Breeding information of Penaeus vannamei

By the end of 20 13, Penaeus vannamei is still a shrimp species with high aquaculture benefits, especially in the sales of Penaeus vannamei and the connection with the internet, which also promotes the sales of Penaeus vannamei and makes the culture get better economic benefits.

Improve survival rate

Since 200 1, the breeding area of Penaeus vannamei has been expanding continuously, and the supply of larvae directly affects the development of this cultured species. According to the continuous research of Penaeus vannamei culture and production, the methods to dilute culture and improve the survival rate and fry quality of Penaeus vannamei were discussed by summarizing all technical links and key points in production. 1. Disinfection of nursery pond and tools: First, soak the tools and nursery pond in clear water and clean them, then soak them in 50- 100ppm bleaching powder or 20-30ppm potassium permanganate for thorough disinfection.

2. Treatment of water for seedling: Although the water for desalted seedlings is not as strict as that for early seedlings, there are certain requirements. The quality of water affects the survival rate of desalination and the quality of seedlings, so attention should be paid to selection and treatment. Mainly: the water quality should be fresh and pollution-free, with high transparency (above 40cm), pH 7.8-8.5, dissolved oxygen above 6mg/L, and ammonia nitrogen below 0.1mg/L/L. The water quality that has been left for a long time should also be properly disinfected to kill pathogens; After the water enters the pond, it is filtered with a nylon mesh bag with a mesh of 120 mesh. On the day before or in the morning, fresh water enters the desalination pond with a depth of 0.6-0.8m, and then the water is adjusted to a salinity similar to that of the shrimp pond with crude salt, potassium chloride, magnesium sulfate, magnesium chloride and calcium chloride. Adding disodium EDTA with a concentration of 3-5g/m2. What needs special attention here is that the salt can be fully dissolved before sowing. The body shape of Penaeus vannamei is similar to that of Penaeus vannamei in China, and it can generally reach 1 1- 13cm under artificial culture conditions. Penaeus vannamei is a tropical shrimp in the wide salt, which often inhabits the muddy seabed, crawls or lurks in the surface of the seabed during the day, and has frequent activities at night, and is quiet and afraid of shock. The water used for shrimp culture is pollution-free river water or mixed with well water after contact. The main technical indicators of water quality are: pH 7.6-8.6, water temperature 16-35℃ (gradient range), salinity 0.5-40‰ (gradient range), ammonia nitrogen L, dissolved oxygen >: 5mg/l, and other indicators shall not exceed the national fishery water quality standard.

Water quality treatment

1, water color changes dramatically.

The ideal water color should be yellow-green or brown formed by green algae or diatoms. In the early stage of aquaculture, because there are too many zooplankton in the pond water, which far exceeds the available number of shrimp larvae, and a large number of unicellular algae are ingested, the oxygen production function of the pond water is reduced, and the water color is turbid and innocent, which affects the normal growth of shrimp.

Treatment method:

(1) Proper water supply and fertilization can adjust the composition of algae in pond water, so that green algae or diatoms can become the dominant population and form a certain number.

(2) In the case of pure freshwater culture, appropriate amount of crude sea salt or crystals can be applied to maintain the micro-salinity of water and meet the physiological needs of Penaeus vannamei.

(3) applying quicklime zeolite powder to adjust the water color, so that the pH value of the water body is within the range of 7.5-8.8, and the transparency of the water body is maintained at 30cm~40cm.

2. Lichen overgrowth

(1) Seedlings should be released in hot season, and the pond water should be filled at one time1.2m ~1.5m. Fertilize as soon as possible to control the water quality and inhibit the growth of lichens at the bottom of the pond.

(2) The shrimps are artificially produced, usually at noon on sunny days, otherwise the shrimps in the pond are prone to lack of oxygen and float their heads.

(3) spraying granular chlorine-containing disinfectant in lichen growing area. When the medicine sinks to the bottom of the pond, it slowly dissolves and exerts its efficacy, so that the base of the lichen will die and rot. After about a day, the overgrown lichens will float to the surface and be fished out manually.

3, harmful substances exceed the standard

The water quality requirements of Litopenaeus vannamei culture pond water are ammonia nitrogen 0.3mg/L ~1.9mg/L and nitrite 0.02mg/L ~ 0.09mg/L. If the water quality is seriously deteriorated, the treatment methods are as follows:

(1) Sprinkle with microecological agents such as Bacillus subtilis or Bacillus.

(2) Use water quality improvers, such as zeolite powder, activated carbon, clay, etc.

