At present, the eel farming species mainly come from the wild, because of the limited resources of wild seedlings. The phenomenon of falling seedlings in fry is becoming more and more frequent, which leads to the spread of disease spread. Breeders often buy seedlings carrying pathogens, which seriously damage the economic interests of farmers. The methods for artificially hatching the natural spawning of sea bream are summarized and summarized by farmers in our province, and are described as follows:
First, pre-spawning work ready spawning box and incubator and hatching sieve and sink basin. One month in advance, place the spawning box and the incubator tank into the water, and put the water peanuts and oil grass to grow. The spawning box can be replaced with aquaculture caged fish cages, and can also be made by using a piece of fire-retardant mesh fabric to meet the specifications of 3m, 4m and 1.5m. Incubation cage specifications should be small, easy to operate, available 25 mesh mesh 1.5 meters by 1 meter 1 meter specifications. Necessary strong mesh joints, double stitch sewing. The hatching screen is 20 cm wide and 2 cm thick. It is connected to a 40 cm 50 cm square wooden frame and the bottom is covered with a 25 mesh screen. Wooden frames can also be based on the size of the water in sinks and basins. One week before the release of the parents or ovaries, 10 g/m3 of bleach or 150 g/m3 of quicklime shall be used to disinfect the cages and sprinkling them. Sprinkle once again with fresh water to avoid burning grass leaves.
Second, the breeding season for the parents to release and select the squid is from April to August each year, in which the peak of spawning is from May to June. The best time to put in the parents from the end of March to the beginning of July is easily distinguishable between male and female. The selection of parents is more stringent: (1) It is preferred to have a healthy body and a smooth body surface without scars, and any anal swelling or valgus cannot be used. 2 From the locally-acquired catfish trapped, grass trapped or netted carp, try to pick the fast growing body color as dark yellow or light yellow varieties. 3 The abdomen was obviously enlarged, soft and elastic, and the anus was reddish or not red as the female parent; the abdomen was tightened, the tail was thin, and the body length was significantly greater than that of the female parent.
Third, the proportion of males and females and the density of appropriate increase in the number of male fish, can stimulate the female oviposition effect, can obtain a higher spawning rate and fertilization rate. The ratio of male to female should be 3:4. Spawning cages were placed at 1500-1750 g/m, females 9-10 tails, and males 12-13 tails. The weight of about 75 grams is the best, and the amount of eggs in each end is about 500 capsules. In practical breeding, parents are rarely allowed to enter once in a row, and they can be distributed in batches according to the acquisition situation.
IV. Collecting Oviparous Eel Before natural spawning, the foam is first spit into a nest, the eggs are produced in a foam, and the buoyancy of the foam develops on the surface of the water. Eggs are yellow, egg diameter 2.5-4 mm, eggs produced in batches, no stickiness, a significant ratio, is a sinking egg, nesting in the gap between plants. When we discovered that there was an ovary, we didn't disturb it. There was a fear that the parent had not finished yet and the egg was tender and weak. Until the next day, use scoops or small pots to gently pick up the foam and eggs, put them in the hatching cage to float on the roots of aquatic plants, or put them in hatching screens for hatching.
5. Incubation Breeding There are two methods for breeding: 1) Incubate the hatching screen with the ovaries on the surface of the water and soak it to a depth of 7 cm. Method for controlling the depth of immersion: wire ropes or ropes are attached to the four corners of the screen frame, and the outer edge of the screen frame at the bottom of the screen frame can be sandwiched with a foam plate and then pinned with a thin plate, and then a small stone is placed to regulate the depth of immersion. Advantages: The shedding of eggs will not sink to the bottom. The hatched seedlings are easy to observe in the wooden frame. When the yolk sac of the stripping seedlings absorbs the scattered groups, it can also be used as a holding box. The feeding and feeding of the yolk sac can be carried out for a few days and then transferred out, which is suitable for large-scale hatching and breeding of seedlings. The hatching screen should be placed in a sink or basin filled with running water, or it can be placed on a cement pond or pond with a slightly larger static surface. 2 Incubation of cages: The collected ovaries are placed on the cultivated overgrown aquatic plants, imitating the position of the parent in the spawning box. Hatchery emergence time, generally 7 days or so on the film emergence, this time about 1.3 cm in body length, after 4-5 days of absorption of the original yolk sac, it began to stray food, this time about 2.5 cm in length. For consistent seed size, the ovaries collected within approximately 5-6 days can be placed in a hatching screen or incubator. Sixth, feeding management When parents start to put 2-3 days, followed by a little try to invest in fresh fish, oysters, snail meat and other attracting openings, when a certain number of put, can be mixed with fresh fish slurry mix feeding materials . As the number of parents continues to increase, the amount of feeding should also be kept up, and the total amount should be controlled at about 4% of body weight. Has been stripped of juvenile fish, waiting for the yolk sac absorption will be scattered, it is necessary to take the initiative to timely feed the red worm or cooked egg yolk or fish pulp, should not avoid seedlings due to food not catch up with or lack of food, did not eat the first bait and " Drift or "old mouth." The seedlings hatched in the incubator are generally cultured in the original box when they are not moving. The seedlings emerging from the hatching screen are generally categorized and intensively cultivated. 7. When the hatchery is hatched at the end, the seedlings can grow to 6-12 centimeters in length, and can be cultivated for 20-25 centimeters in the second year and weigh 20-25 grams. In the third year, it can be used for commercial breeding. After the parents lay eggs, they are the objects of commercial breeding. If farmers can take out 2-3 product boxes to store their parents, 200-300 ovaries can be collected each year, and 10,000-1.5 million seedlings can be hatched. This basically solves the problem of seed breeding in the general family.
