Yangtze catfish is also called long-nosed fish.

breeding technology

Longsnooker is tender and delicious, rich in nutrition and fat, and can be processed into precious fish maw. For a long time, people have always regarded the long kiss as a nourishing aquatic product and a tribute of the imperial court in feudal society. Before 1970s, the production of long snooker was completely controlled by Rivers. Due to long-term overfishing, resources have been seriously exhausted. In order to make this precious fish a delicacy on people's table, China aquatic science and technology personnel began to study the artificial breeding and breeding technology of long snooker in 1980s, and now the technical problem of artificial breeding has been solved.

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There is little silt in the pond, the single mouth area is 4-6 mu, the water depth is more than 1.5 m, and the water quality is fresh. Some aquatic plants such as water hyacinths are raised in the pond, which is suitable for the characteristics of long kisses. In order to control the water quality, fish 1000 with specifications of more than 5 cm per mu should be put in, and some silver carp and bighead carp should be properly matched. Before releasing the fish, soak in 3% salt water or 5ppm potassium permanganate solution for 10- 15 minutes to disinfect the fish. At first, the feed was mainly earthworm and eel feed, and other feeds were gradually tamed. When the feed grows to more than 8-65438 00 cm, the compound feed contains about 30% of protein, peanut bran and bean cake. The daily feeding amount in summer and autumn is 5%-7% of the fish weight, and the daily feeding amount in winter and spring is 1%-4% of the fish weight. Do a good job in water quality management, generally replace one-third of fresh water every week to keep the water fresh, with water color transparency of about 35 cm, ph value of 7.2-7.5 and dissolved oxygen of 3-6 mg/L; Applying quicklime 10 kg per mu per month plays a role in regulating water quality and preventing diseases. Long snooker, as a captive breed, can be mixed with eel, mandarin fish and California bass. 200 species per mu, but not mixed with catfish, tilapia, pomfret, carp and crucian carp to avoid grabbing food.

Many diseases will occur in the feeding process of longicorn beetles, among which cucurbit disease is the most harmful, especially in seedling stage, resulting in a large number of deaths. It is effective to bathe fish with 20-40ppm formaldehyde at the beginning of the disease.

First, the pond conditions require fresh water quality, high dissolved oxygen and pH value of 7 ~ 8.2, so the pond should be located near the water source, with convenient irrigation and drainage and quiet environment. Generally, the pond area is 1, 000 ~ 3,000m2, and the water depth is1.5 ~ 2m. The wall of the pond is hardened with masonry or cement, and the silt at the bottom of the pond does not exceed10cm. Each pond is equipped with a 3 kW impeller aerator.

Second, the stocked fish is one artificially domesticated old winter fish, with strong physique and neat specifications. Generally, 800 ~ 100 species of fish, 250 ~ 300 silver carp, 75 ~ 100 bighead carp, and 5 mandarin fish or perch are released per mu. Fish stocking is generally better in early March. 10 The day before releasing fish, the whole pond was sprinkled with quicklime100 ~150kg/mu chemical slurry, and the water was released to the required water level after 7 days. Before stocking, soak in 15 ~ 20mg/L potassium permanganate solution or 3% ~ 5% salt solution 15min to kill pathogens and enemies.

3. After the feed is domesticated at seedling stage, the long snooker is mainly compound feed, and its crude protein content should reach 40% ~ 45%. The main raw materials are imported fish meal, dried fish, bean cake, peanut cake, wheat bran, yeast powder, mineral salts, vitamins and so on. And made into hard pellet feed with particle sizes of 3mm, 4mm and 5mm. At first, the feed particle size was 3 mm, and later, with the weight gain of fish, it was changed to 4 mm and 5 mm. Feeding should be fixed, timed and quantitative, and a feeding platform should be built on one side of the pond. Domesticate fish after stocking. First, use sound training on the feed table to make the pond fish form conditioned reflex. Then slowly feed them with water by hand, twice a day, at 8: 00 am and 8: 00 pm, with a feeding ratio of 4: 6 in the morning and evening. Be careful every time until the fish is finished and left. The daily feeding amount is generally 1.5% ~ 3%.

Fourth, the water quality adjustment loves the pool water with fresh water quality and high dissolved oxygen. At ordinary times, we should strengthen water quality management, insist on adding fresh water frequently, start the aerator in time, and rationally use biological agents to regulate water quality. June-September is the peak season for the growth of long snooker, so it should be washed every other day, and the water should be changed once a month, and the amount of water changed is 1/4 of the pool water. Increase oxygen-increasing equipment as much as possible and start the oxygen-increasing machine at the right time. Start time is noon on sunny days, early morning on cloudy days, midnight on rainy days, not at night, floating head early, and every day during the growing period. The operation time is short at noon, long at midnight, short in coolness, long in sultry days, heavy in load, long in time, light in load and short in time. Conventional application of photosynthetic bacteria, the dosage is 10 ~ 20g/m3. Sprinkle quicklime water regularly, usually once every half a month in the breeding period, and the dosage per mu is 5 ~ 10 kg. Always keep the dissolved oxygen in the pond at not less than 5mg/L, the pH value at 7.2 ~ 8.2, and the water transparency at 30 ~ 40cm. However, the water quality should be flexibly controlled according to the season and the water quality of the pond. The water quality should not be too thin and the medium water quality should be light. If the water source is sufficient and the temperature is suitable, the micro-flow water can also be supplemented by regular flushing.

Five, the daily management of the patrol pond should be diligent, adhere to the patrol pond every morning, noon and afternoon, remove residual materials, dirt and clean up the feeding table, and observe whether the fish in the pond have floating heads. In the hot summer season and the sudden change of weather, it is necessary to increase the number of pond patrols at night or arrange night shift management. Start eating early and feed and domesticate the fish the next day after stocking. Combined with patrolling the pond, observe the weather, water color and fish eating every day. Every 15 days, fish were randomly selected to check their food intake and fatness. By weighing and counting, the growth rate of fish, the total amount of fish in the pond and the titer of feed are calculated, and the feeding amount in the next stage is determined.

Six, disease prevention and control once every half month, the whole pool is sprinkled with quicklime, the dosage is about 10kg/ mu, and 1.5% allicin is added to the feed for a long time, and then the drug bait is made with Yusukang every month for three days to prevent enteritis, and the whole pool is alternately sprinkled with chlorine, copper sulfate and chlorine, with the concentration of 0.2-0.3 g/month. In feeding management, it is necessary to observe the feeding situation of fish at any time, and find abnormal reactions or sick fish, and treat them as soon as possible.

Before stocking fish, the culture pond in 10 ~ 15d should be strictly dredged and disinfected, with the ratio of 0. 1~0 .2 kg/m? After the quicklime is dissolved, it will splash all over the pool water or be disinfected with chlorine-containing disinfectant. In the process of breeding, it is necessary to clean up straw and other green feed residues in time, and remove dead fish in time. During the epidemic season of fish diseases, 20~25g/m of quicklime should be used every 15d? The water splashed all over the pool; Or spray chlorine-containing disinfectant for disinfection. Before stocking, fish should be soaked in 3%~5% salt water for 5 ~ 10 minutes. Before stocking, the inactivated vaccine of grass carp hemorrhagic disease, bacterial enteritis, gill rot and erythroderma was injected into the muscle of pectoral fin base, and the injection dose was 0.3~0.5 mL per tail.