Method for obtaining high-quality fertilized eggs of wild pseudosciaena crocea

Abstract

The application discloses a method for obtaining high-quality fertilized eggs of wild Pseudosciaena crocea of Lutjanus, and belongs to the technical field of aquatic animal breeding. Wild parent fishes are captured in the breeding season of Pseudosciaena crocea of Lutjanus and are transported to a breeding farm; the wild parent fishes are temporarily raised and intensively cultured, and male and female wild parent fishes with mature gonads are selected, and artificial parturition mixed hormones are injected after anesthesia; after the injection of the artificial parturition mixed hormones, ova and sperm are collected, artificial insemination is performed, and high-quality fertilized eggs are obtained. The technical steps in the application are correlated with each other to form a whole, high-quality fertilized eggs of wild Pseudosciaena crocea of Lutjanus can be successfully obtained, and the proportion of the high-quality fertilized eggs is more than 45%. The high-quality fertilized eggs obtained by the application are used for fry hatching, the hatching rate of the fertilized eggs is more than 62%, and the high-quality fertilized eggs can be used for constructing a basic population of wild Pseudosciaena crocea of Lutjanus, so that artificial breeding of the wild Pseudosciaena crocea of Lutjanus is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aquaculture and breeding of aquatic animals, and particularly relates to a method for obtaining high-quality fertilized eggs of wild Xizhou group of large yellow croaker. BACKGROUND

[0002] In China, large yellow croaker is generally divided into three groups according to population ecology, namely, Min-Yue East group of large yellow croaker represented by Ningde in Fujian, Daiqu group of large yellow croaker represented by Zhoushan in Zhejiang, and Xizhou group of large yellow croaker mainly in the nearshore of Xizhou in Guangdong. There are differences in sexual maturity age, population age composition, and stress resistance of large yellow croaker in the three groups. Due to the differences in biological characteristics and biological learning of each variety, different methods should be used in the field of artificial breeding and propagation technology. At present, the Min-Yue East group and the Daiqu group have broken through the artificial breeding technology and achieved large-scale breeding, while the artificial breeding of the Xizhou group of large yellow croaker has not been perfectly developed.

[0003] The Xizhou group of large yellow croaker has a unique advantage in adapting to high sea conditions of deep-sea farming, which makes it a more advantageous variety in the development of deep-sea farming in Guangdong. Large-scale breeding will effectively solve the bottleneck of industrial development due to the poor high-temperature tolerance of the Min-Yue East group of large yellow croaker in Fujian and the Daiqu group of large yellow croaker in Zhejiang, and is expected to become an important development variety in future deep-sea farming. Breaking through the artificial breeding technology of the Xizhou group of large yellow croaker and obtaining high-quality fertilized eggs are one of the key problems to be solved. Since the wild Xizhou group of large yellow croaker inhabits the middle and lower layers of the nearshore, the stress during the catching process is large, and the survival time under artificial breeding conditions is short, making it difficult to build a basic parent fish population for artificial breeding. Therefore, in the existing artificial breeding method of the Xizhou group of large yellow croaker, the parents with good gonadal maturity are usually caught during the breeding season for artificial spawning and artificial insemination. However, in this method, the spawning process of the parent fish can only be maintained for a short time, the development of the testis and ovary is not synchronized, the ovum is not mature enough when it is squeezed out too early, and the ovum is too mature when it is squeezed out too late, which often results in a low success rate of fertilization. Therefore, the obtaining of high-quality fertilized eggs of the wild Xizhou group of large yellow croaker has become a problem to be solved first in the artificial breeding technology. SUMMARY

[0004] In order to solve the problems in the prior art, the purpose of the present application is to provide a method for obtaining high-quality fertilized eggs of wild Xizhou group of large yellow croaker, and the proportion of the obtained high-quality fertilized eggs is more than 45%.

