Method for cultivating new germplasm of three-way hybrid grouper

Abstract

The invention relates to a three-way hybrid grouper new germplasm cultivation method, and belongs to the technical field of grouper genetic breeding. According to the method, epinephelus moara and golden tiger hybridized fries (female epinephelus fuscoguttatus * male epinephelus coioides) are used as breeding materials, three-way hybridization is carried out in a matching mode of female epinephelus moara * male epinephelus coioides, and breeding of three epinephelus genetic species and fry with excellent characteristics is achieved. The method comprises the steps of parent selection, parent fish reproduction regulation and control, parent fish spawning induction, gamete collection, artificial insemination, incubation and fry rearing. According to the method, on the basis of reproductive regulation and crossbreeding technologies, time and space reproductive isolation of the groupers is broken through, and the new grouper germplasm which is high in survival rate, low in malformation rate and high in growth speed is cultivated.

Description

Technical Field

[0001] This invention relates to the field of grouper genetic breeding technology, specifically to a method for cultivating new germplasm of three-way hybrid grouper. Background Technology

[0002] Grouper is an important marine economic fish in my country, prized for its delicious flavor and rich nutrition, making it a favorite among consumers. In recent years, marine aquaculture has developed rapidly, particularly grouper farming. With the development of the "southern fish breeding in the north, southern fish farming in the north" model, grouper farming has spread throughout the coastal areas of both northern and southern China. In 2024, grouper farming output reached 267,000 tons, ranking among the top three marine fish farms. The grouper industry holds a vital position in fisheries development. With the development of grouper farming, the demand for high-quality seedlings with fast growth and strong resistance is increasing year by year. Hybrid breeding, as an important breeding method, is widely used for the improvement of grouper germplasm. Although three new grouper varieties—Tiger Dragon Hybrid Grouper, Cloud Dragon Grouper, and Golden Tiger Hybrid Grouper—have been developed, further development of new germplasm with growth advantages and excellent resistance is still needed to meet the ever-expanding demand for high-quality seedlings.

[0003] Three-way hybridization refers to the crossbreeding of the first generation of a binary hybrid of two varieties with superior traits with another variety possessing superior traits, thus combining the superior traits of three varieties into a single hybrid and cultivating a new variety with multiple superior traits. Brown-spotted grouper, blue-bodied large-spotted grouper, and cloud-patterned grouper all belong to the grouper family. Brown-spotted grouper is characterized by its long reproductive cycle and high egg production, while blue-bodied large-spotted grouper has the advantage of rapid growth. Previously, brown-spotted grouper was used as the female parent and blue-bodied large-spotted grouper as the male parent to breed the Golden Tiger hybrid grouper, which exhibits rapid growth and strong resistance to adverse conditions. Cloud-patterned grouper has a slow growth rate but is tolerant of low temperatures and has delicious flesh. Therefore, this invention uses cloud-patterned grouper as the female parent and Golden Tiger hybrid grouper as the male parent to breed a three-way hybrid grouper. The three-way hybrid grouper integrates the genetic information of three grouper species, laying a solid foundation for the germplasm improvement of grouper and the cultivation of new three-way hybrid germplasm. There are currently no reports of three-way hybrid grouper breeding within the grouper family. Furthermore, the limited number of male blue-bodied large-spotted groupers, coupled with their low sperm count, significantly restricts the production of hybrids such as the golden tiger grouper. This patent utilizes the golden tiger grouper as the male parent for hybridization, solving the problem of insufficient sperm count in blue-bodied large-spotted groupers while simultaneously showcasing their superior characteristics, greatly promoting production and contributing to the breeding of hybrids with growth advantages and excellent resistance. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention relates to an artificial hybridization breeding method for three-way hybrid grouper, aiming to fully utilize the superior characteristics of the blue-bodied large-spotted grouper and solve the problem of low sperm volume in the blue-bodied large-spotted grouper, which limits its direct use; the purebred cloud-patterned grouper has a slow growth rate and a high deformity rate, but has the advantageous trait of low temperature resistance; through the cultivation of three-way hybrids, the superior traits of the three grouper species are combined to obtain a superior new hybrid germplasm with a low deformity rate, fast growth rate and strong stress resistance.

