1. Polyculture of Penaeus vannamei and river crabs not only makes full use of water body food resources (water plants, residual bait, etc.), but also has the effect of preventing shrimp diseases. River crabs can eat weak and sick shrimps or dead shrimps , reduce the spread of pathogens.

2. Penaeus vannamei, Penaeus vannamei and Macrobrachium rosenbergii are polycultured to increase the variety of shrimp culture and production efficiency.

3. Penaeus vannamei and silver carp are polycultured. During the breeding period, algae in freshwater ponds are prone to overproduction, causing "water diversion". The habit of silver carp to feed on plankton is used to control algae in the water. quantity to regulate and improve water quality. 1. Penaeus vannamei is cultured in grass carp ponds

2. Penaeus vannamei is cultured in carp ponds

3. Penaeus vannamei is cultured in crucian carp ponds. These three breeding modes are all using By increasing the breeding space and food resources of the water body, the number of rotifers in the water body can be well controlled, and the water quality can be adjusted and improved. However, it should be noted that the shrimp must leave the pond in October, otherwise the vannamei shrimp will die if the water temperature drops below 14 degrees, affecting the shrimp production and thus affecting the economic benefits of the pond.

Pool patrol observation

1. Observe the pool water condition, dissolved oxygen and other water quality factors, and measure the dissolved oxygen, pH value, etc. in the pool before sunrise and at 16:00 every day. It is best to measure the transparency once a day, and frequently detect changes in the species and quantity of swimming organisms in the pool. If conditions permit, you can detect changes in ammonia nitrogen and other water quality elements.

2. Observe the activity and distribution of shrimp.

3. Regularly inspect the shrimp body, pay attention to the discovery of diseased and dead shrimps, remove the diseased and dead shrimps in time, and check the cause of death.

4. Measure the growth of shrimp every 10 days. It can measure the body length and weight of shrimp. The length of the shrimp body refers to the length from the base of the eye stalk to the end of the telson. No less than 50 shrimps shall be randomly sampled for each measurement. To measure the weight, you can catch no less than 50 shrimps, weigh the total amount at one time, and then calculate the average tail weight.

5. Observe the shrimp feeding and feed utilization.

6. Regularly estimate the number of shrimps in the pond. For small shrimps of 3-6cm, you can use a small lifting net with a known area to lift the shrimps in multiple places in the pond and estimate the number of shrimps in the pond based on experience. Prawns longer than 6cm can be quantified with a rotary net. Set nets at multiple points in the pond and sample according to the distribution of shrimps in the pond. Based on the number of shrimps caught, use the formula to find the number of shrimps in the entire pond.

7. Pay attention to the safety of gates, ditches, ponds and dams, whether the aerator is operating normally, and pay attention to the safety of electricity during thunderstorms.

Salinity Control

Control of salinity in pool water. Although shrimps can be cultured in fresh water, they are not pure fresh water. There should be some salinity in the water. Salinity control in the water The optimal value is 1-3‰. If it is lower than 0.5‰, the shrimp's resistance will be weakened, it will be easy to get sick, and the breeding effect will be poor. If the salinity is below 0.5‰, brine, seawater essence, industrial salt, etc. can be used for adjustment.

Aeration of pool water

Aerators must be used in closed and semi-closed shrimp farming methods. The functions of the aerator are to increase the dissolved oxygen content of the pool water, mix high dissolved oxygen water on the surface of the pool water with low dissolved oxygen water on the bottom layer, increase the overall dissolved oxygen level of the pool water, avoid pool water stratification, accelerate the decomposition of organic matter in the water, and reduce the concentration of toxic substances. Toxicity, reduce harmful substances in the water, improve water quality, promote the metabolism of shrimp, make shrimp eat vigorously, and enhance disease resistance. Therefore, the use of aerator is no longer simply to rescue floating heads, but has become an important and effective measure to improve water quality. Ponds can use impeller-type or waterwheel-type aerators. The number of aerators depends on the farming method. The main pond generally has 1-2 acres of water surface per kilowatt load.