[0005] The purpose of the present application is also to provide a method for obtaining wild Xizhou group of large yellow croaker fry, which uses the high-quality fertilized eggs according to the present application for hatching, and the obtained hatching rate is more than 62%.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0007] The application provides a method for obtaining high-quality fertilized eggs of wild Pseudosciaena kowarum, comprising the following steps:

[0008] Wild parent fish are captured in the breeding season of Pseudosciaena kowarum, and then are transported to a harbor and then to a breeding farm; the wild parent fish are temporarily cultured for 3-5 days and then are intensively cultured for 8-10 days, and then mature male and female wild parent fish are selected, and the selected wild parent fish are injected with artificial hormone for inducing ovulation after being anesthetized by eugenol; 22-26 hours after the injection, eggs and sperm are collected, and high-quality fertilized eggs are obtained through artificial insemination.

[0009] Preferably, the wild parent fish are captured by setting a trap net in the spawning ground of Pseudosciaena kowarum.

[0010] Preferably, the dissolved oxygen in the live water tank is 5-5.5 mg / L.

[0011] Preferably, during the transportation to the breeding farm, the water temperature is 22-24 DEG C, and the dissolved oxygen is 6-6.5 mg / L.

[0012] Preferably, the conditions for the temporary culture and the intensive culture of the wild parent fish are as follows: the water temperature is 22-24 DEG C, the salinity is 28-30, the pH value is 8.0-8.5, the light intensity is 500-800 lux, the dissolved oxygen is 5-6 mg / L, the ammonia nitrogen is less than or equal to 0.1 mg / L, and the water flow speed is 15-25 cm / s.

[0013] Preferably, no feeding is performed during the temporary culture of the wild parent fish, and during the intensive culture, live body Perinereis aibuhitensis is fed at 8 o'clock and 14 o'clock every day, and the feeding amount is 10-20% of the body mass of the parent fish.

[0014] Preferably, the mass concentration of eugenol is 18-22 mg / L, and the anesthetic time is 8-12 min; the artificial hormone for inducing ovulation is composed of chorionic gonadotropin 1800-2200 IU / mL, luteinizing hormone-releasing hormone analogue No. 2 290-310 mu g / mL and maleic acid diethyl dithiocarbamate 14-16 mg / mL, the injection dose of female fish is 1.8-2.2 mL / kg, and the injection dose of male fish is halved.

[0015] Preferably, the method for obtaining high-quality fertilized eggs through artificial insemination is as follows: in a dry container, 8000-12000 eggs per milliliter of sperm are fully contacted for 25-35 s, then 10-15 mL of natural seawater is added, and the mixture is stirred for 1-2 min; then 300-400 mL of natural seawater filtered by precipitation is added, and the mixture is left to stand for 15-20 min; the fertilized eggs are collected after the mixture is washed with natural seawater for 1-2 times and then left to stand for 18-25 min.

[0016] The application also provides a method for obtaining wild Largemouth bass larvae, comprising the following steps: obtaining high-quality fertilized eggs of wild Largemouth bass according to the method for obtaining high-quality fertilized eggs of wild Largemouth bass, and hatching the fertilized eggs to obtain wild Largemouth bass larvae.

[0017] Preferably, the hatching conditions are as follows: water temperature 22-24℃, salinity 28-30, pH value 8.0-8.5, dissolved oxygen 5-6mg / L, light intensity 500-800lux, and hatching time 24-26h.

[0018] Compared with the prior art, the technical scheme of the application has the following beneficial effects:

[0019] The application comprehensively controls the key links in the whole process from wild parent fish catching, transportation process control, parent fish temporary rearing and intensive culture, artificial induced spawning, artificial spawning and fertilization, fertilized egg collection and separation, and the like, and the technical steps are correlated to form a whole, so that high-quality fertilized eggs of wild Largemouth bass can be successfully obtained, the proportion of the high-quality fertilized eggs is more than 45%, the hatching rate of the obtained fertilized eggs is more than 62%, and the high-quality fertilized eggs can be used to construct a basic population of wild Largemouth bass for breeding, thereby providing high-quality larvae for realizing artificial breeding of Largemouth bass. DETAILED DESCRIPTION

