One of the culture techniques of Penaeus vannamei is to raise high-quality shrimp fry, which is an important guarantee to improve the survival rate and high yield of shrimp culture. When buying fry, you should choose shrimp fry with strong and lively body, slender body joints, uniform size, clean body surface, full muscles, full intestines, sensitive response to external stimuli, obvious orientation when swimming, high body transparency and no lesions on the whole body. If possible, you should carry out virus detection to ensure that there is no virus. At the same time, the water-resistant separation test method was assisted to identify high-quality shrimp seedlings.
The second is to release seedlings at the right time and adopt the technology of gradually weakening and thickening the pond mouth. Draw 3%~5% small water area in each aquaculture pond, seal it with plastic film, and mix it into 3? ~4? In low salinity water, shrimp fry are put into ponds for desalination, and the desalination density is 200 ~ 1, 500 per square meter. After nearly half a month's gradual dilution and desalination, the shrimp seedlings grow to about 2 cm, and are gradually put into ponds for culture. The density of pond culture is about 70,000 fish/mu.
Third, the regulation of water quality, we must first control the water color. The ideal water color of Penaeus vannamei is yellow-green or yellow-brown formed by green algae or diatoms, and this ideal water color should be consciously controlled during the breeding process. For example, in the early stage of applying organic fertilizer to a thin pond, the amount of topdressing should be flexibly controlled according to the transparency, pH and water color of the pond, and topdressing should be done once a week. Due to the increase of residual bait and shrimp manure in culture, the color of water becomes darker, and the color of water can be controlled by changing water properly or applying some quicklime. At the same time, the application of microecological agents, such as photosynthetic bacteria, EM bioactive bacteria, water can be cool and so on. It can degrade the organic matter entering the water body in time, such as residual bait, reduce oxygen consumption and stabilize the water color of the pond. Second, adjust the pH value and dissolved oxygen of pond water. The suitable pH value of Penaeus vannamei is 7.8 ~ 8.5, which can be adjusted by common quicklime. Turn on the aerator to adjust the dissolved oxygen to ensure that the dissolved oxygen in the pond is above 5mg/L and the dissolved oxygen at the bottom of the pond is above 3 ml/L. ..
The fourth is scientific feeding. In production, Penaeus vannamei is generally fed with all ingredients, and the feeding amount depends on the size, survival rate, water quality, weather and other comprehensive factors. The daily feeding amount is 6% ~ 8% of the shrimp weight in the early and middle stages of culture (the shrimp is 3 cm ~ 8 cm long) and 4% ~ 5% of the shrimp weight in the late stage of culture (the shrimp is more than 8 cm long). Feed twice a day, at 7 o'clock and 19 o'clock respectively; Night feeding accounts for 50% of the total daily feeding. The feeding method is to feed evenly along the edge of the pool.
Fifth, strengthen disease prevention and control, adhere to the principle of giving priority to prevention in production, and first adjust the water quality of ponds, which is the key to prevent and control shrimp diseases. Secondly, the water body should be disinfected to kill insects. Disinfection with dibromohydantoin and abamectin in June and August respectively can effectively control the occurrence of diseases.
Ways to save feed in Penaeus vannamei culture. Eliminate wild fish and reduce carnivores.
There are many wild miscellaneous fish and shrimp in the pond, which will compete with Penaeus vannamei for food and even eat Penaeus vannamei. Low-quality fish and shrimp will compete for feed and reduce feed utilization. So pay attention to the removal. The method is to put the seedlings in water for 20? 30 cm, each mu is pulped with quicklime 150 kg, and then splashed all over the pond for thorough cleaning and disinfection to kill wild fish in the pond. Add a filter bag when entering the water to prevent wild fish from entering the pool with the water.
2. Pay attention to the selection and supplement of feed.
2. 1 Select the special feed for Penaeus vannamei produced by regular manufacturers, and the feed formula is reasonable, which can not only ensure the rapid growth of Penaeus vannamei, but also avoid the waste of feed. Don't use other shrimp ingredients instead.
2.2 Pay attention to fertilization in the early stage of aquaculture, and cultivate benthos, plankton and other biological communities conducive to the growth of shrimp. And some beneficial bait organisms can be transplanted into the pond, so that less bait can be thrown or no bait can be thrown. With the consumption of basic bait, we can feed some fresh bait without pathogens and special compound feed for young shrimp, and then gradually feed the special feed for Penaeus vannamei, which can save some feed.
2.3 In the late stage of aquaculture, after the outbreak of shrimp diseases, feeding fresh feed will not cause a large number of shrimp diseases, and some fresh bait can be fed according to local feed sources to save bait cost. But it should be noted that the feed must be fresh and not corrupt.
Step 3 keep the water fresh
Before raising shrimp, you should raise water well. The water quality affects the body color, growth rate and feed coefficient of shrimp. Penaeus vannamei likes fresh water, with good water quality, fast growth and few diseases, which can make full use of bait and reduce bait coefficient. Therefore, we should pay attention to adjusting the water quality to keep it fresh. Water generally requires yellow-green color with a transparency of 30? 40 cm, dissolved oxygen is greater than 4 mg/L.
Commonly used water quality adjustment methods are:
Change the water frequently. Change the water every 7- 10 days, and change10%-20% each time;
(2) Sprinkle quicklime regularly, once every 10- 15 days, with the concentration of15g/m3;
③ Install the inflator and adjust it with the inflator.
④ Use biological agents, such as photosynthetic bacteria, to adjust water quality.
4. Master the bait-throwing skills.
4. 1 a few times: according to the feeding habits and growth characteristics of prawns, the principle of a few times should be adhered to, and the feeding amount is different at different times. Generally, 30% of the daily feeding amount is at 7: 00, 1 10% at 0: 00, and 40% at 18: 00.
4.2 Master the appropriate feeding amount: It is difficult to master the feeding amount, which will lead to feed waste. Too little will lead to insufficient shrimp, which is not conducive to growth. A more practical way is to set up bait tables, and set up several bait tables around the pond, with a height of about 1.0 m2, and spread the bait evenly along the pond. After feeding 1.5-2 hours, check the feeding situation of shrimp. In general, if the satiety rate accounts for 60%? 70%, feeding is reasonable, if the satiety rate is too high, the feeding amount will be reduced, and if it is too low, the feeding amount will be increased.
4.3 Feed with the weather: feed more when the weather is sunny, windy and warm; When the weather is bad, it rains continuously, the weather is sultry or cold, so feed less or not.
4.4 Feeding according to the shrimp situation: flexibly grasp the feeding amount according to the growth of shrimp and the presence or absence of diseases. Shrimp grows vigorously, so it should be fed more when it is not sick, otherwise it should be fed less; When shrimps molt a lot, feed less and feed more one day after molting.
4.5 Feeding according to the water temperature: feed less when the water temperature is lower than 18℃ or higher than 32~C, and feed more when it is 25-30℃.
4.6 Feeding according to water quality: When the water quality is fresh and dissolved oxygen is sufficient, shrimp can be fed normally; When the water quality is poor and the dissolved oxygen is low, feed less or not.