The start-up time of the aerator can be based on the need for dissolved oxygen, but under normal circumstances, in late June, when the water temperature reaches above 25°C, the aerator will be started to activate the water quality and increase the amount of oxygen in the pool. Dissolved oxygen. In the early stage, the machine is usually turned on at noon every day. In the high temperature season of July and August, the machine is turned on at regular times throughout the day.

Use oxygenating agent when necessary. In addition, on cloudy days and rainy days, the startup time and frequency should be increased to ensure that the dissolved oxygen in the water is always maintained above 5mg/l.

Note: When feeding shrimps, the machine should be shut down for half an hour to one hour to facilitate the shrimps' feeding.

Since the use of aerator has been used as an important means to improve water quality, in order to make its effect more obvious, we use the traditional impeller aerator while also developing new aeration methods. Exploration was carried out and good results were achieved.

The specific method is as follows: every 30-40 acres of water surface is equipped with an air pump with a power of 2.2 kilowatts, connected to a 2.5-inch main pipe, and then led to each shrimp pond with a 0.4-inch branch pipe, and then connected to the air-filled pipe to distribute At a distance of 1.5m from the pond bank, 1-2 1.5 kW impeller-type cultivation machines are installed in the pond. When in use, the pipe aeration is carried out throughout the day and the impeller-type intensifier is turned on at night and when necessary during the day. In a demonstration farm that uses inflatable pipe-type aeration facilities for shrimp farming, no disease occurs during the breeding process, the survival rate of shrimp larvae reaches 83%, the maximum yield reaches 10,000 kilograms, and the size of White Penaeus vannamei is 56-60 tails/kg.

Control water quality

Water quality culture before releasing shrimp seedlings

After disinfection of the shrimp pond, filtered seawater enters the clear pond, so that the water level of the shrimp pond reaches 1~ About 1.2 meters, and then seal the gate for disinfection. You can use "Yu'an" or "strong chlorine essence" 2 to 3 ppm or bleaching powder 20 ppm for disinfection. If the pool water glows at night, you can use "Shrimp Cleaner" or "Light-Eliminating Water-Retaining Cleanser" to treat it. After disinfection for 3 to 4 days, apply fertilizer and water. For water cultivation, you can choose plankton auxin, "Fertilizer King", etc. You can also use urea and phosphate fertilizers. The amount of fertilizer used depends on the substrate and water depth of the shrimp pond. The standard for water quality culture before planting is to make the water color reach dark brown or yellow-green, with a transparency of about 40 cm and a pH value of 8.5 to 9.0. Groups of zooplankton can be seen in the evening or morning. After reaching the above standards, shrimp seedlings can be released. Before throwing in the seedlings, you can use a small amount of shrimp seedlings to test the water first. After 2 days, observe that the shrimp seedlings have normal activity before throwing in the seedlings.

Medium-term water quality control after the release of seedlings

One month after the release of shrimp seedlings, as the seedlings grow, their feeding habits shift to mainly artificial compound feed. The role of plankton in shrimp ponds is mainly to regulate the environment of the water body and regulate transparency, etc. Therefore, the growth of zooplankton must be controlled. Due to the continuous increase in feeding artificial feed, the amount of residual bait in the pond has increased accordingly. In addition, the shrimp excrement and the death of plankton in the pond have formed the deposition of organic matter, making the shrimp pond "fat". At this time, efforts must be made to reduce "fat". Control methods: First, when it is observed that the water color is dark and the transparency is too low, some oxidizing disinfectants can be poured into the pool to oxidize the toxic substances deposited at the bottom of the pool and reduce the toxicity. At the same time, it can kill some algae and reduce the "fertility" of the pool water. The second is to add new water, preferably clean fresh water.

