2. Artificial propagation
(1) Selection, preservation and cultivation of parent shrimp: In the breeding season, mature parent shrimp in natural waters can be directly selected for intensive cultivation and reproduction. In autumn and winter, shrimps caught in aquaculture ponds or natural waters can be selected for overwintering for the next year's shrimp fry reproduction. The criteria for selecting and retaining parent shrimps are good body shape, normal body color, full and healthy weight, no disease or injury, and the female shrimps are above 4 cm and the male shrimps are above 6 cm. Male and female are 3: 1.
The male and female differences of freshwater shrimp are as follows:
Individuals of the same age, men are older than women;
B. The male's second foot is stronger than the female's;
C. The distance between the base of the fourth and fifth steps of the abdomen of women is wide, showing a figure of eight, while that of men is narrow;
D male individuals have a pair of vas deferens openings on the inside of the fifth foot base, while female individuals do not;
E. The inner limbs of the male second abdominal limb each have a rod-shaped male appendage, while the female does not.
Parent shrimp culture ponds can be cement ponds or land ponds, with the cement pond area of 100 ~ 300m2, pond area of 2×667 m2 and water depth of1m.. Adequate water source, good water quality and convenient irrigation and drainage are required. The parent shrimp should be strictly disinfected before stocking. The stocking density of cement pond is 250 ~ 500g/m2, and that of pond is 5 ~ 10kg/667m2. Some branches, tiles, nets, etc. It should be put in the pond for shrimp to climb up and live. When the water temperature is above 7℃ in winter, it should be properly fed, and after spring, it should be strengthened and intensively cultivated. Feed with high content of protein, such as wheat bran, bean cake, fresh or cooked snail meat, fish and cooked egg yolk, can meet the nutritional needs during the breeding period.
(2) Breeding in the original pond: Shrimp can naturally mate, spawn and hatch in the culture water. Therefore, the parent shrimp culture pond can be directly used as the spawning incubation pond until the larvae are cultivated. In addition to feeding the parent shrimp, the fry in the original pond should also be sampled regularly. When the fertilized egg has eye spots, organic fertilizer should be applied in the pond, zooplankton should be cultivated for shrimp larvae to eat, and cooked egg yolks should be properly fed after hatching. The transparency of pond water should be controlled at about 30 cm, and when the juvenile shrimp reaches about 65438 0 cm, it should be transferred to the pond for separate culture.
Shrimp has higher requirements for dissolved oxygen in water than common domestic fish, especially in the larval development stage, more attention should be paid to water quality management to keep the water quality fat, alive, tender and cool. Therefore, some pond water should be replaced every day or every other day, topdressing should be done in time, some aquatic plants should be planted on the water surface for shrimp to inhabit and adjust the water quality, and the whole pond should be disinfected with 25PPM lime water every half month.
In addition to improving water quality, it is necessary to supplement artificial feed in moderation. Put soybean milk 1 ~ 1.5 kg every 667 square meters every day, or use 1 cracked egg yolk every 50,000 seedlings. Soymilk and egg yolk should be filtered with a sieve and sprinkled and fed. Feed it three times a day, at 8-9 am, at 17- 18 pm and at 20-2 1 pm, respectively, with the proportions of 30%, 40% and 30%. After a week, you can feed unfiltered soybean milk. When young shrimps become young shrimps, they can be fed with dough feed such as wheat flour, bean dregs and minced fish.
(3) Intensive seedling raising in small cement pond: the area of seedling raising pond is about 1 5m2, and the depth is1m.. Tiles and bricks were placed at the bottom of the pond as hidden objects, some water hyacinths were placed on the water surface, and 80 ~ 65,438+000 parent shrimps were raised, with the male-female ratio of 3: 65,438+0. The parent shrimps were fed with feed for intensive cultivation. We should strengthen water quality management.
The flea larvae of freshwater shrimp have strong phototaxis, and most of them are scattered in the middle and upper layers of the pond. Therefore, the newly hatched flea larvae can be collected by illuminating the pond water at night, and then transferred to a special nursery pond for culture. The area of the nursery pond should be1~ 5m2, the depth should be 0.6m, and the water per cubic meter should be 500 ~ 65438+10,000 fleas.
The aquaculture pond should be thoroughly disinfected before use, and the aquaculture water should be filtered and aerated. Feed it 4~8 times a day, and each time it is full. The feed includes rotifers, branchlets, copepods, adult nauplii and cooked egg yolk. During the breeding process, air should be inflated day and night, and water should be changed and drained frequently to keep the water fresh. When flea larvae are found to be young shrimps, it is necessary to place objects for the young shrimps to attach to in the pond.
If parasitic diseases, such as bell worm and cladoptera, are found in the breeding process, the whole pond can be sprayed with 100PPM formalin or 0.4~0.6PPM malachite green, and the curative effect is good. Or sprinkle 0.5PPM potassium permanganate in the whole pool, and change water by 50%~70% after one hour, which can effectively control the disease.
