Large-scale breeding method for fry of heterophysogobio boulengeri

Abstract

The invention provides a large-scale breeding method of heterophyllobotia tapeinosoma fry, which comprises the following steps: temperature-controlled incubation of a breeding pond, still water heating breeding and ecological cycle breeding, establishes an intensive breeding mode of fry with high density, fast growth and healthy fish body, solves the problem of low survival rate in the breeding process of heterophyllobotia tapeinosoma, and improves the breeding efficiency of heterophyllobotia tapeinosoma. The breeding scale and the breeding efficiency are practically improved, and a key technical support is provided for large-scale enhancement and release.

Description

Technical Field

[0001] The invention relates to a method for large-scale cultivation of naked Heterophyte scorpionfish seedlings, belonging to the field of biotechnology. Background Art

[0002] Xenophysogobio nudicorpa is a unique fish species and one of the important economic fish species that is mainly distributed in the upper reaches of the Yangtze River, the lower reaches of the Jinsha River, the Minjiang River and the Yalong River. However, in recent years, due to the impact of human activities, its habitat has gradually shrunk or even disappeared, and its natural reproduction scale has been sharply reduced, resulting in a sharp decline in its wild resources. In 2000, Xenophysogobio nudicorpa was listed as a key protected fish species in Sichuan Province. Before the start of the ten-year fishing ban in the Yangtze River, wild resources of Xenophysogobio nudicorpa were extremely difficult to obtain and had become an occasional species. The fish resources were very scarce and almost endangered, which led to the delay in its artificial breeding, artificial population construction and other ex situ conservation work. Since the start of the ten-year fishing ban in the Yangtze River, the above situation has eased slightly, but there is still very little research on Xenophysogobio nudicorpa, which mainly focuses on morphological characteristics and population genetics.

[0003] In 2023, the Chinese Sturgeon Research Institute of China Three Gorges Corporation made a breakthrough in the artificial propagation technology of naked Heterophyte and carried out its seedling cultivation work. It was found that naked Heterophyte seedlings are very prone to Ichthyophthirius and bacterial diseases in the breeding environment, resulting in large-scale deaths. Therefore, it is urgent to explore a large-scale cultivation method for naked Heterophyte seedlings to lay a technical foundation for its large-scale release. Summary of the invention

[0004] The present invention provides a method for large-scale breeding of naked heterocysts. The method for large-scale breeding of naked heterocysts can effectively reduce the probability of occurrence of Ichthyophthirius punctatus and bacterial diseases during the breeding of naked heterocysts, improve the breeding survival rate, and facilitate the large-scale release of naked heterocysts.

[0005] The present invention provides a method for large-scale cultivation of naked Heterocystis nativus seedlings, comprising the following steps:

[0006] 1) Incubate the fertilized eggs to be incubated at 18°C ​​and a water intake of 0.15 L / min to obtain newly hatched fry;

[0007] 2) The newly hatched fry are cultured in static water at staged temperatures, with a temperature increase rate of 0.5-1°C / d at 1-4 days old, the temperature is raised to 22°C and maintained for 6 days, and a temperature increase rate of 0.27-0.4°C / d at 10-25 days old, the temperature is raised to 26-28°C, to obtain juvenile fish;

[0008] 3) transferring the juvenile fish to a pond for cultivation to obtain released fry;

[0009] The transfer pond cultivation process includes non-hidden cultivation and hidden cultivation.

[0010] The method for large-scale cultivation of seedlings as described above further includes pretreatment before the hatching process, and the pretreatment includes the following steps:

[0011] The fertilized eggs are stirred to obtain the fertilized eggs to be hatched with an egg diameter of 0.2 cm.

[0012] In the large-scale seedling cultivation method as described above, in step 1), the dissolved oxygen concentration in the hatching water is not less than 6 mg / L, the ammonia nitrogen concentration is <0.5 mg / L, and the nitrite concentration is <0.1 mg / L.

[0013] In the above-mentioned method for large-scale seedling cultivation, in step 1), the hatching water includes nitrifying bacteria and Bacillus subtilis, and the concentration of the nitrifying bacteria is 1.5*10 7 / L or more, the concentration of Bacillus subtilis is 1.5*10 7 Pieces / L or more.

[0014] In the above-mentioned method for large-scale breeding of fry, in step 2), rotifers are fed to fry aged 4 to 10 days, and the density of the rotifers is not less than 10 / mL; the feeding frequency is 4 to 5 times / day;

[0015] and / or, feeding Artemia nauplii of 400 μm to 500 μm to fry of 10-day-old to 25-day-old fish at a feeding frequency of 4 to 5 times per day, wherein the density of Artemia nauplii is 10,000 per L;

[0016] And / or, during the static water temperature raising cultivation, when the average body length of the newly hatched fry is not less than 0.7 cm, flow treatment is carried out, the flow rate is 0.04-0.06 m / s, the flow is created twice a day, the time interval is 10 hours, the flow is created for 2 hours each time, and it lasts for 10 days.

[0017] The method for large-scale seedling cultivation as described above, wherein the stocking density of the non-hidden cultivation is 3000-4000 fish / m 3 ;

[0018] And / or, the breeding density of the hidden culture is 2000-3000 fish / m 3 ;

[0019] And / or, during the hidden cultivation process, flow is created twice a day, the flow rate is 0.2 m / s, the time interval is 10 hours, and the flow is created for 2 hours each time.

[0020] The method for large-scale seedling cultivation as described above, wherein the feed particle size of the transfer pond cultivation is 0.32-0.42 mm, and the feed includes manno-oligosaccharides with a mass content of 0.2%-0.3%;

[0021] And / or, the aquaculture water for the transfer pond cultivation includes biological bait, and the density of the biological bait is 3-4 / mL.