[0005] This invention is achieved through the following technical solution: A new germplasm breeding method for three-way hybrid grouper includes parent selection, parent fish reproductive regulation, parent fish spawning induction, gamete collection, artificial insemination, hatching, and seedling cultivation; The parent selection criteria were as follows: both the female parent fish of the cloud-patterned grouper and the male parent fish of the golden tiger hybrid grouper were over 4 years old; The aforementioned parent fish reproductive regulation: Reproductive regulation of the clouded grouper: Temperature regulation sequence is from early November of the current year to early January of the following year, with the water temperature gradually decreasing from 25~26℃ to 15~16℃ and maintained at this temperature for 1 month; from early February to early April of the following year, the water temperature gradually increases from 15~16℃ to 21~22℃; Nutrition regulation is from early November of the current year to early January of the following year, feeding with fresh iced fish; from February to April, during the early breeding period, feeding with fresh iced feed mixed with nutritional fortifiers; Reproductive regulation of Golden Tiger hybrids: Temperature regulation is carried out from early November of the current year to early January of the following year, with the water temperature gradually decreasing from 25-26℃ to 21-22℃ and maintained at this temperature for one month; from early February to early April of the following year, the water temperature is gradually increased from 21-22℃ to 25-26℃; Nutrition regulation is carried out from early November of the current year to early January of the following year, feeding with fresh iced fish; from early February to early April, during the pre-breeding period, feeding with fresh iced feed mixed with nutritional fortifiers. The broodstock spawning induction method involves selecting broodstock of marbled grouper that have reached stage IV for maturation and spawning induction. The spawning induction hormones used are human chorionic gonadotropin and luteinizing hormone-releasing hormone analogs, with doses of 350-650 IU / kg and 35-55 μg / kg, respectively. The incubation conditions are: water temperature 25~26 ℃, salinity 27~31‰, pH 7.7~8.3, dissolved oxygen greater than 6mg / L, continuous micro-aeration and micro-flow of water. When the eggs develop to the tail bud stage, collect the floating fertilized eggs and transfer them to the seedling pond for incubation. The seedling cultivation conditions are as follows: water temperature 25-26 ℃, salinity 27-31, pH 7.7-8.3, dissolved oxygen greater than 6 mg / L, and egg release density 5-7 g / m³. 3 .

[0006] Preferably, the parent fish selection is as follows: for the grouper, large individuals weighing over 5 kg are selected; for the golden tiger hybrid grouper, the parent fish population is constructed from the fastest-growing golden tiger hybrid grouper juveniles in the family established in 2019, and their weight reaches over 7 kg by the time of production. Preferably, the water temperature for raising broodstock of the cloud-patterned grouper is lowered from 25-26°C in early November at a rate of 1°C / 5-7 days to 15-16°C, and maintained for one month; then the temperature is raised at a rate of 1°C / 10 days to 21-22°C, ready for spawning. Preferably, the water temperature for culturing the golden tiger hybrid parent lines is gradually reduced from 25-26 ℃ in early November to 21-22 ℃ at a rate of 1 ℃ / 10-15 days, and maintained at this temperature for one month; from February to April of the following year, the water temperature is gradually increased from 21-22 ℃ to 25-26 ℃ at a rate of 1 ℃ / 10-15 days.

