Leiocassis longirostris fry large-scale cultivation method based on facility circulating water system

Abstract

The invention discloses a leiocassis longirostris fry large-scale cultivation method based on a facility circulating water system, and relates to the field of artificial breeding, and the method comprises the steps of indoor parent intensive cultivation, fertilized egg batch acquisition, fry incubation in a loop incubation pond, fry large-scale cultivation and the like. And water purification treatment and efficient oxygenation are realized. Different circulating water operation modes are adopted in the seedling breeding and domestication cultivation process, the optimal breeding ecological condition is provided, and the process is controllable. According to the Leiocassis longirostris fry hatching and breeding method, the Leiocassis longirostris fry hatching and breeding based on circulating water are adopted for Leiocassis longirostris fry large-scale breeding of a facility circulating water system, accurate control over the Leiocassis longirostris hatching process can be achieved, water quality stability is achieved, the water temperature can be accurately controlled, and water changing and wastewater discharging in the whole process are avoided.

Description

Technical Field

[0001] This invention relates to the field of artificial breeding technology for fish fry, and in particular to a method for large-scale cultivation of long-snout catfish fry based on a facility-based recirculating aquaculture system. Background Technology

[0002] Long-snouted catfish ( Leiocassis longirostris ), also known as the Yangtze River catfish, belongs to the order Siluriformes, family Bagridae, and genus Croaker. Leiocassis The long-snout catfish (Siniperca fasciatus) is mainly distributed in the main stream and tributaries of the Yangtze River in my country and is a unique and valuable economic fish species. It has tender, flavorful, and fatty meat, is boneless, and rich in protein. Currently, long-snout catfish farming is mainly concentrated in Sichuan, Chongqing, Guangdong, and Hubei provinces. The amount of long-snout catfish farmed in Shanghai is relatively small and cannot meet the growing consumer demand in the region. With the gradual rise of long-snout catfish farming in Shanghai, it has become a promising potential species for the region, with broad development prospects. Therefore, large-scale artificial breeding of long-snout catfish can meet the continuous and stable demand for seedlings in the local long-snout catfish farming industry.

[0003] Modern facility-based fisheries, as an intensive and efficient industrial development model, are of significant practical importance for promoting the transformation and upgrading of fisheries, improving quality and efficiency, and achieving high-quality development of fisheries. The sustainable and healthy development of modern facility-based fisheries requires a large-scale and effective supply of aquatic seedlings as a prerequisite. Constructing a large-scale aquatic seedling breeding system model based on the application scenarios of modern facility-based fisheries can greatly improve the hatching efficiency of aquatic seedlings, achieve a stable supply and industrial promotion of longsnout catfish seedlings, effectively save water resources, promote the large-scale and sustainable development of longsnout catfish aquaculture, and enhance the level of modern technological application in the aquatic seedling breeding industry.

[0004] Currently, traditional artificial breeding of long-snout catfish requires frequent water changes to maintain water quality stability. The process is cumbersome and difficult to scale up with a small number of people, due to numerous uncontrollable factors. Traditional domestication and feeding methods are also tedious, typically requiring animal feed such as bloodworms, which is not conducive to the large-scale transition of seedlings. Therefore, there is an urgent need to develop a large-scale breeding method to address these problems. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the present invention provides a method for large-scale cultivation of *Catfish bream* seedlings based on a facility-based recirculating aquaculture system, comprising the following steps: Step 1, indoor parent intensive cultivation The parent is introduced, and the parent intensive cultivation is carried out in the parent fish culture pond. Water circulation treatment is opened regularly every day. When the water level in the culture pond is higher than a specific water level, the excess water body automatically flows into the solid-liquid separator to remove coarse particulate matter, and then enters the circulating pipeline to the water collecting pool for collection. After further removal of particulate matter by the microfilter, it is sent to the biological filter for biological degradation after sterilization treatment. Harmful substances such as ammonia nitrogen and nitrite in the water body are removed. Finally, after gas-liquid mixing by the high-efficiency pure oxygen system, the water body is exchanged again through the circulating pipeline into the culture barrel. The parent is intensively cultivated in the circulating water system to the target maturity; Step 2: Batch obtaining of fertilized eggs The longsnout catfish parents developed to maturity after intensive cultivation are selected for artificial induced spawning and fertilization to obtain fertilized eggs in batches. Step 3: Hatchling incubation is carried out in a loop incubation pool. Straight-angle elbow pipe tangential water inlet nozzles are uniformly arranged along the loop edge at the bottom of the loop incubation pool. The water inlet flow state in the loop is uniform, and water circulation is achieved through overflow. The circulating pump sends the water to the microfilter to remove particulate matter, and then to the biological filter for biological degradation after sterilization treatment. Finally, it enters the loop incubation pool again through the backwater pipeline. The loop incubation pool can dynamically adjust the water temperature according to different stages of egg laying. Step 4: Scale-up cultivation of hatchlings After the fertilized eggs are all broken, the natural water temperature is maintained, the indoor light is 12 hours and the dark is 12 hours, the dissolved oxygen is maintained above 6 mg / L, and then the bait is dynamically adjusted according to the growth stage. During bait feeding, water circulation treatment is suspended, and the circulation system is opened again 1 hour after bait feeding. During the cultivation of hatchlings, the aeration amount is adjusted in time according to the development of the hatchlings.