[0022] In the large-scale seedling cultivation method as described above, the ammonia nitrogen concentration of the aquaculture water in the transfer pond cultivation is less than 0.5 mg / L, the nitrite concentration is less than 0.1 mg / L, and the dissolved oxygen is not less than 6 mg / L.

[0023] In the above-mentioned large-scale seedling cultivation method, during the non-hidden cultivation stage, the flow rate of the aquaculture water is 0.06-0.08 m / s;

[0024] And / or, during the hidden cultivation stage, the flow rate of the aquaculture water is 0.09-0.14 m / s.

[0025] The method for large-scale cultivation of seedlings as described above, in step 4), the seedling transfer treatment is also included before the transfer pond cultivation;

[0026] The seedling rotation process is achieved by a seedling rotation device; the seedling rotation device includes a plastic box and a screen;

[0027] The plastic box comprises two long sides, two short sides and a box bottom, the long sides and / or the short sides comprise a plurality of hole structures, and the shortest distance between the hole structures and the box bottom is 40-50 cm;

[0028] The mesh covers the hole structure.

[0029] The method for large-scale breeding of naked heterocystis fry provided by the present invention implements staged breeding according to the biological learning ability, physiological, ecological and nutritional demand characteristics of naked heterocystis fry and juveniles at different developmental stages, establishes a high-density, fast-growing and healthy fry intensive breeding model, solves the problem of low survival rate in the breeding process of naked heterocystis fry, effectively improves the breeding scale and production efficiency of fry, and provides key technical support for large-scale reproduction and release. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the stainless steel chassis structure of the concealing device in another specific embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of the cross-sectional structure of a concealing device in another specific embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of the structure of an air propulsion device in another specific embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the stainless steel frame structure of the air propulsion device in another specific embodiment of the present invention;

[0034] Figure 5 A schematic diagram of a specific example of an ecological circulation system in a specific embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the cross-sectional structure of an ecological treatment pool in a specific embodiment of the present invention;

[0036] Figure 7 It is a schematic diagram of a seedling transfer device in another specific embodiment of the present invention.

[0037] Description of reference numerals:

[0038] 1-breeding pond; 2-ground; 3-water inlet pipe; 4-sewage pipe; 5-drainage pipe; 6-fertilizer water fermentation tank; 7-filter material tank; 8-ecological tank; 9-water pump; 10-insect collecting tank; 11-insect attractant lamp; 12-timer switch; 13-ecological treatment tank; 14-nano oxygenation tube; 15-blower; 16-PVC air pipe; 17-plastic box; 18-20 mesh screen; 19-water filter hole; 20-PVC direct; 21-P VC tube; 22-stainless steel outer net; 23-side net fixing pillar; 24-stainless steel bottom net; 25-stainless steel frame; 26-stainless steel inner net; 27-breeding pond PVC standing pipe; 28-support foot; 29-transparent round glass ball with a diameter of 5-8cm; 30-transparent round glass ball with a diameter of 1.5-2cm; 31-stainless steel frame; 32-nano aeration tube; 33-four-way air pipe joint; 34-three-way air pipe joint. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The present invention provides a method for large-scale cultivation of naked Heterocystis nativus seedlings, comprising the following steps:

[0041] 1) Incubate the fertilized eggs to be incubated at 18°C ​​and a water intake of 0.15 L / min to obtain newly hatched fry;

[0042] 2) The newly hatched fry are cultured in static water at stages. When the fry are 1-4 days old, the temperature is increased at a rate of 0.5-1℃ / d. After the temperature is increased to 22℃, it is maintained for 6 days. When the fry are 10-25 days old, the temperature is increased at a rate of 0.27-0.4℃ / d. The temperature is increased to 26-28℃ to obtain juveniles.

[0043] 3) The juvenile fish are transferred to a culture pond to obtain the released fry; the transfer and cultivation treatment includes non-concealment cultivation and concealment cultivation.

[0044] Specifically, in step 1), the fertilized eggs to be hatched are incubated at 18° C. and a water intake of 0.15 L / min. After 120-130 hours of incubation, newly hatched fry are obtained.

[0045] The existing hatching process is usually carried out in an incubator. After the hatching is completed and the newly hatched fry are obtained, the newly hatched fry are transferred to a breeding pond. Since the newly hatched fry are easily injured by bumps and the like during the transfer process, which may lead to the death of the newly hatched fry, the hatching process in the present invention is directly carried out in the breeding unit.

[0046] The present invention does not limit the size and shape of the breeding unit for hatching. In a specific embodiment, the breeding unit is a circular breeding pond with a diameter of 2-4 m and a depth of 0.6-0.8 m.

[0047] In a specific embodiment, in order to prevent the fertilized eggs to be hatched from sinking to the bottom of the breeding unit and affecting the hatching effect, an aeration and oxygenation device is arranged in the breeding unit.

[0048] In order to ensure the hatching effect and improve the hatching success rate, the appropriate hatching density can be controlled, such as 10,000-15,000 grains / m 3 .

[0049] In step 2), the membrane-broken newly hatched fry are cultured in static water at a staged temperature increase, the refrigeration equipment and water inlet in the culture unit are turned off, and a heating device is placed in the culture unit, wherein the heating rate is 0.5-1°C / d at 1-4 days old, and the temperature is kept at 22°C for 6 days, and the heating rate is 0.27-0.4°C / d at 10-25 days old, and the temperature is raised to 26-28°C to obtain fry.

[0050] In detail, the temperature rise rate within 1-4 days of age includes but is not limited to 0.5℃ / d, 0.6℃ / d, 0.7℃ / d, 0.8℃ / d, 0.9℃ / d, 1.0℃ / d or a range between any two of them; within 10-25 days of age, the temperature rise rate includes but is not limited to 0.27℃ / d, 0.28℃ / d, 0.30℃ / d, 0.32℃ / d, 0.34℃ / d, 0.36℃ / d, 0.38℃ / d, 0.40℃ / d or a range between any two of them.

