same shrimp pond should be basically the same size, strong in physique, free from diseases and injuries, with intact limbs, and all of them should be stocked at one time.
(2) The stocking time should be chosen in rainy days, sunny morning or evening to avoid direct sunlight and high temperature, which will affect the survival rate of shrimp fry stocking.
(3) When raising shrimps, we should stick to the operation with water, and the movement should be light, so it is not appropriate to pile shrimps in containers.
3. Bait types and feeding methods The growth period of freshwater shrimp is about 5-6 months a year. When the water temperature is above 18℃, artificial feeding should be started. Shrimp has a wide range of feeding habits. The larvae feed on plankton, while the adults feed on rotten stems and leaves of aquatic plants and the carcasses of fish and shellfish. In the case of high-density culture in ponds, natural bait alone can no longer meet the needs of the growth of freshwater shrimp. Therefore, shrimp culture in ponds should not only fertilize regularly to cultivate natural bait, but also feed artificial bait on time. At present, all kinds of commercial bait used in freshwater aquaculture production can be used to raise freshwater shrimp. The production practice shows that the preference degree and utilization ratio of freshwater shrimp to various commercial bait are different. Shrimp prefer to eat animal foods, such as snails, silkworm chrysalis, fish meal, earthworms, fly maggots and so on. Among a variety of plant bait, I prefer to eat bean cake, rice bran and distiller's grains, but I don't like vegetable cake. As far as the bait system is concerned, bean cake is 0.96 and rice bran is 2.08. The compound bait composed of the above bait has a bait coefficient of 1.68.
Generally, 40% animal bait and 60% plant bait mixed feeding can promote the growth of freshwater shrimp and improve the utilization rate of bait.
It is better to make the artificial bait of freshwater shrimp into granules than powder bait. The formula can be mainly composed of plant bait, with animal bait accounting for 20%-30%, and a small amount of bone powder, clam shell powder, crab shell powder and trace elements are added.
The feeding method should be scientifically mastered according to the habitat activity and growth and development law of freshwater shrimp. Shrimp like to be active at night and feed by the pool. Therefore, the feeding of green shrimps should generally be carried out around 5 pm, and the bait should be evenly scattered in the shallow water around the shrimp pond as much as possible so that all green shrimps can eat the bait. The feeding frequency can be one day 1 time or every other day 1 time, and the feeding amount should not be too large each time. Usually, the daily feeding amount can be controlled at 2%-3% of the shrimp weight in the pond. In early summer and late autumn, invest less appropriately, and in the peak season of shrimp growth, invest more. The general principle of feeding is to master the weather, water quality, shrimp activities and eating conditions flexibly, and adjust them in time to make the green shrimp eat well, promote growth and achieve the purpose of increasing production and income.
4. Feeding and management of freshwater shrimp, a crustacean, is intolerant of anoxic environment and likes to live in water with fresh water quality and rich dissolved oxygen. When the dissolved oxygen in the water area is above 5 mg/L, the feeding intensity of freshwater shrimp increases, its metabolism is vigorous and it grows rapidly. However, when the dissolved oxygen is lower than 2.5 mg/L, the freshwater shrimp gradually stops eating, and even floats to death. Therefore, it is very important to manage the water quality of shrimp ponds and provide a good ecological environment for the growth of freshwater shrimp.
To do a good job in water quality management, we should first inject fresh water regularly, generally 1 time per week, and change the water 1/3 each time to keep the transparency of shrimp pond water above 40 cm. I usually patrol the pond every morning and observe it carefully. If freshwater shrimps are found to climb ashore, they should be replenished with fresh water immediately or the aerator should be started to increase oxygen to prevent the floating shrimps from dying. The second is to apply fertilizer reasonably according to water content. In order to cultivate rich natural bait, shrimp ponds usually need to be fertilized regularly. It is best to apply some organic fertilizers with lasting and stable fertilizer effect, such as manure, compost and mixed compost. However, quick-acting fertilizers, such as chemical fertilizers and human excrement, are generally not suitable for use to keep the water quality fat, lively and cool and promote the growth of freshwater shrimps. It is also an important management work to eliminate the enemy damage of freshwater shrimp in the pond. First of all, before stocking, the pond should be thoroughly cleaned to eliminate pests. Second, fish retaining facilities should be set up in the water intake ditch to prevent wild fish from entering. Third, every month 1 time, catch summer flowers fish in the whole pond 1 time, and fish out all kinds of fish. Fourth, we should try our best to kill water snake rats, drive away water black, and do everything possible to improve the survival rate of freshwater shrimp. Shrimp is particularly sensitive to pesticides. It is best to change water to improve the ecological conditions of pond water and prevent fish and shrimp diseases. When diseases occur in fish and shrimp polyculture, if drugs must be used for treatment, the drugs should be used with special caution and the pharmacological dose should be strictly controlled to ensure safety.
