Analysis and treatment of swimming pond phenomenon of Penaeus vannamei

□ article / Zhejiang Guangdong Feed Co., Ltd. Qiu Xunhua shrimp swimming pond refers to the abnormal activities of shrimp in the surface of the water body, such as slow swimming, slow swimming, group swimming and so on. As swimming ponds are often accompanied by the death of prawns, many farmers treat them as a disease. All kinds of drugs were used, but with little effect. The main causes and countermeasures of shrimp swimming in the current environment are as follows, which can be used as a reference for breeders. 1. Analysis and diagnosis of swimming ponds caused by environmental changes: after high temperature, low pressure, storm, rainstorm and typhoon, due to the shallowness of shrimp ponds, the polluted bottom is easy to be muddy by continuous strong winds and heavy rain, and the changes of physical and chemical factors or toxic factors in the water environment of shrimp ponds exceed the standard, resulting in the death of a large number of beneficial algae, the sudden clearing of pond water or the change of plankton groups in shrimp ponds (that is, "inverted algae"), and the water quality deteriorates. In practice, it is also found that if the cloudy and rainy days last for more than 5-7 days, the water will suddenly thicken under the intense sunlight after clearing up, which will also lead to stress swimming in prawns. The pathogenic strains in the pond are concentrated in the bottom of the pond and are easy to activate and proliferate. at the same time, the physique of shrimp is weak, which provides an opportunity for bacteria to enter, and it is very easy to induce disease. Solution: 1. When the weather changes, new water is injected to raise the water level of the shrimp pond. 2. Before the weather changes sharply, the whole pond is sprinkled with organic acid or EDTA to degrade heavy metals and other toxic components, increase the permeability of the water body, and create a comfortable environment for shrimp. Then sprinkle anti-stress agents, such as glucose + salt or vitamin C + vitamin E, to enhance the anti-stress ability of prawns. If the continuous rainfall is too long, you can sprinkle quicklime 1-2 times, using 10-12kg per mu / m. 3. In case of algae phase change, you can sprinkle sodium humate or organic acid, and then sprinkle microbial agents, such as compound bacillus, photosynthetic bacteria or EM bacteria, in the whole pond the next day. If the water body is clear and transparent, multiple biological fertilizers can be used to culture algae. 4. Use high-quality feed or high-quality additives to reduce the stress swimming of prawns. Practice has proved that regular oral administration of immune polysaccharides, VC+VE or Shuanghuanglian and Genlian jiedu Powder before the sudden change of weather can effectively prevent shrimp from stress swimming. 2. Analysis and diagnosis of anoxic swimming ponds: in the process of culture, when there is not enough dissolved oxygen in the water, prawns will swim in groups to the water surface with more dissolved oxygen to breathe oxygen. This phenomenon is called anoxic swimming ponds (commonly known as "floating heads"). The phenomenon of swimming pond caused by hypoxia occurs in each culture stage, which is due to the high culture density, excessive feeding, deterioration of pond water, green, red or black water color, and floating head phenomenon in thunderstorm in the evening. Swimming pools mostly occur in the early hours of the morning, sometimes in the middle of the night or even during the day. Farmers can be diagnosed according to water quality and weather conditions. Solution: if the shrimp floating head swimming pond, should immediately take corresponding measures for rescue. (1) to turn on the aerator to increase oxygen; (2) to sprinkle chemical oxygenators such as sodium percarbonate; (3) to inject fresh water into the pool and sprinkle glucose + salt or VC+VE;4, and stop feeding during the period of floating head, and then feed it after the oxygen condition has completely improved. 