First, pre-spawning work ready spawning box and incubator and hatching sieve and sink basin. One month in advance, place the spawning box and the incubator tank into the water, and put the water peanuts and oil grass to grow. The spawning box can be replaced with aquaculture caged fish cages, and can also be made by using a piece of fire-retardant mesh fabric to meet the specifications of 3m, 4m and 1.5m. Incubation cage specifications should be small, easy to operate, available 25 mesh mesh 1.5 meters by 1 meter 1 meter specifications. Necessary strong mesh joints, double stitch sewing. The hatching screen is 20 cm wide and 2 cm thick. It is connected to a 40 cm 50 cm square wooden frame and the bottom is covered with a 25 mesh screen. Wooden frames can also be based on the size of the water in sinks and basins. One week before the release of the parents or ovaries, 10 g/m3 of bleach or 150 g/m3 of quicklime shall be used to disinfect the cages and sprinkling them. Sprinkle once again with fresh water to avoid burning grass leaves.
Second, the breeding season for the parents to release and select the squid is from April to August each year, in which the peak of spawning is from May to June. The best time to put in the parents from the end of March to the beginning of July is easily distinguishable between male and female. The selection of parents is more stringent: (1) It is preferred to have a healthy body and a smooth body surface without scars, and any anal swelling or valgus cannot be used. 2 From the locally-acquired catfish trapped, grass trapped or netted carp, try to pick the fast growing body color as dark yellow or light yellow varieties. 3 The abdomen was obviously enlarged, soft and elastic, and the anus was reddish or not red as the female parent; the abdomen was tightened, the tail was thin, and the body length was significantly greater than that of the female parent.
Third, the proportion of males and females and the density of appropriate increase in the number of male fish, can stimulate the female oviposition effect, can obtain a higher spawning rate and fertilization rate. The ratio of male to female should be 3:4. Spawning cages were placed at 1500-1750 g/m, females 9-10 tails, and males 12-13 tails. The weight of about 75 grams is the best, and the amount of eggs in each end is about 500 capsules. In practical breeding, parents are rarely allowed to enter once in a row, and they can be distributed in batches according to the acquisition situation.
IV. Collecting Oviparous Eel Before natural spawning, the foam is first spit into a nest, the eggs are produced in a foam, and the buoyancy of the foam develops on the surface of the water. Eggs are yellow, egg diameter 2.5-4 mm, eggs produced in batches, no stickiness, a significant ratio, is a sinking egg, nesting in the gap between plants. When we discovered that there was an ovary, we didn't disturb it. There was a fear that the parent had not finished yet and the egg was tender and weak. Until the next day, use scoops or small pots to gently pick up the foam and eggs, put them in the hatching cage to float on the roots of aquatic plants, or put them in hatching screens for hatching.
5. Incubation Breeding There are two methods for breeding: 1) Incubate the hatching screen with the ovaries on the surface of the water and soak it to a depth of 7 cm. Method for controlling the depth of immersion: wire ropes or ropes are attached to the four corners of the screen frame, and the outer edge of the screen frame at the bottom of the screen frame can be sandwiched with a foam plate and then pinned with a thin plate, and then a small stone is placed to regulate the depth of immersion. Advantages: The shedding of eggs will not sink to the bottom. The hatched seedlings are easy to observe in the wooden frame. When the yolk sac of the stripping seedlings absorbs the scattered groups, it can also be used as a holding box. The feeding and feeding of the yolk sac can be carried out for a few days and then transferred out, which is suitable for large-scale hatching and breeding of seedlings. The hatching screen should be placed in a sink or basin filled with running water, or it can be placed on a cement pond or pond with a slightly larger static surface. 2 Incubation of cages: The collected ovaries are placed on the cultivated overgrown aquatic plants, imitating the position of the parent in the spawning box. Hatchery emergence time, generally 7 days or so on the film emergence, this time about 1.3 cm in body length, after 4-5 days of absorption of the original yolk sac, it began to stray food, this time about 2.5 cm in length. For consistent seed size, the ovaries collected within approximately 5-6 days can be placed in a hatching screen or incubator. Sixth, feeding management When parents start to put 2-3 days, followed by a little try to invest in fresh fish, oysters, snail meat and other attracting openings, when a certain number of put, can be mixed with fresh fish slurry mix feeding materials . As the number of parents continues to increase, the amount of feeding should also be kept up, and the total amount should be controlled at about 4% of body weight. Has been stripped of juvenile fish, waiting for the yolk sac absorption will be scattered, it is necessary to take the initiative to timely feed the red worm or cooked egg yolk or fish pulp, should not avoid seedlings due to food not catch up with or lack of food, did not eat the first bait and " Drift or "old mouth." The seedlings hatched in the incubator are generally cultured in the original box when they are not moving. The seedlings emerging from the hatching screen are generally categorized and intensively cultivated. 7. When the hatchery is hatched at the end, the seedlings can grow to 6-12 centimeters in length, and can be cultivated for 20-25 centimeters in the second year and weigh 20-25 grams. In the third year, it can be used for commercial breeding. After the parents lay eggs, they are the objects of commercial breeding. If farmers can take out 2-3 product boxes to store their parents, 200-300 ovaries can be collected each year, and 10,000-1.5 million seedlings can be hatched. This basically solves the problem of seed breeding in the general family.