(2) shrimp culture in cages
Cage culture of freshwater shrimp is generally carried out in rivers, lakes, reservoirs and other waters with good conditions. Because the large water surface has the advantages of good water quality, sufficient dissolved oxygen and convenient removal of wild fish, it is very beneficial to the growth of freshwater shrimp. Therefore, it is a promising way to make full use of the superior natural conditions of large water surface and actively develop cage culture of freshwater shrimp, which is also an important way to develop and utilize large water surface resources.
1. Selection of aquaculture waters Generally speaking, the waters for cage shrimp culture should be reservoirs, lakes, tributaries and rivers with fresh water quality, sufficient sunshine, slightly slow water flow, pH value of 7-8.5, water depth of more than 2 meters, flat sediment, less sludge and no pollution. This kind of water area has superior environmental conditions, is suitable for the growth of freshwater shrimp, and generally can achieve better culture effect.
2. The structure and arrangement of the cage are made of bamboo floats and polyethylene mesh sheets, and the rope is wound around the bottom of the cage and fastened with the bamboo tips and the lower ends of the bamboo sheets to replace the sinkers. In order to reduce the cost of cage, increase the exchange of water, improve the wind resistance, and facilitate seed selection and fishing in the field, the cage should be made into a rectangle with the specification of 10 m X6.67 m X 1.3 m, and the mesh is the main factor affecting the water quality in the cage. If the net is too dense, the attachments on the wall of the box are easy to increase and block the net, and the water inside and outside the box is not easy to exchange, and the water quality will deteriorate; Although the water exchange is good when the mesh is too large, small miscellaneous fish are easy to get into cages to prey on shrimp seedlings, which affects the survival rate and yield of shrimp seedlings. Therefore, the mesh number of box bottom and box wall should be 24 mesh /cm2. Considering that the breastplate of freshwater shrimp head is difficult to bear large water pressure, the depth of the cage sinking into the water is 0.9 meters. If the water layer is too deep, its gills will be compressed and it will be difficult to breathe. The height of the escape net should be 0.4m ... Because the second pair of prawns is well developed and has strong climbing ability, the mesh size of 196 mesh /cm2 is suitable for making escape nets. 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: Bundle 4 Phyllostachys pubescens into a rectangular bamboo frame of10 m× 6.67 m. Punch a round hole with a diameter of 5cm at each corner of the bamboo frame, insert a bamboo tip with a length of 1.4m into each hole, and insert it 0.9m below the hole. A simple pulley is installed at the lower end of the bamboo tip, and the four corner ropes at the bottom of the box are tightened by the pulley and fixed on the bamboo frame. The four corners of the upper mouth of the escape net are also tied to the upper end of the bamboo tip with tethers and bamboo tips. Tie a thick bamboo piece with a length of 1.3m on the bamboo frame of the box every 2-3m, and tie the lower end of the bamboo piece with a lever rope at the bottom of the box and the upper end with a lever rope on the escape net. Near the four corners of the box, make a bamboo pile with the lower end in the mud and the upper end out of the water. Then, tie the bamboo pile fixed on the top of the hair tip on the net cage with a rope. Make the cage sink 0.9 meters underwater and expose 0.4 meters above the water surface as an escape net. Cage layout: every five cages are arranged in a row, with box spacing of 4-5 meters and row spacing of 5-6 meters. Don't bring a fixed bait table because the shrimps are scattered to find bait at night. Each box is stocked with aquatic plants such as water hyacinths of 3-5 square meters. The integrated strips of aquatic plants are arranged along the longitudinal direction of the box, and shall not be close to the escape net to prevent shrimps from climbing along the box wall with aquatic plants as ladders. The functions of stocking aquatic plants in the box are as follows: first, it can be used as a natural bait platform for feeding bait; Second, the underwater roots can be used as the habitat of shrimp; Thirdly, tender roots can be used as green feed for shrimp; Fourth, the leaves can cool the sun and promote the appetite of shrimp; Fifth, after winter, the water plants frost and sink into the bottom of the box as a warm place for shrimps to spend the winter.
