Tongling, Anhui Province: success in cage culture of long-snout fish

People's Daily, Anhui window Information: on October 23, employees and relevant experts of Anchor Zhou Special Culture Company in Tongling County, Anhui Province, observed the growth of long-snout fish in the cage culture base of Jiajiang River in Tongling Yangtze River section. In the second half of last year, the company raised precious fish species such as long-snout fish in cages in Jiajiang, Xuba Township, Tongling County. According to Jianghe, a researcher and deputy director of the Fisheries Research Institute of the Provincial Academy of Agricultural Sciences, "the successful cage culture in Tongling has provided valuable information for the demonstration and promotion of Changkou in the whole province." Leiocassis longirostris belongs to the order Clariformes, Lepidopodidae, Genus Linnaeus. Commonly known as: mackerel, Jiangtuo, Feituo, Feiwang Fish, Grey River Tuoyu. English name: Longsnout catfish. The shallow waters north of 40 °N include France in Western Europe, eastern England, western Norway, Siberia in the Soviet Union, Alaska and Canada in the United States. Both the Heilongjiang River system and the Ertix River in China are distributed. body length, snout cone, protruding forward. The lower position of the mouth is in the shape of a crescent, thick lips and small eyes. Must be 4 pairs, small. Scaleless, the hard spines of the dorsal and pectoral fins are serrated, the fat fins are thick, and the caudal fins are deeply bifurcated. The body color is pink, the back is slightly gray, the abdomen is white, and the fins are grayish black. They generally live at the bottom of rivers and live in the middle and lower layers of the water when foraging, and spend the winter in gravel cracks in the deep water of the main stream. The long-snout mackerel is a carnivorous fish and its main food is small fish and aquatic insects. The youngest age to reach sexual maturity is 3 years old, usually 4-5 years old. Adult fish begin to mature from March to April each year and then go up to the rapids of the river at the bottom of the gravel to lay eggs. The spawning period is from April to June, and it goes down around August. The number of eggs varies from 1 to 100000 or more. The spawning ground of the Yangtze River is concentrated in the Jingjiang River bend in the middle reaches and the Tuojiang River in the upper reaches. Changkou is distributed in the Liao River, Huaihe River, Yangtze River, Minjiang River to Pearl River and western Korea, mainly in the Yangtze River system. The growth rate of long snout is faster, and it is the largest of the same kind of fish. the largest individual can reach 15 kg, and most of the common ones are 2-4 kg. It accounts for a large proportion of the catch in the Yangtze River basin, and the proportion in the middle and lower reaches is significantly higher than that in the upper reaches. Mackerel is a large economic fish, its meat is tender and delicious, rich in fat, without fine thorns, protein content is 13.7%, fat is 4.7%, known as the top grade of freshwater edible fish. The most beautiful thing about this fish is its belly with soft edges. And its swim bladder is very thick, dried into a valuable fish belly. The "penholder fish belly" produced in Shishou City, Hubei Province is famous. It has a thick glue layer, pure taste, translucent color, unique production technology, the shape of dry products and a beautiful natural pattern embedded in Shishou, looking after the light source, which is very similar to the Bijia Mountain standing in Shishou City, hence the name "penholder fish belly". And there is "this thing is only the stone head, there is no other place in the world," it is the treasure in the food. As early as the early Ming Dynasty, it was presented as a treasure to Zhu Yuanzhang, the ancestor of the Ming Dynasty, and has been listed as a tribute ever since. Du Fu, a famous poet of the Tang Dynasty, Su Shi, a poet of the Song Dynasty, and Bi Ye, a modern poet, all wrote poems and articles for it. However, the resources of long-term snout in the Yangtze River have been declining in recent years, and the output has decreased sharply. In order to protect and develop this precious fish, the Institute of Aquatic Biology of the Chinese Academy of Sciences cooperated with Shishou Special Aquatic products Research Institute, and made a breakthrough in artificial reproduction and aquaculture technology in 1987. The dorsal fin thorn and pectoral fin thorn of the mackerel have toxic glands, which is more toxic to the freshwater venomous fish. after being stabbed, sharp pain and burning will occur immediately, the wound will be punctured and torn, bleeding, local swelling, some will cause fever, and the affected area will be itchy. Half an hour to 1 hour later. Stabbing accidents often occur when they are caught, so you should be careful. Ecological characteristics of the long snout mackerel body color gray-black fins, snout cone-shaped, protruding forward, small eyes, with four pairs of whiskers. It is a carnivorous demersal fish, which preys at night. The survival temperature is 0 ℃-38 ℃, the optimum growth water temperature is 24 ℃-28 ℃, the food intake decreases and the growth slows down below 20 ℃, the tolerance to hypoxia is similar to that of domestic fish, and the sexual maturity is 3 years old, and the male fish spawn from April to June every year. The fry bred in that year can grow to 100-150 grams at the end of the year, and can be raised to 500 grams in the following year. 3-year-old fish weigh up to 1 kilogram. The culture technology stocking pond has less silt, a single mouth area of 4-6 mu, a water depth of more than 1.5 meters, fresh water quality, and some aquatic plants such as water floating lotus are stocked in the pond, which is suitable for the characteristics of dark and dark. The main culture per mu of more than 5 cm specification of 1000 fish, and appropriate matching of some silver carp, bighead carp, in order to control water quality. Before stocking, the fish were soaked in 3% salt water or 5ppm potassium permanganate solution for 10-15 minutes to disinfect the fish. At the beginning of feed feeding, earthworms and eels were mainly fed, and other feeds were gradually fed. When growing to more than 8-10 cm, compound feed containing about 30% protein or peanut bran and bean cakes were used. The daily feed amount was 5% of fish body weight in summer and autumn, and 1% of fish body weight in winter and spring. Do a good job in water quality management, generally change 1/3 of fresh water every week, keep the water quality refreshing, water color transparency about 35cm, ph 7.27.5, dissolved oxygen 3-6mg / L; 10 kg quicklime per mu per month to regulate water quality and prevent diseases. As a breed, it can be mixed with eel, mandarin fish and California perch, with 200 fish per mu, but should not be mixed with catfish, tilapia, white Pomfret, common carp and crucian carp to avoid forage. There are many diseases in the culture of long-snout mackerel, among which melon disease is the most harmful, especially in the seedling stage, which causes a large number of deaths. Formaldehyde 20-40ppm is effective in the early stage of the disease. The reproductive habit is usually 300-500 mm. It grows rapidly in the first 4 years and slows down in the last 4 years. The life span is longer. The highest known age is 22, the sexual maturity is late, and the minimum mature age is 3 years old. The spawning period is from December to January of the following year, and the water temperature is about 2 ℃ when spawning. Spawning occurs in sandy or gravelly beaches 1-3 meters below the ice, and haddock, which lives in lakes, also migrates to the river to lay eggs. When spawning, the male fish first reaches the spawning ground, and only after 3-4 days does the female fish come. The male fish often chase the female fish in circles. After the rotation, the female and male fish tremble to spawn and ejaculate respectively, and the spawning activities are mostly carried out at night. The number of eggs varies greatly with the size of the fish, with a body length of 340mm and a body length of 870mm and 3 million eggs, respectively. The hatching period of the larvae is about 60 days, and the newly hatched larvae are 3.84.3mm in length. Ferocious carnivorous fish and night eaters. The juvenile fish with a body length of 50 mm feed on the larvae of plankton, Hymenoptera, Diptera and so on. Adult fish feed entirely on fish. Almost non-selective, cannibalize each other when food is scarce. I've learned a lot, but I've never heard of it before! Seeing something new, it seems that you really have no knowledge and no knowledge.