[0051] In step 3), the fry are transferred to the second breeding unit for transfer pond cultivation, and non-concealment cultivation and concealment cultivation are carried out in the second breeding unit in sequence to obtain release fry that meet the release standards.

[0052] Among them, non-concealed cultivation means that there is no hidden device in the second breeding unit, while concealed cultivation means that a hidden device is placed in the second breeding unit.

[0053] The present invention does not limit the specific type of the concealing device, and a suitable concealing device can be set according to the habits of the naked heterotrophic loach.

[0054] In one specific embodiment, the concealing device is composed of a stainless steel base and a round glass ball. Figure 1 Schematic diagram of the stainless steel base for the concealed device. Figure 2 The cross-sectional structure diagram of the concealment device is shown in FIG. The stainless steel base is a concentric circle structure, which is composed of a support foot 28, a side net fixing pillar 23, a stainless steel frame 25, a stainless steel bottom net 24, a stainless steel outer net 22 and a stainless steel inner net 26. The support foot 28 is 5-10 cm high, the side net fixing pillar 23 is 20 cm high, the stainless steel frame 25 is circular, with a diameter of 0.8-0.9 m, and the stainless steel bottom net 24 is circular, connected to the stainless steel frame 25, with a mesh of 0.5 cm. The stainless steel inner net 26 and the stainless steel outer net 22 are rectangular, 20 cm high, and connected and fixed to the side net fixing pillar 23; the round glass balls have two specifications, one is a transparent round glass ball 29 with a diameter of 5-8 cm, and the other is a transparent round glass ball 30 with a diameter of 1.5-2 cm, and each specification of ball is arranged in 2 layers.

[0055] The method for large-scale breeding of naked heterocysts provided by the present invention is targeted at the biological learning ability, physiological, ecological and nutritional demand characteristics of naked heterocysts at different developmental stages. Naked heterocysts are cultivated in stages to establish a high-density, fast-growing and healthy intensive breeding model for seedlings, solve the problem of low survival rate of fry in the later stage during the breeding process of naked heterocysts, effectively improve the breeding scale and production efficiency of seedlings, and provide key technical support for large-scale reproduction and release. The inventor analyzed this and believed that the reason may be that: on the one hand, the water temperature of the newly hatched fry stage is increased to accelerate the absorption rate of the yolk sac, so that the fry can open their mouths to eat as soon as possible, which greatly improves the survival rate of the newly hatched fry. In addition, by increasing the water temperature, not only the growth rate of the fry is increased, but more importantly, the life cycle of the Ichthyophthirius gambiae is shortened, so that the time that the trophozoite of the Ichthyophthirius gambiae stays on the fish body is as short as possible, which greatly reduces the damage of the trophozoite to the fish body. In addition, the ecosystem is used to control the cysts and larvae of the Ichthyophthirius gambiae in the water body, thereby achieving the purpose of preventing the occurrence of Ichthyophthirius gambiae disease. At the same time, by hiding the fry for hiding, the fry's stress is reduced, and the resistance of the fry is enhanced, thereby improving the fry's ability to avoid natural enemies and improving the survival rate after release.

[0056] Furthermore, in a specific embodiment of the present invention, the incubation process further includes a pretreatment, and the pretreatment includes the following steps:

[0057] The fertilized eggs were stirred to obtain fertilized eggs to be hatched with an egg diameter of 0.2 cm.

[0058] Specifically, after the naked Heterophyte eggs are fertilized, the fertilized eggs are stirred to obtain fertilized eggs to be hatched with an egg diameter of 0.2 cm.

[0059] In one embodiment, the stirring treatment is carried out in a device having a diameter of 0.6-0.8 m.

[0060] Stirring not only ensures uniform mixing of the fertilized eggs, reduces aggregation, and promotes uniform hatching of the fertilized eggs, but also controls the egg diameter to a specific size, which can further improve the hatching success rate.

[0061] It is understandable that the water quality during the incubation process also has an important influence on the hatching success rate. Further, in a specific embodiment of the present invention, in step 1), the dissolved oxygen concentration in the incubation water is not less than 6 mg / L, the ammonia nitrogen concentration is <0.5 mg / L, and the nitrite concentration is <0.1 mg / L.

[0062] In order to ensure that the dissolved oxygen concentration, ammonia nitrogen concentration and nitrite concentration in the hatching water are within the above ranges and to prevent the deterioration of water quality due to the accumulation of egg membranes in the water body caused by the rupture of the fry membranes during the hatching process, in a specific embodiment, in step 1), the hatching water includes nitrifying bacteria and Bacillus subtilis, and the concentration of nitrifying bacteria is 1.5*10 7 / L or more, the concentration of Bacillus subtilis is 1.5*10 7 Pieces / L or more.

[0063] Further, in a specific embodiment of the present invention, in step 2), rotifers are fed to fry aged 4 to 10 days, and the density of rotifers is not less than 10 / mL; the feeding frequency is 4 to 5 times / day;

[0064] Specifically, the newly hatched fry absorb the yolk sac as a source of nutrition when they are 1-5 days old, and are fed rotifers at a feeding frequency of 4-5 times / day when they are 4 days old, and the rotifer density is controlled to be no less than 10 / mL.

[0065] By feeding rotifers at 4 days old, not only is the food palatable to the newly hatched fry and can provide them with rich bait, but it can also enable the fry to gradually adapt to the external bait, stimulate the fry's appetite, reduce stress, and improve the fry's adaptability.