3. Two batches of shrimp can be caged 1 year. 1 batch is stocked in summer, usually in March and April. The release specification is 1000-2000/kg, and the yield per mu is 50,000-60,000. After fishing in mid-July, it will be cultured in autumn. Generally, shrimp species cultured in that year will be released from late July to August. Shrimp species size is 2000-5000/ kg, and the yield per mu is 8-65438+ 10,000. Shrimp should be weighed, counted and operated with water before entering the box. During the operation, shrimp species shall not be piled up, and the water outlet time shall generally not exceed 5 minutes, nor shall they be exposed to the sun. Shrimp species stocked in the same box should have uniform specifications and be stocked all at once. The sowing time should be chosen in the morning and evening of cloudy or sunny days, and the transported shrimp seeds should be kept 1 day before entering the box. The captured natural shrimp species should be released, and the dead seedlings should be removed before release.
4. The feeding and management system of cage shrimp culture is basically the same as that of pond shrimp culture. However, it is necessary to appropriately increase the daily feeding times for shrimp culture in cages, generally twice a day, feeding 65438+ 0/3 of the daily feeding amount at 8: 00 am, and feeding 2/3 of the daily feeding amount after 5: 00 pm. Powdered bait is put on aquatic plants, and other bait is put in a whole box. The daily feeding amount is generally controlled at 5%-8% of the weight of boxed shrimp. After the bait is put in, it is necessary to carefully observe the eating situation of the freshwater shrimp. If the bait is eaten up quickly, the amount of bait 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 be appropriately increased. Generally, freshwater shrimps are cultured with compound feed, and the feed coefficient is generally between 4.34 and 5.47. The protein content of compound bait should be above 35%. The loss of powdered feed is serious and the feed coefficient is high. We should actively promote the cultivation of freshwater shrimp with granular bait. Cage culture of freshwater shrimp. The management of shrimp culture in cages is also very important, and it is necessary to achieve four diligence, four prevention and wild elimination. The four diligence are: diligent patrol, diligent inspection, diligent box brushing and diligent maintenance; The four precautions are: preventing caissons from escaping shrimp, preventing man-made destruction and theft, preventing strong winds from overturning boxes, and preventing pesticide pollution; Eliminating the wild is to eliminate the wild fish and enemy damage of dangerous freshwater shrimp. Shrimp species, such as mandarin fish, carp, spike fish, striped fish, eel, river crab, etc., will be dangerous to freshwater shrimp after being cultured in cage for 1 month, so it is necessary to prevent its invasion, and remove it in time if found. 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 with your hands. Generally, it is cleared once every half month 1 time. The rat eats shrimp very badly. Try to kill it. Waterbirds often attack them and can be killed with shotguns.
(3) Mixed culture of fish and shrimp
Shrimp is a benthic crustacean with poor swimming ability and often crawls in aquatic plants or underwater. Therefore, green shrimp can be raised alone or mixed with some fish. Mixed culture of fish and shrimp can not only make full use of water resources, but also achieve the goal of double harvest of fish and shrimp without adding bait and affecting the growth of fish species. It is a good culture method.
1. Selection of fish and shrimp polyculture pond. Fish and shrimp polyculture is generally carried out in fish ponds, and the pool area should not be too large, preferably 3-5 mu. It requires a flat bottom, less sludge, close to water sources, convenient water intake and drainage, quiet environment and good ecological conditions. In ponds where fish and shrimp are mixed, it is best to avoid using raw masons and use croton or tea residue as cleaning drugs.
