(1) Broodstock breeding. The broodstock should be raised in a special pool. The broodstock is generally 1-2 mu in area and 1.5-2 meters deep. The water source of the fish pond should be fresh, drainage and irrigation are convenient, and the bottom is better with aquatic plants. Feed the appropriate amount of bait fish every day and keep the male and female fish in separate ponds two months before breeding. In some lakes or reservoirs, if squid is rich in natural resources, broodstock can also be selected from the adult fish caught in the spring. Individuals weighing more than 0.5 kilograms of fish and 1-3 kilograms of individual females can be selected without injury.
(2) Identification of male and female. The front of the lower jaw of the female fish has a rounded shape and slightly exceeds the upper jaw. The genital hole is in a shape of "one", surrounded by pink, located between the anus and the urine. Male mandibles have a pointed shape at the front of the mandible, which is much larger than the upper jaw. The genital hole and the urine leaking hole are coincident with the excretory hole, and they are point-like holes located behind the anus. When sexually mature, the abdomen of the female fish is enlarged, soft and elastic, the contour of the ovary is obvious, the midline of the abdomen is concave, and the genital hole is swollen and open. When the male fish is lightly pressured, milky white semen flows out.
(3) oxytocin hatching. The oxytocic agent was used as a mixture of salmon pituitary (PG) and chorionic gonadotropin (HCG) and an analogue of releaserin (LRH-A). The dosage of the two oxytocics is: 1PGl. 5.2 mg ten HCGl000 international units; 2PGl0 mg ten LHR-A300 micrograms. The site of the injection is at the base of the pectoral fin, which is usually injected once or twice or three times. Its effect time is 6-12 hours longer than that of a fish. The fertilization method depends on the size of the production and whether the broodstock is sufficient. The natural fertilization method has little damage to broodstock and is suitable for large-scale breeding. The successful grasp of artificial insemination is great, and the broodstock has more damage and is suitable for small-scale production. It is also possible to combine natural spawning and artificial insemination. When the natural spawning is completed, the broodstock is caught and artificial ovum insemination is performed on the broodstock that has not produced eggs or has not produced eggs. The rays of the squid are sharp and hard. When catching the fish, use the thumb and forefinger to pinch the squid's mandible and lift the fish. Then use a gauze or towel to wrap the fish and leave the injection or spawning site. It will neither hurt the fish nor hurt anyone. Fertilized eggs hatch directly in the ring. As the eggs are slightly viscous and semi-floating, the specific gravity is slightly heavier than that of water, and they will sink into the bottom of the water in still water. Therefore, the flow rate of water in the loop should be maintained at more than 20 cm per second, otherwise the eggs will sink and affect the hatching rate. In the absence of a loop, fertilized eggs can also hatch in a running water hatching tank or hatching tank. During the incubation process, it is necessary to control the quality of the water, require fresh water, adequate dissolved oxygen, and no pollution, and keep the water temperature at 23-29°C so that the fertilized eggs can develop smoothly at the optimum temperature. The fertilized egg embryo develops at a slower rate than the domestic fish. From fertilization to emergence at a water temperature of 25-30 °C, it takes about 30 hours.
(4) Seed cultivation. The cultivation process of carp fry can be carried out either in seedling ponds or in cages, but it must be carefully managed. Seed cultivation ponds generally have an area of ​​0.1-0.2 mu or less, water depth of 1.5 meters, fresh water, convenient drainage, and less silt in the bottom of the pool. For ease of operation and better management, most production units now place seedlings in the hatchery ring or place cages in the pool. The cage is set in a micro-flow basin, and the release tank and the fish body are sterilized before stocking. From the fry completely disappeared to the emergence of fins, known as the opening period, about 3 days. The open bait fish is a 24-72-hour head-of-head salmon trout or a 24-60 hour stripping grass carp seedling. General squid priming larvae or grass carp began 1-2 days after oxytocin production. The open bait fish density is 15 times that of the carp seedlings, so that the carp seedlings can be preyed by opening the mouth. From the opening to the stage where the fish scales are fully formed, that is, to 3.3 cm, they can be sold as fish species or transferred into adult fish ponds. The time takes about 12-18 days. At this stage, ensuring the supply of adequate and palatable bait fry and frequently carrying out disinfection, disease prevention and parasite prevention is the main measure to increase the survival rate. At this stage, the diseases most at risk are saprophyte, and worms, worms, and small melon worms. These diseases will multiply at large water temperatures of 20-30°C and infect fry, often resulting in large numbers of fish fry, so pay special attention to it. Prevent disease. For the prevention method, the bait fish to be put in must be sterilized, and it is usually dipped in 3% saline for 10-20 minutes; the concentration of carp fry is 150-200g/cubic water in formal rings or carousel. formalin solution Medication 1 -2 minutes. Disease treatment methods, trichoderma and caterpillar fungus, can be sprayed with 0.7 g/cubic sulphate and ferrous sulfate mixture (5:2) 2-3 times per cubic meter of water per day, and then use 2% o-3 g Spill; or dip for 10–10 minutes with 100 g/cubic of formalin solution. For small echinococcosis, the diseased fish should be dipped in 2 g/cubict of mercuric nitrate solution for 3 to 5 minutes, or 0.1 g/m3 of Quanchipid, or 40 g/m3 of formalin. Rickets disease, with 0.2-0.5 g / cubic crystal trichlorfon spill; or 1.5 g / cubic potassium permanganate bath 5-10 minutes. When the fry reaches more than 3.3 cm, the disease gradually decreases after the scales are basically grown. The form at this time has been similar to adult fish, and its ability to actively eat food has increased. Since eel fry seedlings feed on live fry and different stages of growth have different requirements on the type and size of live feed, if the food is not served in time, the quantity cannot be satisfied or it is not suitable, the eel will eat on its own. Was killed, stuck, or died of hunger. Therefore, according to the start time and growth rate of the carp seedlings, it is necessary to produce and supply live feed fish of various specifications in a planned manner so that the timing, quantity, specification, and variety meet the requirements. If the squid species still need to be raised, they can be reared on a 3.3-cm scale. It can either keep feeding in cages or cultivate in cement pools or small earthen ponds. The stocking density of the flow pool is 200-500 per cubic meter of water body, and the stocking density of the static pool is 100 fish per cubic meter of water. The live fish fry or wild fish and shrimp are used as bait.
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