During the whole process from the beginning of stocking to the cultivation of Penaeus vannamei, there will be a phenomenon of swimming pool of shrimp. The so-called swimming pond phenomenon refers to a phenomenon in which the shrimps have abnormal activities such as jogging, roaming, and group travel in the water surface. Because swim pools are often accompanied by the death of shrimps, many farmers treat them as a disease and use various medicines, but with little success. After analyzing and observing the phenomenon of multiple swimming pools, the author believes that the reasons for the formation of swimming pools are different, mainly including pathology, discomfort in water environment, and nutrition. Most of the swimming pool phenomenon is caused by the discomfort of the water environment, followed by pathological or nutritional problems. Here are some of the main causes and countermeasures of the phenomenon that caused the shrimp swim pool to be discussed below, for reference by farmers.
First, due to PH, water temperature caused by discomfort
On May 20, 2003, a Xiaoshan reclamation farmer reported that most of the 10 shrimp ponds in the newly restocked shrimp ponds were floating on the water and could not sink. Some shrimps died after 2 hours. The ten shrimp ponds of the farmer share the same water source, which can eliminate the problem of water pollution. The two shrimp ponds in the swimming pool are light in color. Further water quality tests revealed that the pH of the two shrimp ponds was 8.9 and 9.2, respectively, which was higher than the rest of the shrimp ponds. The pH of desalinated shrimp seedlings in the emergence ponds is generally between 7.5-7.8, which differs from that of shrimp pond water PH by more than one unit. It can be said that the high PH is the main reason for the shrimp seedlings to swim. Immediately after changing the water, the water was drained while entering the water. The pH fell to 8.5 the next morning. The shrimps had all sneaked into the bottom of the pool. Checking the bottom of the pool with the scooping net had become normal. Therefore, the farmers must pay attention to the pH of shrimp pond water before releasing, and the appropriate pH is between 7.5-8.5.
On June 28, 2003, a farmer in Hangzhou's Xihu District reported that shrimp seedlings could not sink and many shrimps would swim slowly on the surface. Farmers put their seedlings at 4 o'clock in the afternoon and the shrimp ponds have an average water depth of 0.6 meters. Spot water PH, DO and other water quality indicators are in the normal range. Only the pool water temperature is found to be high, the surface layer is measured at 37 degrees Celsius, and the bottom layer is at 32 degrees Celsius. Since June of this year, the area has been dominated by sunny days and few clouds. At the end of June, high-temperature weather has also emerged. The water temperature in Outer Ponds is generally high. Breeders are also stocking at high water temperatures in the afternoon. Therefore, it is believed that the larger temperature difference is caused by shrimps. The main reason for Miao Youchi.
The best time for planting seedlings has always been a problem for some farmers. The author suggests that in the early period (early April-May mid-season), seedlings should be planted with sunlight at noon and in the middle (late May-June-early period) in the evening. Putting on seedlings, the high temperature period after the end of June is good for early morning seedlings, because the water temperature in shrimp ponds in the early morning is relatively low, and the water temperature is basically the same, which is favorable for the stocking of shrimps. In addition, the water level during the later period of stocking should also be increased accordingly to prevent the shrimp pond water temperature is too high, inhibit the growth of shrimp, post-cultivation water level control at 1.0 meters is appropriate.
Second, the swimming pool caused by lack of oxygen in the swimming pool caused by lack of oxygen appears in various breeding stages due to high density of ponds, excessive feeding, deterioration of water, dark or over-saturated water, and extremes of thunderstorms in the evening. Easy to happen. Most of the swimming pools occur in the wee hours, and sometimes they start in the middle of the night and even in the daytime. Farmers can be diagnosed according to the weather and water quality.
The main preventive measures taken are:
(1) Regularly use sediment and water quality improver, such as zeolite powder, photosynthetic bacteria, Bacillus subtilis, etc., and use it once every half month to adjust usage according to water quality;
(2) Strictly control the amount of feed, ensure that the shrimp can be full 7-8, the appropriate method of determining the amount of feeding is that there is no residual bait after 1.5 hours of feeding, and 7-8 percent of the prawns are full of gastrointestinal tract;
(3) When the oxygen aerator is turned on in time, the mechanical aeration can also generate a flow of water to prevent stagnant water in the shrimp pond and promote the growth of prawn shells.
Third, due to pollutants caused by swimming pool
On July 20, 2001, a farmer in Fuyang County reported that the shrimp that had been farmed for more than 50 days had been swimming for several days. At first, only to see a few prawns roaming on the surface of the water in the evening. Suspected of lack of oxygen and a large water exchange, the result was that the swim pool phenomenon was aggravated, and the shrimps appeared one after another in the pool. Two consecutive disinfectants did not improve. The on-site observation showed that there were more dead shrimps in the pool, the hepatopancreas of the diseased shrimp was reddened, there was no food in the intestine, and they roamed on the surface of the water. The PH, DO, ammonia nitrogen, total number of bacteria and other indicators in the pool water were quickly detected. Further understanding revealed that there are several paper mills near the farm’s water sources. Although the sewage from the paper mills has been treated and discharged, it may still pollute the farming water sources. Immediately recommend stopping the water intake, adopting closed culture, and using EDTA 2ppm to disinfect the pool water, while taking oral VC and Chinese Herbal Hubaobao for two consecutive weeks. After one week, the shrimp ceased to die, and the food intake gradually recovered. Two months later, the yield per mu was arrested. Duty.