[0066] Feed 10-day-old to 25-day-old fry with Artemia nauplii of 400um-500um in size, 4-5 times a day, with a density of 10,000 Artemia nauplii / L;

[0067] Among them, the present invention does not limit the source of Artemia nauplii, which can be obtained through commercial channels or cultivated by themselves. In a specific embodiment, Artemia nauplii are Artemia nauplii newly hatched larvae that have been hatched for 18 hours under the conditions of water temperature of 30°C, salinity of 3%, and sufficient light. By controlling the hatching time, it is possible to prevent the Artemia individuals from becoming larger due to the hatching time being too long and the fry from being unable to ingest it.

[0068] Feeding Artemia nauplii will not bring the cysts and larvae of Ichthyophthirius gambiae into the breeding pond, which greatly reduces the probability of Ichthyophthirius gambiae outbreak in the fry at this stage.

[0069] During the still water warming cultivation, when the average body length of the newly hatched fry is not less than 0.7 cm, flow treatment is carried out with a flow rate of 0.04-0.06 m / s. The flow is created twice a day with an interval of 10 hours and each time for 2 hours, which lasts for 10 days.

[0070] Among them, flow treatment can be achieved by adding a flow pump in the breeding unit. Through flow treatment, the dirt in the breeding unit can be concentrated for easy discharge, and the swimming ability of the fry can be trained, the predation ability can be improved, and the foundation for subsequent cultivation can be laid.

[0071] Furthermore, in a specific embodiment of the present invention, the stocking density without hidden cultivation is 3000-4000 tails / m 3 ;

[0072] And / or, the stocking density of concealed culture is 2000~3000 fish / m 3 ;

[0073] And / or, during the hidden cultivation process, flow is created twice a day, with a flow rate of 0.2 m / s, a time interval of 10 hours, and each flow creation is 2 hours.

[0074] Specifically, the stocking density without hidden breeding includes but is not limited to 3000 tails / m 3 、3200 / m 3 、3400 / m 3 、3600 / m 3 、3800 / m 3 、4000 / m 3 Or a range between any two of them.

[0075] The stocking density of hidden breeding includes but is not limited to 2000 fish / m 3 、2200 / m 3 、2400 / m3 、2600 / m 3 、2800 / m 3 、3000 / m 3 Or a range between any two of them.

[0076] When the stocking density of non-concealed cultivation and concealed cultivation is within the above range, it can not only efficiently utilize space according to different stages, increase growth rate and improve water quality control, but also reduce cultivation costs.

[0077] In a specific embodiment, air propulsion device is used to create flow.

[0078] The present invention does not limit the specific type of the air propulsion device. A common air propulsion device in the art may be selected, or a device with an air propulsion effect may be independently developed.

[0079] In another specific embodiment, Figure 3 As shown, the air propulsion device consists of a nano oxygenation tube 32, a stainless steel plate 31, a four-way air pipe joint 33 and a three-way air pipe joint 34. The stainless steel plate 31 is a concentric circle structure with a diameter of 0.8 m. The nano oxygenation tube 32 is wound around the stainless steel plate 31 for 3 circles. The joints of the two outer circles are connected with the four-way air pipe joint 33, and the innermost circle is connected with the three-way air pipe joint 34. Figure 4 This is a schematic diagram of the stainless steel plate structure of the air push device.

[0080] Flow treatment can not only promote the discharge of waste and organic matter in the breeding unit and reduce water pollution, but also encourage the fry to swim and forage more, which is helpful for the exercise of physical strength and swimming ability, reduce emergency response and improve survival rate.

[0081] Further, in a specific embodiment of the present invention, the particle size of the feed cultivated in the transfer pond is 0.32-0.42 mm, and the feed includes 0.2%-0.3% manno-oligosaccharide by mass;

[0082] And / or, the aquaculture water in the transfer pond culture includes biological bait, and the density of the biological bait is 3-4 / mL.

[0083] Specifically, during the transfer pond culture (including non-hidden culture and hidden culture), the feed particle size includes but is not limited to 0.32mm, 0.34mm, 0.36mm, 0.38mm, 0.40mm, 0.42mm or a range between any two of them. The feed within the above particle size range matches the intake capacity of the fry and can better provide nutrition for the fry.

[0084] Among them, the mass content of manno-oligosaccharide in every 100g of feed includes but is not limited to 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30% or a range composed of any two thereof.

[0085] The addition of mannan oligosaccharides helps to enhance the immunity and intestinal health of fry, promote the growth of fry, increase the digestion and absorption rate of feed, and further improve the immunity of fry.

[0086] The present invention does not limit the cultivation rules after the transfer pond cultivation, and the feeding frequency and feeding amount can be adjusted according to the feeding situation of the fry. In a specific embodiment, the feed is fed 2-3 times a day, and the feeding amount is 1.2 times the normal feeding amount.

[0087] The present invention does not limit the nutritional composition of the feed after the transfer pond cultivation, and the common feed in the art can be selected.

[0088] Among them, the trapping and cultivation of biological baits and the rotation pond cultivation can be combined to form a circulating aquaculture system to improve the efficiency of aquaculture.

[0089] In one embodiment, the recirculating culture system is as follows Figure 5 As shown, it includes an ecological treatment unit 13, a breeding unit 1, an insect trap unit 11, and a fertilizer and water fermentation unit 6. The ecological treatment unit 13 is a cement pool with a length of 100m, a width of 5m, and a depth of 1.2m. The whole is located below the ground and is 0.3m above the ground. Figure 6 As shown, the ecological treatment unit 13 is divided into 6 pools, namely, the fertilizer water fermentation pool, the filter material pool, the ecological pool 8, the ecological pool 8, the ecological pool 8, and the insect collection pool. The sum of the areas of the fertilizer water fermentation pool and the filter material pool is the same as that of the single ecological pool 8 and the insect collection pool. The fertilizer water fermentation pool is 5m long, 5m wide, and 1.2m deep, the filter material pool is 15m long, 5m wide, and 1.2m deep, and the ecological pool 8 and the insect collection pool are 20m long, 5m wide, and 1.2m deep.

