Disease prevention and control techniques of herring

Herring is an important fishery resource in the middle and lower reaches of the Yangtze River and the main breeding objects in lakes and ponds along the Yangtze River. it is one of the "four major domestic fish" in freshwater farming in China. Herring was prone to hemorrhagic disease and 2-year-old fish suffered from enteritis. Sporidiosis and Gill rot disease are also very common. Let's take a look at the prevention and control techniques of herring disease.

Herring hemorrhagic disease

[symptoms] caused by an unnamed virus. Similar to the hemorrhagic disease of grass carp, the body surface congestion is not obvious, mainly manifested as intestinal tract and muscle congestion.

[prevention and treatment] during the season of ①, every cubic meter of water in the fish pond was sprinkled with 0.6g of carbendazim or 0.7g of copper sulfate throughout the pond for 2 days as a course of treatment. Herring fingerlings were injected with inactivated vaccine by ② in the same way as grass carp fingerling. ③ every ten thousand fish species were ground into powder, boiled or soaked in boiling water overnight, mixed with bait and fed for 5 days. And feed with Cleo Yufukang bait, 50 grams of bait for every 100 kg of fish, once a day, for 5 days.

Chinese parasite disease

[symptoms] the diseased fish have difficulty in breathing and restlessness, turn over or swim wildly on the surface of the water, the upper leaves of the caudal fin often come out of the water, and finally lose weight and suffocate to death. There is a lot of mucus on the Gill of the diseased fish, and the end of the Gill filament expands into a rod, pale and bloodless.

[control method] ① used quicklime to clear the pond and kill the eggs. ② was sprinkled with 90% crystal trichlorfon in the whole pool, with a dosage of 0.5mg / L. ③ was sprinkled with a mixture of copper sulfate and ferrous sulfate, including 0.5mg / L cupric sulfate and 0.2mg / L ferrous sulfate.

Bacterial enteritis

[symptoms] the diseased fish have blackening, loss of appetite, or even hunger strike, congestion and inflammation of the intestinal wall, poor elasticity, a large amount of mucus in the intestine, and redness and swelling of the anus.

[prevention and treatment] the whole pool was sprinkled with chlorine dioxide, the dosage was 0.2 mg / L ~ 0.5 mg / L, and garlicin was fed with 10-30 g / kg body weight for 4-6 days.

Hepatobiliary syndrome

[symptoms] the liver of diseased fish is obviously enlarged, yellowed and whitish, forming "flower liver" and even partially or mostly turning into "green liver". The body color is black, the color is dark, the diseased fish usually have a big belly, fat, the scales are loose and easy to fall off, swimming irregularly, poor appetite, dull reaction.

[prevention and treatment methods] use high-quality compound feed, feed more live snails, clams and other animal feed, regularly use microbial preparations to regulate water quality, and timely spray hepatobiliary rehabilitation and vitamin C in the compound feed when the disease is found.

Bacterial septicemia

[symptoms of onset] 1-2 days before death, the diseased herring grabs food vigorously, floats on the water at the same time, swims slowly, rises and falls up and down, serious fish anorexia or no food, motionless or paroxysmal swimming occurs, some rub at the edge of the pool, and finally die of exhaustion.

[preventive measures] ① cleaning pond disinfection: dry pond desilting in winter, thoroughly disinfect with quicklime or bleach. ② fingerling disinfection: long-term inbreeding is strictly prohibited to ensure the stocking of healthy and disease-resistant fry. Before entering the pond, the fish should be bathed in 15-20 mg / L potassium permanganate solution or 3-5% salt solution for about 20 minutes. ③ drug prophylaxis: use long-acting water disinfectant once a month from June to September, every 30-45 days, according to 1 gram of fish Funing mixed feed per kilogram of fish body for 2 days. During the epidemic season, the whole pool should be sprinkled with 0.2 grams of chlorine dioxide per cubic meter of water every half a month.

[treatment] on the first day of ①, insecticides were used to kill fish ectoparasites. ② every cubic meter of water was sprinkled with 0.3g chlorine dioxide and water in the whole pool, and the medicine was used again every one day. ③ per kilogram of fish was fed with pellet feed made of 0.05g sulfamethoxazole, twice a day for 5 days.

Sporozoosis

[symptoms] there are white round cysts on the fish's body surface and skin, and the internal organs, whether adipose tissue or other organs, are also white cysts, and there are more obvious white spots on the gonads, which can be easily distinguished from the ovaries.

[prevention and treatment methods] ① was thoroughly cleaned and disinfected with quicklime. ② was fed with 75 grams of sulfur powder every 50 kg of fish, once a day for 4 consecutive days. ③ was sprinkled with 0.15mg / L insecticide in the whole pool. Or put 500 grams of potassium permanganate per cubic meter of water, fully dissolve, wash the diseased fish for 30 minutes. ④ sprinkled with 40 kg of raw limed water in the whole pool, adjusted the pH value of the pool water to about 8, and sprinkled with 30 kg of raw limed water in the whole pool on the third and fifth day.

Bacterial Gill rot

[symptoms] the mucus on the Gill of the diseased fish increases, the Gill filament is swollen, and in severe cases, the end of the Gill filament is defective, the cartilage is exposed, the skin on the inner surface of the Gill cover is congested and inflamed, and the middle part is eroded into a round or irregular transparent window, commonly known as "open skylight". The edge color of the fin is often lightened.

[prevention and treatment] 0.4 mg / L ~ 0.5 mg / L trichloroisocyanuric acid or 0.2 mg / L ~ 0.5 mg / L chlorine dioxide or 0.2 mg / L ~ 0.3 mg / L dibromohydantoin was sprinkled in the whole pool and fed with sulfadiazine per mg / kg body weight for 5 days. Take multivitamins and vitamin C for aquatic products orally for a week.