[0020] The application provides a method for obtaining high-quality fertilized eggs of wild Largemouth bass, comprising the following steps: catching wild parent fish in the breeding season of Largemouth bass; transporting the wild parent fish to a harbor after being put into a live water tank; temporarily rearing the wild parent fish for 3-5 days and then intensively culturing the wild parent fish for 8-10 days; selecting male and female wild parent fish with mature gonads, and injecting artificial induced spawning mixed hormones after being anesthetized by eugenol; collecting eggs and sperm after 22-26 hours of injection of the artificial induced spawning mixed hormones, and performing artificial fertilization to obtain high-quality fertilized eggs.

[0021] The application adopts the method of setting a trap net to catch wild parent fish near the spawning ground of Largemouth bass in the breeding season of Largemouth bass. The trap net is preferably a special catching net for Largemouth bass, which is composed of a net wall, a net body and a net bag, and has a total length of 140 meters, a total width of 140 meters, a total height of 5 meters, a net wall part with a mesh size of 5 centimeters, and a net body with a mesh size of 10 centimeters. This method can avoid the problem of short survival time of wild parent fish caused by great stress in the catching process, and can improve the survival rate of wild parent fish.

[0022] Largemouth bass has the habit of reproductive migration, and the Lianwan of Lianyungang (20 degrees 52 minutes north latitude, 110 degrees 36 minutes east longitude) is its spawning ground. The catching location of Largemouth bass in the application is preferably near the Lianwan of Lianyungang.

[0023] The captured wild parent fish is transported to a harbor in a live water tank, and then transported to a breeding farm. The dissolved oxygen in the live water tank is 5-5.5 mg / L, and the water temperature during the transportation to the breeding farm is 22-24℃, and the dissolved oxygen is 6-6.5 mg / L. Pure oxygen is used to increase the oxygen in the water during transportation. By controlling the dissolved oxygen content and water temperature, the death of the wild parent fish caused by excessive stimulation of external factors can be avoided, and the survival rate of the wild parent fish can be improved.

[0024] After the wild parent fish arrives at the breeding farm, the damaged part of the fish body is preferably treated by smearing erythromycin ointment to kill pathogenic bacteria and promote wound healing, thereby avoiding the death of the parent fish. As an optional embodiment, after the wild parent fish arrives at the breeding farm, the fish is slowly lifted by hand with a net and placed in a plastic bucket containing half a bucket of water, then the fish's eyes are covered with a wet towel, the damaged part of the fish body is smeared with erythromycin ointment, and then slowly transferred to an indoor cement pool (5m long*4m wide*1.5m high).

[0025] The treated wild parent fish is temporarily cultured in the oxygen-increasing micro-flow water for 3-5 days, preferably 4 days, and then the parent fish is intensified for 8-10 days, preferably 9 days. The temporary culture and intensification culture conditions of the wild parent fish are as follows: water temperature 22-24℃, salinity 28-30, pH value 8.0-8.5, light intensity 500-800 lux, dissolved oxygen 5-6 mg / L, ammonia nitrogen ≤0.1 mg / L, and water flow rate 15-25 cm / s. The water temperature is preferably 23℃; the salinity is preferably 29; the light intensity is preferably 600-700 lux; and the water flow rate is preferably 20-22 cm / s. High ammonia nitrogen concentration can easily lead to poisoning of Pseudosciaena crocea in the Naozhou population, affecting its growth and development, respiratory metabolism, and immune function. High ammonia nitrogen concentration may cause a large number of Pseudosciaena crocea in the Naozhou population to die. The present application sets the ammonia nitrogen concentration to be ≤0.1 mg / L, which does not cause stress response of Pseudosciaena crocea in the Naozhou population, thereby avoiding the influence on the growth and gonadal development of Pseudosciaena crocea in the Naozhou population.