[0007] More preferably, the broodstock rearing environment should have a dissolved oxygen level greater than 6 mg / L, a salinity of 27–31, a pH of 7.7–8.3, and a water exchange rate of 3–5 m³ / L. 3 / h, breeding density is 2 fish / m 3 The male-to-female ratio is 4-6:1. Preferably, the nutritional fortifier is a mixture of vitamin C, vitamin E and cod liver oil, with contents of 4~8 g / kg, 4~8 g / kg and 1~2 g / kg, respectively; Preferably, the artificial insemination involves: sperm and eggs being inseminated at a volume ratio of 1 ml: 1~1.5 L; adding the sperm to seawater at 20% of the egg volume, stirring quickly and then quickly pouring it into the eggs, stirring thoroughly; after standing for 5~10 minutes, adding seawater at 80% of the egg volume and a salinity of 35, and collecting the floating eggs; Preferably, the incubation process involves rinsing the floating eggs with seawater of salinity 30, then placing the fertilized eggs in an incubation tank with salinity 30 for incubation. The water temperature is 25-26°C, pH 7.7-8.3, dissolved oxygen is greater than 6 mg / L, and the egg release rate is no more than 4 kg / m³. 3 Dead eggs are released every 2 hours; incubation is carried out using circulating water with a water exchange rate of 1 m³. 3 / h; Preferably, the seedling cultivation involves feeding the ternary hybrid spotted bait series with SS rotifers (3-7 rotifers / ml) from 2 to 8 days old, L rotifers (2-5 rotifers / ml) from 6 to 22 days old, Artemia larvae (1-3 rotifers / ml) from 18 to 40 days old, and starting to feed pelleted feed after 35 days old; this ensures rapid and healthy growth of the seedlings; during the rotifer feeding period, Chlorella is supplemented daily, and the seedlings are cultivated in a slightly flowing or still water environment; Seedling Management: For the first 20 days, provide 24 hours of light at an intensity of 700-1300 lx; ​​from 20-30 days old, provide 12 hours of light at an intensity of 750-1300 lx; ​​after 30 days, turn on the lights during feeding and production operations, and keep them in darkness at other times to prevent cannibalism; for the first 30 days, do not change the water and cultivate them in still water. Add beneficial bacteria to the water every 2-3 days to maintain water quality; after 30 days, begin small-scale water changes, with an inlet flow rate of 0.4-0.6 m³ / h. 3 / h, as the fish fry grow, the water exchange rate gradually increases to 2.0~2.5m. 3 / h, based on the differences in the size of the fry, the fry are screened and graded for further cultivation.

[0008] More preferably, SS rotifers, L rotifers, and Artemia larvae are thoroughly rinsed to ensure they are free of pathogens and are nutritionally fortified with fortifiers rich in DHA and EPA. Microalgae are used to fortify the rotifers, and fish oil is used to fortify the Artemia larvae.

[0009] The principle of this invention is: for the first time, by using reproductive regulation and distant hybridization breeding technology, a binary hybrid is crossed with a third type of grouper to cultivate a ternary hybrid, namely, a cloud-patterned grouper♀ × (brown-spotted grouper♀ × blue-bodied large-spotted grouper♂)♂, which combines the genetic material of the three types of grouper, breaks through reproductive isolation, and cultivates a new hybrid grouper germplasm with a fast growth rate.

[0010] The differences and beneficial effects of this invention compared to other marine fish breeding methods are as follows: 1. The method of this invention cultivates sexually mature male golden tiger hybrids, which is an important step in carrying out three-way hybridization. The high-vitality golden tiger hybrid semen obtained provides a material guarantee for carrying out three-way hybridization. 2. The method of the present invention regulates the reproduction of the cloud-patterned grouper and the golden tiger hybrid grouper, so that the sexual maturity time of the two fish is synchronized, and the eggs and sperm can be collected at the same time, ensuring the quality of gametes and creating excellent conditions for obtaining high-quality fertilized eggs. 3. The sperm of the Golden Tiger Hybrid Grouper not only makes up for the lack of sperm in the Blue-bodied Large Spotted Grouper, but also combines the superior traits of both the Brown Spotted Grouper and the Blue-bodied Large Spotted Grouper parents, exhibiting excellent characteristics such as fast growth rate and strong resistance. 4. The three-way hybrid grouper combines the genetic information of three grouper species: the cloud-patterned grouper, the brown-spotted grouper, and the blue-bodied large-spotted grouper. It breaks through the reproductive isolation between the three species and combines their advantageous characteristics, greatly promoting the cultivation of new hybrid germplasm. Attached Figure Description

[0011] Figure 1 This invention refers to the hybrid offspring of a female cloud-patterned grouper and a male golden tiger grouper. Figure 2This invention relates to the parent fish of the cloud-patterned grouper; Figure 3 This invention relates to hybrid spotted broodstock of the Golden Tiger species. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention.