[0090] The fertilizer water fermentation unit 6 includes a fertilizer water fermentation tank and an aeration and oxygenation device, which includes a blower 15, a PE pipe, an air valve, a 0.8 cm diameter hose, and a nano aeration pipe. The blower 15, PE pipe, an air valve, a 0.8 cm diameter hose, and a nano aeration pipe are connected in sequence to form the aeration and oxygenation device.

[0091] The breeding unit consists of a water pump 9, a main water inlet pipe 3, a main water outlet pipe 5 and a two-stage series breeding pool. The two-stage series breeding pool is composed of two circular pools with a diameter of 1m and PP material connected by a PVC inlet and outlet pipe system. There are two levels of breeding pools. The first-level breeding pool is 1.2m high and 0.6m deep; the second-level breeding pool is 0.8m high and 0.6m deep; the bottom of each breeding pool is supported by a PP board. The water inlet pipe of the first-level breeding pool is a 6.3cm diameter PVC pipe, and the outlet pipe is the water inlet pipe of the next-level breeding pool, which is a 7.5cm diameter PVC pipe. The drainage pipe of the second-level breeding pool is connected to the main water outlet pipe, and the main water outlet pipe is connected to the ecological treatment unit. A sewage pipe is set at the bottom of each breeding pool, and a valve is provided, and it is connected to the main sewage pipe.

[0092] A stainless steel plate is laid at the bottom of the filter pool. The plate is 14.8m long and 4.8m wide, with a support foot 0.3m high. Biological filter materials are placed on the stainless steel plate. From top to bottom, the biological filter materials are expanded clay, bio-balls and volcanic rocks, with particle sizes of 3cm, 8cm and 15cm respectively. Their function is to remove large suspended particles and purify water quality.

[0093] The insect attracting unit is composed of an insect attracting lamp 11, a timer switch 12, and an insect collecting pool. The insect attracting lamp 11 is a halogen lamp with an illumination of 200 lx, which is turned on at 8 o'clock in the evening and turned off at 6 o'clock in the morning. The bait organisms in the water are attracted to the lamp and pumped into the breeding pool by the water pump for the fry to eat.

[0094] Two weeks before the fry are transferred to the pond for cultivation, the water body of the ecological treatment unit is prepared: add water to the fertilizer water fermentation tank to a depth of 80cm, pour in 20kg of feed, turn on the aeration and oxygenation device, and stir 3 times a day to make the feed fully dissolved in the water body; after 4 days, when the feed is completely dissolved, the water body is earthy yellow. At this time, the source of microalgae such as Chlorella is connected to the fertilizer water tank at a rate of 1000g / m 3 Add Bacillus subtilis and Bacillus licheniformis to the fertilizer water, add a multivitamin preparation at 600 g / m3 of fertilizer water, and cultivate for another 5 days until the fertilizer water turns green, then open the water inlet of the fertilizer water fermentation tank to allow the fermented fertilizer water to slowly overflow into the filter tank and ecological pool. After the fertilizer water is added, turn on the ecological spraying equipment and aeration and oxygenation device. After 8 days of cultivation, the water in the ecological treatment unit turns green, the density of all bait organisms such as rotifers, cladocerans, and copepods is 1-2 / mL, and the ammonia nitrogen concentration in the water is <0.5mg / L and the nitrite concentration is <0.1mg / L, then transfer the fry into the system for transfer pond cultivation.

[0095] Before the fry are transferred in, the water temperature is controlled at around 26-28℃ by switching on and off the spraying equipment; one day before the fry are transferred in, the water pump operation system is turned on and the water inlet of each breeding pond is controlled at 0.5m3 / h. The purpose is to filter and intercept bait organisms such as cladocerans and copepods through the screen of the middle station pipe of the breeding pond, and retain the bait organisms in the breeding pond, so that the density of bait organisms in the breeding pond is 3~4 / mL.

[0096] Furthermore, in a specific embodiment of the present invention, the ammonia nitrogen concentration of the aquaculture water in the transfer pond cultivation is <0.5 mg / L, the nitrite concentration is <0.1 mg / L, and the dissolved oxygen is not less than 6 mg / L.

[0097] Maintaining these water quality parameters within the recommended range helps create a healthy culture environment, thereby promoting healthy growth and high survival rates of fry.

[0098] Further, in a specific embodiment of the present invention, there is no hidden cultivation stage, and the flow rate of the aquaculture water is 0.06-0.08 m / s;

[0099] And / or, during the hidden cultivation stage, the flow rate of the aquaculture water is 0.09-0.14m / s.

[0100] In detail, there is no hidden cultivation stage, and the aquaculture water flow rate includes but is not limited to 0.06m / s, 0.062m / s, 0.064m / s, 0.066m / s, 0.068m / s, 0.070m / s, 0.072m / s, 0.074m / s, 0.076m / s, 0.078m / s, 0.08m / s or a range between any two of them.

[0101] During the hidden cultivation stage, the flow rate of the aquaculture water includes but is not limited to 0.09 m / s, 0.10 m / s, 0.11 m / s, 0.12 m / s, 0.13 m / s, 0.14 m / s or a range between any two of them.

[0102] In another specific embodiment of the present invention, during the first 10 days of the hidden cultivation stage, the flow rate of the aquaculture water is 0.09-0.10 m / s, and after 10 days of the hidden cultivation stage, the flow rate of the aquaculture water is 0.11-0.14 m / s.

[0103] When the flow rate of the aquaculture water is controlled in stages within the above range, the physiological needs and behavioral characteristics of the fry at different growth stages are met. These flow rate differences help optimize the environment and improve the health and growth of the fry.