[0026] The wild parent fish is not fed during the temporary culture, and live Perinereis aibuhitensis is fed at 8 o'clock and 14 o'clock every day during the intensification culture. The feeding amount is 10-20% of the body weight of the parent fish, preferably 12-18%, more preferably 14-16%, and most preferably 15%. The temporary culture of the parent fish can reduce the stress of the parent fish, the intensification culture of the parent fish can promote the gonadal development of the parent fish, improve the quality of the eggs, and promote the ovulation of the parent fish after the gonadal maturation, thereby increasing the proportion of high-quality fertilized eggs. The water flow rate is an important environmental factor affecting the gonadal development of Pseudosciaena crocea in the Naozhou population. Pseudosciaena crocea in the Naozhou population can obtain spawning signals according to the water flow rate. The water flow rate is set in the present application, which can effectively stimulate Pseudosciaena crocea in the Naozhou population to spawn.

[0027] The application selects male and female brood fish with mature gonad development after intensive culture of brood fish, and injects artificial labor-inducing mixed hormone after eugenol anesthesia; the mass concentration of eugenol is 18-22 mg / L, and the anesthesia time is 8-12 min; the mass concentration of eugenol is preferably 20 mg / L; the anesthesia time is preferably 10 min; the artificial labor-inducing mixed hormone is composed of chorionic gonadotropin 1800-2200 IU / mL, luteinizing hormone-releasing hormone analogue No. 2 290-310 μg / mL and maleic acid diethylcarbamazine 14-16 mg / mL; preferably, the artificial labor-inducing mixed hormone is composed of chorionic gonadotropin 1900-2000 IU / mL, luteinizing hormone-releasing hormone analogue No. 2 300 μg / mL and maleic acid diethylcarbamazine 15 mg / mL; the injection dose of female fish is 1.8-2.2 mL / kg, preferably 2 mL / kg; the injection dose of male fish is half of that of female fish.

[0028] The application places the brood fish after injection of labor-inducing into the same cement pool, so that the female brood fish and the male brood fish are in full contact, and the female fish is promoted to sexual maturity by means of the sexual signal released by the male fish in the water body. The brood fish culture conditions in the application are as follows: water temperature 22-24℃, salinity 28-30, pH value 8.0-8.5, light intensity 500-800 lux, dissolved oxygen 5-6 mg / L, ammonia nitrogen ≤0.1 mg / L, and water flow rate 15-25 cm / s. The water temperature is preferably 23℃; the salinity is preferably 29; the light intensity is preferably 600-700 lux; and the water flow rate is preferably 20-22 cm / s.

[0029] The wild brood fish has uncontrollable spawning process in the natural environment, and the testis and ovary development is not synchronized. The application can induce the male and female brood fish to develop to phase V at the same time by selecting the components of artificial labor-inducing mixed hormone, controlling the injection amount of artificial labor-inducing mixed hormone and the culture conditions of the brood fish after injection of labor-inducing, and overcomes the problem of unsynchronized gonad development of wild brood fish, which can effectively improve the fertilization rate and the quality of fertilized eggs.

[0030] The application collects the eggs and sperm 22-26 hours, preferably 24-25 hours, after injection of artificial labor-inducing mixed hormone. As an optional embodiment, the application presses the testis of the male fish gently, extrudes the testis, collects the sperm in the cloaca with a rubber head dropper, and puts it into a dried container. The fish body of the female fish is wiped dry with a dry towel, and the eggs are extruded into the dried container.

[0031] The application collects the ova and the sperm to obtain high-quality fertilized eggs by artificial insemination. The method for obtaining high-quality fertilized eggs by artificial insemination is as follows: in a dry container, 8000-12000 ova per milliliter of sperm are fully contacted for 25-35 seconds, then 10-15 mL of natural seawater filtered by sand is added, and stirred for 1-2 minutes, then 300-400 mL of natural seawater is added and left for 15-20 minutes, the fertilized eggs floating on the water surface are collected after the natural seawater is washed for 1-2 times and left for 18-25 minutes again. The ratio of the sperm and the ova is preferably 1 mL: 9000-11000, and more preferably 1 mL: 10000. The rapid contact time of the sperm and the ova is preferably 28-32 seconds, and more preferably 30 seconds.