Water quality control in the later stage

As shrimp culture enters the later stage (after 60 days), it is necessary to accurately grasp and control the amount of feeding and avoid excessive feeding. Second, the bottom of the pond must be cleaned and sewage discharged. Ponds with intermediate sewage discharges must be discharged frequently. For ponds without intermediate sewage discharge, a sewage suction pump can be installed to suck out the sewage at the bottom of the pond. However, you should pay attention to the method of absorbing dirt and do not turn the pool water into a "bottom". Third, after cleaning, sprinkle some pool bottom detergent, zeolite powder, white stone powder and other substances to improve the pool bottom environment and sprinkle oxidizing disinfectant. Fourth, some beneficial live bacteria should be put in 3 to 4 days after disinfection to purify the water quality. Observed with the naked eye, the water quality standards in the later stage have reached: the water is dark brown but not turbid, not muddy, smells of algae but not smelly, and feels refreshing but not sticky. Practice has proven that the aerator and oxygenation method that currently has the best oxygenation effect and the lowest energy consumption is the combination of a blower pipe-type bottom aeration oxygenation and a water wheel type aeration machine on the water surface to form a three-dimensional oxygenation. This method makes the pool The dissolved oxygen in the medium is uniform and sufficient, which can promote the healthy growth of shrimp.

Feed Requirements

Penaeus vannamei has a wide and varied feeding habit and has low food requirements. As long as the feed contains 25-30% protein, it can grow normally. However, under artificial high-density breeding conditions, the protein content of the bait should be about 40% to facilitate the rapid growth of shrimp.

Feeding matters

1. Do not feed spoiled or toxic feeds, and feed less plant-based feeds with low potency.

2. Feed less in ponds with fatter water and rich feed organisms. Feed more appropriately in ponds with thin water and few feed organisms.

3. When the water temperature is higher than 30℃, you should feed less and feed more often; when the wind is warm and the sun is warm, feed more; when there are heavy storms, rains, and cold currents, you should feed less or temporarily not feed.

4. Feed less prawns on the day they molt in large quantities (can be reduced by about 20%), and feed them more appropriately two days after they molt.

5. When there are many competing organisms in the pool, you should feed them more appropriately.

6. The size of shrimps in the pond is seriously differentiated and uneven, which may mean that there is a long-term lack of bait and should be fed appropriately.

7. When the water quality deteriorates or anoxic floating heads occur, feeding should be reduced or even temporarily stopped. Measures should be taken to improve the water before feeding normally.

8. Decentralized feeding is better than centralized feeding; alternate feeding of multiple feeds is better than long-term feeding of a single feed.

Feeding management

Penaeus vannamei farming adopts a feeding method that combines natural feed and full-price artificial compound feed. In the early stage of shrimp larvae, shrimp feed on natural feeds in the pond, mainly rotifers and cladocerans. Later, artificial compound feeds are gradually added. In the middle and later stages of culture, artificial compound feeds are mainly used. Artificial compound feeds should be nutritionally comprehensive, have good adhesion, and have good particle size. Appropriate granular bait has a crude protein content of more than 36%. In terms of feeding management, since shrimps and fish are different, they have small stomachs and short intestines, and the amount of food consumed each time is small, but digestion and excretion are fast. Therefore, feeding should be done in small amounts and multiple times, and the feeding status of the shrimp should be checked at any time, and the food intake of shrimps should be checked in time. Adjust feeding amount.

In addition, the feeding methods of shrimps and fish are also different. Fish mostly swallow, and the adhesion of the bait does not need to be too strong, while shrimps feed by hugging, which requires good adhesion of the bait. Otherwise, the shrimps will fall apart as soon as the bait enters the water. Not only will the shrimps not be full, it will affect their growth, resulting in a waste of bait, increasing the cost of breeding, but also easily damaging the water quality and inducing diseases.