[0013] Example 1: A method for raising fry of three-way hybrid grouper, comprising the following steps: Selection of parent fish for hybrid grouper and golden tiger grouper a. Female parent fish of the cloud-patterned grouper: Select female cloud-patterned groupers that are 4 years or older, of normal body size, free from disease, and in good health, weighing over 5 kg; b. Male parent fish of Golden Tiger hybrid spotted fish: In 2019, multiple Golden Tiger hybrid spotted fish families were established. They were screened at 6 months and 12 months of age, and the fast-growing, normal-sized, healthy and active fry were selected as reserve parent fish for breeding. The selection pressure was 5%, and a breeding population was constructed. The water temperature was maintained at 24~26 ℃ all year round, and they reached sexual maturity after 5 years of breeding.

[0014] (2) Reproductive regulation of parent fish Reproductive regulation of broodstock of the grouper: The culture environment is a factory-style recirculating water system. The water temperature is lowered from 25-26℃ in early November at a rate of 1℃ / 5-7 days to 15-16℃, which coincides with the beginning of January of the following year, and maintained for one month. In early February of the following year, the temperature is raised at a rate of 1℃ / 10 days to 21-22℃, which coincides with the beginning of April, ready for spawning. Nutritional regulation is as follows: from early November to early January of the following year, fresh fish such as mackerel are fed, with a feeding amount of 1-2.5% of body weight. From early February to the pre-breeding period in April, fresh feed such as mackerel, squid, scallops, and oysters mixed with a nutritional fortifier is fed. The nutritional fortifier is a mixture of vitamin C (4-8 g / kg), vitamin E (4-8 g / kg), and cod liver oil (1-2 g / kg), with a feeding amount of 2-3.5% of body weight. Reproductive regulation of golden tiger hybrid parent stock: The culture environment is a factory-style circulating water system. The water temperature is gradually reduced from 25-26℃ in early November to 21-22℃ at a rate of 1℃ / 10-15 days, just in time for early January of the following year, and maintained at this temperature for one month. From early February to early April of the following year, the water temperature is gradually increased from 21-22℃ to 25-26℃ at a rate of 1℃ / 10-15 days. Nutritional regulation is as follows: From early November to early January of the following year, mackerel and other chilled fish are fed at a rate of 1-2.5% of body weight. From early February to the pre-breeding period in April, chilled feed such as mackerel, squid, scallops, and oysters are fed with a nutritional fortifier, which is a mixture of vitamin C (4-8 g / kg), vitamin E (4-8 g / kg), and cod liver oil (1-2 g / kg), at a rate of 2-3.5% of body weight. The parent stock culture environment should have a dissolved oxygen level greater than 6 mg / L, a salinity of 27–31, a pH of 7.7–8.3, and a water exchange rate of 3–5 m³ / L. 3 / h, breeding density is 2 fish / m 3 The male-to-female ratio is 4-6:1.

[0015] (3) Inducing spawning in parent fish Starting in April, broodstock of the spotted grouper, developed to stage IV, were selected for maturation and spawning induction. The water temperature was maintained at 21-22℃. The spawning-inducing hormones used were human chorionic gonadotropin (hCG) and luteinizing hormone-releasing hormone (LH) analogs, at doses of 550 IU / kg and 45 μg / kg, respectively, using 0.9% physiological saline as a solvent. The injection was administered in a single dose at the base of the pectoral fins. After this initial reproductive regulation, semen could be directly collected from the golden tiger hybrid grouper broodstock.

