About artificial breeding technology of squid

The squid can spawn naturally in flowing or still water, but artificial breeding can achieve better spawning and hatching effects.
1, broodstock breeding
(1) Sexual maturation and sexual cycle The eel reared in lakes, wandering dams, reservoirs and ponds in the Yangtze River basin begins to mature at the second instar of females, reaches maturity above 1 year of age, and generally matures and produces gonads in May. The time of the egg. After the oviposition period, the ovaries of stage VI were absorbed and degraded to the first stage in July. Since then, they gradually developed into the fourth stage in November. During this period, they were overwintering, and during the second year of March and April, they encountered suitable environmental conditions. The ovary is rapidly maturated and quickly develops from stage W to stage V. Sexually mature males degenerate into the third stage of the testis after their breeding, enter the fourth stage from August to September, and enter the first stage of the V period in December, and overwinter period.
The spawning season varies from place to place in the north and south. The spawning period in the Pearl River basin in the southern region is 2-3 months; the period in the Yangtze River basin is 4-5 months: May-June in the Yellow River Basin; 6-7 months in the Northeast region, spawning The period is generally sustainable for about 2 months.
(2) Male and female identification of herring male and female identification.
(3) The choice of broodstock and feeding of female squid should be more than 2 years of age, weight more than 1 kilogram, male squid is slightly smaller, weighing about 0.75 kilograms, the choice of broodstock should be high, thick back, strong constitution, slightly longer body shape and activity Strong without injury. The source is lakes, net enclosures, outfielding, pond culture, and is a pollution-free quality parent.
The broodstock area is generally 3-4 mu and the water depth is 1.5-1.8 meters. It is necessary to clear the pond once a year. The stocking density of broodstock is generally 150 kg/mu, and a small amount of quail and squid can also be mixed to control the over-breeding of phytoplankton. Before and after the wintering, the male and female relatives must be kept separately to prevent the temperature from rising and the rainstorm suddenly occurs. When the squid reproduces naturally and sporadically spawns, it can usually be divided between males and females or raised in the same pond. Carp is a species of omnivorous fish that has a large amount of food. During the rearing period, sufficient food should be given. Fertilizer can also be fertilized properly to supplement the natural food and attention should be paid to intensive cultivation with high-quality feed 15-20 days before spawning. Gonadal development.
2. Natural spawning and fertilization
(1) The choice of spawning and hatching pool The spawning pool is 2 acres and the water depth is about 1.2 meters. Should choose to shelter from the wind, sunny, less silt at the bottom of the pool. It is easy to enter and drain, and it is a quiet pond. Before broodstock is released for 3-5 days, clear ponds such as quicklime are used. When the water is irrigated, the water is tightly filtered, the water is fresh, and the oxygen content is high, more than 5 milligrams per liter.
Generally, ponds reared with fry are also used as hatching ponds. The use of double ponds as hatching pools must have 3-5 rounds of pond turns. This is easy to operate when hatching. The pond area is required to be 2-3 mu and the water depth is 0.8-1.0 meters, but put Before the fish must clear the pond.
(2) Production and setup of fish nests The carp is a viscous egg that requires attachments to allow the fertilized egg to adhere to it. Artificially placed eggs are often called fish nests. The natural materials that make up the fish nests can be applied as long as the texture is soft, and the slender whiskers are more easily dispersed in the water. The root system of poplar and willow is commonly used in production. Because it grows on the riverside, the willow tree root system is the most ideal for fish nests. In recent years, fish nests made from man-made fibre 60-mesh sieves have become more durable. The fish nest material is sterilized and bundled into bundles of suitable size. Then tie it to the thin bamboo or tree line. Common settings are suspended and flat columns. Normally, the fish nests are arranged 1.2 meters away from the shore of the pond, or can be raised in the middle of a pond to hang a fish nest, so that the fish nest is submerged in water 15-20 centimeters, and the fish nest is floating. When managing, pay attention to the prompt exchange of fish nests according to the condition of the ovaries.
(3) Egg-laying squid can lay eggs naturally in rivers, lakes, wandering ponds and ponds. When spring water temperature rises above 18°C, it begins to spawn. Male and female bred broodstock need to be pooled with the group, should be sunny in the windless, or the weather after the first sunny, select mature male and female broodstock, according to a 1:1 ratio, into the spawning pool spawning. From midnight to 5:00-9:00 on the following day, the most productive spawning will be until noon.
