Penaeus vannamei can be raised

Selection of farms and preparations before releasing seedlings

Selection of farms

Adult shrimp breeding ponds There are no special requirements. Shrimp can be raised in any water body that can raise fish. However, shrimp production is closely related to pond conditions, so you should choose a sandy mud or hard mud substrate with good water retention, sufficient water sources, good water quality, and non-toxic. A pond with no pollution sources, convenient drainage and irrigation, no worries about droughts and floods, and convenient transportation. The pond area is generally about 1,300 to 6,700 square meters, and the water depth is 1.5 to 2 meters. The shrimp pond should be filled with a storage tank. The water filtered by the screen first enters the storage tank for disinfection, sedimentation, full aeration, and then enters the stocking tank. Each pond is equipped with 2 to 3 aerators of 0.75kw to 1.5kw.

Preparation before releasing seedlings

Pond cleaning and disinfection

Pond cleaning and disinfection is a key measure to eliminate harmful organisms in the pond, improve the pond environment, and ensure the success of shrimp farming. one. For newly built ponds, water can be soaked first and then disinfected; for old ponds and shrimp ponds transformed from fish ponds, the pond silt and weeds must be completely removed first to ensure that the silt does not exceed 10 cm. It is best to expose the shrimp ponds to the sun for more than a week before Carry out disinfection.

Pond disinfection can be carried out about 20 days before the release of shrimp seedlings. It is best to use quicklime as the disinfectant. The specific method is: fill the pond with 20 centimeters of water, use 100 to 150 kilograms of quicklime per 667 square meters, sprinkle the entire pond evenly, and drain the pond water after soaking for 2 to 3 days.

Timely fertilization and watering

Fertilization and watering can be carried out about 10 days before releasing seedlings to ensure that there is a sufficient number of plankton in the pool water. This is one of the technical keys to improving the survival rate of shrimp seedlings. Filter the water inlet with a sieve bag with an aperture of 80 mesh, fill the water level to about 40 to 60 centimeters, apply 200 to 300 kilograms of fermented and decomposed manure/667 square meters to cultivate the water quality, and add fertilizer or add new water according to the color and transparency of the water. It is best to make the water color gradually turn yellow-green or brown, and keep the transparency between 35 and 40 cm. Farmers who have the conditions to use organic fertilizers mixed with microbial preparations will achieve better results.

Establish temporary breeding facilities and adjust salinity

The shrimp seedlings sold by the nursery are in the larval stage that has not yet fully developed. The degree of desalination is not enough and the adaptability to the environment is poor. In order to buffer the differences in breeding conditions It is best to put the purchased shrimp seedlings through the central breeding tank, also known as the temporary breeding tank.

Users who have the conditions can establish special temporary breeding tanks. Farmers without temporary breeding conditions can set up plastic boxes in the shrimp ponds as temporary tanks to further desalinate and buffer differences in water quality conditions. They can also be used for agricultural purposes. The membrane intercepts part of the shrimp pond and adjusts the water locally, gradually allowing the shrimp seedlings to adapt to the water quality of the entire pond.

Use 500~600 kg/667 square meters of non-toxic industrial salt 1 to 2 days before planting seedlings to adjust the salinity of the temporary water in the holding pond and control it between 1.25‰-3‰. In the middle and later stages of breeding, the pond water level is raised to gradually reduce the salinity. The salinity of the pond water is maintained above 0.5‰ throughout the breeding period, which is beneficial to the growth and survival rate of Penaeus vannamei.

Purchase and transportation of shrimp larvae

The shrimp larvae you choose can be 0.6-2 cm long, with complete appendages, smooth body surface, neat specifications, and symmetrical eyes. , the tail fan is open, the body is strong and active, transparent and free of dirt, lesions and viruses. An effective method to identify the health of shrimp seedlings is the anti-water separation method: that is, randomly pick some shrimp seedlings from the nursery pond, wrap them in a wring-out wet cloth, and after 10 minutes, take them out and put them back into the original water. If the shrimp seedlings are still alive, they are High quality shrimp seedlings.