[0032] The application also provides a method for obtaining wild Lutjanus groisii larvae, which comprises the following steps: obtaining high-quality fertilized eggs of wild Lutjanus groisii according to the above method, and hatching the fertilized eggs to obtain wild Lutjanus groisii larvae.

[0033] The hatching conditions are as follows: water temperature 22-24℃, salinity 28-30, pH value 8.0-8.5, dissolved oxygen 5-6 mg / L, light intensity 500-800 lux, and hatching time 24-26 hours. The water temperature is preferably 23℃, the salinity is preferably 29, the dissolved oxygen is preferably 5.5 mg / L, the light intensity is preferably 600-700 lux, and the hatching time is preferably 25 hours.

[0034] The dissolved oxygen in the water body is one of the important environmental factors for the breeding of Lutjanus groisii parent fish. Too low or too high dissolved oxygen concentration will cause certain damage to the physiological metabolism, behavior activity and reproductive development of Lutjanus groisii. According to the physiological needs of Lutjanus groisii at different stages of capture, transportation, temporary breeding, intensive culture and hatching, the application precisely controls the dissolved oxygen in the water body, and sets the corresponding dissolved oxygen size, thereby effectively improving the survival rate and the proportion of high-quality fertilized eggs of Lutjanus groisii.

[0035] The technical solutions in the application will be clearly and completely described below in combination with the embodiments in the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0036] In the specific embodiments of the application, eugenol is purchased from Jianbo Rui Fragrance Oil Co., Ltd.; chorionic gonadotropin, luteinizing hormone-releasing hormone analogue No. 2 and diethylcarbamazine maleate are purchased from Ningbo Second Hormone Factory. Example 1

[0037] High-quality fertilized eggs of wild Pseudosciaena kowarum in the breeding season in 2023 were obtained:

[0038] (1) Capture wild parent fish: In the breeding season of Pseudosciaena kowarum, wild parent fish were captured in the sea area near the Xiazhu storey in the breeding season of Pseudosciaena kowarum (north latitude 20 degrees 52 minutes, east longitude 110 degrees 36 minutes), 8-10 m water depth, using the method of setting trap net. The trap net is composed of net wall, net body and net bag, the total length is 140 meters, the total width is 140 meters, the total height is 5 meters, the net wall part is 5 cm, and the net body is 10 cm. After 2 days of netting, the parent fish were collected in the net bag in the morning at 4-5 o'clock, and the parent fish were slowly lifted into the speedboat water tank by hand net, and the water tank was filled with oxygen to 5 mg / L, and then transported back to the harbor.

[0039] (2) Transport back to the breeding farm: After the parent fish were transported back to the harbor, the Pseudosciaena kowarum was slowly transferred to the special live fish transport vehicle with a plastic bucket with water, the live fish transport vehicle was oxygenated to 6 mg / L, and the compartment was cooled with ice strips. The water temperature during transportation was controlled at 23℃. After arriving at the breeding farm, the fish were slowly lifted into a plastic bucket filled with half a bucket of water using a hand net, then the fish's eyes were covered with a wet towel, and the damaged parts of the fish's body were smeared with erythromycin ointment before being slowly transferred to an indoor cement pool (5m long x 4m wide x 1.5m high).

[0040] (3) Parent fish temporary culture and intensive culture: In the cement pool, the water temperature was 23℃, the salinity was 29, the pH value was 8.5, the light intensity was 700 lux, the dissolved oxygen was 5.5 mg / L, the ammonia nitrogen was ≤0.1 mg / L, and the water flow velocity was 20 cm / s. The parent fish were temporarily cultured for 4 days, and no feeding was performed during the temporary culture stage; the parent fish were intensively cultured for 10 days, and the parent fish were fed with live Perinereis aibuhitensis at 8 o'clock and 14 o'clock every day, with the amount of 15% of the body weight of the parent fish.