For swimming pools caused by pollution, prevention methods mainly include:
(1) Establish a reservoir, degrade the toxicity of contaminants through sedimentation of water, planting aquatic plants, applying quicklime and other measures;
(2) Closed breeding to reduce external pollution;
(3) Regularly taking Chinese herbal medicine with Vc and cool detoxification and hepatoprotective liver function.
(4) For the disease pool, the heavy metal complex EDTA should be rapidly used to reduce its toxicity first, and then treat with cool detoxification drugs.
Fourth, swimming pools caused by hunger caused by hunger have obvious group swiming. They swim around the pool and check the lack of food in shrimp intestines. This phenomenon often occurs within half a month of the shrimps in the lower pool. Since the shrimps are small at this time, they cannot feed the larger pellets, basically using plankton in the water as baits, but the effect of fertilizer and water in each pond is not the same. The lean shrimp ponds have relatively few food creatures and cannot meet the feeding needs of the shrimps and cause the shrimp swimming phenomenon. Therefore, in the early culture of shrimp, it is necessary to scientifically feed bait according to the biological conditions of the food in the shrimp pond. It is necessary to ensure the nutrient demand of the shrimp and ensure the palatable shrimp. It is recommended that more feeds such as surimi, soymilk, and microparticulate feed should be fed in early culture.
5. The swimming pond caused by pathology The swimming pond phenomenon caused by pathology is not obviously different from the above-mentioned ones. However, in inspection of shrimps, it can be found that the shrimps in the swimming pool often appear in the larvae, hepatopancreas, gastrointestinal tract and body surface. Typical pathological features, caused by pathological causes including viruses, bacteria, parasites, and other pathogens, caused the pneumonia's respiratory function to be inhibited. As a result, the diseased shrimp ran slowly on the surface of the water due to lack of oxygen and roamed until it finally died.
Control methods:
(1) Regular use of disinfectants, such as chlorine preparations, quaternary ammonium salts, povidone iodine, etc., and timely application of microbial agents to maintain the microecological balance and stability of the pond;
(2) Regularly use internal medicine such as VC, Allicin, Huganbao to improve the immune function and disease resistance of shrimp;
(3) The swimming pool phenomenon caused by parasite can be sprinkled with the whole net, such as shrimp, crab and fimbriae. At the same time, the shellfish and VC can be taken internally to promote shelling of shrimp.
First, due to PH, water temperature caused by discomfort
On May 20, 2003, a Xiaoshan reclamation farmer reported that most of the 10 shrimp ponds in the newly restocked shrimp ponds were floating on the water and could not sink. Some shrimps died after 2 hours. The ten shrimp ponds of the farmer share the same water source, which can eliminate the problem of water pollution. The two shrimp ponds in the swimming pool are light in color. Further water quality tests revealed that the pH of the two shrimp ponds was 8.9 and 9.2, respectively, which was higher than the rest of the shrimp ponds. The pH of desalinated shrimp seedlings in the emergence ponds is generally between 7.5-7.8, which differs from that of shrimp pond water PH by more than one unit. It can be said that the high PH is the main reason for the shrimp seedlings to swim. Immediately after changing the water, the water was drained while entering the water. The pH fell to 8.5 the next morning. The shrimps had all sneaked into the bottom of the pool. Checking the bottom of the pool with the scooping net had become normal. Therefore, the farmers must pay attention to the pH of shrimp pond water before releasing, and the appropriate pH is between 7.5-8.5.
On June 28, 2003, a farmer in Hangzhou's Xihu District reported that shrimp seedlings could not sink and many shrimps would swim slowly on the surface. Farmers put their seedlings at 4 o'clock in the afternoon and the shrimp ponds have an average water depth of 0.6 meters. Spot water PH, DO and other water quality indicators are in the normal range. Only the pool water temperature is found to be high, the surface layer is measured at 37 degrees Celsius, and the bottom layer is at 32 degrees Celsius. Since June of this year, the area has been dominated by sunny days and few clouds. At the end of June, high-temperature weather has also emerged. The water temperature in Outer Ponds is generally high. Breeders are also stocking at high water temperatures in the afternoon. Therefore, it is believed that the larger temperature difference is caused by shrimps. The main reason for Miao Youchi.