The bait feeding method is artificial feeding. The artificial bait is fed evenly along the edge of the pool. The principle of feeding frequently and feeding sparingly must be adhered to, and the bait is fed 4-6 times a day. In the first month after the seedlings are released, the number of daily feedings can usually be arranged four times, at 6-7 o'clock, 10-11 o'clock, 15-16 o'clock, and 20-21 o'clock every day. In the future, as the shrimp grows, the amount of feed will be increased, and the frequency of feeding can be increased. Feeding is done 6 times a day, from 6 a.m. to 22 p.m., about once every three hours, and feeding after the afternoon takes up about the entire day. 60% of the feeding amount. The feeding amount is 3-5% of the total weight of the shrimp in the pond, and will increase or decrease with the weather, temperature, water quality, and shrimp activity.

In order to observe the feeding situation of the shrimp, you can set up several feeding trays in the pond, put the bait in, and observe the shrimp's eating and satiety of the bait. If the bait is eaten up quickly after feeding, it is The amount of feeding should be increased. If there is still bait left before the next feeding, the amount of feeding should be reduced. You can also check the fullness of the shrimp stomachs 1 hour after feeding. If more than 2/3 of the shrimps have full stomachs, it means that the feeding is sufficient. If the shrimps with full and half-stomachs are less than 1/2, it means that the shrimps have been fed. If it is not enough, the amount of bait should be increased. Causes and prevention methods of white spot syndrome

Pathogen: White spot syndrome virus (WSSV) or subcutaneous and hematopoietic tissue necrosis baculovirus (HHNBV).

Symptoms: No food intake, empty stomach; inability to swim, slow reaction; white or light yellow spots on the inner surface of the carapace, especially the head and chest carapace, some are mottled, and the carapace is easy to peel off; the body color is red.

Prevention and treatment:

There is no effective prevention and treatment drug for shrimp viral diseases. Viral diseases are also likely to occur when seawater shrimps are cultured in fresh water. The main thing is to strengthen health management, cut off the transmission routes of pathogens and carry out comprehensive prevention.

(1) Thorough cleaning and elimination: after cleaning, use 120-150 kg of quicklime or 25 kg of bleaching powder (containing 30% effective chlorine) per acre for disinfection;

(2) Stock high-health shrimp larvae (SPF) free of specific pathogenic infections and control the stocking density;

(3) Use pollution-free and virus-free water sources. When infectious epidemics occur, the breeding ponds should not be in large numbers Exchange water;

(4) If the virus is found in the shrimp pond but has not yet developed, oxygenation measures should be taken to ensure that the dissolved oxygen is not lower than 5mg/l; add 0.1%-0.2% to the feed for stability Good vitamin C and immune-enhancing drugs; spreading Qiang Ke 101 (i.e. super iodized quaternary ammonium salt) drug throughout the pond has a better effect on eliminating red body symptoms;

(5) Keep the environmental factors of the shrimp pond stable , the algae phase in the pool is stable and reduces disturbance;

(6) Use medicated feed to prevent the occurrence of concurrent diseases such as bacteria and parasites.

The causes and prevention methods of Taura Syndrome

Pathogen: Taura virus (TSV)

Symptoms: Red beards, red tails, and body color of sick shrimps Turns into tea red; gastrointestinal tract is red and swollen, no or less food intake, empty stomach; activity ability is significantly weakened, reaction is slow, swimming slowly on the water surface, and will die after being removed from the water body; the carapace and muscles of some diseased shrimps are easy to separate, Irregular black spots appear on the carapace of sick shrimps that have not recovered from the disease. The disease develops rapidly and has a high mortality rate. Generally, most shrimps die about 10 days after the onset of the disease in shrimp ponds. Most of the affected shrimps are 6-9cm in size. The onset time is generally 30-60 days after breeding. The disease is more likely to occur in drastic changes in the environment. . Prevention and treatment: Same as vitiligo syndrome.

