First, the choice of broodstock and cultivation In the fall or early winter from the sea area to catch or from the sea, brackish freshwater cultured adult fish, select the intact intact as a broodstock. Females require 3 instars and more than 1.5 kg in weight; males have 2 instars and more than 1 kg in weight. The area of ​​the broodstock pool should not be too large, suitable for 1500 square meters to 2,000 square meters, water depth of 1.5 meters to 2 meters, there is a sea, fresh water, irrigation and drainage convenience. The stocking rate per mu of broodstock should not exceed 100 kg. Pay attention to spring prenatal intensive cultivation, but also do a good job of cultivation and management throughout the year. Barracuda starts a small amount of cable feeding at a water temperature of 4°C and feeds normally above 10°C. In broodstock breeding, artificial feeding of food bait can be completely adopted, and feeding and fertilizer can also be used. The types of commodity foods are peanut cakes, bean cakes, wheat buds, and shrimps. Fertilizer should be organic fertilizer, fertilizer should not be used. The transparency of the pro-fish pond is controlled at about 30 cm.
Prenatally, "excessive salt water" and water stimulation are required. “Brine excess†refers to broodstock that is cultivated at a salinity of 5 , or less. It is introduced into the broodstock cultivation pool in the autumn and in the spring to gradually increase the salinity of the pool water to more than 15 ,, which is very effective in increasing the gonad development and maturation rate of the broodstock. . In addition, fresh water is injected into the broodstock every half to 20 days in the fall, every week to 10 days in the spring, and the side row of old water is added to promote appetite, reduce disease, and stimulate gonad development.
Second, spawning barracuda optimum production water temperature is 16 °C ~ 20 °C, the production season from the end of April to mid-June, generally concentrated in late April to mid-May. The culling season is related to the cultivation of broodstock sooner or later. The identification of broodstock maturity: Male fish, hand squeeze the upper part of the vent hole, milk white semen out, scattered in the water, this type of male fish do not need to be injected with hormones, such as the extrusion of semen like a toothpaste, water is not scattered, then need injection Oxygen production drugs; females, abdomen full of elasticity, red vents rotaculum evacuation, with the oviduct from the dive hole to take eggs observed, microscopic examination, egg diameter above 700 microns, full and elastic egg, egg translucent Apricot yellow, fatty oil droplets evenly dispersed, clearly visible. The oxytocic drugs and dose combination can be referred to as follows (weight per kilogram of fish): 15 mg to 20 mg pituitary and carp pituitary alone, HCG 2000 IU to 4000 IU alone, LRH-A 150 micrograms to 300 micrograms alone, or pituitary and carp pituitary 5 Mg ~ 10 mg + HCG1000IU ~ 2500IU + LRH-A 100 micrograms ~ 150 micrograms, carp, carp pituitary 10 mg + HCG1500IU ~ 2500IU, carp, carp pituitary 100 mg + LRH-A100 micrograms ~ 300 micrograms. Normal females are divided into 2 injections at intervals of 24 hours. The first dose is 1/3, and the second dose is 2/3. When it is not produced, 1/2 to 2/3 of the total dose can be added. The irritation of fresh water during the oxytocin has a great influence on the increase of the productivity.
Artificial insemination is by far the only method of barracuda reproduction. How to master the main key technologies of artificial insemination has the following points: The best time for mature eggs to maintain fertilization is at water temperature of 16°C～20°C; mature eggs are characterized by full and transparent oocyte, about 1mm egg diameter, and a large central Oil ball, diameter 0.45 mm ~ 0.5 mm, egg size uniform, shiny round, full of elasticity, showing a bright orange; egg flow is characterized by hand-squeeze abdomen, smooth egg discharge, no blood clots, egg blocks. Insemination can be dry or semi-wet.
Third, the fertilized eggs hatch at salinity below 13 时 when the egg was sinking, 15 ‰ above floating. Incubation water temperature 16 °C ~ 20 °C, running water, static water can be, but the higher the hatching rate of running water. The speed of embryonic development depends on the temperature of the water. When the water temperature is between 16°C and 20°C, embryo development can be completed in 46 hours to 52 hours.
Fourth, the cultivation of barracuda seedlings is currently mostly based on carp breeding techniques, that is, in ponds, breeding natural food by fertilization, while feeding food bait for cultivation.