(3) To replenish or change water reasonably, it is best to directly drain the bad pool water, then inject fresh water into the pool, and use the aerator correctly.

4, cyanobacteria flooding.

In the later stage of aquaculture, a layer of emerald "water bloom" floats on the water surface of the lower air outlet of the shrimp pond. These "water blooms" are caused by excessive feeding of feed. In the process of degradation and transformation of residual bait and shrimp manure in pond water, the nitrogen content of organic matter in pond water increases, and the pH value of water generally reaches 8.0 ~ 9.5, which is alkaline, resulting in a large number of indigestible cyanobacteria in shrimp, which eventually become the dominant population of phytoplankton in pond water. When the dissolved oxygen content in the pond water is insufficient, a large number of cyanobacteria will die quickly, and the protein after algae death will easily decompose to produce a large number of toxic hydroxylamine and hydrogen sulfide, resulting in serious flooding accidents. The treatment method is as follows:

(1) The reproduction of cyanobacteria can be controlled by adding clean water frequently and adjusting the water quality.

(2) When there are a large number of cyanobacteria in the pond, when downward flow is chosen at noon on a sunny day, the water in the pond should be drained to the lowest level as far as possible, which can generally be about 1/3 of the water in the pond, and then the mixture of copper sulfate and ferrous sulfate should be used to kill the cyanobacteria. However, attention should be paid to observation, and rescue measures such as adding water and increasing oxygen should be taken at any time, otherwise it should not be used.

(3) The cyanobacteria can be fished out from the water surface of the lower air outlet of the pond with a dense mesh screen, or the mixture of copper sulfate and ferrous sulfate can be sprayed locally to kill the cyanobacteria.

Water quality improvement

The purpose of using water quality improver regularly and quantitatively is to increase dissolved oxygen, stabilize algae phase fluctuation, reduce PH fluctuation, reduce ammonia nitrogen, and reduce harmful substances produced by organic matter and its decomposition. Proper use of biological agents such as photosynthetic bacteria can adjust and maintain the stable micro-ecological environment of water body, so as to reduce the impact of environmental changes on prawns and achieve the purpose of ecological culture.

Specific practice: every half month, medical stone, zeolite powder or water quality improver with zeolite powder and calcium peroxide as main components are added. In general, the dosage of zeolite powder is 20-30 kg per mu every half month to 20 days, or it is used according to the product sales instructions. In addition to zeolite powder and medical stone, there are microbial preparations.

Microbial agents, also known as probiotics and probiotics, mainly include photosynthetic bacteria, Bacillus, nitrifying bacteria and EM raw dew. Microbial agents can reduce ammonia nitrogen, nitrite, organic pollutants and harmful substances produced by their decomposition in water, stabilize pH value, and improve DO in water and biodiversity of microorganisms and plankton in aquatic ecological environment.

In addition, some microbial agents, such as Bacillus, can also use a variety of enzymes and antibiotics secreted by them to inhibit the growth of other bacteria, reduce or even eliminate the influence of pathogens, so as to improve water quality and achieve the purpose of disease prevention. According to relevant research and testing, some microbial preparations can greatly reduce the infectivity of the virus, and its mechanism is related to the extracellular substances secreted by these microorganisms in the process of water proliferation, which can inhibit the infectivity of white spot virus.

Therefore, in order to ensure the quality and safety of aquatic products, we should vigorously advocate the use of microbial agents to carry out pollution-free and healthy farming, and use little or no drugs in the farming process. Shrimp ponds can be developed or rebuilt by using the original ponds. The suitable area of each shrimp pond is 5-30 mu, rectangular or square, and the pond depth is 2.5-3.0 meters. During the breeding period, the water depth can be kept at 2.0-2.5 meters, the bottom of the pond is flat, the dike slope is intact, and the water retention performance is strong. HDPE geomembrane is generally used as impervious material in shrimp ponds. The shrimp pond is equipped with a water inlet and drainage system, and the water inlet and drainage gate should be equipped with a filter screen, or it can be pumped without a drainage system. It is best to have a reservoir in the shrimp farm to support the shrimp to change water.

Dredging and the whole pond

The residual bait, shrimp manure, animal carcasses, dead algae and dead aquatic plants in shrimp ponds are the basis for the comprehensive formation of sludge, and are also one of the reasons for the aging, disease occurrence and low yield of shrimp ponds. The purpose of dredging is to remove these harmful sediments.