After about 20~30 days of culture, flea larvae can metamorphose into larvae and enter adult shrimp culture.
After intensive cultivation, the parent shrimp can lay eggs and hatch seedlings again.
Double cropping cultivation
The soil in the pond is loam, close to the water source. Rich water source, good water quality, convenient irrigation and drainage, and no pollution source within 3 kilometers. The water quality meets the standard requirements of NY505 1, in which the dissolved oxygen reaches 5 mg/L, the pH value is about 7.5, and the transportation and electricity are convenient.
Pond conditions The pond is rectangular, with an east-west trend and a slope ratio of 1:3. The bottom of the pond is flat and slightly inclined to the drain. Pond silt 10 cm, which can be injected with water 1.5 m, with an area of 5 mu. The pond is equipped with 1.5 kW impeller aerator 1 and 2.2 kW submersible pump 1, and it has a complete water intake and drainage system. There is a net fence around the Eryi Shuikou, and the entrance and exit are wrapped with screen wire for more than 60 months to prevent harmful organisms such as wild miscellaneous fish from flowing in with the water and prevent the freshwater shrimp from fleeing.
Disinfect and clean the pond, pump the pond water dry, remove excess sludge, and keep 10cm. After repeated fire exposure, it was disinfected with 600 kg of quicklime, and the dosage per mu was 100 kg. Dilute the quicklime with water to make the pond splash evenly. The next day, the sludge and lime at the bottom of the pond were stirred and raked evenly, so that the wild fish and pathogens in the pond died completely. Fresh water was injected in February 15, and the first inflow was 60 cm. In order to cultivate enough plankton and benthos, 1500 kg fermented and decomposed organic fertilizer was applied in Tang Qian for 7 days, and the dosage was 300 kg per mu. Before stocking the second crop of freshwater shrimp, all the freshwater shrimp and silver carp in the pond should be taken out of the pond, and the pond can be cleaned again with tea seed cake before stocking.
At the end of February, the first crop was stocked with about 2,500/kg, with a body length of 2.5 ~ 3 cm and a yield of 1.2 kg per mu, about 30,000. Soak in 3% salt water for 2 ~ 3 minutes before stocking, and the young shrimps are free from diseases and injuries, clean and free from attachments, bright in color, sound in appendages, strong in vitality, complete in basic specifications, and fully stocked at one time. At the same time, a proper amount of filter-feeding fish are raised in the pond. After 10 days, 100 silver carp and 200 silver carp were built. In August, the second crop of black shrimps was stocked, with 3000-4000 shrimps/kg, body length 1.5-2 cm, and stocking amount per mu 13 kg, about 45500 shrimps. Shrimp seedlings have uniform specifications and strong physique. After disinfection, they enter the pond. Half a month later, 65,438+0,200 striped silver carp fingerlings were finalized in summer. Soak shrimps in 3# salt solution for 2-3 minutes before stocking.
The "shrimp nest" is set in the shallow water area 2 meters away from the shore of the pond, around and in the pond. Planting aquatic plants such as water peanuts, water spinach and water hyacinth, with grass width 1 m. The hose should be fixed with a rope to avoid fluttering in the wind. Aquatic plants must be disinfected with bleaching powder or copper sulfate solution before entering the pool to prevent eel, crayfish and wild fish from being brought into the pool. The coverage of aquatic plants accounts for about 25% of the pond. When aquatic plants grow vigorously in summer, it will affect the surface ventilation and photosynthesis of phytoplankton, so it is necessary to remove too many aquatic plants.
The first batch of commercial shrimp was caught at the end of May, and the second batch of commercial shrimp was caught at 5438+ 10 at the end of June.
Feeding management measures
A well-cultivated water. 5-7 days before shrimp fry go down to the pond, pile up base fertilizer and organic fertilizer (chicken manure, pig manure and grass fermentation fertilizer), apply base fertilizer 150-250kg every 667m2 in new and old ponds and thin ponds, pile up 2-3 chopping boards every 667m2 when the fertilizer is 6-8m away from the pond, and inject water for 70cm-80cm to cultivate palatability. If the pond water is not fat in the early stage, topdressing can be used, and it is better to pour concentrated chicken manure water after soaking and fermentation, so that the pond water will gradually become a suitable fertilizer. 9 ~ 10, nitrogen 1~2 times, phosphorus and potassium (compound fertilizer) 5~7.5 kg per 667 square meters.
B. Water quality supervision. Keep the PH7~8 between 7 and 8, and spray quicklime 165438+20 days at a dose of 5 kg per mu from early September to early October, so as to improve the water quality of shrimp culture and ensure sufficient dissolved oxygen. C "smelly green sand" treatment. First, catch (release) the "smelly green sand" when it blows downwind and the water surface is concentrated; Second, when the "smelly green sand" is concentrated in the downwind water surface, choose to sprinkle 0.4~0.5 kg of copper sulfate every 667 square meters on a sunny morning 10; The overflow range shall not exceed1/5 of the total area; Pay attention to the weather when using copper sulfate to avoid water quality deterioration.
