What's the matter with dead shrimp under the North American shrimp oxygenator?

There are dead shrimps under the oxygenator of North American prawns. The reasons are as follows:

1. The high nitrite makes it difficult for prawns to shed their shells and die;

2. The lack of oxygen in the bottom water leads to the death of prawns, and prawns, like fish, have the phenomenon of top water. In addition, when prawns molt on a full moon night, they consume a lot of oxygen. If the bottom water lacks oxygen at this time, prawns will die.

3. Bacterial infection leads to death, which requires microscopic examination to confirm the cause;

4. Weak constitution and liver diseases can also cause "bottom death" of prawns.

change water in time and scientifically increase oxygen

where conditions permit, change fresh water in a timely and appropriate amount according to the change of water quality, and change water in a small number of times, and avoid large drainage and irrigation, and appropriately raise the water level to keep it above 1.5m as far as possible, so that the water temperature in the middle and lower layers can still be kept within 32℃. In general, the daily water exchange of shrimp farms is 8% ~ 1% of the pool water. If it is increased to 2%, the growth rate of shrimp will be obviously improved. When the daily water exchange rate is increased to 3%, the growth trough of shrimp in midsummer basically disappears. 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 ~ 2 m, and it should be kept above 2.2m in the high temperature period. To this end, in the spring tide period, it is necessary to keep changing water once every d; In low tide and dry season, it is best to make the water exchange rate between 3% and 5% in order to reduce the water temperature. When changing water, it is best to use 8-mesh mesh to filter water at the water inlet in order to prevent the invasion of living organisms carrying shrimp fulminant virus.

In summer, due to the high water temperature, stratification phenomena such as thermocline and oxycline are easy to occur, which leads to anoxia in the shrimp pond. In view of this characteristic of the pond water in the high temperature period, we should persist in turning on the machine for several hours every morning and noon to eliminate the stratification of the water body in time and avoid the formation of oxygen debt. Due to the changeable weather, we should pay attention to the weather forecast every day, and take precautions against thunderstorms and strong winds. If we find signs of hypoxia, we should inject water in time, start the machine to increase oxygen or sprinkle granular oxygen, etc., so as to avoid drowning shrimp. On the basis of installing an aerator in a conditional pond, the bottom aerator of nanotubes can be used, and the pond without an aerator can be stirred and killed by a water pump. 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 oxycline, and the dissolved oxygen in the middle and bottom layers of ponds is less than 4mg/L, and some of them are only 1.5mg/L, which is one of the main reasons for the decrease of food intake, slow growth, disease occurrence and floating head death of white shrimp culture in summer.