Common abnormal phenomena and treatment methods of cultured Penaeus vannamei

Abnormal phenomenon 1: before releasing seedlings, the pond could not be fertilized after many times of application of fertilizer and water, or the water color was very poor. The cause of ⑴: due to toxic substances such as heavy metal ions seriously exceeding the standard, or the proliferation of harmful bacteria and zooplankton in the pond, or the breeding of filamentous algae and green mud moss in the pond, or the serious aging of the pond, acidification and consolidation of the pond bottom, the material exchange between pond water and sediment was stagnant, which inhibited the growth of plankton. ⑵ treatment method: ① exposure to the bottom of the pond, thoroughly disinfect with quicklime, tea cakes and other drugs, or planting forage grass at the bottom of the dry pond; ② sprinkled Paidu Yangshuibao or jiedubao and other drugs in the pond; ③ filamentous algae and mud moss breeding ponds were killed with chelating copper or Chongzajing and other drugs; ④ applied fermented organic fertilizer or inorganic fertilizer to cultivate water.

Abnormal phenomenon 2: shrimp seedlings grow slowly, body color is dim, molting is difficult, and the size is different. The cause of ⑴: poor seedling quality or malnutrition. ⑵ treatment method: ① regularly sprinkles microbiological preparations such as Diaoshuiwang or probiotics to recuperate the water quality; ② chooses high-quality feed to feed scientifically and rationally; adds aquatic multi-dimensional or aquatic nutrients and other nutritional additives in the feed; ③ is supplemented with small miscellaneous fish, snail, clam, clam and other animal feed once a week.

Abnormal phenomenon 3: in the early stage of culture, the pond water was yellow, gray, etc., and turbid. ⑴ reason: the dominant species of phytoplankton which are easy to be digested by shrimp in the pond water are consumed, and the algae that are not easy to be digested by shrimp multiply in large numbers. ⑵ treatment method: ① first sprinkled with chlorine-containing and iodine-containing disinfectants in the whole pool; ② replaced part of the old water and injected new water to regulate the plankton population; ③ appropriate amount of fertilization, or sprinkled ecological nutrition agents such as concentrated bacteria and algae solution in the whole pond.

Abnormal phenomenon 4: in the middle and later stage of culture, there was dead shrimp at the bottom of the pond. ⑴ causes: lack of dissolved oxygen at the bottom of shrimp pond, environmental deterioration, accumulation of a large number of toxic and harmful substances; poor nutrition, poor resistance and difficulty in molting. ⑵ treatment method: ① improved the living environment of shrimp and increased the amount of dissolved oxygen in pond water; ② was diluted with povidone iodine and Baidu decoction, then changed proper amount of water after 24 hours, and adjusted the water quality with EM bacteria; ③ was fed with feeds such as liver heme, Ganwei Bao, immune polysaccharide and vitamin C for 5 days.

Abnormal phenomenon 5: the pool water is sticky and greasy, has foam, the transparency is very low, and the pool water is dark green or reddish brown. The cause of ⑴: a large amount of residual bait and shrimp excrement sink into the bottom of the pond, resulting in excessive fertilizer and deterioration of water quality. ⑵ treatment method: ① whole pool sprinkled chlorine dioxide, virus net and other disinfectants; ② whole pool sprinkled Bacillus, hydrolysin and other microbial preparations to purify water quality; ③ with water purification agent, change king and other drugs adsorption and precipitation.

Abnormal phenomenon 6: shrimp swimming pond, soft shell, red body, and a large number of death. ⑴ cause: nitrite, ammonia nitrogen, hydrogen sulfide and other toxic substances in the water exceeded the standard. ⑵ treatment method: ① was sprinkled with microecological agents such as Bacillus subtilis or Bacillus subtilis in the whole pool, while live bacteria preparation was mixed in the feed; ② used water quality improver (such as zeolite powder, activated carbon, clay, etc.); ③ rationally replenished or changed water, and correctly used aerator.

Abnormal phenomenon 7: in the later stage of culture, there was a layer of emerald-green bloom floating on the downwind of the shrimp pond. The reason for ⑴: the high nitrogen content of organic matter in pond water and the alkalinity of water (pH = 8-9.5) lead to the proliferation of indigestible cyanobacteria in shrimp and become the dominant population of phytoplankton. ⑵ treatment method: ① often adds clean water to regulate water quality, control algae reproduction, and regularly use EM bacteria and photosynthetic bacteria to treat pond water; when cyanobacteria multiply in large numbers in ② ponds, choose to discharge pool water in the downwind at noon on a sunny day, falling to the lowest water level as far as possible, generally to about 1x3, and then sprinkle it with the mixture of copper sulfate and ferrous sulfate or the whole pond. ③ catches cyanobacteria on the downwind surface of the pond with a close-eyed sieve net, and can also locally sprinkle the mixture of copper sulfate and ferrous sulfate to kill cyanobacteria.