[0016] (4) Gamete collection Sperm collection of hybrid golden tiger fish: First, wipe the area around the genital opening clean with a towel to avoid seawater pollution. Gently press the abdomen of the male hybrid golden tiger fish to collect the semen into a plastic tube and temporarily store it in a foam box at 4 ℃. Examine its motility under a microscope. When the motility is greater than 80%, it can be used for artificial insemination. Egg collection of the clouded grouper: Select clouded groupers with swollen abdomen and slightly red genital opening after induced spawning for egg extraction. First, wipe the area around the genital opening clean with a towel, then squeeze the abdomen from front to back and place the extracted mature eggs into a basin for fertilization. (5) Artificial insemination Fertilization was performed using a sperm-to-egg volume ratio of 1 mL: 1-1.5 L. The sperm was divided into two portions. One portion was added directly to the eggs and stirred thoroughly. After 1 minute, the other portion of sperm was added to 20% of the egg volume of fresh, filtered seawater and stirred thoroughly. This mixture was then poured into the eggs and stirred again. After standing for 8 minutes, seawater with a salinity of 35 (80% of the egg volume) was added, mixed well, and allowed to stand for 10 minutes. The floating eggs were then collected and placed in an incubation tank for hatching.

[0017] (6) Hatching Rinse the floating eggs with seawater with a salinity of 30‰, then place the fertilized eggs in an incubation tank with a salinity of 30‰ for incubation. The water temperature should be 25-26℃, pH 7.7-8.3, dissolved oxygen greater than 6 mg / L, and the egg release rate should be 2 kg / m³. 3 Dead eggs are released every 2 hours; incubation is carried out using circulating water with a water exchange rate of 1 m³. 3 / h; When the fertilized eggs develop to the tail bud stage, collect the floating fertilized eggs and transfer them to the nursery pond for further incubation. The nursery pond is an indoor constant-temperature cement pond with a length of 5 m, a width of 5 m, and a depth of 1.5 m, and the egg stocking density is 4 g / m³. 3 The cultivation conditions were 27–28 °C, pH 8.0, dissolved oxygen 6 mg / L, and salinity 30‰. In this example, the hybrid fertilized eggs hatched in 27 h 25 min, while the purebred marbled grouper fertilized eggs hatched in 27 h 48 min. The fertilization rate of the three-way hybrid was as high as 90.5%, and the hatching rate was 81.2%; the fertilization rate of the marbled grouper was 93.6%, and the hatching rate was 86.5%.

[0018] Example 2: A method for raising fry of three-way hybrid grouper, including the following steps: (1) Cultivation environment: Grouper ternary hybrid embryos that have developed to the tail bud stage were placed in a cement pool 5 m long, 5 m wide, and 1.5 m deep. The water temperature was 25-26℃, dissolved oxygen was ≥6 mg / L, pH was 7.8-8.0, and salinity was 30‰.

[0019] (2) Feeding seedlings: When the rotifers reach 2 days old, they are fed SS rotifers as their first food at a density of 4-6 rotifers / mL for 2-8 days. From 6-22 days old, they are fed L rotifers at a density of 3-5 rotifers / mL. From 18-40 days old, they are fed Artemia larvae at a density of 2-3 larvae / mL. After 35 days old, acclimatization to pelleted feed begins. During the rotifer feeding period, Chlorella is added to the water daily. In the early acclimatization stage, pelleted feed is given in small amounts frequently, and Artemia larvae are fed once a day. In the later acclimatization stage, the amount of Artemia larvae is gradually reduced. SS rotifers, L rotifers, and Artemia larvae are thoroughly rinsed to ensure they are free of pathogens and are nutritionally fortified with a fortifier rich in DHA and EPA. Microalgae are used to fortify the rotifers, and fish oil is used to fortify the Artemia larvae.