[0006] In a preferred embodiment of the present application, in step 3, the water pH is maintained at 7.6-8.1, the dissolved oxygen is >5.0 mg / L, the ammonia nitrogen is <0.1 mg / L, and the nitrite is <0.05 mg / L.

[0007] In another preferred embodiment of the present application, in step 4, the water quality is maintained at pH 7.5-8.0, the dissolved oxygen is >5.0 mg / L, the ammonia nitrogen is <0.1 mg / L, and the nitrite is <0.1 mg / L.

[0008] In another preferred embodiment of the present application, in step 1, water quality purification treatment and efficient oxygenation are carried out by microfilter, ultraviolet sterilization, biological filtration and pure oxygen oxygenation.

[0009] In another preferred embodiment of the present application, in step 3, the water temperature is precisely controlled by the electromagnetic valve and the temperature probe.

[0010] In another preferred embodiment of the present application, in step 1, the water body during the parent breeding period is controlled at more than 6 mg / L of dissolved oxygen, pH 7.5-8.2, TAN <0.2 mg / L, and NO2-N <0.04 mg / L.

[0011] In another preferred embodiment of the present application, in step 3, when the water level in the hatching ring channel is higher than the overflow of the insertion pipe, the excess water body is automatically overflowed back to the water collecting pool through the insertion pipe, is pumped by a circulating pump to remove particulate matter, then is treated by ultraviolet sterilization, is biologically degraded in a biological filter tank, and finally is re-entered into the ring channel hatching pool through a backwater pipeline.

[0012] In another preferred embodiment of the present application, in step 3, two stainless steel circular frames with different diameters and the same height are respectively arranged in the middle of the hatching pool, the bottom of the frame is suspended, the outer periphery of the suspended part is 30 cm upwardly enclosed by silk mesh, the outer periphery of the upper part is not covered with mesh, which facilitates water circulation, and the outer periphery of the part 30 cm from the top is continuously enclosed by silk mesh, which facilitates the adhesion of fertilized eggs.

[0013] In another preferred embodiment of the present application, in step 3, before the eggs are laid, the circular hatching frame mesh and the hatching ring channel are disinfected with 10 mg / L potassium permanganate solution, the water temperature is maintained at 24℃ before the eggs are laid, the water temperature is increased to 25℃ on the day after the eggs are laid, and the water temperature is increased to 26℃ on the next day, and then the water temperature is maintained at 26℃ until the fertilized eggs break the membrane, and the water body is kept in a circulating state; the fertilized eggs of Leiocassis longirostris are uniformly laid in the inner and outer circular hatching meshes, and the fertilized eggs are uniformly pushed and adhered to the mesh by water flow.

[0014] In another preferred embodiment of the present application, in step 4, the newly hatched fry is fed with cooked egg yolk slurry as the opening bait on the 4th day after hatching, and the bait is uniformly sprayed and fed in the whole pool after sieving; the fry is fed with Cladocera live bait on the 5th-6th day after hatching, the feeding of live bait is reduced and the feeding proportion of microparticle compound bait is increased on the 7th-9th day; after the 10th day, the feeding of live bait is stopped and the fry is completely switched to microparticle compound bait with a particle size suitable for the fry.

[0015] In another preferred embodiment of the present application, in step 4, when the fry reaches 3 cm in length, the fry is put into an outdoor pond for breeding on the 25th-27th day of breeding.