The best time for planting seedlings has always been a problem for some farmers. The author suggests that in the early period (early April-May mid-season), seedlings should be planted with sunlight at noon and in the middle (late May-June-early period) in the evening. Putting on seedlings, the high temperature period after the end of June is good for early morning seedlings, because the water temperature in shrimp ponds in the early morning is relatively low, and the water temperature is basically the same, which is favorable for the stocking of shrimps. In addition, the water level during the later period of stocking should also be increased accordingly to prevent the shrimp pond water temperature is too high, inhibit the growth of shrimp, post-cultivation water level control at 1.0 meters is appropriate.
Second, the swimming pool caused by lack of oxygen in the swimming pool caused by lack of oxygen appears in various breeding stages due to high density of ponds, excessive feeding, deterioration of water, dark or over-saturated water, and extremes of thunderstorms in the evening. Easy to happen. Most of the swimming pools occur in the wee hours, and sometimes they start in the middle of the night and even in the daytime. Farmers can be diagnosed according to the weather and water quality.
The main preventive measures taken are:
(1) Regularly use sediment and water quality improver, such as zeolite powder, photosynthetic bacteria, Bacillus subtilis, etc., and use it once every half month to adjust usage according to water quality;
(2) Strictly control the amount of feed, ensure that the shrimp can be full 7-8, the appropriate method of determining the amount of feeding is that there is no residual bait after 1.5 hours of feeding, and 7-8 percent of the prawns are full of gastrointestinal tract;
(3) When the oxygen aerator is turned on in time, the mechanical aeration can also generate a flow of water to prevent stagnant water in the shrimp pond and promote the growth of prawn shells.
Third, due to pollutants caused by swimming pool
On July 20, 2001, a farmer in Fuyang County reported that the shrimp that had been farmed for more than 50 days had been swimming for several days. At first, only to see a few prawns roaming on the surface of the water in the evening. Suspected of lack of oxygen and a large water exchange, the result was that the swim pool phenomenon was aggravated, and the shrimps appeared one after another in the pool. Two consecutive disinfectants did not improve. The on-site observation showed that there were more dead shrimps in the pool, the hepatopancreas of the diseased shrimp was reddened, there was no food in the intestine, and they roamed on the surface of the water. The PH, DO, ammonia nitrogen, total number of bacteria and other indicators in the pool water were quickly detected. Further understanding revealed that there are several paper mills near the farm’s water sources. Although the sewage from the paper mills has been treated and discharged, it may still pollute the farming water sources. Immediately recommend stopping the water intake, adopting closed culture, and using EDTA 2ppm to disinfect the pool water, while taking oral VC and Chinese Herbal Hubaobao for two consecutive weeks. After one week, the shrimp ceased to die, and the food intake gradually recovered. Two months later, the yield per mu was arrested. Duty.
For swimming pools caused by pollution, prevention methods mainly include:
(1) Establish a reservoir, degrade the toxicity of contaminants through sedimentation of water, planting aquatic plants, applying quicklime and other measures;
(2) Closed breeding to reduce external pollution;
(3) Regularly taking Chinese herbal medicine with Vc and cool detoxification and hepatoprotective liver function.
(4) For the disease pool, the heavy metal complex EDTA should be rapidly used to reduce its toxicity first, and then treat with cool detoxification drugs.
Fourth, swimming pools caused by hunger caused by hunger have obvious group swiming. They swim around the pool and check the lack of food in shrimp intestines. This phenomenon often occurs within half a month of the shrimps in the lower pool. Since the shrimps are small at this time, they cannot feed the larger pellets, basically using plankton in the water as baits, but the effect of fertilizer and water in each pond is not the same. The lean shrimp ponds have relatively few food creatures and cannot meet the feeding needs of the shrimps and cause the shrimp swimming phenomenon. Therefore, in the early culture of shrimp, it is necessary to scientifically feed bait according to the biological conditions of the food in the shrimp pond. It is necessary to ensure the nutrient demand of the shrimp and ensure the palatable shrimp. It is recommended that more feeds such as surimi, soymilk, and microparticulate feed should be fed in early culture.
5. The swimming pond caused by pathology The swimming pond phenomenon caused by pathology is not obviously different from the above-mentioned ones. However, in inspection of shrimps, it can be found that the shrimps in the swimming pool often appear in the larvae, hepatopancreas, gastrointestinal tract and body surface. Typical pathological features, caused by pathological causes including viruses, bacteria, parasites, and other pathogens, caused the pneumonia's respiratory function to be inhibited. As a result, the diseased shrimp ran slowly on the surface of the water due to lack of oxygen and roamed until it finally died.
Control methods:
(1) Regular use of disinfectants, such as chlorine preparations, quaternary ammonium salts, povidone iodine, etc., and timely application of microbial agents to maintain the microecological balance and stability of the pond;
(2) Regularly use internal medicine such as VC, Allicin, Huganbao to improve the immune function and disease resistance of shrimp;
(3) The swimming pool phenomenon caused by parasite can be sprinkled with the whole net, such as shrimp, crab and fimbriae. At the same time, the shellfish and VC can be taken internally to promote shelling of shrimp.
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