[0020] (3) Seedling management: For the first 20 days of seedling cultivation, the light duration is 24 hours and the light intensity is 750-1300 lx; ​​after 20 days, the light duration is 12 hours and the light intensity is 750-1300 lx; ​​after 30 days, the light duration is 0 hours. For the first 30 days, no water changes are performed, and the seedlings are cultivated in still water. Beneficial bacteria such as photosynthetic bacteria and Bacillus subtilis are added to the water every 2-3 days to maintain water quality. After 30 days, small-scale water changes begin, with an inlet flow rate of 0.4-0.6 m³. 3 As the fry grow, the water exchange rate gradually increases. After 40 days, based on the fry's growth, fry screening is conducted every 5-7 days. Two days before and after screening, electrolyte multivitamins and stress relievers are added to the rearing water to reduce fry stress. The fry' feeding and activity levels are observed daily.

[0021] In this embodiment, a total of 0.6 kg of three-way hybrid spotted fertilized eggs were hatched and cultivated. At 45 days of age, approximately 42,000 seedlings were cultivated. The seedlings were of normal size, healthy and vigorous.

[0022] Example 3: Comparative culture of three-way hybrid grouper and cloud-patterned grouper fry While conducting a three-way hybridization of grouper (using the spotted grouper as the female parent and the golden tiger hybrid as the male parent), a control grouper (spotted grouper) was also bred for comparative culture. The specific procedures for obtaining, hatching, and raising fry of the hybrid and purebred were the same as in Examples 1 and 2. 0.5 kg of fertilized eggs from both the three-way hybrid and spotted grouper were obtained, with no significant difference in fertilization and hatching rates between the hybrid and purebred. Fry were raised in a factory-scale recirculating aquaculture system under conditions of 25-26 ℃, dissolved oxygen above 6 mg / L, pH 8.0, and salinity 30‰. At the initial fry screening, three-way hybrids and purebred spotted grouper of the same size and quantity were selected for comparative culture. By 3 months of age, the average weight of the three-way crossbred was (30.6±9.0) g, and the average total length was (13.1±1.5) cm, while the average weight of the striped grouper was (22.7±6.8) g, and the average total length was (11.7±1.0) cm. The weight and total length of the three-way crossbred were 1.35 and 1.12 times that of the striped grouper, respectively. At 3 months of age, a total of 51,000 three-way crossbred individuals and 46,000 striped grouper individuals were bred. The survival rate of the three-way crossbred grouper was 19.6%, which was 10.1% higher than that of the purebred striped grouper. The deformity rate of the three-way crossbred grouper was 8.5%, which was 37.8% lower than that of the purebred striped grouper. The three-way crossbred exhibited excellent characteristics of rapid growth, high survival rate, and low deformity rate.

[0023] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for breeding a new germplasm of Epinephelus tricuspis, characterized in that, The method comprises parent selection, parent fish reproductive regulation, parent fish labor induction, gamete collection, artificial insemination, hatching and seedling cultivation; The parent selection: the female parent of Epinephelus merra and the male parent of the hybrid grouper are both over 4 years old; The parent fish reproductive regulation: the reproductive regulation of Epinephelus merra: the temperature regulation time sequence is from early November of the current year to early January of the next year, the water temperature is gradually reduced from 25-26 DEG C to 15-16 DEG C, and is maintained at this temperature for one month; from early February to early April of the next year, the water temperature is gradually increased from 15-16 DEG C to 21-22 DEG C; the nutrition regulation is that fresh ice fish is fed from early November of the current year to early January of the next year; from February to the early stage of reproduction in April, fresh ice bait mixed with a nutrition enhancer is fed; The reproductive regulation of the hybrid grouper: the temperature regulation time sequence is from early November of the current year to early January of the next year, the water temperature is gradually reduced from 25-26 DEG C to 21-22 DEG C, and is maintained at this temperature for one month; from early February to early April of the next year, the water temperature is gradually increased from 21-22 DEG C to 25-26 DEG C; the nutrition regulation is that fresh ice fish is fed from early November of the current year to early January of the next year; from early February to early April of the next year, fresh ice bait mixed with a nutrition enhancer is fed; The parent fish labor induction: the parent fish of Epinephelus merra developed to stage IV is selected for maturation and labor induction, and the labor induction hormone used is chorionic gonadotropin and luteinizing hormone-releasing hormone analog, and the dosages are 350-650 IU / kg and 35-55 mu g / kg, respectively; The hatching: the hatching conditions are water temperature 25-26 DEG C, salinity 27-31 ‰, pH 7.7-8.3, dissolved oxygen content greater than 6 mg / L, continuous micro-aeration and micro-flow water, and when developed to the tail bud stage, the floating fertilized eggs are collected to a seedling rearing pond for hatching; The seedling cultivation: water temperature 25~26 ℃, salinity 27~31, pH 7.7~8.3, dissolved oxygen content greater than 6 mg / L, and egg laying density 5~7 g / m 3 .