[0016] Technical effects

[0017] The application adopts a loop incubation pool based on circulating water to carry out the hatching and cultivation of Megalobrama amblycephala fry, and the scale cultivation of Megalobrama amblycephala fry by using the facility circulating water system can realize the precise control of the hatching process of Megalobrama amblycephala, realize the stable water quality, and precisely control the water temperature, without water change and wastewater discharge throughout the process. Meanwhile, the micro-particle is used to cooperate with the feed for the conversion and domestication, which is convenient for the scale breeding in the room, so that the Megalobrama amblycephala fry can adapt to the commercial feed faster, and the scale cultivation can be carried out faster. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structure schematic view of the parent fish breeding pool in the embodiment of the application.

[0019] Figure 2 It is a structure schematic view of the loop incubation pool in the embodiment of the application.

[0020] Figure 3 It is a flow chart of the water quality circulating treatment system in the embodiment of the application.

[0021] Among them, 1 is a parent fish breeding pool, 2 is an overflow end, 3 is a center insertion pipe, 4 is a water inlet pipe, 5 is a solid-liquid separator, 6 is a loop incubation pool, 7 is a backflow pipe cover, 8 is an inner loop incubation frame, and 9 is an outer loop incubation frame. DETAILED DESCRIPTION

[0022] The following reference description of drawings introduces a plurality of preferred embodiments of the application, so that the technical content thereof is more clear and convenient to understand. The application can be embodied by many different forms of embodiments, and the protection scope of the application is not limited to the embodiments mentioned herein.

[0023] In the drawings, the same components have the same reference numerals, and components with similar structures or functions have similar reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the size and thickness of each component are not limited in the application. In order to make the drawing clearer, the thickness of some components is appropriately exaggerated in some places in the drawing.

[0024] Embodiment 1: In order to achieve the above-mentioned purpose, the application provides a Megalobrama amblycephala fry scale breeding method based on a facility circulating water system, which comprises the following steps of indoor circulating water parent fish intensive cultivation, batch fertilized egg acquisition, loop circulating water hatching, and fry scale cultivation.

[0025] 1) Indoor parent fish intensive cultivation

[0026] Healthy and disease-free Megalobrama amblycephala with no injury on the surface are selected from 3-year-old or more than 3-year-old outdoor Megalobrama amblycephala breeding population as breeding parent fish, or the parent fish can be directly introduced from a corresponding qualified seed (good) field. Figure 1The parent of Leiocassis longirostris was intensively cultured in a round barrel made of indoor PP material. The culture tank was 6 m in diameter, 1.2 m in depth, and 1 m in water level, and the parent was stocked at a density of 7 kg / m 3 . The stocking ratio of female to male was 3:1. The feed used was a special compound feed for Leiocassis longirostris, which was fed once a day at 16:00, with a feeding amount of 3% of the body weight of the parent fish. A special multi-vitamin for aquatic products was added at 5‰ of the feeding amount to improve the immunity of the parent. The initial water temperature was maintained at 21-22°C, and after 2 days of stabilization, it was gradually increased to 22-23°C. Every 3 days, live bait such as loach and Japanese marsh shrimp was supplemented to promote the further development and maturation of the gonads, and the feeding ratio of live bait to special compound feed was 1:1. The circulation treatment was turned on from 07:00 to 10:00 and from 12:00 to 15:00 every day. When the water level in the culture tank was higher than 1 m, the excess water flowed into the solid-liquid separator to remove coarse particulate matter, then entered the circulation pipeline to the collection tank for collection, and then passed through the further removal of particulate matter by the full-automatic drum-type microfilter, and then was treated by ultraviolet sterilization before being sent to the biological filter for biological degradation to remove harmful substances such as ammonia nitrogen and nitrite in the water body. Finally, the high-efficiency pure oxygen system was used for gas-liquid mixing, and then the circulation pipeline was used to enter the culture barrel. The water exchange rate during circulation was 4.7 m 3 / h. Two rectangular nanoceramic aerators (35x10x2.5 cm) were installed in the culture tank, with a gas flow rate of 1.2 L / min. During the culture of the parent, the dissolved oxygen in the water was controlled to be above 6 mg / L, the pH was 7.5-8.2, the TAN was <0.2 mg / L, and the NO2-N was <0.04 mg / L. Black plastic film was covered on the upper part of the parent culture tank to ensure a quiet environment and reduce the stress response of the parent, promoting better development of the parent. The parent of Leiocassis longirostris was intensively cultured in this indoor recirculating water system for 1-2 weeks, and more than 85% of the parents could reach the target maturity for breeding. In production, the target can be set according to the breeding of fry, and the temporary parent culture is intensively cultured in batches to obtain fertilized eggs in batches for subsequent batch fry incubation and culture.