[0104] Furthermore, in a specific embodiment of the present invention, in step 4), the seedling transfer process is also included before the transfer pond cultivation;

[0105] The seedling rotation process is achieved by a seedling rotation device; Figure 7 As shown, the seedling transfer device includes a plastic box 17 and a screen 18;

[0106] The plastic box comprises two long sides, two short sides and a box bottom, the long sides and / or the short sides comprise a plurality of hole structures 19, and the shortest distance between the hole structures 19 and the box bottom is 40-50 cm;

[0107] A screen 18 covers the aperture structure.

[0108] During use, the water in the breeding pond is drained to a depth of 30 cm, the device is inserted into the drain pipe outside the breeding pond, the standing pipe with a screen in the middle of the breeding pond is pulled out, and the fry are brought into the fry collecting device along the direction of the water outflow. When the water in the pond is almost drained, the water inlet of the breeding pond is opened to the maximum, and the fry remaining in the drain pipe is flushed into the fry collecting device, the device is lifted, and the fry are transferred to the next-level breeding facility.

[0109] The present invention does not limit the size of the plastic box, and a plastic box of appropriate size can be selected according to actual needs. In a specific embodiment, the plastic box is 1-1.5m long, 0.5-1m wide, 0.8-1.0m high, and 0.2-0.3cm thick.

[0110] It is understandable that the number of hole structures and the hole spacing on the long side and / or short side of the plastic box can be adjusted according to actual conditions.

[0111] In one specific embodiment, the long side of the plastic box has 20-30 rows of holes with a diameter of 2 cm, each row has 5-8 hole structures, and the hole spacing is 2 cm. The short side of the plastic box has 10-20 rows of holes with a diameter of 2 cm, each row has 5-8 holes, and the hole spacing is 2 cm.

[0112] You can choose a suitable screen according to actual needs, as long as it can ensure that the fry are not carried away from the fry transfer device by the water flow, for example, choose a 20-mesh screen.

[0113] In order to improve the firmness of the screen, in a specific method, a 20-mesh screen is used to seal the hole structure of the long side and the short side and fixed to the box with hot melt adhesive. The long side screen is 0.9-1.3m long and 0.3-0.4m wide, and the short side screen is 0.5-0.9m long and 0.3-0.4m wide.

[0114] In another specific embodiment, Figure 7As shown, the seedling transfer device also includes a PVC pipe 21 and a PVC pipe 20, wherein the bottom of the plastic box 17 includes a hole structure 19 with a diameter of 110 mm in the middle, the diameter of the PVC pipe 21 is 110 mm, matching the diameter of the drainage pipe at the bottom of the pool; the diameter of the PVC pipe 20 is 110 mm, and its size matches the PVC pipe 21; the PVC pipe 21 is connected to the PVC pipe 20, fixed and glued with PVC glue, and then inserted into the hole at the bottom of the box and fixed, and glued with hot melt glue. All naked loach and bream seedlings lie on the bottom of the pool. When the fry are transferred to the pool for cultivation, the fry are all on the bottom and the total length is less than 1 cm. Using a scoop net to scoop the fry will cause a large number of fry to be injured and die. The use of the above-mentioned seedling transfer device can completely avoid this problem, and the survival rate of the transferred fry reaches 100%.

[0115] The following is an introduction to the large-scale cultivation method of seedlings provided by the present invention through specific examples.

[0116] In April 2024, the method provided by the present invention was used to carry out large-scale breeding of naked Heterophyte scorpion seedlings at the Wudongde Reproduction and Release Station of the Chinese Sturgeon Research Institute of China Three Gorges Corporation, which specifically includes the following steps:

[0117] 1. Incubation treatment:

[0118] After the eggs are fertilized, they are stirred in a basin with a diameter of 0.6m. When the diameter of the eggs reaches about 0.2cm, they are poured into the breeding pond for incubation. The hatching density of fertilized eggs is 15,000 eggs / m 3 A 2m diameter and 0.8m deep breeding pond was selected as the breeding and hatching pond. An aeration and oxygenation device was installed in the breeding pond. The water temperature in the breeding pond was adjusted to the same as the induced spawning water temperature before the fertilized eggs were transferred in. During the incubation process, the water temperature was controlled at around 18°C, the water intake was 0.15L / min, the dissolved oxygen was maintained above 6mg / L, the ammonia nitrogen concentration was <0.5mg / L, and the nitrite concentration was <0.1mg / L. When the fertilized eggs entered the tail teeth stage, 300g / m 3 Nitrifying bacteria and Bacillus subtilis were added, and newly hatched fry were obtained after 120 hours of incubation.

[0119] 2. Stage static water temperature cultivation:

[0120] After the newly hatched fry breaks the membrane, turn off the refrigeration equipment of the circulation system, turn off the water inlet of the breeding pond, place a heating device in the breeding pond, and slowly increase the water temperature at a rate of 1°C / d. At 4 days old, the water temperature reaches 22°C and maintains this temperature for 6 days. At 4 days old, that is, the day before the yolk sac is absorbed, start feeding rotifers, feeding 4 to 5 times a day, and the rotifer density in the water in the pond should reach more than 10 / ml. When the fry reaches 10 days old, start feeding Artemia nauplii, feeding 4 to 5 times a day. During the 10-day-old-25-day-old cultivation stage, the water temperature gradually increases from 22°C to 28°C, with a rate of 0.4°C / d. Artemia nauplii are newly hatched Artemia nauplii that have been hatched for 18 hours under the conditions of water temperature of 30°C, salinity of 3%, and sufficient light. When the fry reach a total length of 0.7 cm, add a flow pump to the breeding pond to create flow for 2 hours a day, once in the morning and once in the evening. Control the flow rate at 0.04 m / s. Monitor the water quality every day. The ammonia nitrogen concentration is <0.5 mg / L, the nitrite concentration is <0.1 mg / L, and the dissolved oxygen is maintained above 6 mg / L to obtain fry.