Proper maintenance of aquatic plants. The aquatic plants that are beneficial to the hidden habitat of freshwater shrimp are black algae, POTAMOGETON malayi and Ceratophyllum japonicum. If there are no aquatic plants, you can plant some Alternanthera philoxeroides or Sophora alopecuroides 3-4 meters away from the beach of the pond for a week. The area of aquatic plants of 667 square meters should be controlled at around110, and various aquatic plants should be removed in time to avoid competing with shrimp for oxygen.
E reasonable feeding. The feed for feeding freshwater shrimp includes snail meat, minced fish, silkworm chrysalis, earthworm, fly maggot, bean cake, rice bran, distiller's grains, etc. , but compound feed is better. Generally, the main compound feed and animal feed are used to feed. For 20-30 days, the freshwater shrimps can be fed with self-made feed, 30% fish meal or silkworm chrysalis with green chaff, or feed with broken pellets, with a daily dose of 0.5- 1 kg of 667 square meters, and then feed with full-price freshwater shrimp pellets. The daily feed of 667 square meters can be 1.2 in late August. 1October 1.5 ~ 1.5 kg,1October 1 1.5 ~ 0.5 kg. Production of special feed for freshwater shrimp with compound feed. From August to September, the protein content of feed 1 was about 35%, and the protein content of feed 10 ~11was about 32%. Oily and shiny, slightly yellow and fishy, staying in water for 1~2 hours. Feed it twice a day, 30% at 6~7 in the morning and 70% at 5~6 in the afternoon. In the morning, it is around the shrimp pond, 2~3 meters away from the ridge, and evenly scattered at the ridge 1~2 meters away at night. In the early stage, 15 ~ 20kg of crushed material or 20 ~ 25kg of self-ingredient is needed, and in the middle and late stage, 90 ~10kg of granular material, 500 ~ 700kg of snails or100 ~/50kg of small miscellaneous fish are needed, with a general feed coefficient.
Since September, shrimp culture in ponds can adopt the method of catching large shrimps and keeping small ones, and catching adult shrimps over 4.5 cm and putting them on the market. Shrimp cages can be used to trap shrimps, and shrimp nets can be used to catch them in habitats near pools. At the end of the year, they can be caught in dry ponds.
(2) Paddy field culture, the ecological environment of paddy field is suitable for the growth of freshwater shrimp, which can increase economic benefits. Choose a field close to the water source, with convenient water intake and drainage and good soil quality. Dig a wide shrimp ditch with a width of 2m and a depth of 1 m at one end of the field, and form a shrimp ditch with a width of 1 m and a depth of 0.8m around and in the center of the field. Clean and disinfect the paddy field before transplanting, and release the young shrimp one week after transplanting. Generally, the shrimp seedlings cultured in that year are put in 667 square meters1~ 20,000 shrimps. Choose rainy days or sunny mornings to stock up at different points.
High yield can only be obtained by feeding shrimp in rice fields every day. Feed can be bran, bean cake, snail and shellfish meat, minced fish, etc. Or mixed feeding twice a day, mainly in the evening, and the daily feeding amount is generally 2%~4% of the shrimp weight.
To raise shrimp in rice fields, it is necessary to change the water regularly to keep the water in shrimp ditches fresh, especially in summer and high temperature seasons. After rice harvest, the water level in shrimp ditch should also remain stable. Shrimp is particularly sensitive to pesticides and should be avoided as much as possible. If you use it, you should also use high-efficiency and low-toxicity pesticides, and pay attention to the use method to prevent phytotoxicity. In addition, special attention should be paid to enemies such as water snakes, frogs, rats and waterfowl.
Shrimp culture in rice fields is carried out by releasing water. First, arrange a net at the water outlet, slowly drain the field water, and let the shrimp enter the net with the water, so that the shrimp in the shrimp ditch can be completely caught.
(3) temporary support. Every year around June 5438+ 10, freshwater shrimps are listed in a centralized way. At this time, the price is low, so you can use the idle pond to buy shrimps with smaller specifications and raise them temporarily, and wait until they are listed around the Spring Festival to get better benefits. The temporary breeding pond is required to be selected in a place with convenient transportation and more shrimp sources, and other conditions are the same as those of the breeding pond. The temporary pond must be thoroughly cleaned and disinfected, and it can be temporarily raised 100~200 kg per 667 square meters of water surface, according to the specifications. The transparency of the pool water should be kept at 30~40 cm, and it should be fed every day, and the water temperature should be properly fed above 7℃ in winter. Do a good job in the management of escape and theft prevention. According to the market situation, catch the market with shrimp tow, shrimp rake and net.
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