3. Artificial insemination occurs when natural spawning occurs due to the weather. When spawning is not normal and the delay time is too long, artificial ovulation and artificial insemination can promote egg maturation, spawning, and neat emergence. The dose requirements of squids for oxytocin are not very strict, and pituitary, chorionic hormone, and the like are all effective for the production of squid. The injected dose of the female fish is 4-10 mg/kg in the pituitary gland, 1500-2 000 IU/kg in the chorionic hormone or 35-100 μg/kg in the releasing hormone analogue. The combination of the two hormones can also be used, and the effect is better. The dose of male fish is half of that of females, and one injection method is used. The injections are prepared and injected in the same way as the four homes.
Injection time: Usually in the afternoon 15:00-16:00 hours, after the injection of broodstock into the spawning pool, flushing 1-2 hours, into the brood, etc., usually the evening or the next morning can lay eggs .
After oxytocin, it is allowed to produce but can also be artificially inseminated. The quail eggs do not meet the water and are not sticky. Dry insemination is generally used. First dry the broodstock's body surface, squeeze the eggs into the box, and squeeze the spermatozoon onto the egg immediately. Mix gently with the feathers so that the sperm and eggs are in full contact. Add a trace of water to fertilize it. Spread the insemination evenly on the egg. Shallow water fish hatch on nest.
4. Hatching
(1) Incubation of ponds in fact means that after oxytocin production, they are allowed to produce in ponds. The nests of fish eggs that have been produced are then placed in the pool 10 cm below the surface of the water and are fixed. About 250,000 - 300,000 eggs are laid per acre of water. If the survival rate is 50% - 60%, the low density per acre of fry is reached. 125,000 to 150,000 tails, with a high density of 150,000 to 180,000 tails. When the fry is newly hatched, the fish nest can't be taken out immediately. At this time, the young seedlings are attached to the fish nest most of the time, and the nutrients are provided by the yolk sac until the fish can move away from the fish nest to swim and feed in the pond. Remove fish nests to prevent seedlings from decreasing.
(2) Drip incubation Incubate the fish nest on the shelf or hang it on a shelf. Keep the fish nest moist by keeping the water spray. This method is considered as a method of controlling the indoor temperature during hatching and carefully observing the development of the embryo. It has the advantages of uniform hatching speed, reduced water mold damage, and no influence of climate change due to hatching. When the embryo develops to the mating stage, the fish nest should be immediately hatched into the hatchery, but special attention should be paid that the temperature difference between the indoor and outdoor pools cannot exceed 5°C. If weather changes are abnormal, you should master the series of requirements such as time and water temperature. At present, there are very few applications in our country's production practice.
(3) De-viscosity water hatching The viscous eggs of squid are reduced after artificial insemination, and then hatching equipment of broodstock is used for water-incubation. This method can avoid the invasion of predators. In a breeding field with a superior water environment, it can be produced on a large scale without producing fish nests, saving the cost of materials and labor, thereby achieving the purpose of cost saving.
1 Slurry detackification method: The actual practice is to synthesize thin muddy water with Huangdi soil, usually adding 10-20% of yellow mud to the water. After filtering by a 40-mesh mesh cloth, the fertilized eggs are slowly poured into the mud and the slurry water is constantly turned. In 2-3 minutes, the de-adhered eggs can be moved into the cage to wash away the mud, which can then be placed in the incubator to incubate.
2 talcum powder debonding method: 100 grams of talcum powder or magnesium silicate plus 20-25 grams of salt dissolved in 10 liters of water, stirring into a mixed suspension, can be used to desensitize 1-1.5 kilograms of salmon eggs. During the operation, the egg was slowly immersed in the suspension and gently stirred with feathers. After half an hour, the fertilized eggs were dispersed particles. After rinsing, the fertilized eggs were placed in an incubator for running water.
At present, in the production field, the use of de-viscosity flowing water hatching is more scientific and reasonable, high hatching emergence rate, does not affect the genetic mutation, is a kind of cost-effective artificial hatching method. The dehydration water hatching method has been used for the aquatic product improvement field in Liyang City, Jiangsu Province for nearly 20 years.

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