[0121] 3. Use Figure 7 The seedling transfer device shown in the figure is used to transfer fry, wherein the seedling transfer device is composed of a plastic box, a 20-mesh screen, a PVC pipe, and a PVC pipe; the plastic box is 1m long, 0.5m wide, 0.8m high, and 0.2cm thick, including 2 long sides, 2 short sides, and 1 box bottom; there are 20 rows of holes with a diameter of 2cm on the long side of the plastic box, 5 holes in each row, and a hole spacing of 2cm, and the distance between the bottom row of holes and the box bottom is 40cm; there are 10 rows of holes with a diameter of 2cm on the short side of the plastic box, 5 holes in each row, and a hole spacing of 2cm, and the distance between the bottom row of holes and the box bottom is 40cm; a hole with a diameter of 110mm is punched in the middle of the box bottom. The PVC pipe is a PVC pipe with a diameter of 110mm, and its diameter size matches the diameter of the drainage pipe at the bottom of the pool; the PVC pipe is a PVC pipe with a diameter of 110mm, and its size matches the PVC pipe; the PVC pipe is connected to the PVC pipe, fixed and glued with PVC glue, and then inserted into the hole at the bottom of the box for fixing, and fixed with hot melt glue. Use a 20-mesh screen to seal the perforated areas on the long and short sides and fix them to the box with hot melt adhesive. The long side screen is 0.9m long and 0.3m wide, and the short side screen is 0.5m long and 0.3m wide.

[0122] Drain the water in the culture pond to a depth of 30 cm, insert the seedling transfer device into the drain pipe outside the culture pond, pull out the standing pipe with a screen in the middle of the culture pond, and the fry are brought into the fry collection device along the direction of the water outflow. When the water in the pond is almost drained, open the water inlet of the culture pond to the maximum, and flush the fry remaining in the drain pipe into the fry collection device. At this time, insert a PVC pipe with a length of 40 cm and a diameter of 110 mm directly into the PVC of the fry collection device to prevent the fry from flowing out from the middle. Then lift the device and transfer the fry into the second culture unit.

[0123] 4. Transfer pond cultivation

[0124] 1) Build an ecological cultivation system

[0125] The ecological cultivation system consists of an ecological treatment unit, a breeding unit, an insect trap unit, and a fertilizer and water fermentation unit. The ecological treatment unit is a cement pool with a length of 100m, a width of 5m, and a depth of 1.2m. It is located below the ground as a whole and is 0.3m above the ground. The ecological treatment unit is divided into 6 pools, namely, the fertilizer and water fermentation pool, the filter pool, the ecological pool, the ecological pool, the ecological pool, and the insect collection pool. The sum of the areas of the fertilizer and water fermentation pool and the filter pool is the same as that of a single ecological pool and an insect collection pool. The fertilizer and water fermentation pool is 5m long, 5m wide, and 1.2m deep, the filter pool is 15m long, 5m wide, and 1.2m deep, and the ecological pool and insect collection pool are 20m long, 5m wide, and 1.2m deep.

[0126] The fertilizer and water fermentation unit includes a fertilizer and water fermentation tank and an aeration and oxygenation device. The aeration and oxygenation device includes a blower, a PE pipe, an air valve, a 0.8 cm diameter hose, and a nano aeration pipe. The blower, PE pipe, air valve, 0.8 cm diameter hose, and nano aeration pipe are connected in sequence to form the aeration and oxygenation device.

[0127] The breeding unit consists of a water pump, an inlet main pipe, an outlet main pipe and a two-stage series breeding pool. The two-stage series breeding pool is composed of two 1m diameter PP circular pools connected by a PVC inlet and outlet pipe system. There are two levels of breeding pools. The first-level breeding pool is 1.2m high and 0.6m deep; the second-level breeding pool is 0.8m high and 0.6m deep; the bottom of each breeding pool is supported by a PP board. The inlet pipe of the first-level breeding pool is a 6.3cm diameter PVC pipe, and the outlet pipe is the inlet pipe of the next-level breeding pool, with a diameter of 7.5cm PVC pipe. The drainage pipe of the second-level breeding pool is connected to the outlet main pipe, and the outlet main pipe is connected to the ecological treatment unit. A sewage pipe is set at the bottom of each breeding pool, with a valve and connected to the main sewage pipe.

[0128] The filter pool has a stainless steel plate at the bottom. The plate is 14.8m long and 4.8m wide, with a support foot 0.3m high. Biological filter media are placed on the plate. From top to bottom, the biological filter media are expanded clay, bio-balls and volcanic rocks, with particle sizes of 3cm, 8cm and 15cm respectively. Their function is to remove large suspended solids and purify water quality.

[0129] The insect attracting unit consists of an insect attracting lamp, a timer switch, and an insect collecting pool. The insect attracting lamp is a halogen lamp with an illumination of 200lx, which is turned on at 8 pm and turned off at 6 am. The bait organisms in the water are attracted to the lamp and pumped into the breeding pool by the water pump for the fry to eat.

[0130] Two weeks before the fry enter the transfer pond for cultivation, add water to the fertilizer water fermentation tank to a depth of 80cm, pour in 20kg of feed, turn on the aeration and oxygenation device, and stir 3 times a day to make the feed fully dissolved in the water body; after 4 days, when the feed is completely dissolved, the water body is earthy yellow. At this time, the source of microalgae such as Chlorella is connected to the fertilizer water tank at a rate of 1000 g / m 3 Add Bacillus subtilis and Bacillus licheniformis to the fertilizer water at 600 g / m 3 Add multivitamin preparations to the fertilizer water, and then cultivate it for 5 days until the fertilizer water turns green. Then, open the water inlet of the fertilizer water fermentation tank to allow the fermented fertilizer water to slowly overflow into the filter tank and ecological pool.