Specific measures are as follows: after shrimp harvest, drain the accumulated water in the pond, seal the pond to bask in the sun, maintain dams and gates, thoroughly remove silt and weeds in the pond, with the dredging depth of 10-20cm, and focus on cleaning the feeding path and dead angle of the pond. The newly-built pond can be dredged, but it needs drug disinfection.

Cleaning of drug pool

1, drain the pool water as much as possible before cleaning the pool to save consumption;

2. Sunny weather should be chosen to improve the curative effect;

3. Apply medicine along the wind and spray evenly with the help of wind;

4. After the medicine enters the pool, continuously stir the water, so that the medicine is splashed and stirred at the same time, so that the medicine is evenly mixed with the accumulated water;

5. Pay attention to the dead angle in the pool, potholes and crab holes on the edge of accumulated water, and contact with the liquid medicine;

6. After cleaning the pool, it is necessary to comprehensively check the efficacy. If live fish are still found after application, the pool should be cleaned again;

7, all kinds of drugs have certain toxicity and corrosiveness, pay attention to safety when operating, don't contact with human skin, used instruments should be cleaned in time.

Disinfect and kill pests

Because the shrimp seedlings are only 0.7- 1.0cm when they go down to the pond, they are weak in physique and have poor ability to avoid enemies, especially when molting, and they are more vulnerable to attack. Therefore, shrimp ponds require higher conditions than fish ponds, and they should be dredged and disinfected every year to kill enemies and pathogens in the ponds.

Medicine for clearing pond and its application

1, quicklime

Quicklime is a broad-spectrum disinfectant, which can kill viruses, bacteria, fungi and parasites. Quicklime can also stabilize water quality conditions, change soil structure, increase the permeability of sediments, and also play a role in direct fertilization, which is beneficial to the growth of basic feed organisms. Therefore, quicklime is an ideal pool cleaning drug.

Usage: Before releasing shrimp seedlings in spring, spread 75- 100 kg of quicklime per mu over the pond, and then enter the washing pond. You can also clean the pond with water at a dosage of 0.5- 1.0 kg per cubic meter of water, and sprinkle it evenly into the pond with a spade.

2, bleaching powder or bleaching essence

Bleaching powder or bleaching essence is a broad-spectrum disinfectant, which can completely kill microbial pathogens such as fish, crustaceans, shellfish, algae, viruses and bacteria. After bleaching powder enters the water, it can produce hypochlorous acid with strong bactericidal ability. The higher the available chlorine of bleaching powder, the stronger its bactericidal ability.

Dosage: Add 50-70g of bleaching powder containing 25%-30% available chlorine or 25-35g of bleaching essence containing 60% available chlorine to each cubic meter of water, dissolve it in water, then sprinkle it all over the pool water, and sprinkle this liquid on the surface of the dew pool.

3. Tea seed cake

Tea seed cake is the residue left after oil extraction from Camellia oleifera fruit, and its effective component is saponin. Gleditsia saponin is a hemolytic poison, which can selectively kill fish and mollusks, but it is less toxic to crustaceans and other feeds. Saponin is 50 times more toxic to fish than shrimp. This drug has a short duration and can disappear due to biodegradation in just a few days. Therefore, tea seed cake has a good effect on removing harmful fish, but it is ineffective on viruses, bacteria, fungi and other germs.

Usage: When in use, the tea seed cake is dried and crushed, soaked in water for one day and night, and sprinkled into water according to the dosage of 15-20g per cubic meter of water, and fish and shellfish can be killed after 1-2 hours. In order to improve the disinfection and insecticidal effect of ponds, some ponds adopt the method of combining quicklime with tea seed cake, which has achieved good results.

Water intake mode

Before cleaning the pool, a water filter net should be installed to prevent enemy creatures from entering the pool through the gap of the gate after cleaning the pool. A flat net with a mesh of about 1cm should be installed in the outer sluice to prevent floating grass and sundries from entering the sleeve net. 60 mesh conical sleeve mesh shall be installed in the inner brake groove. The mesh length of conical sleeve mesh is 8- 10 meter. The filter net should be installed tightly, and the gap between the drain tank and the bottom of the drain tank should be plugged with brown silk, rubber strip or hemp.

After the drug is cleared, it can enter the pond in 10 days. Feed water slowly, and don't break through the filter screen because the water is too fast. Check whether the filter screen is damaged before each water inflow, and tie the screen tightly to avoid slipping. After entering the water, the fish, shrimp and other sundries in the net bag should be poured out of the pool, the net mouth should be tied tightly, cleaned and hung on the door frame to cool.