Fifth, the preparation of fry pool In the fish before the pond, fry pool must clear the pond with clear drugs. After the clear pond, the water is injected from 50 cm to 60 cm in the 7 days to 10 days before the fish seedlings, and the basic fertilizer is used to cultivate natural food. Application of livestock manure from 3,750 to 6,000 kilograms per acre of water, less use of Laotang, Xintang Shishi. After 10 days of basal fertilization, zooplankton in the pond began to multiply and peaked in about two weeks.
Sixth, the fry fish barramundi seedlings began to swim 4 days to 5 days after filming, can take the initiative to eat, it is necessary to timely fry stocking in the nursery pond, stocking 80,000 to 120,000 per mu. The following points should be noted when fish fry the pond: The water temperature difference between the hatching pond and the fry pool should not exceed 3°C; when the fry are stocked, the salinity of the pool water can not be less than 7 ‰; the time of the lower pond should be sunny and non-windy day, with 3 pm ~ 4 o'clock is appropriate; fry under the pond to bring water, and should be in the fish before the pond 1 day ~ 2 days to "test water" to observe whether the fish fry activities are normal.
VII. Feeding and management should adopt different feeding and management measures according to the food habits of barracuda at different periods. Early use of a combination of fertilization and splashing soy milk. Every 10,000 fish fry use about 20 kilograms to 25 kilograms of soybean milk, and according to the water quality, dressing 3 times to 4 times, the total amount of top dressing is 100 kg to 150 kilograms per acre. If the food organisms in the pool are not rich enough, Artemia larvae, rotifers, and egg yolks may be added 10 days before the nursery. When the fry grows to 1.5 cm to 2.0 cm, it is transferred to the mixed culture stage of animal and vegetable diets and fed with bean cake, peanut cake paste, bean dregs, cornmeal and rice bran. As the fry gradually grows, the nursery pond should gradually increase the amount of water, each time water injection 15 cm to 20 cm, and can gradually inject fresh fresh water into the pool, reducing the pool water salinity. After 25 days to 30 days of cultivation, the fry grow into 2.5 cm to 3 cm of summer flowers, and they can fully adapt to live in fresh water. Summer fish species should be pulled in time for exercise, dilute the pond and raise it, and it can be transferred to the fry cultivation pool. The species can be cultured in a special pool, and it can also be polycultured with carps or shrimp. The cultivation of special pools has 7000 to 10,000 tails per acre of summer stock, combined with fertilization and investment of food bait, and the daily feeding amount is 3% to 5% of the total fish weight. Commercial food can be used as bean cakes, peanut cakes, cornmeal, sweet potato noodles, gluten, or artificial diets.
Prenatally, "excessive salt water" and water stimulation are required. “Brine excess†refers to broodstock that is cultivated at a salinity of 5 , or less. It is introduced into the broodstock cultivation pool in the autumn and in the spring to gradually increase the salinity of the pool water to more than 15 ,, which is very effective in increasing the gonad development and maturation rate of the broodstock. . In addition, fresh water is injected into the broodstock every half to 20 days in the fall, every week to 10 days in the spring, and the side row of old water is added to promote appetite, reduce disease, and stimulate gonad development.
Second, spawning barracuda optimum production water temperature is 16 °C ~ 20 °C, the production season from the end of April to mid-June, generally concentrated in late April to mid-May. The culling season is related to the cultivation of broodstock sooner or later. The identification of broodstock maturity: Male fish, hand squeeze the upper part of the vent hole, milk white semen out, scattered in the water, this type of male fish do not need to be injected with hormones, such as the extrusion of semen like a toothpaste, water is not scattered, then need injection Oxygen production drugs; females, abdomen full of elasticity, red vents rotaculum evacuation, with the oviduct from the dive hole to take eggs observed, microscopic examination, egg diameter above 700 microns, full and elastic egg, egg translucent Apricot yellow, fatty oil droplets evenly dispersed, clearly visible. The oxytocic drugs and dose combination can be referred to as follows (weight per kilogram of fish): 15 mg to 20 mg pituitary and carp pituitary alone, HCG 2000 IU to 4000 IU alone, LRH-A 150 micrograms to 300 micrograms alone, or pituitary and carp pituitary 5 Mg ~ 10 mg + HCG1000IU ~ 2500IU + LRH-A 100 micrograms ~ 150 micrograms, carp, carp pituitary 10 mg + HCG1500IU ~ 2500IU, carp, carp pituitary 100 mg + LRH-A100 micrograms ~ 300 micrograms. Normal females are divided into 2 injections at intervals of 24 hours. The first dose is 1/3, and the second dose is 2/3. When it is not produced, 1/2 to 2/3 of the total dose can be added. The irritation of fresh water during the oxytocin has a great influence on the increase of the productivity.
