The South American carp, also known as the Brazilian carp, is a member of the genus Oleopithecus, Anodontis, Pterodontiforme, and Leptosphaeria. It is mainly distributed in the waters of lakes, rivers and reservoirs in Brazil, Paraguay, and Argentina in South America. It is the main freshwater economic fish in Brazil. The color of this fish is silver-white, and the phosphorus is rough, like a sea fish. The main body muscles are mainly red muscles, and the mouthfeel is tender and not greasy; the diet is omnivorous and vegetal, the source of the feed is wide, the culture cost is low, and the suitable temperature range is 9-36°C. In addition to consumption in Brazil, South American salmon is also used to extract fish oil and process fishmeal. The freshwater aquaculture test field in Wendeng City, Shandong province, combined with the site's thermal resources, introduced the South American carp from the Zhejiang Institute of Freshwater Fisheries in August 1999. After 21 months of careful cultivation, it was artificially propagated on May 22, 2001. success. First, broodstock breeding In August 1999, Wendeng City, freshwater breeding test site introduced 5-6cm South American carp 100, the survival rate of 98%, into the water depth of 1m, an area of ​​60 square meters of cement ponds for cultivation, in October of that year Transferred to a 200-square-meter pond and polycultured with tilapia, with an average size of 10cm, a water depth of 2m, an overwinter water temperature of 15°C to 25°C, regular, fixed-point, fixed feeding, and oxygenation. By early May 2001, 80 % of broodstock reaches sexual maturity, with an average of about 800 individuals. two. Artificial breeding Male and female discrimination: South American salmon are difficult to distinguish between male and female before sexual maturity. When sexually mature, the females have larger individuals, the abdomen is swollen and soft, the genitals are protruding, and the cloacal cavity is full; the males have small schools, narrow abdomen, genital triangles concave, cloacal body outer narrow, and light pressure abdomen white Semen outflow. 2. Prenatal inspection and management of broodstock: On May 5th, 2001, we selected 10 groups of broodstock with relatively good development (male-to-male ratio of 1:1) and entered the egg production pool for prenatal management. At the same time, inject luteinizing hormone-releasing hormone A2 (LHRH-A2, 0.3 μg per kilogram of fish, ripening. Pro-fish into the spawning pool after the food is stopped, the water temperature is maintained at 24-26°C, and water is flushed with a 1.5-kw submersible pump every day. 5-6 hours to stimulate the sexual maturity of the fish.After 10 days of prenatal examination and management, artificial oxytocin production was conducted at 17 o'clock on May 15, 2001. 3.Oxygen production dose: HGG+LHRH-A2 was used as an oxytogenic agent, one injection, and the dosage was respectively For: HGG1000 international unit per kilogram of female fish, LHRH-A2 3μg, male fish halved 4. After broodstock spawning: After the broodstock injection, the spawning pool is flushed once every two hours, the water temperature is controlled at 25°C, approximately After 14 hours, the broodstock began to estrus, and the females were basically stationary near the spawning pool with their heads down and the caudal fins swinging upwards on the water; the male fish swims in the spawning pool for a while and approaches the female's belly with the mouth or The females play around, leave for a while, and swim in the spawning pool.When the females are estrus and spawn, the female and the male swim side by side, the abdomen is affixed, swim for some distance, the females begin to ovulate, and the males start to row. The females are generally spawned 3 times, spawning each time The interval time is about 50 minutes, from the beginning of spawning to the end of spawning, which is about 3 hours.In the 10 groups of artificial fish spawning, 7 females were all born, 3 females were not produced, and the rate was 70%. A total of 1.75 million fish eggs were obtained, and an average of 250,000 eggs were laid per broodstock, and the fertilization rate was 79%. 5. Incubation: After spawning of South American salmon, the eggs were placed in a 8 cubic meter body of water in a hatching ring to carry out running water incubation. Controlled at 25-27 °C, because the fish eggs belong to the lower part of the floating eggs, so the hatching flow rate is 40 seconds / circle, after 14 hours of fertilized eggs, began to rupture the membrane, hatched after 80 hours. When the yolk is completely absorbed, the digestive tract Smooth, hatching fry can be cultivated in the pond, and the hatching rate is 60%.The introduction of South American salmon and the use of spring advance breeding technology is still the first case in northern China, and the use of hot spring water breeding can be 5 months ahead of normal water temperature conditions. In the future, South American carp will lay a good foundation for promotion in the northern region.
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