Causes and prevention methods of red body disease in shrimp

There are many reasons for red body disease in Penaeus vannamei. The shrimp is infected with white spot syndrome virus, Tora syndrome virus, bacteria Symptoms of red body color may occur, but when the breeding environment deteriorates, it may also cause the body color of Penaeus vannamei to turn red. Therefore, when red body symptoms appear on individual shrimp in the shrimp pond, the cause should be found from multiple aspects, and then the main cause should be prescribed or comprehensive treatment measures should be taken to control the development of the disease. Under normal circumstances, if the white shrimp eats and swims normally, but only the appendages are red, you can consider whether it is caused by changes in water quality; if the shrimp body is red, does not eat, and swims slowly, it may be a virus or Bacterial disease infections. In breeding production, the treatment of erythrozoonosis is usually a comprehensive treatment method of water disinfection, water quality improvement and oral administration of antibiotics and antiviral drugs. Practice has proved that although red body disease in Penaeus vannamei is very harmful to aquaculture production, as long as it can be detected in time and comprehensive treatment methods are adopted early, the disease can mostly be effectively controlled

Symptoms of sessile ciliate disease And prevention and treatment

Symptoms: The gill area is black, and the appendages, eyes and body surface are covered with gray-black villi. Take gill filaments or dip slices from attachments on the body surface, and observe under a microscope that ciliates are attached. Shrimp float on the surface of the water and swim alone, with slow reaction and loss of appetite. They may even stop eating and cannot molt. From midnight to just before dawn, when the dissolved oxygen in the pool water is lower than 3mg/l, they often die due to difficulty in breathing.

Prevention and control: (1) Change the water appropriately in the middle and late stages of breeding, feed appropriately, and reduce the organic matter content in the shrimp pond; (2) Take oxygenation measures to keep the dissolved oxygen in the pond water not less than 5mg/l; (3) ) Check and diagnose whether there is bacterial or viral infection in the shrimp body for symptomatic treatment; (4) Sprinkle tea seed cake throughout the pond with a concentration of 10-15ppm to prompt the shrimp to molt, and then change the water; (5) Use drugs that kill ciliates. treat.

Jejunal and jejunal gastric morbidity

Penaeus vannamei morbidity caused by Vibrio parahaemolyticus is related to the salinity, PH value, water quality, organic matter, and inorganic content of the shrimp pond. It is related to the quality content of shrimp ponds. The time, speed and degree of shrimp disease in shrimp ponds with different conditions are different:

The lower the salinity of the pond, the later the time of the first disease after the seedlings are released. For example, in ponds with a specific gravity below 1.005, The onset time is 30-40 days after the seedlings are released. A small amount of rotten red dead shrimps float up every day. After the feed is stopped, the number of dead shrimps will decrease. When the shrimps are raised for 60 days, not many dead sick shrimps are found; the salinity of the pond The higher the value, the faster the initial onset of disease after the seedlings are released. For example, in a pond with a specific gravity above 1.020, the shortest onset time is 6-7 days after the seedlings are released, and the longest is no more than 20 days. When a small amount of rotten red dead shrimp is found, When floating, most shrimps will die at the bottom of the pond within 3-5 days.

If the pH value is lower than 7-8, the survival rate will be higher; if the pH value is higher than 8-9, the survival rate will be lower.

The lower the water temperature, the later the first onset of disease after seedlings are released; the higher the water temperature, the faster the time of first onset of disease after seedlings are released.

Shrimp ponds with thin water and low organic suspended matter content have higher survival rates; ponds with dense water and fertilizer and high organic matter content have lower survival rates. 1. Shrimp trap net (or ground cage net): The net is usually lowered in the evening and closed the next morning. The quantity to be removed from the network on the day can be determined based on the demand for the next day. This method can continuously supply the market and achieve a balanced listing.

2. Release water to collect shrimps: According to the habit of shrimps being more active around dusk or dawn, open the gate at 5-6 o'clock in the evening or 4-5 o'clock in the morning to release water to collect shrimps. Release the water slowly first. When the formation of Increase the amount of water released after the water flows. This method is generally used when the pond needs to be dried.

3. Pull net: For ponds with flat bottoms, use a pull net to collect shrimps in the evening or dawn. Generally, the catch rate of the pull net can reach 70%. No matter which method is used to collect shrimps, all shrimp caught in the net should be sold and cannot be returned to the pond, otherwise a lot of losses will be caused.