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What does aquaculture technology learn,

That's enough. It feels good. I suggest you breed Penaeus vannamei, which is a very popular breeding project now. Every summer, the culture of Penaeus vannamei enters the stage of high temperature management, the culture density of Penaeus vannamei in the pond is high, and the physiological function of Penaeus vannamei is vigorous.

Shrimp is at the peak of growth; The large amount of bait feeding increases the residual bait and excrement in the pond, which aggravates the water pollution and reduces the transparency of water color; Algae, bacteria and other organisms flourish and have a large biomass, and the water body is prone to stratification such as thermocline and oxycline.

Many factors, such as lack of oxygen, are easily caused by oxygen debt in pond water. Especially in typhoon and rainstorm weather, the water quality of shrimp culture ponds often deteriorates, accompanied by floods, resulting in a large number of deaths of cultured shrimp. Red body disease, white spot disease, red leg disease and other diseases are high, and the sudden change of water environment is easy to cause emergency response of prawns.

It is common to cause polycythemia. According to the above high-temperature water quality characteristics, in order to ensure the healthy culture of Penaeus vannamei, tide over the difficulties smoothly and obtain high yield, combined with the accumulation of breeding disease forecast data in recent three years, the following key points of breeding management are put forward.

1 Change the water in time. Where it is possible to scientifically increase oxygen, change the water in a timely and appropriate amount according to the change of water quality, and change the water in a small amount to avoid large irrigation and drainage, and raise the water level appropriately.

Try to keep it above 1.5m, so that the water temperature in the middle and lower layers can still be kept within 32℃. Generally speaking, the daily water exchange of shrimp farms is 8% ~ 10% of the pool water. If it is increased to 20%, the growth rate of shrimp will be obviously improved. When the water exchange rate increased to 30% that day, the growth trough of shrimp basically disappeared in midsummer.

With the increase of water temperature and the growth of prawns, the water depth should be continuously increased, especially in the middle and late stage of aquaculture, the water level must be raised to 1.8m ~ 2m, and it should be kept above 2.2m in the high temperature period. Therefore, in the spring tide period, it is necessary to keep changing water 1 time every d; In low tide and dry season,

In order to carry out mechanical irrigation and drainage, it is best to make the water exchange rate between 30% and 50% to reduce the water temperature. When changing water, in order to prevent the invasion of living organisms carrying shrimp outbreak virus, it is best to filter with 80 mesh screen at the water inlet.

Due to the high water temperature in summer, stratification phenomena such as thermocline and oxycline are easy to occur, which leads to hypoxia in shrimp ponds. In view of this characteristic of pool water in high temperature period, aeration should be started for several hours every morning and noon to eliminate water stratification in time and avoid the formation of oxygen debt.

As the weather is changeable, we should pay attention to the weather forecast every day and take precautions against thunderstorms and strong winds. If signs of hypoxia are found, timely water injection, startup and oxygenation, or spraying particulate oxygen should be carried out. , in order to avoid drowning shrimp. On the basis of installing aerators in conditional ponds, nanotube bottom aerators can be used, and ponds without aerators can also be used.

The water pump can be used to stir the lower water body. During the high temperature period, the water quality of aquaculture ponds in Ninghai Changjie and other places was measured on the spot. Most ponds have obvious oxygen and alkali, and the dissolved oxygen in the bottom layer of ponds is less than 4mg/L, and some of them are only 65438 0.5 mg/L, which is one of the main reasons for the decrease of food intake, slow growth, illness and floating head death of white shrimp culture in summer.

2. Adjust water quality and improve sediments.

The ideal water color for cultivating Penaeus vannamei is yellow-green or yellow-brown, which is formed by green algae or diatoms. It is a benign biological community in the micro-ecological environment of the pond and has a net effect on water quality. In the middle and late stage of aquaculture, the water color of the pond changes.

The deep color of water is mainly caused by the lack of magnesium ions needed for the reproduction of green algae or diatoms. The whole pond is sprayed with calcium hydrophosphate 10 ~ 10 every day with a concentration of 2× 1 0× e-6 ~ 3×10× e-6 and a concentration of 20×10. 36638.8686866666686

The contents of calcium, magnesium and phosphorus in supplementary water. Generally, the whole pond is sprayed with 1 times zeolite powder every 3 to 5 days, and the dosage is 10 ~ 15 kg per mu. Sunny morning, dissolve and spray. Use beneficial microorganisms every 7 ~ 10d. At present, the commonly used biological agents are photosynthetic bacteria, EM raw dew,

Fish and shrimp auxin (CBS), living water treasure (Bacillus), etc. The commonly used matrix modifiers are zeolite powder, Youdejing or (1+ 1) bottom modification, particulate oxygen, etc. And photosynthetic bacteria can be used together with zeolite powder.

Use Bacillus in sunny morning and start or use oxygenator at the same time. The suitable pH value of Penaeus vannamei is 7.8 ~ 8.5. However, a peak of 9.2 appeared in the middle and late stage of aquaculture.

Therefore, special attention should be paid to adjusting the pH value in the process of culture, and it should not be too high, otherwise it will increase the toxicity of ammonia nitrogen and inhibit the growth of shrimp. In ponds with high pH value (pH value: 8.6 ~ 9.0), "Luwei" (compound polybasic organic acid salt, dosage1×10× e-6 ~ 2×10× e-6) and acetic acid (/kloc-) can be used.

When the whole pool splashes water, adjust the pH value; For ponds with high pH value (pH value: greater than 9.0), low transparency and high algae density, firstly use the concentration of "Luwei"1×10× e-6 ~ 2×10× e-6, and after 2 hours,

Then spraying the composite strontium ferrate with the concentration of 0.15×10× e-6 ~ 0.3×10× e-6 in the whole pool. If the pH value drops below 7.5 due to sudden rainstorm or continuous cloudy days, 6 ~ 8 kilograms of quicklime should be sprinkled per mu and applied throughout the pond.

In the process of Penaeus vannamei culture, with the growth of shrimp, the demand for dissolved oxygen in water is also greater, so the start-up time of the aerator should be gradually extended.

For intensive culture ponds and high-density and high-yield culture ponds, it takes 24 hours to start and ensure that the dissolved oxygen in the ponds is 5 mg/L.