3. Analysis and diagnosis of swimming ponds caused by excessive ammonia nitrogen and nitrite: when the content of nitrite nitrogen in normal culture water is lower than that of 0.1mg/L (fresh water) or 0.5mg/L (sea water), and when the concentration of ammonia nitrogen is lower than 0.2mg/L (fresh water) or 0.6mg/L (sea water), shrimp can live normally without causing any health damage, but if it exceeds this value, it will lead to a decrease in the activity of many enzymes in shrimp. Reduce the oxygen delivery capacity of blood, destroy the Gill filament epithelial tissue, lead to poor exchange of oxygen and waste and liver failure, shrimp agitation, crawling (sand climbing) phenomenon, and even irregular group swimming or wandering on the surface of the water. Solutions: 1. Strengthen the management of pond water quality and sediment to create a good growth environment for shrimp; 2. When the ammonia nitrogen in shrimp ponds is too high, sodium humate + compound bacillus or photosynthetic bacteria can be used to reduce the level of ammonia nitrogen. 3. When nitrite nitrogen exceeds the standard, chemical preparations and nitrifying bacteria that can rapidly reduce nitrite can be used in time, or according to the aging of water body, the level of organic matter in water body, timely change of water, such as serious nitrite exceeding the standard, shrimp poisoning symptoms, should also be sprinkled with organic acid or EDTA for detoxification. 4. analysis and diagnosis of swimming pond caused by discomfort of pH value; when the pH value is lower than 6.5, the respiratory rhythm of shrimp increases and the metabolic frequency increases. at the same time, acidic water can decrease the pH value of blood and the partial pressure of oxygen in blood, resulting in the dysfunction of hemoglobin to transport oxygen. When the pH value was higher than 9.2, the toxicity of harmful factors in the water increased, the liver of shrimp was overburdened, and the detoxification was not timely, which led to shrimp poisoning and asphyxiation. Solution: at present, many farmers ignore the regulation of the pH value of pond water, which leads to the frequent occurrence of shrimp swimming phenomenon caused by pH discomfort. Therefore, in the process of culture, the pH value of pond water quality should be monitored twice a day (7 00 in the morning; 4:30 in the afternoon). When the water quality is slightly sour, it should be treated with quicklime in time, using 8-10kg per mu / m for 2-3 days. When the water quality is too alkaline, drain the 15-25cm pool water and return the 10-15cm new water, then treat it with baking soda + calcium superphosphate mixture, use 5-8kg per mu / m, and then use compound bacillus + biofilm to stabilize the pH value. Fifth, the analysis and diagnosis of swimming ponds caused by the deterioration of sediment; in the middle and later stages of high-density shrimp ponds, especially in the aging ponds where shrimp culture has not been completely desilted in successive years, with the increase of feeding, shrimp residual bait, feces and plankton corpses continue to gather at the bottom of the pond, resulting in the deterioration of sediment, ammonia nitrogen, nitrite nitrogen, hydrogen sulfide and other harmful indicators exceed the standard, prawns swim to the upper and middle layers of the water in order to avoid the bad sediment environment. This kind of swimming pond has no obvious regularity, there are both group travel and loose travel, which may exist on the surface or in the upper and middle layers of the water, and in serious cases, it will cause a large number of prawns to die. Solutions: (1) to start an aerator at ordinary times to beat the residual bait and excreta from the bottom of the pool to the water surface to oxidize harmful substances into non-toxic substances; (2) to regularly use microecological agents, such as compound bacillus, photosynthetic bacteria or EM bacteria, to make full use of the functional advantages of the synergism of various strains in compound microorganisms to decompose the hidden dangers affecting the deterioration of substrate, such as residual bait, excreta, animal carcasses, etc. 3. Sprinkle particulate aerator or bottom modifier with oxygen-increasing function to improve and stabilize the water body. Sixth, the analysis and diagnosis of swimming pond caused by disease: shrimp infected with red body, white spot, rotten black Gill, fluorescence, ciliate and other diseases can cause swimming pond. In action, the diseased shrimp is shown to swim slowly or wildly on the surface of the water, not in groups, and people are often slow to respond to stimulation, sometimes swirling or swimming up and down undirectionally on the surface of the water, and sometimes lying on the side of the pool in