How to improve the success rate of cultivating Penaeus vannamei in soil pond

Using the annual fallow period (10 to March of the following year), proper dredging and pond drying can better oxidize the bottom mud, improve the soil redox potential, optimize the soil oxygen pool and nutrient pool, thus improving the buffer capacity of the pond and reducing the deterioration of the bottom material and the accumulation of toxins caused by long-term cultivation; Reserved reservoirs or drilling wells can better cut off the spread of exogenous diseases during the breeding process; Cement slope protection and film laying are used to solve the water leakage in the pond and improve the water retention capacity of the pond.

Aerobic capacity directly determines the aquaculture yield, shrimp growth rate and aquaculture cost (bait coefficient). When the aerobic capacity of the pond is 0.5kW/ mu and the shrimp culture reaches about 200kg/ mu, it is easy to have problems. When the aerobic capacity of the pond is 1kw/ mu, and the prawns are raised to about 600 kg/mu, problems will easily occur. When the aerobic capacity of the pond is 1.5kW/ mu, and the prawns are raised to about 900kg/ mu, problems will easily occur. Therefore, increasing oxygen determines the output, and the design of output should be based on the equipment with increasing oxygen capacity. Don't blindly pursue high yield regardless of your own conditions.

The difference of seed source and standard thickness technology will lead to uneven quality of shrimp seedlings. Therefore, it is very important to choose seed production enterprises with high technical means and good management level. Mainly lies in: high standard water quality treatment; Do not use antibiotics, raise seedlings at high temperature; Natural bait culture; The whole process of virus and Vibrio monitoring; The pressure test is qualified; The coefficient of variation is low.

Seedling density is too high, limited by conditions (water source, aerobic capacity, management capacity, etc. ), slow down the growth rate of prawns, and the lack of oxygen for a long time in the later stage of culture leads to high feed coefficient and increased flooding risk; The seedling density is too low, the yield is low, and the breeding profit is reduced or even lost. Therefore, according to the analysis of local aquaculture situation, it is suggested that the seedling density should be 30,000-35,000 fish/mu, guided by aquaculture profit. According to the survival rate of 80%, the yield per mu can reach 800-900 kg after 70 days of cultivation.

Starting from the second day of seedling release, feed 654.38+ 10,000 seedlings /kg, twice a day, increasing the feeding amount by 654.38+00% per day. This breeding technology has the following advantages: short breeding time and fast growth rate (up to 60 heads/kg in normal 40 days); If there is a reservoir or well water supply, the output will be further improved; Low risk. But this technology must match the corresponding aerobic capacity, otherwise the growth rate of shrimp will be greatly reduced.

Bubble disease caused by supersaturation of dissolved oxygen is the biggest culprit affecting the survival rate of shrimp in the early stage of culture. Due to the lack of aerobic capacity in the later stage of cultivation, the pond that should have cultivated large-scale shrimp has no choice but to catch shrimp. Based on these two points, we can get the key to prevent bubble disease in the early stage and hypoxia in the later stage.

So how to operate? First of all, a yellow water body (slightly turbid) dominated by diatoms should be cultivated in the early stage (40 days ago), so that the pH value of the water body is not easy to rise and it is very stable. Microbial agents and long-acting carbon sources ("multi-seedling" and "multi-water") can be used frequently, which can effectively control the proliferation of microalgae and cyanobacteria. Secondly, in the later stage, it is necessary to cultivate green water bodies mainly composed of green algae. The key is:

1, increase the pH value. Repeated use of a small amount of quicklime can improve the pH value of water and reduce the toxicity of nitrite. At the same time, it neutralizes the weak acid environment and reduces the number of acidophilic harmful bacteria, thus preventing the occurrence of yellow gill. In addition, weakly alkaline water can stabilize the water environment, promote the growth of algae, and be beneficial to fertilizer water.

2. Proper application of phosphate fertilizer can reduce the ratio of nitrogen to phosphorus, accelerate the metabolism of nitrogen-containing water, and inhibit the increase of ammonia nitrogen and nitrite. At the same time, phosphate fertilizer can press the bottom, which has a certain effect on preventing water from becoming muddy. In addition, phosphorus and calcium in phosphate fertilizer can prevent soft shell of prawn.

The above two methods can effectively prevent chronic poisoning, long-term hypoxia or even hypoxia caused by bad algae or deterioration of water quality in the later aquaculture pond.