[0041] (4) Injection of hormone to induce spawning: Select mature male and female Pseudosciaena kowarum with developed gonads, male fish with a body weight of more than 600 g, male fish with a body weight of more than 800 g, 5 male and 5 female fish, anesthetize with eugenol (eugenol mass concentration is 20 mg / L) for 10 min, and inject artificial labor mixed hormone (chorionic gonadotropin 2000 IU / mL, luteinizing hormone releasing hormone analogue No. 2 300 μg / mL and maleic acid diethylcarbamazine 15 mg / mL) into the chest of the parent fish at one time. The injection dose is 2 mL per 1000 g of female fish and 1 mL per 1000 g of male fish. The Pseudosciaena kowarum injected with the hormone was placed in the same indoor cement pool, and the water temperature was 23℃, the salinity was 29, the pH value was 8.5, the light intensity was 700 lux, the dissolved oxygen was 5.5 mg / L, the ammonia nitrogen was ≤0.1 mg / L, and the water flow velocity was 20 cm / s.

[0042] (5) Artificial insemination: 24 hours after injection of mixed oxytocin, the male fish was gently pressed, the testes were squeezed, and the sperm was collected in the cloaca with a rubber-tipped dropper and placed in a dried beaker. The female fish was dried with a dry towel, the eggs were squeezed into a dried plastic basin, then 10000 eggs were added to 1 mL of sperm, and the sperm and eggs were allowed to contact for 30 seconds. Then, 13 mL of natural seawater filtered through sand was added to activate the fertilized eggs. After 1.5 minutes of continuous stirring, 400 mL of natural seawater was added, and the mixture was allowed to stand for 18 minutes. The mixture was then washed twice with natural seawater and transferred to a 2L measuring cylinder.

[0043] (6) Collection of high-quality fertilized eggs: Since the fertilized eggs are buoyant, after standing in the fertilized egg cylinder for 20 minutes, the high-quality fertilized eggs float on the water surface, and the bad fertilized eggs sink to the bottom. Record the number of floating eggs and the number of sinking eggs, and calculate the fertilization rate.

[0044] In this example, the survival rate of the wild parent fish captured in step (1) was 73%; after transportation in step (2), the survival rate of the wild parent fish transported back to the breeding farm was 85%; after the parent fish was temporarily raised and intensively cultured in step (3), the survival rate of the parent fish was 72%; and after the parent fish was anesthetized and injected with oxytocin in step (4), the survival rate of the parent fish was 100%. In this example, the fertilization rate was 45.2%, and a total of 115g of fertilized eggs were collected, of which 52g were high-quality fertilized eggs, accounting for 45.22% of the total. Example 2

[0045] In 2024, high-quality fertilized eggs of wild Pseudosciaena crocea in the Naozhou tribe were obtained during the breeding season:

[0046] (1) Capture of wild parent fish: During the breeding season of Pseudosciaena crocea in the Naozhou tribe, wild parent fish were captured in the sea area near the Naozhouliangwan (20 degrees 52 minutes north latitude, 110 degrees 36 minutes east longitude), 8-10 meters deep, by setting a trap net. The trap net is composed of a net wall, a net body and a net bag, with a total length of 140 meters, a total width of 140 meters, a total height of 5 meters, a net wall with a mesh size of 5 centimeters, and a net body with a mesh size of 10 centimeters. After 3 days of netting, the parent fish were collected in the net bag in the morning at 4-5 o'clock, and were slowly lifted into a speedboat live tank using a hand scoop net. Oxygen was added to the live tank to 5.5 mg / L, and then the fish were transported back to the harbor.

[0047] (2) Transport back to the breeding farm: After the parent fish were transported back to the harbor, they were slowly transferred to a special live fish transport vehicle using a plastic bucket with water. The live fish transport vehicle used pure oxygen to increase the oxygen content to 6.5 mg / L, and ice strips were used to cool the vehicle compartment. The water temperature during transportation was controlled at 24°C. Upon arrival at the breeding farm, the fish were slowly lifted using a hand scoop net and placed in a plastic bucket containing half a bucket of water. The fish's eyes were then covered with a wet towel, and the damaged parts of the fish's body were treated with erythromycin ointment. The fish were then slowly transferred to an indoor concrete pool (5m long x 4m wide x 1.5m high).