Fertilizer and water model

Fertilization and watering in the pond should be started 15 days before seedling release. In order to facilitate the reproduction of basic feed organisms, 70-80cm of water should be injected in the early stage, and fertilizer should be applied in sunny days. It is best to try fermented organic fertilizer in the new shrimp pond, applying 20-25 kg per mu and putting it in 2-3 times. It is appropriate to apply chemical fertilizer to the old shrimp pond. Generally, nitrogen fertilizer 1 kg and phosphorus fertilizer 1 kg per mu are applied once a week, and the dosage is halved. Shrimp seedling selection

(1) shrimp fry specifications should be unified as much as possible;

(2) the figure is relatively thick;

(3) the body color is white and bright;

(4) The specification is preferably about 1.0cm;

(5) Active swimming, strong countercurrent ability, easy to attach to the wall and bottom;

(6) Oversatiated food in gastrointestinal tract;

(7) there is no deformity, and it is easy to cause deformity by raising seedlings at high temperature or using some drugs;

(8) The body surface is smooth without lumps and other attachments and spots;

(9) Shrimp fry desalination requires salinity below 2‰ (or depending on pond water quality), and the whole desalination process shall not be less than 7- 10 days;

(10) It's best to isolate the virus in units with conditions.

Counting method

Shrimp fry are counted by dry weight method or cup method. Through these two methods, the number of shrimp seedlings is more accurate, which is convenient for management during breeding.

Shrimp seedling transportation

The transportation of shrimp seedlings should be based on the transportation distance, transportation time and the conditions of the transporter. Usually fish boxes can be used for short-distance transportation, and nylon bags can be used for long-distance oxygen transportation.

1. Fish box transportation: add 1/3 water to the fish box and aerate. When the water temperature is below 20℃, 400,000 shrimps with a total length of 1cm can be accommodated per 0. 1 m3, which can withstand transportation for 5-8 hours. Avoid the hot weather at noon during transportation, and you can't stop halfway.

2. Nylon bag transportation: A nylon bag with a capacity of 30 liters is used, filled with 1/3 of water, and 20,000 shrimps with a body length of 1cm can be transported, and it can be transported at about 20℃ for10-5 hours.

Sowing density according to

The seedling density in the pond should be determined according to the shrimp pond conditions, water exchange conditions, bait supply, shrimp seedling specifications, culture technology and management level, and the reasonable seedling release amount should be determined according to the planned output, specifications and expected shrimp seedling survival rate.

Calculation of seedling number

Number of seedlings per mu (tail/mu) = planned shrimp yield (kg/mu × tail number per kg when leaving the pond, estimated survival rate.

In general, the survival rate of shrimp seedlings without intermediate culture is 30%-50%, and the survival rate of shrimp seedlings after intermediate culture is 70%-80%.

Release condition

(1) The water depth of the aquaculture pond should reach 70-80cm, the water quality should be fertile, the water color should be yellow-green, yellow-brown, green and the transparency should be 30-40 cm.

(2) The constant temperature of the pool water should be above 65438 08℃, and the temperature difference during seedling release should not exceed 2℃.

(3) The salinity of the shrimp pond should not be less than 0.5‰, and the salinity difference between the water in the nursery pond and the water in the shrimp pond should not exceed 2‰. Otherwise, the method of gradual transition should be adopted to make shrimp seedlings gradually adapt to the salinity of pond water before releasing them.

(4) The pH value of pond water is between 7.8 and 8.7.

(5) Not suitable for sowing in stormy weather.

Precautions for seedling release

(1) The pond water should be analyzed before the seedlings are released, and the seedlings can be released only after the conditions of aquaculture water quality are confirmed. After no dead seedlings are found, a large number of seedlings should be released.

(2) The shrimps in a shrimp pond should be fully released at one time to avoid multiple releases. Otherwise, it is easy to cause shrimp seedlings to have different lengths and sizes, and the phenomenon that prawns eat shrimps without bait appears.

(3) Choose the sheltered side of the shrimp pond as the place to put the seedlings, and don't put the seedlings in the windward or shallows, so as to avoid the shrimp seedlings being blown directly to the beach surface by the wind and dying.

(4) Shrimp seedlings should be counted accurately, and it is best to count them again when stocking.

(5) Units that transport seedlings for a long distance without intermediate cultivation can take out 0.5%- 1% of seedlings and put them in the cage of the cultivation pond, and count them again after one day of normal management to estimate the survival rate of seedlings.