How did the shrimp die?

According to the book, there are many reasons, such as nitrite N, white spots, red body, lack of oxygen, poor physique, poor water quality, bacteria, sloughing or soft shell, high temperature, flooding and algae poisoning. . . . . There is also a comprehensive factor, this cow, invincible explanation.

But the biggest problem is that no one and no book can explain the physiological process of stealing death. It is estimated that no one has studied it seriously or will not study it.

In the Pearl River Delta (south), shrimp farmers usually put a cage next to the impeller aerator in order to know if there are any dead shrimps in the pond. After a long time (more than one or two hours), the dead shrimps brought by the current will gradually accumulate in cages, and most of them will be full in half a day. Like a hill, they usually weigh more than 20 kilograms. How many dead shrimps (quantity and weight) are under the aerator every day is an extremely important index to guide shrimp farmers to take preventive and coping measures. . .

As far as I know, no white shrimp died under the aerator, and the number of dead shrimp in the cage simply can't reflect the existence and severity of theft. Take one of my ponds in the first half of the year as an example. It is estimated that at least1500kg is stolen within 30 days, with an average of 50kg per day. In the worst case, it may exceed 100 kg! ! ! To be clear, even if you steal 100 kg, don't tell me that even the so-called conventional indicators can deceive people-they are all within the normal range! Don't believe it? It doesn't matter if you don't believe me, I won't argue with you, because this is what I have proved, and I don't need to rely on arguments to prove it. Ha ha. . . So many shrimps died. Is the water bad? Of course, it's not good, but it's similar to the usual rotten water, but not to the extent of algae flooding. Who knows what caused the poor water quality this time? When you haven't learned your lesson, where do you think stealing is caused?

Is there any way to determine theft? Yes, but none of them are reliable. I have two ways to identify white shrimp and steal it. First dive into the water and feel it, like a ten-acre pond. I stayed in the water for an hour and a half, but my feet never touched the ground. In severe cases, you can touch more than 30 heads (more than one kilogram), and then it is estimated that there are more than 30 kilograms according to the area and distribution of the touch, but in fact it is definitely more than that, and even the average is less than. So it can only be qualitative, not quantitative. . . . Method two, wait for the dead shrimp to float. It is basically certain that when a large number of dead shrimps are stolen and fed normally, the dead shrimps can't be eaten up, so in about 2 days at high water temperature (30-35 degrees), the unfinished shrimps will float up. But the actual experience is that when you find dead shrimp floating up, it is quite+quite+quite serious, for example, according to my experience, 10 mu. In other words, after you find this situation, if you find it for two consecutive days, there may be about 200 pounds of death. If you find it for seven days in a row, it may weigh a thousand pounds. Maybe you haven't had a chance to find it for seven days in a row. You must clean the pond in 3 to 45 days. I've seen one or two drifting, and I've seen more than 30, up to more than 200, and the temporary and specific severity is not enough. But it must belong to the level of heavy losses. I estimate that only 20-50% of the total number of stolen deaths is floating. . . . According to my experience, I stole more than 30 kilograms (65438+5000 kilograms per mu) two days ago (that day), and it is possible to find floating life (otherwise it may be eaten in time). . .

Generally speaking, a large number of dead shrimps are found under the aerator. I'm not afraid. I'll take it step by step. If not, I will clean it up. . . What I fear most is that one day, when you calculate the bait coefficient, you find that something is obviously wrong. Then you will know that there are many stories at the bottom of the pool that have happened for a long time. . . . Therefore, in the Pearl River Delta, many shrimp farmers find dead shrimp floating, and immediately arrange nets or clear ponds.

Why is this happening? Why not choose a good place to steal and die everywhere? Why do thousands and dozens of pounds of deaths basically not swim under the aerator and die? My ancestors, don't you know there is a savior there?

Can it be said that white shrimp died of stealing food, basically sudden death? It's too late to run to a safe place or a place that can alleviate the disease.

What's the reason? Heart attack? White spot virus bites you? Poison you? Stuck eating? Cann't take off the shell and suffocate? After molting, everyone died? . . .

There are also some phenomena, such as sudden death of shrimp while feeding on the bait platform, sudden death of shrimp after turning off the aerator, and sudden death of shrimp when starting up, but it is not found out.

There may be three reasons for stealing death (I don't know if it's right, just at our level-nonsense).

First, there are substances in the intestines of dead shrimps, and the shells are hard, which is basically sudden death, that is, acute hypoxia.

Second, dead shrimps have no substance in their intestines, and their shells are soft, or they have no shells at all (I have seen them with my own eyes). Basically, the nitrite is very high, the PH value is very low, and the dissolved oxygen is also very low (sometimes it is also very high, but it is said that the shrimp does not need it, and the blood first combines with nitrite)-the water quality deteriorates, and it is poisoned and died. This kind of death is very tragic, and many people have died.

Third, there is no substance in the dead shrimp intestines, and the shrimp shells are hard. Most of them are liver atrophy and hardening, and white spots appear. This kind of death is also very tragic, and many people died, which has nothing to do with water quality. This morning, I think that's it.

Bottom death means that prawns die at the bottom of the aerator and the bottom of the pond, which is also called "stealing death" and "taking the bottom". The following situations are common:

(1) Deterioration of sediments and water quality: high nitrite content and low pH value are caused by functional hypoxia of prawns. This kind of sudden death is generally hard, often accompanied by a small amount of bacterial infection.

Treatment method: compound calcium peroxide+Jiedu Dan is used to increase dissolved oxygen at the bottom of the pond to improve the environment at the bottom of the pond (oxygen-increasing Jiedu Qing can also be used alone), and herbal stress spirit is sprinkled at the same time; Re-treat nitrite (see question 38 for details. What are the methods for treating nitrite? )。

⑵ The hardness of the water body is small, and the shrimp is weak, so it is difficult to shell: this kind of dead shrimp generally has a soft or double shell (shell failure), and often has the phenomenon of broken whiskers, which is common when the weather changes or it is bad (cold).

Treatment: compound calcium peroxide or active source of calcium and magnesium can be sprayed to increase the hardness of water body, and ginseng polysaccharide can be taken orally to supplement calcium.

⑶ Sudden stress death: The obvious feature is that the liver is swollen, yellow, white and even atrophic and transparent. It is common after changing ponds, crossing seedlings, scraping shrimps and typhoons. The consumption of prawns is not affected, and the consumption sometimes increases suddenly and sharply.

Treatment: stop feeding or reduce feeding immediately, spray herbal stress spirit and Jiedu Gaojing C, and take oral immunization star and ginseng polysaccharide to protect liver. It is forbidden to change water for disinfection at this time.

Note: the molting period near the first and fifteenth day of the lunar calendar is prone to bottom death (because the prawns in molting period are weak). Therefore, before molting, we should apply calcium and magnesium active source or compound calcium peroxide, and take ginseng polysaccharide orally to do preventive work.