[0027] 2) Batch acquisition of fertilized eggs

[0028] According to the requirements of fry culture, the mature parents of Leiocassis longirostris after intensive culture were selected for artificial induction and fertilization to obtain fertilized eggs in batches.

[0029] 3) Loop recirculating water incubation

[0030] For example Figure 2As shown, the glass fiber reinforced plastic material incubation ring channel is used as the seedling incubation pool. The diameter of the ring channel incubation pool is 3 m, the pool depth is 1.2 m, the water level is maintained at 1 m, 8 straight angle bent pipe tangential water inlet nozzles are uniformly arranged along the ring edge of the pool bottom to realize uniform flow state of water inlet in the ring channel. Every 1 water inlet nozzle is fixedly provided with a 15*5 cm oxygen increasing column. The oxygen increasing column gas inlet end is connected with a 4 mm inner diameter hose. The aeration hose is communicated with a PVC gas inlet pipe with a regulating valve. When water is inletted, the gas amount is adjusted by opening the gas inlet valve, and the water and gas are rapidly mixed through the water jet of the water inlet nozzle to realize high efficient oxygen increasing of the water body. A PVC insertion pipe (h=1 m, Φ=7 cm) is arranged at the center of the bottom of the ring channel. The outside of the insertion pipe is covered with a 80 mesh circular frame (Φ=40 cm) to prevent fish fries and the like from being sucked in. When the water level in the incubation ring channel is higher than the overflow port of the insertion pipe, the excess water body is automatically overflowed back to the water collecting pool through the insertion pipe, is pumped to the micro filter to remove particulate matters, then is treated by ultraviolet sterilization, is biologically degraded in the biological filter, and finally is re-entered into the ring channel incubation pool through the backwater pipeline. Two stainless steel circular frames with a diameter of 1.2 m and 2 m and a height of 1 m are respectively arranged in the middle of the incubation pool. The bottom 10 cm of the frame is suspended, the suspended part is surrounded by a 40 mesh gauze net in the outer periphery of the upper 30 cm, the upper 30 cm is not covered with the net in the outer periphery, the water body is circulated, and the top 30 cm is continued to be surrounded by the 40 mesh gauze net in the outer periphery to facilitate the adhesion of the fertilized eggs.

[0031] Before the egg laying, the circular incubation frame net and the incubation ring channel are disinfected with 10 mg / L potassium permanganate solution. The circular incubation net is washed clean with water and is placed in the incubation ring channel. 2-3 days before the egg laying, 1 m of water is inletted into the incubation ring channel, the water is heated by the water tank to circulate, and the water temperature is maintained at 24℃. The water temperature of the circulating water tank is precisely controlled by the gas boiler, the electromagnetic valve and the temperature probe. The water tank is heated by the gas boiler, the built-in water pump of the water tank is started after the set target temperature is reached to circulate with the incubation pool to realize the temperature rising of the target pool. The fertilized eggs of the Leiocassis brevirostris are uniformly laid in the inner and outer circular incubation nets, the fertilized eggs are uniformly pushed and adhered to the net by the water flow. The fertilized egg density is 10,000 pieces / m 3 When all the fertilized eggs are laid, the water flow is controlled at 0.03-0.05 m / s by adjusting the water inlet valve to reduce the water flow, and the water body circulation update frequency is 2.3 m 3 / h. The temperature is raised to 25℃ on the day after the egg laying, and is raised to 26℃ on the next day. The water temperature is maintained at 26℃ and the water body is kept in the circulating state until the fertilized eggs break the membrane. The water quality is regularly monitored during the incubation to maintain the pH value at 7.6-8.1, the dissolved oxygen at more than 5.0 mg / L, the ammonia nitrogen at less than 0.1 mg / L, and the nitrite at less than 0.05 mg / L. After 53-60 h, the fertilized eggs are hatched.