2. The method of claim 1, wherein, The water temperature for the parent fish cultivation of Epinephelus merra is 25-26 DEG C from early November, the temperature is reduced at a rate of 1 DEG C / 5-7 days, when the temperature is 15-16 DEG C, the temperature is maintained for one month, then the temperature is increased at a rate of 1 DEG C / 10 days, and the temperature is increased to 21-22 DEG C, and the parent fish is ready for spawning.

3. The method of claim 1, wherein, The water temperature for the parent fish cultivation of the hybrid grouper is 25-26 DEG C from early November, the temperature is gradually reduced to 21-22 DEG C at a rate of 1 DEG C / 10-15 days, and the temperature is maintained at this temperature for one month; from February to April of the next year, the water temperature is gradually increased to 25-26 DEG C at a rate of 1 DEG C / 10-15 days.

4. The method of claim 1, wherein, The broodstock breeding environment has a dissolved oxygen content of greater than 6 mg / L, a salinity of 27-31, a pH of 7.7-8.3, a water exchange of 3-5 m 3 / h, a breeding density of 2 tails / m 3 , and a male-to-female ratio of 4-6:

1.

5. The method of claim 1, wherein, The artificial insemination: the sperm and the eggs are inseminated at a volume ratio of 1 ml:1-1.5 L, the sperm is added to seawater with an egg volume of 20%, and is quickly stirred and poured into the eggs, and is fully stirred and mixed; after standing for 5-10 minutes, seawater with an egg volume of 80% and a salinity of 35 is added, and the floating eggs are collected.

6. The method of claim 1, wherein, The said hatching: the floated eggs are washed with seawater with salinity of 30‰, then the fertilized eggs are placed in a hatching tank with salinity of 30‰, water temperature of 25-26 ℃, pH of 7.7-8.3, dissolved oxygen of more than 6 mg / L, and the amount of eggs is not more than 4 kg / m 3 ; the dead eggs are removed every 2 hours; the water is circulated and the water replacement amount is 1 m 3 / h.

7. The method of claim 1, wherein, The seedling cultivation: the bait series for the three-way hybrid grouper is 2-8 day-old SS rotifer, 3-7 pieces / ml, 6-22 day-old L rotifer, 2-5 pieces / ml, 18-40 day-old artemia nauplii, 1-3 pieces / ml, and granular feed is started to be fed after 35 days old; the seedlings grow rapidly and healthily; during the feeding of rotifer, chlorella is supplemented every day, and the seedlings are cultivated in micro-flow water or static water; Seed management: 20 days before the fry, the light time is 24 h, the light intensity is 700-1300 lx; 20-30 days old, the light time is 12 h, the light intensity is 750-1300 lx; After 30 days, feed and production operation when the light, the rest of the time is dark, to avoid mutual injury; 30 days before the fry, no water change, static water culture, interval 2-3 days, water body is added with beneficial bacteria to maintain water quality, 30 days later, start small water change, the water inlet flow is 0.4-0.6 m 3 / h, with the growth of fry, the water change gradually increases to 2.0-2.5 m 3 / h, according to the size difference of fry, start fry screening, grading culture.

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