Polyethylene film bags can be used to transport shrimp seedlings. Add 1/4 volume of water to a bag, put the seedlings at a density of 500-1000 shrimp/liter, and fill it with oxygen (3/4 volume of oxygen). Tight bag opening.

Putting out seedlings

Penaeus vannamei is cultured under natural conditions, and the seedlings can only be released when the water temperature reaches 18°C ??and stabilizes above 16°C. When releasing seedlings, seedlings should be released before 10:00 on a sunny day or after 18:00. Seedlings should not be released at noon or on rainy days; when releasing seedlings, seedlings should be placed upwind, and seedlings should be released dispersedly and not too concentrated. ; After testing the water with a small amount of shrimp to confirm it is safe, you can stock the shrimp seedlings.

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Slow down the seedlings: After the shrimp seedlings are transported back, first put the shrimp seedling bags into the temporary breeding tank, gently turn the bag, and use a ladle to get water to "drench" the bag. Later, add a large amount of water to the bag. Place a plastic pot on the water surface of the temporary breeding pond, and fill it with a little pond water. Slowly pour the shrimp seedlings into the basin with the water. At this time, use a ladle to continuously add pond water and drain the basin water. After a while, slowly lift one side of the basin to allow the shrimp seedlings to slowly flow into the pool water. After the shrimp seedlings enter the pond, the amount of oxygen should be increased appropriately in a timely manner.

Stocking density: Generally, 15,000 to 25,000 seedlings per 667 square meters for extensive culture, 50,000 to 60,000 seedlings per 667 square meters for intensive culture, and 8-60,000 seedlings per 667 square meters for intensive culture with good conditions. 100,000 seedlings, and 200,000 to 500,000 seedlings can be released per mu in factory farming. After intermediate cultivation, the amount of seedlings released can be appropriately reduced.

Cultivation management?

Feeding?

Although Penaeus vannamei does not have high requirements for feed, it still needs to pay attention to nutritional matching and scientific feeding. During the breeding period, special compound feed for Penaeus vannamei is mainly used to promote the rapid growth of shrimp seedlings.

Selection of feeding site:

The feeding site should be determined according to the activity habits of the shrimp. The feed should be fed evenly around the pond, so that the shrimp can be fed well. , without wasting feed. During the shrimp period, they mostly move in shallow waters near the pond. The depth of 0.3-0.5m around the pond is an ideal feeding area. As the shrimp grows, the shrimp gradually moves to the deep water area. In the mid-term, feeding can be fed at a depth of 0.5-1.0m, and in the later stage of breeding, feeding should be fed at a depth of 1.0-1.5m. Do not throw bait in deep areas such as the central ditch, because there is insufficient oxygen in deep water areas above 2m, and shrimps rarely feed and inhabit there. A long strip of pond can be used as a refuge for shrimps to inhabit and lack oxygen when there is no feeding at the water inlet end.

Determination of feeding frequency, time and feeding amount

Within 15 days of stocking shrimp seedlings, the water is rich in food organisms and only needs to be supplemented with a small amount of compound feed. 2 shrimp feeds are added daily. times (7:00, 19:00); in the future, as the shrimp body gradually grows, the amount of feed should be increased accordingly and shrimp feed with corresponding particle size should be fed, and the daily feeding should be increased to 4 times (7:00, 11:00) :00, 15:00, 19:00, 21:00). Because Penaeus vannamei has the habit of being diurnal and nocturnal, feed less during the day, accounting for 20%-30% of the feeding amount, and feed more at night, accounting for 70%-80% of the feeding amount. Generally speaking, the daily feeding amount is: before the body weight is 10 grams, the feeding amount accounts for 5%-6% of the body weight; when the body weight is 10-15 grams, the feeding amount accounts for 4.0%-4.5% of the body weight; when the body weight exceeds 20 grams, the feeding amount accounts for 4.0%-4.5% of the body weight. The feeding amount accounts for 2.5%-3.0% of the body weight.

In order to speed up the growth of shrimp seedlings, feed fresh freshwater fish slurry 1-2 times a week, and mix in vitamin C, E and cod liver oil appropriately to enhance the disease resistance of the shrimp. . It is better to feed fresh food at night.