[0032] 4) Scale-up cultivation of seedlings

[0033] Newly hatched fry cannot swim and lie on their sides at the bottom of the pond. Once all fertilized eggs have hatched, the incubation frame is removed promptly. Heating is stopped during this period to maintain natural water temperature, with 12 hours of light and 12 hours of darkness indoors. Dissolved oxygen is maintained above 6 mg / L through four aeration columns installed in the incubation pond. Newly hatched fry begin feeding on the fourth day after hatching, gradually transitioning from endogenous to exogenous nutrition. At this time, they begin to eat palatable food. Cooked egg yolk paste is used as the initial feed, sieved through a 100-mesh screen and evenly sprinkled throughout the pond. Feeding is done daily at 07:30 and 16:00, with one egg yolk per 16 m³ each time. 3 On days 5-6 after hatching, feed live cladocerans filtered through an 80-mesh silk screen twice daily at 10:30 and 16:00. If cladocerans are unavailable, newly hatched Artemia nauplii can be fed, maintaining a feeding density of 5 nauplii / mL. The live food should be sterilized with methionine iodine to ensure no pathogens are introduced from external feed. Simultaneously, supplement with microparticle feed suitable for 6-10 mm larvae, fed once daily at 13:00 at a rate of 0.35 g / 1000 larvae per feeding, to facilitate a smooth transition to artificial feed and complete the acclimatization process. Before feeding, add Clostridium butyricum to the microparticle feed at a ratio of 0.5 mL per 1 g of microparticle feed to improve the intestinal microecology of the fry, enhance their digestive and absorptive capacity, and increase their disease resistance. On days 7-8, reduce live bait feeding to once a day at 10:30 AM, and increase the proportion of microparticle feed. Feed 9-14 mm fry with microparticle feed at 7:30 AM and 4:00 PM daily at a rate of 0.5 g / 1000 fry per feeding. On days 9-10, feed live bait once at 10:30 AM, and feed 13-18 mm fry with microparticle feed at 7:30 AM and 4:00 PM daily at a rate of 0.7 g / 1000 fry per feeding. After day 10, stop feeding live bait and switch entirely to microparticle feed with a particle size suitable for 18-28 mm fry at a rate of 1.5 g / 1000 fry per feeding. When over 95% of the fry completely consume the microparticle feed, the transition to a new diet is successful, and feed acclimatization is complete. Subsequently, based on the fry's growth, gradually replace the feed with a microparticle formulated feed suitable for fry measuring 25-35 mm, at a rate of 3.5 g / 1000 fry per feeding, ensuring palatability. From day 25 to 27, when the fry reach 3 cm in length, they can be transferred to outdoor ponds for further rearing. During daily feeding, suspend water circulation; restart the circulation system 1 hour after feeding, circulating 1.4 m³ of water. 3 / h, during the fry rearing period, adjust the aeration rate in a timely manner according to the development of the fry, and maintain the water quality at pH 7.5~8.0, dissolved oxygen >5.0 mg / L, ammonia nitrogen <0.1 mg / L, and nitrite <0.1 mg / L.

[0034] Example 2: Using the above method, in May 2024, using 4-year-old parent Megalobrama amblycephala, two batches of artificial breeding of Megalobrama amblycephala were carried out. On May 7, 5 female fish and 2 male fish were selected, and ovulation was performed at 11:00. On May 8, 2 fish oviposited at 10:30 and 20:00, respectively, and by May 11, 10,000 fry were obtained. After 26 days of indoor cultivation, 85,000 fry with a body length of 3 cm were obtained. On May 12, 7 female fish and 3 male fish were selected, and ovulation was started at 10:00. On May 14, 6 fish oviposited at 10:30, and on May 16, 15,000 fry were obtained. After 27 days of indoor cultivation, 128,000 fry with a body length of 3 cm were obtained.