[0048] (3) Parent fish temporary culture and intensive culture: water temperature 24℃, salinity 28, pH value 8.4, light intensity 600 lux, dissolved oxygen 5 mg / L, ammonia nitrogen ≤0.1 mg / L, water flow rate 20 cm / s. The parent fish was temporarily cultured for 3 days, and no feeding was performed during the temporary culture stage. The parent fish was intensively cultured for 9 days, and the live body weight of Perinereis aibuhitensis was 20% of the body weight of the parent fish, which was fed at 8:00 and 14:00 every day.

[0049] (4) Injection of labor-inducing hormone: mature male and female P. aibuhitensis of the Lutjanus groiso group were selected, the body weight of the male fish was more than 600 g, the body weight of the female fish was more than 800 g, and 5 male fish and 5 female fish were used. The fish was anesthetized with eugenol (eugenol mass concentration 20 mg / L) for 10 min, and then the parent fish was injected with a mixed labor-inducing hormone (chorionic gonadotropin 2000 IU / mL, luteinizing hormone-releasing hormone analogue No. 2 300 μg / mL and diethylstilbestrol maleate 15 mg / mL) in the chest cavity at one time. The injection dose was 2 mL per 1000 g of female fish and 1 mL per 1000 g of male fish. The parent fish injected with the labor-inducing hormone was placed in the same indoor cement pool, and the water temperature was 24℃, the salinity was 28, the pH value was 8.3, the light intensity was 600 lux, the dissolved oxygen was 5 mg / L, the ammonia nitrogen was ≤0.1 mg / L, and the water flow rate was 20 cm / s.

[0050] (5) Artificial insemination: 24 h after the injection of the mixed labor-inducing hormone, the male fish was gently pressed, the sperm sac was squeezed, and the semen was collected in a dried beaker using a rubber-tipped dropper at the cloaca. The female fish was dried with a dry towel, and the eggs were squeezed into a dried plastic basin. Then, 10000 eggs were added to 1 mL of semen, so that the sperm and eggs could fully contact for 30 s. Then, 15 mL of natural seawater filtered by sand was added to activate the fertilized eggs. After 2 min of continuous stirring, 350 mL of natural seawater was added, and the mixture was left to stand for 20 min. The mixture was washed twice with natural seawater, and then transferred into a 2 L measuring cylinder.

[0051] (6) Collection of high-quality fertilized eggs: Since the fertilized eggs are buoyant, after the fertilized eggs were left to stand in the measuring cylinder for 20 min, the high-quality fertilized eggs floated on the water surface, and the bad fertilized eggs sank to the bottom. The number of the floating eggs and the number of the sinking eggs were recorded, and the fertilization rate was calculated.

[0052] In this example, the survival rate of the wild parent fish after being captured in step (1) was 68%. After being transported in step (2), the survival rate of the wild parent fish transported back to the breeding farm was 78%. After the temporary culture and intensive culture of the parent fish in step (3), the survival rate of the parent fish was 65%. After the parent fish was anesthetized and injected with the labor-inducing hormone in step (4), the survival rate of the parent fish was 100%. In this example, the fertilization rate was 64%, and a total of 86 g of fertilized eggs were collected, of which 41 g were high-quality fertilized eggs, accounting for 47.67%. Example 3

[0053] Wild Naozhou group Pseudosciaena crocea larvae were obtained in 2023:

[0054] Steps (1)-(6) are the same as in Example 1.

[0055] (7) Fertilized egg hatching: high-quality fertilized eggs were transferred into a cubic water hatching barrel for hatching, and the hatching conditions were as follows: water temperature 23℃, salinity 29, pH value 8.5, dissolved oxygen 5.5 mg / L, light intensity 600 lux, and hatching time 25 h. After the larvae hatched, the hatching rate was calculated.

