South American salmon using hot spring water early breeding technology

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's freshwater aquaculture test site introduced 5 to 6cm of South American salmon, with a transport survival rate of 98%. It was placed in a concrete tank with a water depth of 1m and an area of ​​60 square meters for cultivation. In October of that year, it was transferred to 200 square meters. The rice ponds are mixed with tilapia, with an average size of 10cm, a water depth of 2m, a winter water temperature of 15°C to 25°C, regular, fixed-point, constant feeding, and oxygenation. By early May 2001, 80% of the broodstock reached sexual status. Mature, individuals average about 800.
two. Artificial Propagation
1. 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 inspection and management, artificial oxytocin production was conducted at 17 o'clock on May 15, 2001.
3. The oxytogen dose: HGG+LHRH-A2 was used as the oxytocicure and one injection was used. The dosages were: HGG1000 international unit per kilogram of female fish and LHRH-A2 3 μg per kilogram of female fish. The male fish was halved.
4. The broodstock spawned: After the broodstock was injected, the spawning pond flushed once every two hours. The water temperature was controlled at 25°C. After about 14 hours, the broodstock began to heat. The females were basically still at the spawning pool, head down, tail fins. Swing upwards on the water; the male swims in the spawning pond for a while and swims to the female side, approaches her female's belly with her mouth, or plays around the female, and then leaves for a while and swims wildly in the spawning pool. When the female estrus spawns, the female and the male swim side by side, the abdomen is affixed, swim for some distance, the female begins to ovulate, the male fish begin to line fine, the female generally divides 3 times to lay eggs, each time of spawning interval In about 50 minutes, it takes about 3 hours from the beginning of spawning to the end of spawning. In this artificially inducing 10 group of broodstock, 7 females were all-breed, 3 females were not produced, and the rate of inducing females was 70%. A total of 1.75 million fish eggs were obtained. The average number of spawning fish was 250,000, and the fertilization rate was 79%. .
5. Incubation: After spawning of South American salmon, the eggs are placed in the 8 cubic meters of water in the hatching loop and the water is incubated. The temperature of the water is controlled at 25-27 °C. Since the eggs are half floating eggs, the incubation rate is 40 seconds/cycle. After 14 hours, the fertilized egg began to break the membrane and hatched after 80 hours. When the yolk is completely absorbed and the digestive tract is unblocked, the hatching fry can be cultivated in the lower pond and the hatching rate is 60%.
The introduction of South American salmon and the use of spring spawning technology research is still the first case in northern China. The use of hot spring water breeding can be 5 months ahead of normal water temperature conditions, which lays a good foundation for the promotion of South American salmon in northern China.