The highest yield of prawns in the greenhouse is 10,000 jin per mu

The shrimp ponds are covered with cement and steel sheds, and the whole reinforced concrete shrimp ponds are like "extensive swimming pools", which are raised in the greenhouse of Binyuan Aquaculture Co., Ltd., Ninghai County, Zhejiang Province. The average yield of shrimp cultured in greenhouse is 7000 jin ~ 8000 jin per mu, the highest yield per mu in single pond is 10 000 jin, and the body size of shrimp is 28 ~ 35 jin / jin.

Shrimp can also be raised in the greenhouse like vegetables and fruits. The shrimp ponds are covered with cement and steel sheds, and the whole reinforced concrete shrimp ponds are like "extensive swimming pools". This is the greenhouse culture of Binyuan Aquaculture Co., Ltd., Ninghai County, Zhejiang Province. it is the first batch of high-standard shrimp greenhouse culture enterprises introduced by Ninghai Sanmen Bay Modern Fisheries Park in 2013. It has made gratifying achievements when it was put into production for the first time this year: 30 ponds have produced about 250000 jin of South American white shrimp. The average yield per mu is 7000 jin ~ 8000 jin, the highest yield per mu is 10 000 jin per mu, and the shrimp body size is 28 ~ 35 jin / jin. Recently, the author went to Shepantu, Ninghai County to explore the "password" of the high mu yield of this "Tuhao breeding shed".

Factory culture in greenhouse

The author followed Lu Guihua, a technician of the enterprise, down the aisle of the shrimp pond. I saw that the workers were packing the freshly caught Penaeus vannamei into the compartment where they came to buy goods. The prawns were alive and bustling, with a long palm. Lu Guihua told me that since the first batch of Penaeus vannamei was caught in mid-May, buyers from all over the country have come to buy every day, with sales of about 10,000 jin.

"the main reason for such a high yield lies in the adoption of high and new technology and scientific management." Lu Guihua said that in March 2014, the company began to build high-level ponds and purchase advanced supporting equipment to control the entire production process of shrimp through factory culture in the greenhouse, so as to improve the survival rate of shrimp, thus changing the traditional shrimp culture model of "eating shrimp from heaven." In September last year, Penaeus vannamei began to try to live in the greenhouse, after the early trial production of low-density seedlings, ushered in a large number of listings in May this year.

The biggest difference between greenhouse factory culture and traditional open-air shrimp farm is that an integrated aeration system is installed in the field. Through the greenhouse window, you can see that there are four machines in the four corners of the "swimming pool", and there are blisters in the middle of the pool. "these are aerators and play different roles." Lu Guihua explained that through air compression, the Roots blower in the center of the pool presses the air into the aeration pipe to form very fine blisters, and then melts the oxygen into the water, stirring the water to form upper and lower convection; the jet aerator can slowly increase the oxygen of the water body, which is diagonally distributed around the water wheel aerator, which can better help the water to promote the formation of circulation.

Changing drainage is another key to the success of farming. In the process of high-density shrimp breeding, residual bait, metabolic waste, self-shelling and other garbage accumulate at the bottom of the pond, which is very easy to breed bacteria and harm the shrimp, so the shrimp pond needs to change water every day. The amount of water exchange is generally 10% in the middle stage, and the amount of feed becomes larger in the later stage, and the amount of water exchange becomes 30% accordingly. "adding new water can not only remove the dirt, but also improve some of the trace elements and minerals lost in high-density culture." so as to enhance the hardness of shrimp shells and improve shrimp resistance, which plays a more obvious role in later culture. " Lu Guihua said.

The shrimp shed has "air conditioning" all the year round.

The shrimp shed provides "air conditioning" all the year round to maintain the most suitable temperature for shrimp growth, which is a subversion of the traditional culture pond.

Near the shrimp pond window, the thermometer is set above 25 ℃. "Penaeus vannamei can only be raised once a year in traditional ponds, and the setting of the heating system makes the temperature controllable." Lu Guihua said that the most suitable temperature for the growth of Penaeus vannamei is 26 ℃ ~ 29 ℃, and not less than 14 ℃ during the growth process. In order to ensure the normal growth of shrimp, the water temperature in the greenhouse and shrimp ponds should be kept constant, and heating equipment plays an important role.

In addition, there is also the design of plastic film and high-level pool. Looking up at the top of the pond, you can see that the plastic film is covered with a steel greenhouse, which improves the disadvantage of large temperature difference in open ponds. According to reports, shrimp culture in high ponds can raise the water temperature to a certain extent.

Transfer of seedling division to high income

At present, the enterprise's entire culture pond "eight systems" linkage (water intake, drainage, sewage collection, anti-seepage, oxygen, heat preservation, heating, electricity), so that each culture pond to form an independent, constant temperature ecological cycle, at the same time the use of photosynthetic bacteria and other biological agents to keep the pond water fat, alive, tender and cool.

The availability of equipment is not all the "password" of high yield per mu. Lu Guihua uses the word "habit" as the final answer. "when shrimp seedlings are flown in from the United States or Thailand, they need to be raised in the pond first. it takes about 21 days from egg-holding and fertilization to the larvae. If the conditions are good, they do not need to be transferred, but it is customary to do so." Lu Guihua explained that the transfer of seedlings can improve the utilization rate of resources. for example, during the current receiving period, the shrimp has not yet been sold out, so there are several ponds free. first, all the seedlings are concentrated in several ponds, and when they are raised for 20 to 30 days, wait for the shrimp in other ponds to be sold out, tidy up the ponds, and then transfer the seedlings from the original ponds after the water is cultivated, so that the bottom of the ponds will be cleaner and conducive to the second production. It is worth noting that there is a high risk in the transfer mode, and it will be more difficult to manage if there are more seedlings in the same pond. "the risk is higher in the previous month, and once the transfer is successful, it will be more stable in the later stage than traditional seedling cultivation." Lu Guihua said that although seedling distribution has the risk of high-density seedling release, as long as it is scientifically managed to survive the risk period, it can be listed in seasons and batches, which will not only improve the utilization rate of resources, but also increase income. The stocking density is generally 300000 ~ 350000 tails / mu. After about 65 days of breeding, we can begin to screen and catch. If 36 mu of Penaeus vannamei is calculated according to 7000 jin / mu and 27 yuan / jin, the income this season will exceed 6 million yuan, which will probably reach the investment return of 1 ∶ 1.5.