shallow water. the most obvious feature is that swimming pond shrimp often have a variety of typical pathological features in the body surface, parotid silk, hepatopancreas distension, intestines and stomach and other tissues. Encounter this situation is the precursor of the outbreak of diseased shrimp, should be closely observed, careful examination of diseased shrimp, the right medicine after diagnosis, so as not to cause greater economic losses. Solutions: 1. During the high incidence period of the disease, sprinkle Shuanghuanglian or rhubarb extract + compound iodine 1-2 times in the whole pond to inhibit the growth of germs. if there are ciliates, zinc sulfate or matrine should also be sprinkled; 2. Microbial preparations such as compound bacillus and biofilm should be used regularly to keep the balance of beneficial microflora in the pond, generally every 7-15 days. 3. Immune polysaccharides, VC+VE, Gandanning and other ingredients are often used, and when necessary, some antibiotics (such as florfenicol, enrofloxacin, etc.) are fed timely and appropriately, so as to improve the immunity and disease resistance of shrimp. 7. Analysis and diagnosis of nutritious swimming ponds: insufficient food intake of shrimp is caused by lack of bait or insufficient feeding in the water. The swimming pond caused by hunger mainly appeared in the early or middle and late stages of culture. In the early stage of culture, the shrimp seedlings are small and can not eat the formula feed with larger particles, which is mainly composed of plankton in the water. Especially in ponds with high culture density, bait organisms can not meet the feeding needs of prawns. In the middle and later stages of culture, farmers often have a large deviation in the estimation of shrimp storage and feeding, resulting in insufficient feeding and unable to meet the normal feeding and growth needs of shrimp, resulting in shrimp swimming in the pond because of hunger. Diagnostic method: this kind of swimming pond phenomenon has obvious group swimming, swimming around the pool along the edge of the pool. Check the lack of food in the shrimp intestines, there is no pathological changes in the body, when some bait is thrown by the pool, that is, many shrimp stop to eat. Solution: 1. About 10 days before release, sprinkle compound bacillus + biological water fertilizer to cultivate algae to ensure that shrimp seedlings have sufficient basic bait when they go down to the pond; 2. After shrimp fry go down to the pond, if the density is high, they should also be properly fed with high-grade bait (such as Prawn Crackers, BP, etc.). After a week of shrimp fry adaptation, they should mainly be fed with broken materials, so it is appropriate to bring water and sprinkle them in the whole pond to ensure that shrimp fry can get sufficient bait. 3. In the process of shrimp culture, we should flexibly adjust according to the individual size of shrimp, the change of weather, the condition of water quality and sediment, the health status, physiological condition and actual food intake of shrimp, so as to feed scientifically and reasonably. 4. When there is hunger swimming pond, we should increase the amount of bait, add immune polysaccharide and VC+VE to the feed, and change the water appropriately. Eighth, physiological swimming pond analysis and diagnosis: whenever the first and fifteenth day of the lunar month, the full moon is absent, and the tide is high, the shrimp will move frequently with the change of the tide. This kind of swimming pond is not very strong, has a certain periodicity and habit, and the phenomenon of concentrated shelling occurs at the same time. This kind of swimming pond belongs to physiological swimming pond, which is generally harmless, but when it is in the shelling stage, shrimp disease caused by insufficient dissolved oxygen should be prevented. In addition, it is suggested that disinfection, insecticidal and fertilization are taboo during this period. Solutions: (1) in the swimming pool, drain more than 20cm, then add water 10cm, stop feeding at the same time, and sprinkle active calcium + immune polysaccharides or VC+VE to promote shrimp shelling synchronously and promote its growth; (2) turn on the aerator or chemical aerator to increase the dissolved oxygen in the water, such as granular oxygen, to ensure that there is sufficient dissolved oxygen in the pool water. -- the summary is more comprehensive