Culture technique of Ophiocephalus Argus

Opniocepnalus argus var Kimnra is also called white mullet, commonly known as white black stick, belonging to Perciformes, Channa family genus. The meat is tender, less prickly and delicious. White mullet medicated diet can prolactin, muscle and blood circulation, is a nourishing treasure for pregnant women and young and old. Rich in nutrition, can be made a variety of famous dishes, such as raw fried fish, white chrysanthemum fish, white black stick stewed snake. Muscle composition of white mullet: moisture, 77.90. Crude ash 1.10, crude protein 20.69, crude fat 0.76, compared with other freshwater fish: crude protein content is higher than that of catfish (14.85), crude fat content is lower than that of catfish (3.22), indicating that white mullet is a kind of middle and high grade economic fish with low fat and high protein. The amino acid contents of muscle nutrition of white mullet were as follows: aspartic acid 2.08, threonine 0.95, serine 0.86, glutamic acid 3.92, glycine 1.09. Alanine 1.32, cystine 0.13, valine 1.00, methionine 0.43, isoleucine 0.92, leucine 1.81, tyrosine 1.66. phenylalanine 0.88, lysine 1.80, histidine 0.52, arginine 1.10, proline 0.54. White mullet is white in color, beautiful in posture, tolerant of hypoxia, and has certain ornamental value. China has a long history of breeding black stick, but there is no systematic research on breeding technology of white black stick, resulting in the reduction of natural resources. We began to study white mullet and its breeding technology in 1992, which has received great attention from aquaculture circles and achieved good results. The project won the first prize of Science and Technology Progress Award of Provincial Hydropower Department in 1997. 1. Biology of Channa argus 1.1 Morphological characteristics. The white snakehead is rod shaped, with flat head, large head scales, fine tail scales, dorsal fin rays 47, anal fin rays 38, lateral line scales 63, gill rakes 13, vertebrae 55, body length 7.8~8.2 times of body height. 1.2 Growth. The optimum temperature for white mullet survival is 0~39℃. The optimum temperature for growth is 25~28℃, and there is no feeding at 12℃. It has auxiliary respiratory organs on gills, suitable pH value is 6.0~9.0, likes to gather, good at jumping, easy to drill mud, the fastest weight gain in summer, the daily weight gain rate is 3%. 1.3 Habit. Mouth end position, teeth distribution on both sides of the upper jaw, lower jaw front, mainly carnivorous, fry stage to kill each other, can domesticate feed. Female mullet cultured in pond can reach sexual maturity in two years. The gonadal development cycle of female mullet is IV stage from February to March, III stage from March to April, V stage from May to July, and III stage gradually in August. The number of eggs of parent fish with body length of 30~35cm is about 15,000, 8 eggs per gram. The relationship between body length and body weight is logW=3.032 logL-1.9433. The relationship between individual fecundity Y(1000 eggs) and body length is Y=2.68532-79.08513. 2 Artificial reproduction techniques 2.1 Brood fish breeding. Choose a pond with good water source, the size of the pond should be 60~100 square meters, the height of the pond should be 1.5 meters, the water level should be 1 meter, there should be anti-escape facilities, there should be water plants or water hyacinth in the pond, which can shade and regulate the temperature. White mullet has gills respiratory organs, strong adaptability to the environment, stocking density can be higher than ordinary fish, 1~2 2~2.5 kg parent fish can be placed per square meter, the ratio of male to female is 1:1. White mullet is carnivorous fish. The bait of parent fish is generally fed by small miscellaneous fish in the pond and some low-quality fry. It can also be fed with terrestrial earthworms, aquatic earthworms, loach, etc. The feeding rate is generally 3~5% of body weight. Before spawning, the spawning period often flush change the pool water to ensure that the pool water fresh, so that the parent fish normal development. 2.2 And hatching. In reproductive season, female fish abdominal expansion, elastic, slightly red genital hole protruding, male genital hole invagination. General selection of white body color, physical health, maturity can be better parent fish. The oxytocin agents include pituitary gland (PG) and chorionic gonadotropin (HCG) of carp and crucian carp, according to PG 1g and HCG1800~2000 international units per kilogram of body weight. The dose of male fish was halved and the ratio of male to female was 1∶1 or 2∶1. The effect time is related to the water temperature, 26~36 hours at 22~23℃; 25~30 hours at 24~25℃; 18~22 hours at 26~30℃. As far as possible, eggs should be laid before dawn. Mullet spawning needs a quiet environment, spawning when a scare, will terminate spawning. placing the fertilized eggs in an incubator, controlling the exchange volume of water in the incubator, controlling the circulating water volume to be 50 cubic meters per hour, controlling the water temperature to be 22 - 27 DEG C, controlling the dissolved oxygen to be more than 4mg/L, and controlling the pH value to be 7.0 - 8.0. Indoor incubation avoids the disadvantages of outdoor incubation: such as light, because eggs float on the water surface, strong radiation makes embryos die, enemies, other wild miscellaneous fish eat eggs, as long as the favorable conditions for incubation are guaranteed, the hatching rate can reach 90%. It can also be incubated in still water. 