2. Preparation before stocking: In order to create a suitable living environment for South American prawns, it is necessary to sterilize the prawn pond 1 month in advance. Usually, the appropriate amount of quicklime is used for disinfection, and then the proportional bleaching powder is added 7 days in advance. Finally, a certain amount of water fertilizer is put into the shrimp pond, so that the nutrient supply of the shrimp pond is sufficient after stocking.
3. Selection of fry: Shrimp fry selection should be based on local breeding environment, market demand and seasonal conditions. Penaeus vannamei is native to the salty waters of South America, so it is necessary to choose the desalinated shrimps for freshwater culture in China. In order to avoid unnecessary losses caused by the death of shrimp seedlings that do not conform to the water quality environment.
4. Feeding and management methods of prawns
(1) regulation and control of pool water. The most suitable water color for cultivating Penaeus vannamei is yellow-brown, yellow-green, which is formed by diatoms or green algae. Artificial regulation is to add a certain proportion of phosphate fertilizer and nitrogen fertilizer to water. In the middle and late stage of culture, the excrement or leftover bait of shrimp gradually increases, which leads to the dark color of water, so it is necessary to replace a part of water body, or add new water, or add a certain amount of quicklime powder or zeolite powder to the water to regulate the color of water.
(2) Maintain and protect the ecological balance of shrimp ponds. It has been proved by a lot of practice that if there is less plankton in the pond, the shrimp will get sick earlier, and it may get sick when the body length is 5cm, while only a few shrimps with a body length of more than 8cm will get sick. Plankton will absorb some harmful substances in the water, such as ammonia nitrogen and hydrogen sulfide, thus increasing the dissolved oxygen in the water, improving the water quality environment and the geology at the bottom of the pool, and reducing the harm of harmful substances. In order to effectively maintain the ecological balance of the shrimp pond, generally, after the pond is disinfected for 3 days, the active microecological agent is mixed evenly in the sandy soil according to the dosage of 1 kg/mu, and then sprinkled on the bottom of the pond. In the case of receiving water and fertilizer water, 2 grams of pond bottom improver is used for uniform sprinkling throughout the pond.
(3) Pay attention to the transparency, dissolved oxygen content and PH value of the pool water. In the early stage of shrimp culture, the transparency of pond water should be 25-40cm, and it should be kept at about 35-60cm in the middle and late stage. If the transparency is lower than 20cm, fresh water should be added or a part of water body should be replaced appropriately, or a proper amount of quicklime powder or zeolite powder can be added. If the transparency is too high, a proper amount of phosphate fertilizer and nitrogen fertilizer should be added for adjustment.
With the growth of prawns, there is a great demand for dissolved oxygen content in the water. In the early stage, the aerator can be turned on intermittently according to the water quality, and then the start-up time can be slowly extended. In the middle and late stage, the industrialized high-density culture pond and intensive culture pond need to be turned on 24 hours to ensure that the dissolved oxygen in the water is above 5mg/L, and the dissolved oxygen in the bottom of the pond is above 3mg/L, but not below1.2 mg/L. It is also necessary to control the PH value of the water. If it is too high, it will increase the toxicity of ammonia nitrogen in the water, which is unfavorable for the growth of prawns.
(4) Feeding amount and method of bait. The feeding amount of bait should be determined according to the survival rate of prawns, water quality, weather conditions, the size of prawns, the quality of feed and other conditions. When the shrimp body size is about 1-3cm in the early stage of culture, the daily feeding amount should be 8- 10% of the shrimp body weight, 5-7% when the shrimp body size is about 3- 10cm in the middle stage and 3-4% in the later stage. It can be fed many times a day, and a small amount accounts for about 30%-40% in the daytime. Mainly feed some small shellfish, chilled fish paste and artificial feed.
(5) Daily management of aquaculture ponds. Patrol the pond every morning, noon and midnight to observe whether the color of water is qualified, whether the growth of prawns is normal, whether there are other abnormalities, whether the dissolved oxygen is sufficient, adjust the water quality and feeding amount in time, and turn on the aerator if necessary.
Penaeus vannamei is a newly emerging special aquaculture project, and its appearance is similar to that of Penaeus China. The meat of Penaeus vannamei is rich in taurine and zinc, which can reduce human serum cholesterol and improve the growth disorder caused by zinc deficiency.