The specific amount of feed should also be comprehensively considered based on various factors such as the previous feeding amount, water quality, weather conditions, and the physiological state of the shrimp. ?

Principles of feeding P. vannamei:

A. Feeding should not be too concentrated.

B. Feed frequently and feed sparingly.

C. It is best to eat the feed within 2 hours.

D. Do not turn on the aerator when feeding.

E. Try to use one type of feed to grow them, and do not add other feeds in between.

F. Feed more at dawn and evening (60%), and less at noon and midnight.

G. Throw bait along the edge of the pool.

H. When the water quality is poor, dissolved oxygen decreases, ammonia nitrogen and hydrogen sulfide content increase, and the water temperature exceeds 32°C, feeding should be reduced.

I. Feed less or not at all when shrimps are molting, and feed them more after 1 day after molting.

Water quality adjustment?

In the early stage of breeding (within 30 days of releasing seedlings), new water is gradually added to the breeding pool until the maximum water level is 1.5 to 2.0m. In the middle and later stages, a small amount of water should be changed, usually about 20 cm of water should be added every 10-15 days, and the salinity of the pool water should be adjusted at the same time. If there is a reservoir, you can first adjust the salinity of the reservoir to be consistent with the pond, and then directly add water to the pond. The entire breeding period relies on relatively fresh water quality, which is conducive to the growth and survival of shrimp. If the water quality is too fertile, a few more silver carp can be released to adjust.

The water environment is the first factor for shrimp to survive. It directly affects the survival rate and growth rate of shrimp. When water quality deteriorates, shrimps are prone to disease, death, or even total annihilation. Therefore, after planting seedlings, quicklime, bleaching powder, aerator and other methods should be used to adjust the water quality according to the water color to keep the water quality "fat", "living", "tender" and "refreshing".

Use of aerator

The rational use of aerator can play a great role in improving water quality. Under normal circumstances, in the early stage, the machine is turned on for 2 to 3 hours every day around dawn and noon. In the mid-term, the startup time can be extended as needed. In the later stage, due to the increase in water pollution, the total mass of shrimps and the increase in oxygen consumption, the machine needs to be turned on all day long. Whether to turn on the aerator depends on comprehensive conditions such as weather, time, density and water quality. The general principle is: open less in the early stage and more in the later stage; open at noon on sunny days and open at night; open less on sunny days and more on cloudy and rainy days. ?

Daily management

Inspection and monitoring. In order to determine and grasp the dynamics of the shrimp situation, the pond must be patrolled no less than four times a day, at least every morning, evening, and midnight, and the water quality, feed consumption, shrimp body condition, pond water color, and enemy status in the pond must be carefully monitored. Observe and record, and deal with situations promptly and appropriately if found.

Observation of shrimp growth can be done at night, using flashlight positioning and fixed net observation. The light can be used to observe the quantity, and the fixed net can be used to observe the feeding and growth conditions. The specific method is to place a fixed net and lower it in the feeding area. The density of the feed on the net is the same as the density of the surroundings. After 2 hours, lift it up and observe the remaining feed and the excretion of feces in order to observe the size of the feeding amount and the digestion and absorption situation.

Disease prevention?

Litopenaeus vannamei has strong disease resistance. Under normal breeding conditions, the shrimp pond only needs to maintain a dissolved oxygen of more than 3mg/L and a pH value of 7.5~ 8.5. As long as proper transparency and good water color are maintained, diseases will generally not occur. In order to ensure the safety of breeding, during the breeding process, we adhere to the policy of "prevention first, prevention is better than cure". Starting from the middle stage of breeding, 5-10 kg/667 square meters of quicklime or 1ppm bleaching powder is used to disinfect the water body every 15 days to improve the pool water. Water quality; in the middle and late stages of breeding, add allicin, immune proteins, immune polysaccharides, ecdysone and other immune enhancers and nutritional fortifiers to the feed (every 15 days) to enhance the shrimp's physical fitness and disease resistance. , activates the immune system and promotes growth.