[0035] The above has specifically described the preferred embodiments of the present application, but the present application is not limited to the described embodiments, and those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application. These equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A method for large-scale cultivation of Leiocassis longirostris fry based on a facility circulating water system, characterized in that, The method comprises the following steps: Step 1: indoor parent intensive cultivation The parent is introduced, and the parent is intensively cultivated in a parent culture pond. Water circulation treatment is regularly started every day. When the water level in the culture pond is higher than a specific water level, the excess water automatically flows into a solid-liquid separator through an overflow end to remove coarse particulate matter, and then enters a circulating pipeline to a water collecting pool for collection. The particulate matter is further removed by a microfilter, and then the water is subjected to sterilization treatment and then sent to a biological filter for biological degradation to remove ammonia nitrogen and nitrite in the water. Finally, the water is subjected to gas-liquid mixing by a high-efficiency pure oxygen system and then enters the culture barrel through the circulating pipeline to realize water exchange. The parent is intensively cultivated in the circulating water system until the target maturity is reached. Step 2: batch obtaining of fertilized eggs The longsnout catfish parent developed to maturity after intensive cultivation is selected to perform artificial induced spawning and insemination to obtain fertilized eggs in batches. Step 3: hatchling incubation is performed in a loop incubation pool. Straight-angle elbow pipe tangential water inlet nozzles are uniformly arranged along the loop edge at the bottom of the loop incubation pool. The water inlet flow state in the loop is uniform, and water circulation is realized through overflow. The water is sent to a microfilter by a circulating pump to remove particulate matter, and then subjected to sterilization treatment and then enters a biological filter for biological degradation. Finally, the water reenters the loop incubation pool through a backwater pipeline. The loop incubation pool can dynamically adjust the water temperature according to different egg laying stages. Step 4: hatchling large-scale cultivation After the fertilized eggs are all broken, the natural water temperature is maintained, and indoor 12 h light and 12 h darkness are provided. The dissolved oxygen is kept above 6 mg / L. Then the bait is dynamically adjusted according to the growth stage. Water circulation treatment is suspended during bait feeding. The circulation system is started again 1 h after bait feeding. The aeration amount is adjusted in a timely manner according to the development of the hatchlings during hatchling cultivation.

2. The method of claim 1, wherein, In step 3, the water pH is maintained at 7.6-8.1, the dissolved oxygen is greater than 5.0 mg / L, the ammonia nitrogen is less than 0.1 mg / L, and the nitrite is less than 0.05 mg / L.

3. The method of claim 1, wherein, In step 4, the water quality is maintained at pH 7.5-8.0, the dissolved oxygen is greater than 5.0 mg / L, the ammonia nitrogen is less than 0.1 mg / L, and the nitrite is less than 0.1 mg / L.

4. The method of claim 1, wherein, In step 1, the water quality purification treatment and efficient oxygenation are performed by a microfilter, ultraviolet sterilization, biological filtration and pure oxygen oxygenation.

5. The method of claim 1, wherein, In step 3, the water temperature is precisely controlled by an electromagnetic valve and a temperature probe.

6. The method of claim 1, wherein, In step 1, the water dissolved oxygen is controlled to be above 6 mg / L, the pH is 7.5-8.2, the TAN is less than 0.2 mg / L, and the NO2-N is less than 0.04 mg / L during parent cultivation.

7. The method of claim 1, wherein, In step 3, when the water level in the incubation loop is higher than the overflow port of the cannula, the excess water automatically overflows back to the water collecting pool through the cannula, is sent to a microfilter by a circulating pump to remove particulate matter, and then subjected to ultraviolet sterilization treatment and then enters a biological filter for biological degradation. Finally, the water reenters the loop incubation pool through a backwater pipeline.

8. The method of claim 1, wherein, In step 3, two stainless steel circular frames with different diameters and equal heights are respectively arranged in the middle of the incubation pool. The frame bottoms are suspended, the suspended parts are surrounded by silk nets up to 30 cm from the outer periphery, the outer periphery is not covered with a net further up, which is convenient for water circulation, and the outer periphery 30 cm from the top is surrounded by a silk net, which is convenient for adhering fertilized eggs.

9. The method of claim 1, wherein, In the step 3, the circular hatching frame net and the hatching ring channel are disinfected with 10 mg / L potassium permanganate solution before the eggs are laid, the water temperature is maintained at 24℃ before the eggs are laid, the water temperature is increased to 25℃ on the day when the eggs are laid, the water temperature is increased to 26℃ on the next day, and then the water temperature is maintained at 26℃ until the fertilized eggs break the membrane, and the water body is kept in circulation state; the fertilized eggs of the Leiocassis longirostris are evenly laid in the inner and outer circular hatching nets, and the fertilized eggs are uniformly pushed and adhered to the net by water flow.

10. The method of claim 1, wherein, In the step 4, the newly hatched fry is fed with cooked egg yolk slurry as the opening bait on the 4th day after hatching, and the bait is evenly sprayed and fed after sieving; the cladoceran live bait is fed on the 5th to 6th day after hatching, the feeding amount of the live bait is gradually reduced, and the feeding proportion of the microparticle compound bait is gradually increased on the 7th to 9th day; the live bait is stopped feeding after the 10th day, and the microparticle compound bait with suitable particle size is completely converted; the fish fry is put into an outdoor pond for breeding when the body length reaches 3 cm on the 25th to 27th day.

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