3. Seed breeding techniques. Newly hatched larvae, black in color, floating on the water surface or lying on the edge of weeds or suspended matter, clustered in the pool, pool corner, static and not easy to move. The yolk sac accounts for about half of the body length. When the yolk sac gradually disappears and the fry can swim horizontally, transfer the fry to an outdoor fry pond for cultivation. 3.1 fry breeding. The stocking amount is generally 200~400 fish/square meter. At this time the pool water should be fresh, there is sufficient palatable daphnia, or fry will be due to lack of food and kill each other. At this stage, the gill respiratory organs of fry have not yet developed perfectly, and their respiration depends entirely on dissolved oxygen in water, so the water quality should be kept good at this time, the survival rate of fry is high, and the growth is fast. The key lies in sufficient dissolved oxygen in water and abundant palatable bait. In the fry breeding stage to eliminate enemies, such as frogs, water centipedes, so after 12 to 25 days of cultivation, fry length up to 5 to 8 cm, body color from black to white from the top of the head gradually. At this stage, the auxiliary respiratory organs of fry are well developed, the activity is very strong, and the food intake is constantly increasing. With the growth and development of fry, individual increase, the pool density increases, at this time should be sifted, graded into the fingerling pool for cultivation. 3.2 Fish breeding. The culture pond is 25 - 60 square meters, and the water depth is 0.5 - 0.8 meters. The fry with the length of 5 cm are put into the culture pond according to 50 - 80 fish/square meter, and the water earthworm, terrestrial earthworm, sand earthworm and water spray of low-quality fish, such as grass carp, etc., are fed. Feed white mullet to eat less and more meals, because the fish has a bad habit of eating greedy, overeating, such as feeding too much at a time, will cause overeating death. Pool water should be changed frequently. Generally, one-third of the water should be discharged from the bottom of the water every week, and then new water should be injected from the water inlet, so that it can have a comfortable living environment before it can grow normally. After 25~30 days of cultivation, the size of the fish can reach 8~13 cm. We adopt the following key techniques to improve the survival rate of fry: ① improve the water quality to keep the pool water fresh;② reasonable stocking density to select suitable bait;③ regularly screen fry to keep the specifications relatively consistent. 4 Adult fish farming. White mullet adaptability is strong, can be raised alone, can also be raised. 4.1 Interbreeding: white mullet can catch small wild fish in the pool, reduce the waste of bait in the pool, reduce the consumption of dissolved oxygen in the pool, and improve fish production. Because the caliber is smaller than that of the catfish, it does not pose a threat to the cultured commercial fish, so farmers everywhere can accept this fish as a good breed for breeding. 4.2 pond condition ① Cultivation conditions: soil pond, stone pond can be cultured, water depth 1.5~2.0 meters, pool depth 2.0~2.5 meters, appropriate production and sales management area in 1~1.5 mu is appropriate, pool water inlet and drainage should be convenient, water inlet and drainage outlet and around to set up escape prevention facilities. Before stocking, pond cleaning must be done well. Generally, quicklime is used. 100~150kg quicklime slurry water is sprinkled per mu to ensure that no dead corners are left. Water is injected one week after disinfection. Water can be stocked for about 10 days. 2 breeding technology: stocking specifications more than 10 cm (3~5 inches) when stocking as much as possible to control the same specifications, stocking with 3~5% salt water soaked for 10~12 minutes before the pool. The stocking density is 2~3 per square meter, that is, about 1500~2000 per mu. Feed feeding types: first, fresh animal feed, such as small miscellaneous fish, small crucian carp, wheat ear fish, meal strips, fish skin, white mullet favorite fish skin fish, can be put in the pond appropriately some mussels, let it naturally reproduce fish skin fish, for its needs; second, fresh fish meat paste and powdered feed, mixed with eel feed feeding. Feeding method adopted four fixed "timing, quantitative, qualitative, positioning." The