[0056] The hatching rate in this example was 62.7%. Example 4

[0057] Wild Naozhou group Pseudosciaena crocea larvae were obtained in 2024:

[0058] Steps (1)-(6) are the same as in Example 2.

[0059] (7) Fertilized egg hatching: high-quality fertilized eggs were transferred into a cubic water hatching barrel for hatching, and the hatching conditions were as follows: water temperature 24℃, salinity 30, pH value 8.3, dissolved oxygen 5.5 mg / L, light intensity 700 lux, and hatching time 25 h. After the larvae hatched, the hatching rate was calculated.

[0060] The hatching rate in this example was 65.8%.

[0061] The above only describes the preferred embodiments of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for obtaining high-quality fertilized eggs of wild Pseudosciaena crocea, characterized in that, The method comprises the following steps: Wild parent fishes are captured in the spawning season of the Lutjanus groisio group in Luhuitou, and then are transported to a harbor and then to a breeding farm; the wild parent fishes are temporarily cultured for 3-5 days and then are intensively cultured for 8-10 days, and then mature male and female wild parent fishes are selected, anesthetized by eugenol and injected with a mixed hormone for artificial spawning; 22-26 hours after the injection, eggs and sperm are collected to obtain high-quality fertilized eggs through artificial insemination; The mass concentration of the eugenol is 18-22 mg / L, and the anesthetic time is 8-12 minutes; the mixed hormone for artificial spawning is composed of chorionic gonadotropin 1800-2200 IU / mL, luteinizing hormone-releasing hormone analogue No. 2 290-310 μg / mL and diethylstilbestrol maleate 14-16 mg / mL, and the injection dose of the female fish is 1.8-2.2 mL / kg, and the injection dose of the male fish is halved; The method for obtaining high-quality fertilized eggs through artificial insemination comprises the following steps: in a dry container, 8000-12000 eggs per milliliter of sperm are fully contacted for 25-35 seconds, then 10-15 mL of natural seawater is added, and the mixture is stirred for 1-2 minutes, then 300-400 mL of natural seawater filtered by sedimentation is added and is left to stand for 15-20 minutes, the fertilized eggs are washed with natural seawater for 1-2 times, and then are left to stand for 18-25 minutes, and the fertilized eggs floating on the water surface are collected.

2. The method of claim 1, wherein, The wild parent fishes are captured by setting a trap net in the spawning ground of the Luhuitou group of large yellow croakers.

3. The method of claim 1, wherein, The dissolved oxygen in the live water tank is 5-5.5 mg / L.

4. The method of claim 1, wherein, During the transportation to the breeding farm, the water temperature is 22-24 ℃, and the dissolved oxygen is 6-6.5 mg / L.

5. The method of claim 1, wherein, The conditions for the temporary culture and the intensive culture of the wild parent fishes are as follows: water temperature 22-24 ℃, salinity 28-30, pH value 8.0-8.5, light intensity 500-800 lux, dissolved oxygen 5-6 mg / L, ammonia nitrogen ≤0.1 mg / L, and water flow speed 15-25 cm / s.

6. The method of claim 1, wherein, No feeding is performed in the temporary culture stage of the wild parent fishes, and live Perinereis aibuhitensis are fed at 8 o'clock and 14 o'clock every day in the intensive culture stage, and the feeding amount is 10-20% of the body mass of the parent fishes.

7. A method for obtaining wild Pseudosciaena kowarum larvae, characterized in that, The method comprises the following steps: high-quality fertilized eggs of the wild Luhuitou group of large yellow croakers are obtained according to the method in any one of claims 1-6, the fertilized eggs are hatched, and wild Luhuitou group of large yellow croaker larvae are obtained.

8. The method of claim 7, wherein, The hatching conditions are as follows: water temperature 22-24 ℃, salinity 28-30, pH value 8.0-8.5, dissolved oxygen 5-6 mg / L, and light intensity 500-800 lux, and the hatching time is 24-26 hours.