Artificial breeding technique of barracuda

Selection and cultivation of parent fish: among adult fish caught from the sea area or cultured from seawater and brackish water in autumn or early winter, intact individuals are selected as parent fish. The female fish should be 3 years old and weigh more than 1.5 kg, and the male fish should be 2 years old and weigh more than 1 kg. Fish pond area should not be too large, 1500-2000 square meters is appropriate, water depth 1.5-2 meters, there are sea, fresh water sources, convenient drainage and irrigation. The stocking amount per mu of parent fish pond should not exceed 100 kg. The barracuda began to ask for a small amount of food when the water temperature was 4 ℃, and more than 10% of it was fed normally. In the breeding of parent fish, the method of artificial feeding commercial bait can be completely adopted, or the method of feeding and fertilizing water can also be adopted. The best kinds of commercial bait are peanut cake, bean cake, sprouts and hairy shrimp. Organic fertilizer should be used in fertilization, but chemical fertilizer should not be used. The transparency of the fish pond is controlled at about 30 cm. Prenatal "excessive saline" and running water stimulation should be carried out. "excessive saltwater" means that the parent fish cultivated below 5 ‰ in salinity are poured into the parent fish culture pond after autumn and spring, so that the salinity of the pond water is gradually raised to more than 15 ‰, which is very effective to improve the gonadal development and maturity rate of parent fish. In addition, fresh water is injected into parent fish ponds every semimonthly to 20 days in autumn, every week to 10 days in spring and every 2-3 days before delivery, so as to promote the appetite of parent fish, reduce diseases and stimulate gonadal development.

Induction of labor: the optimum water temperature for induced labor of barracuda is 16%-20%. The induction season is from the end of April to mid-June, generally concentrated from late April to mid-late May. Sooner or later, the spawning season is related to the quality of parent fish cultivation. The drug and dose combination can be referred to as follows (per kilogram of fish body weight): common carp and crucian carp pituitary 15mg 20mg, HCG2000~4000IU alone, LRH-A150~300 microgram alone; or carp and crucian carp pituitary 5mg 10mg + HCG1000~2500IU+LRH-A100~150 microgram, carp and crucian carp pituitary 10mg + HCG1500~2500IU, carp and crucian carp pituitary 100mg + LRH-A100~300 microgram. Generally, the female fish were injected twice, with an interval of 24 hours. The first dose was 1 × 3, the second dose was 2 × 3, and the total dose of sterility was 1 × 2, 2, 3. The stimulation of fresh water in the process of induced labor has a great influence on increasing the rate of induced labor. Artificial insemination is the only breeding method of barracuda so far. The best time for a mature egg to maintain its fertilization ability is when the water temperature is 16% to 20 ℃; the mature egg is characterized by a full and transparent egg ball with a diameter of about 1 mm, with a large oil ball in the center, with a diameter of 0.45 mm to 0.5 mm, and the egg is uniform in size, glossy, round, elastic and bright orange; the egg flow is characterized by light hand squeezing on the abdomen, smooth egg excretion, no blood clots and egg clots. Both dry and semi-wet methods can be used for insemination.

The hatching of fertilized eggs: the eggs were sunk when the salinity was below 13 ‰ and floated above 15 ‰. The incubation water temperature is 16 ℃ ~ 20 ℃, both in running water and still water, but the hatching rate is higher in running water. The speed of embryonic development depends on the water temperature. When the water temperature is 16 ℃ ~ 20 ℃, the embryonic development can be completed in 46-52 hours.

Seedling cultivation of barracuda: at present, the breeding techniques of cyprinid fishes are mostly adopted, that is, natural bait is propagated by fertilization and commercial bait is fed at the same time in the pond.

Preparation of the fry pond: before the fry goes into the pond, the fry pond must be thoroughly cleared with pond-clearing drugs. After clearing the pond, 50 cm of water was injected into the fish fry 7-10 days before the fry went into the pond, and basic fertilizer was applied to cultivate natural bait. The amount of livestock and poultry manure per mu of water is 3750-6000 kg, less in the old pond and sufficient in the new pond. After applying basal fertilizer for 10 days, the plankton in the pond propagated initially and reached the peak in about half a month.

Fish fry in the pond: barracuda fry began to swim 4-5 days after coming out of the film, and if they can take the initiative to feed, they should be put in the fry pond at the right time, with 8-120000 fry per mu. The difference in water temperature between the hatching pond and the fry pond should not exceed 3 ℃; when the fry is released, the salinity of the pond should not be less than 7 ‰; the time for entering the pond should be sunny and windless, and the appropriate time for entering the pond should be 3: 4 p.m.; the fry should be put into the pond with water, and "water test" should be carried out 1-2 days before fry entering the pond to observe whether the fry activity is normal.

Feeding and management: different feeding and management measures should be taken according to the feeding habits of barracuda fry in different periods. The combination of fertilization and soy milk was used in the early stage. Soybean milk is about 2025 kg per 10,000 fish fry, and according to the water quality, topdressing is 3 times, and the total amount of topdressing per mu is 100kg to 150kg. If the bait organisms in the pond are not rich enough, Artemia larvae, rotifer, egg yolk and so on can be added 10 days before breeding. When the fry grew to 1.5-2.0 cm, it was transferred to the mixed culture stage of animal and plant bait, and fed with bean cake, peanut cake paste, bean dregs, corn flour, rice bran and so on. With the gradual growth of fish fry, the amount of water in the breeding pond should be gradually increased by 15-20 cm each time, and fresh water can be gradually poured into the pond to reduce the salinity of the pond water. After 25 years and 30 days of cultivation, the fry grow into summer flowers of 2.5 centimeters and 3 centimeters, which can fully adapt to living in fresh water. Summer flower fry should be trained in time, sparsely reared in separate ponds, and can be transferred to fry cultivation ponds. Fish species can be cultured in special ponds or mixed with cyprinid fish or prawns. 7000 ~ 10000 summer flowers per mu are cultivated in a special pond, and the daily feeding amount is 3% ~ 5% of the total weight of pond fish with the combination of fertilization and commercial bait. Commercial bait can be fed with bean cake, peanut cake, corn flour, sweet potato noodle, bran Kang or artificial bait, which can be bred into fish species of 12 centimeters in that year.