feeding amount is 6~10% of the fish weight, and gradually decreases to about 6% with the increase of fish weight. When feeding, you can see the lively scene of group scrambling for food, and some will jump out of the water surface. In the whole breeding stage, we should insist on patrolling the pond, one is to see whether the escape prevention measures are appropriate, the other is to observe whether the fish activities are normal, and the third is to see the changes in water quality. Especially in the high temperature season, the water quality changes frequently and is easy to blacken and stink. At this time, the pool water should be exchanged frequently, so as to change one third of the pool water every three days, and change two thirds of the pool water every 10 to 15 days to keep the water quality fresh. The water level in winter and high temperature season is relatively high to keep the water temperature relatively stable. Under certain breeding conditions, the survival rate of 16~20 cm fingerlings is more than 80% after 5 months of growth, and the yield per mu can reach more than 500kg. The main growth period of white mullet is from July to October, especially in September. The average temperature of water in July to September is in the range of 21.4~30.8℃. In this stage, we should seize the opportunity to strengthen cultivation and make it play the best growth effect. 5 Feed. White mullet is a fierce carnivorous fish, it must be domesticated through the conversion of feeding habits in order to achieve the purpose of breeding adult fish with compound feed. We began to feed on powder and small pellet feed when the size of fry reached about 13 cm, and changed to compound feed within 18~20 days. Formula screening tests were carried out in 94~96. In the experimental culture pond with an area of 25 square meters and a stocking density of 30 fish/square meter, 70% of the fry could eat compound feed well after 22 days. Due to the habit of feeding on wild miscellaneous fish under natural conditions, only efforts should be made to select the color, smell and taste of the attractant and improve the feed formula, so that 91.8% of the tested fish could eat the compound feed after 15~20 days. The basic feed for adult fish culture consists of fish meal, bean cake, wheat and corn, and mineral substances and special additives are added. Feed coefficient 2.5~2.8, nutrient composition, crude protein 42.3~44.3, crude fat 5.65~6.51. crude fiber 1.23~2.83, ash 11.3~12.4, moisture 8.01~9.91. 6. Disease prevention and treatment of white mullet. Carry out the principle of prevention first, combining prevention with treatment, prevention more important than cure, and early cure. Enhance the disease resistance of fish body, select healthy and orderly fish species, reasonably close culture, timely separate culture, strengthen management, and achieve four stability. Regulate feed nutrients. Cautious fishing, transportation and operation are required to prevent fish injuries and feed bait to prevent them. Eliminate pathogens, thoroughly clean the pond, disinfect the seed pool in advance, disinfect the seed before entering the pool, disinfect the water regularly, feed live bait, such as earthworm and miscellaneous fish, after disinfection with salt solution. Improve the environment, change water regularly, plant green, increase oxygen. Common diseases of white mullet: 6.1 Melon worm disease. The pathogen is multi-seed small melon worm. After parasitism, the fry move slowly and do great harm. Use 2ppm methylene blue to sprinkle and soak in the whole pool for prevention. Treatment with 0.1~0.2ppm mercurous nitrate immersion, or the whole pool splash; with malachite green according to 0.2ppm the whole pool splash, continuous three days, there are good results. 6.2 Chlamydia. Pathogen: There are many kinds of wheel worms will cause disease, parasitic in the body surface of fish, gills, damage muscle energy, tissue, affect respiration and lead to death. Prevention and control methods: clear the pond with quicklime, keep the water fresh, and splash the whole pond according to 0.7ppm copper sulfate and ferrous sulfate (5:2). 6.3 Water mold. The pathogen is a water mold. When the disease occurs, the muscles on the body surface are stiff, the fish moves slowly, floats on the water surface of the pool and does not sink, and gradually dies. Prevention and control methods: try to avoid hurting fish during operation, especially in low temperature seasons. Sprinkle the whole pool with formalin 20~ 30ppm or potassium permanganate 30~ 50ppm, and soak it in 3~5% saline for 5~10 minutes. 6.4 Hemorrhagic septicemia. Common at the adult stage, the fin base and jaw of the diseased fish are red, eyeballs protrude, scales are loose, muscles are swollen, and there is no effective treatment for this disease. Only to prevent the main, thoroughly clear the pond, with formalin 30~50ppm after the whole pool splash, and then inject new water, try to avoid sewage sources.