2. Fish suitable for polyculture should be polyculture of fish and shrimp. Do not choose carnivorous fish and benthic fish, such as mandarin fish and carp, to avoid these fish swallowing freshwater shrimp. In the larval stage of planktonic life, it is not suitable to mix with bighead carp which feeds on zooplankton to avoid being swallowed. In addition, freshwater shrimps need aquatic plants as habitats and hidden places, so they cannot be mixed with herbivorous fish such as grass carp and bream. Usually, silver carp and bighead carp are put in after the larvae of freshwater shrimp have metamorphosed and grown into shrimps, and mixed culture of fish and shrimp is implemented.
To sum up, it is best to match freshwater shrimps with filter-feeding larvae and silver carp, but not with bream, bream and crucian carp, not to mention carnivorous fish, which is the key to match fish and shrimp.
3. The proportion and density of polyculture of fish and shrimp are all polyculture in ponds. It is required to clear the pond in May-June, and put 500-800 shrimps with eggs or 5,000-8,000 young shrimps with specifications of 2,000-5,000 per catty per mu; 7000-8000 silver carp and summer flowers will be released in mid-July. Fish and shrimp are mixed in the cage. In late June, 2,000-4,000 female shrimps with eggs were released per mu, or in early July, 3,000-4,000 young shrimps with specifications of 1.500-3.000/kg were released per mu, and then 80,000-1.20,000 silver carp summer flowers were released per mu.
4. Feeding management measures can refer to pond (cage) shrimp culture. However, it is worth noting that the mesh size of cage mixed with fish and shrimp should not be greater than 24 mesh per square centimeter to prevent shrimp from escaping; Don't use cages with too dense mesh, otherwise the water passing through the net will be poor, the mesh will be blocked, and the water quality will easily deteriorate. Fish and shrimp mixed culture in ponds should also pay attention to prevent floating heads. Remove wild fish every month 1 time. In the clearing operation, silver carp should not be injured. When fish diseases are found, it is best to catch the fish for treatment. When preventing fish diseases in the original pond (box), attention should be paid to the safety of freshwater shrimp to prevent shrimp from being killed. In ponds (boxes) where fish, eggs and shrimps are mixed, the wintering shrimps must be caught before mid-July.
(4) shrimp culture in paddy field
Culturing freshwater shrimp in paddy field can not only improve the ecological environment of paddy field, but also increase production and income, which is a promising breeding method. The technical points of operation are as follows:
1. Choose a good field and open a shrimp ditch to cultivate freshwater shrimp, which requires fresh water quality and stable water level. Therefore, we should choose fields close to water sources, with convenient water intake and drainage and good soil quality. After harrowing, a shrimp ditch with a width of 2m and a depth of 1m can be dug at one end of the site, or a shrimp ditch with a width of 1m and a depth of 0.8m can be formed around and in the middle of the site. Build a water intake and drainage system, fill the water well, and prevent wild fish from polyculture.
2. Sow in time to improve the survival rate. One week after the seedlings were planted, the young shrimps were released. Usually, the young shrimps cultured artificially in that year are released, with the specification of 2000-5000/ kg, and can be released 1 10,000-10.5 million per mu. Choose rainy days or sunny mornings for stocking, and put them at different points, so that the young shrimps are distributed in the whole water area, so as to avoid the death of the young shrimps due to too high oxygen concentration. Be agile when stocking, so as to improve the survival rate of young shrimp.
3. Feed scientifically, strengthen the management of juvenile shrimp stocking, and start feeding immediately. Generally, bran, bean cake, or fish (shrimp) can be fed with granular bait, and some animal bait such as snails, shellfish and fish should also be properly fed. Feed it twice a day, mainly in the evening, and the daily feeding amount can be controlled to 2%-4% of the body weight of the shrimp in the field, and it can be reasonably adjusted according to the season, weather and the eating situation of the freshwater shrimp, so as to make the shrimp eat well and promote its growth.
It is very important to manage shrimp culture in rice fields.
First of all, we must change the water regularly to keep the water fresh in the shrimp ditch, especially in the high temperature season in summer and autumn. Even if rice is put in the field, the water level in the shrimp ditch should be kept stable to provide a good ecological environment for the growth of freshwater shrimp. The second is to avoid using pesticides as much as possible. If you want to use pesticides, you should choose low toxicity and high efficiency, pay attention to the use method, and don't kill the shrimps. Third, we should pay attention to eliminating the enemy's harm. Frogs, snakes, water rats, etc. Will swallow green shrimp, should take effective measures to eliminate in time.