Note: severe death of eel caused by summer syndrome

Since the beginning of summer, eel debonding, septicemia and other comprehensive diseases have occurred one after another in eel ponds in Fujian province, causing serious death of eels. According to some cases we have dealt with on the spot in southern Fujian, the following prevention and control methods are put forward for reference by eel farmers.

The symptoms of the disease are as follows: the diseased eel has obvious symptoms of debonding or septicemia in the early stage of death. Eel vitality weakens, a large number of hanging in the bait table or gathered around the sewage outlet, do not eat. There are few symptoms of debonding in dead eels, but the symptoms of septicemia are obvious. Due to the decrease in the number of symptoms of debonding or septicemia in the later stage, red head or Gill and jaw congestion and edema were common, other parts of the body surface were basically intact, some abdominal cavity was filled with blood water, blood clots and liver faded, Gill filaments became white and swollen, similar to the phenomenon of discoloration and whitening after being immersed in water. The number of deaths has increased rapidly, and the mortality rate is high. The whole onset cycle of one pool is 15 ~ 20 days.

Effective handling:

Salt + traditional Chinese medicine + antibiotics, salt can be kept at 4 ‰ ~ 7 ‰. Traditional Chinese medicine mainly includes Coptis chinensis, rhubarb, Scutellaria baicalensis, Radix Rehmanniae, Yinchen, gallnut and so on. Antibiotics can choose to use doxycycline, norfloxacin, faranus and so on. The treatment cycle requires 1 ~ 2 courses of treatment, and even 3 ~ 4 courses of treatment in severe cases.

It should be noted that:

The treatment of pool water. As it may take a long time to use the drug, it is easy to worsen the water quality, so it is best to change the water greatly and keep the water environment clean at the end of each medication cycle.

In the high temperature period, we should pay attention to the changes of water temperature and water quality. In general, ventilation should be strengthened, dissolved oxygen in water should be increased, and if necessary, the water level should be raised to prevent the increase of eel death caused by sharp changes in water temperature during medication.

In the early stage of the disease, the use of antibiotics can not significantly inhibit the development of death, we can choose bromochlorohydantoin, chlorine dioxide, blue angel + virus net and other conventional disinfectants to control the development of the disease first, if there are a large number of deaths, and then use the method described above.

After the peak period of death, eels in the pond must be fed as soon as possible in order to recover their strength. Can be fed with bait to eliminate bacteria in the eel. At this time to disinfect the water body, it is necessary to use less irritating drugs, at the same time, Haizhongbao, multi-dimensional, glucose and other water baths can be used to promote eel eating.

In the treatment of bacteria should pay attention to check whether there are Gill mold and parasitic diseases, if so, should be dealt with first, especially Gill mold must be killed first. Otherwise, the use of antibiotics will cause an outbreak of Gill mildew, resulting in a large number of deaths. If the number of parasites is small, the treatment can be postponed.