Artificial insemination is by far the only method of barracuda reproduction. How to master the main key technologies of artificial insemination has the following points: The best time for mature eggs to maintain fertilization is at water temperature of 16°C～20°C; mature eggs are characterized by full and transparent oocyte, about 1mm egg diameter, and a large central Oil ball, diameter 0.45 mm ~ 0.5 mm, egg size uniform, shiny round, full of elasticity, showing a bright orange; egg flow is characterized by hand-squeeze abdomen, smooth egg discharge, no blood clots, egg blocks. Insemination can be dry or semi-wet.
Third, the fertilized eggs hatch at salinity below 13 时 when the egg was sinking, 15 ‰ above floating. Incubation water temperature 16 °C ~ 20 °C, running water, static water can be, but the higher the hatching rate of running water. The speed of embryonic development depends on the temperature of the water. When the water temperature is between 16°C and 20°C, embryo development can be completed in 46 hours to 52 hours.
Fourth, the cultivation of barracuda seedlings is currently mostly based on carp breeding techniques, that is, in ponds, breeding natural food by fertilization, while feeding food bait for cultivation.
Fifth, the preparation of fry pool In the fish before the pond, fry pool must clear the pond with clear drugs. After the clear pond, the water is injected from 50 cm to 60 cm in the 7 days to 10 days before the fish seedlings, and the basic fertilizer is used to cultivate natural food. Application of livestock manure from 3,750 to 6,000 kilograms per acre of water, less use of Laotang, Xintang Shishi. After 10 days of basal fertilization, zooplankton in the pond began to multiply and peaked in about two weeks.
Sixth, the fry fish barramundi seedlings began to swim 4 days to 5 days after filming, can take the initiative to eat, it is necessary to timely fry stocking in the nursery pond, stocking 80,000 to 120,000 per mu. The following points should be noted when fish fry the pond: The water temperature difference between the hatching pond and the fry pool should not exceed 3°C; when the fry are stocked, the salinity of the pool water can not be less than 7 ‰; the time of the lower pond should be sunny and non-windy day, with 3 pm ~ 4 o'clock is appropriate; fry under the pond to bring water, and should be in the fish before the pond 1 day ~ 2 days to "test water" to observe whether the fish fry activities are normal.
VII. Feeding and management should adopt different feeding and management measures according to the food habits of barracuda at different periods. Early use of a combination of fertilization and splashing soy milk. Every 10,000 fish fry use about 20 kilograms to 25 kilograms of soybean milk, and according to the water quality, dressing 3 times to 4 times, the total amount of top dressing is 100 kg to 150 kilograms per acre. If the food organisms in the pool are not rich enough, Artemia larvae, rotifers, and egg yolks may be added 10 days before the nursery. When the fry grows to 1.5 cm to 2.0 cm, it is transferred to the mixed culture stage of animal and vegetable diets and fed with bean cake, peanut cake paste, bean dregs, cornmeal and rice bran. As the fry gradually grows, the nursery pond should gradually increase the amount of water, each time water injection 15 cm to 20 cm, and can gradually inject fresh fresh water into the pool, reducing the pool water salinity. After 25 days to 30 days of cultivation, the fry grow into 2.5 cm to 3 cm of summer flowers, and they can fully adapt to live in fresh water. Summer fish species should be pulled in time for exercise, dilute the pond and raise it, and it can be transferred to the fry cultivation pool. The species can be cultured in a special pool, and it can also be polycultured with carps or shrimp. The cultivation of special pools has 7000 to 10,000 tails per acre of summer stock, combined with fertilization and investment of food bait, and the daily feeding amount is 3% to 5% of the total fish weight. Commercial food can be used as bean cakes, peanut cakes, cornmeal, sweet potato noodles, gluten, or artificial diets.
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