Abnormal phenomenon 8: the water color suddenly turns black, white or red, and the pool water is turbid. ⑴ cause: seasonal change or wind direction change, commonly known as "anti-algae". ⑵ treatment method: ① whole pool sprinkles water purifying agent, detoxifying water purification king, etc.; ② stabilizes water quality with drugs such as detoxifying treasure, detoxifying Yangshuibao, etc.; ③ whole pond sprinkles concentrated bacteria and algae liquid and other ecological nutrition agents to restore water color.

Abnormal phenomenon 9: shrimp anorexia or refusing to eat. ⑴ reason: hot and muggy, continuous rainy weather, shrimp is in a state of stress. ⑵ treatment method: ① deepens the water level and reduces feeding; ② uses sediment modifiers such as detoxification Water King, High efficiency Water purification Bao, Di Gao Wang, etc.; ③ sprinkles pond antidotes such as jiedu Bao, Paidu Yangshui Bao, etc.; ④ puts in oxygen-increasing agents; ⑤ strengthens nutrition, promotes shrimp feeding, and feeds with Yangkang, aquatic nutrients and Baogantai mixed feed.

Abnormal phenomenon 10: prawns often have white or dark blue spots on their chest and abdomen. In the later stage of the disease, white spots or softening of carapace appeared in the hypodermis, carapace and appendages, the head and chest nail was easy to peel off, and the shell was separated from the dermis. Cause of ⑴: White spot disease caused by virus. ⑵ treatment method: ① seedlings must be tested to be non-toxic before entering the breeding pond; ② is fed with high-quality full-price feed, in which immune polysaccharides, ginsenosides and stable vitamin C are added; ③ is sprinkled with bromochlorohydantoin or dibromohydantoin in the whole pond every 5-7 days; during the ④ breeding season, quaternary ammonium salt complex iodine is sprinkled in the whole pond every 15 days; ⑤ uses biological agents to keep the water environment stable.

Abnormal phenomenon 11: the appendages of prawns turn red (swimming feet are more obvious), and the Gill area of cephalosternum is yellow. Most of the sick shrimps roam by the pool and are anorexic. Cause of ⑴: red leg disease caused by Vibrio infection. ⑵ treatment method: ① prawns must be treated with pond cleaning before stocking; photosynthetic bacteria and activated zeolite powder are regularly sprinkled on the culture water body in ② high temperature season; dichlorohydantoin or bromochlorohydantoin is sprinkled in the whole pond of ③; while ④ spills drugs outside, take Shrimp Poison or Difenkeli internally.

Abnormal phenomenon 12: filamentous fungi grow on the Gill filaments, appendage bristles and swimming feet of shrimp, and can also be seen on the surface of the carapace in severe cases. Affect the respiratory function of shrimp, so that the growth of shrimp is slow, and easy to die due to hypoxia. The cause of ⑴ is caused by Mucor bright bacteria (hairy white mycelium) and thiomycetes, which is mainly related to the deterioration of water quality and sediment in the culture environment, which usually occurs when the pond water is eutrophicated. ⑵ treatment method: ① to maintain good water quality and sediment, thoroughly clear the pond before stocking; ② stocking density must not be too large, appropriately increase the amount of water exchange; ③ feed added an appropriate amount of desquamate to promote the normal molting and growth of shrimp; ④ whole pond sprinkled quaternary ammonium salt complex iodine; ⑤ whole pond sprinkled tea meal, to be diseased shrimp after shelling a big change of water.

Abnormal phenomenon 13: the digestive tract of shrimp is red, the stomach of some shrimp is also red, the midgut becomes red and swollen, part of the rectum is muddy and the boundary is not clear. The vitality of diseased shrimp is weakened, anorexia and slow growth. Cause of ⑴: enteritis caused by Aeromonas hydrophila infection. ⑵ treatment: dibromohydantoin was sprinkled in the whole pool of ①, nitrifying bacteria were sprinkled in the whole pool after 3 days, and Changyanting and allicin were added to the feed of ② for 3-5 days.