[0131] After the fertilizer water was added, the ecological spraying equipment and aeration oxygenation device were turned on. After 8 days of cultivation, the water in the ecological treatment unit turned green, the density of all bait organisms such as rotifers, cladocerans, and copepods was 1~2 / mL, and the ammonia nitrogen concentration in the water was <0.5mg / L, and the nitrite concentration was <0.1mg / L.

[0132] Before the fry are transferred in, the water temperature is controlled at around 26-28℃ by switching on and off the spraying equipment. One day before the fry are transferred in, the water pump operation system is turned on and the water inflow of each breeding pond is controlled at 0.5m 3 / h. The purpose is to intercept cladocerans, copepods and other bait organisms through the screen of the middle station pipe of the breeding pond, retain the bait organisms in the breeding pond, and make the density of bait organisms in the breeding pond be 3~4 / mL.

[0133] 2) Transfer pond cultivation

[0134] No hidden cultivation stage: When the 26-day-old fry are just transferred into the culture system, the culture density of each 1m diameter culture pond is 3000 fish / m 3 Clean the screen of the intermediate station pipe once a week, feed twice a day with a particle size of 0.32-0.42mm, and add 0.2-0.3g of manno-oligosaccharide to every 100g of feed to improve the disease resistance of Ichthyophthirius multifiliis; the feeding amount is 1.2 times the normal feeding amount, and the remaining uneaten feed is discharged into the fertilizer water fermentation tank as the raw material of fertilizer water. The cultivation time of this stage lasts for 15 days, during which the breeding water temperature is controlled at 26-28℃, the ammonia nitrogen concentration in the water is <0.5mg / L, the nitrite concentration is <0.1mg / L, and the dissolved oxygen is maintained above 6mg / L.

[0135] Hidden cultivation stage: When the fry reach 41 days old, they enter the ecological cycle hidden cultivation stage. A hidden device that can hide is placed in the breeding pond. An air push device is placed under the hidden device. The air push device is turned on once a week to backwash the hidden device to wash away the dirt deposited in the hidden device. In addition, by turning on the air push device, a reverse flow rate of 0.2m / s is generated to exercise the swimming ability of the fry. The breeding density at this stage is adjusted to 2000 / m 3 Clean the screen of the intermediate station pipe once a week, feed twice a day with a particle size of 0.32-0.42 mm, and add 0.2-0.3 g of manno-oligosaccharide to every 100 g of feed to improve the disease resistance of Ichthyophthirius multifiliis; the feeding amount is 1.2 times the normal feeding amount, and the remaining uneaten feed is discharged into the fertilizer and water fermentation tank as the raw material of the fertilizer and water. During this stage, the fish are cultivated until release to obtain the release seedlings.

[0136] The hidden device is composed of a stainless steel base and a round glass ball. The stainless steel base is a concentric circle structure, consisting of a support foot, a side net fixing pillar, a stainless steel frame, a stainless steel bottom net, a stainless steel outer net and a stainless steel inner net. The support foot is 5 cm high, the side net fixing pillar is 20 cm high, the stainless steel frame is circular, with a diameter of 0.8 m, the stainless steel bottom net is circular, connected to the stainless steel frame, and has a mesh of 0.5 cm. The inner and outer stainless steel nets are rectangular, 20 cm high, and connected and fixed to the side net fixing pillars; the round glass ball has two specifications, one is a transparent round glass ball with a diameter of 5 cm, and the other is a transparent round glass ball with a diameter of 1.5 cm. Each specification of ball is arranged in 2 layers.

[0137] The air propulsion device is composed of a nano oxygenation tube, a stainless steel plate, a four-way air pipe joint and a three-way air pipe joint. The stainless steel plate is a concentric circle structure with a diameter of 0.8m. The nano oxygenation tube is wrapped around the stainless steel plate for 3 circles. The joints of the two outer circles are connected with a four-way air pipe joint, and the innermost circle is connected with a three-way air pipe joint.

[0138] Within 1 to 15 days after the fry are transferred in, the water flow rate in the pond is controlled at 0.06m / s by adjusting the water inlet volume and water inlet angle; within 16 to 25 days after the transfer, the water flow rate in the pond is controlled at 0.10m / s; thereafter, until the release, the water flow rate in the pond is controlled at 0.14m / s; the breeding pond is discharged 1 to 2 times a day, and the sewage enters the fertilizer water fermentation tank for fermentation. The fertilizer water fermentation tank is regularly hydrated at 1000g / m 3 Bacillus subtilis and Bacillus licheniformis are added to the fertilizer water, and the fermented wastewater can be used as a nutrient source for the microalgae in the ecological pond. The sewage in the fertilizer water fermentation pond is always in a full storage state. The amount of sewage discharged every day will overflow into the filter tank and the ecological pond to produce fermented fertilizer water, truly achieving zero discharge of circulating water.

[0139] Through the above-mentioned breeding method, the Wudongde Stocking and Release Station of the Chinese Sturgeon Research Institute of China Three Gorges Corporation will cultivate 50,000 seedlings of release specifications in 2024, and release 30,000 on June 29, 2024.

[0140] Example 2

[0141] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0142] Step 1) No pretreatment is performed before the hatching process, and the fertilized eggs are directly hatched in the breeding pond.

[0143] Example 3

[0144] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0145] In step 1), the dissolved oxygen concentration is 5.5 mg / L.

[0146] The hatching rates of the seedling-scale cultivation methods provided in Examples 1-3 were statistically analyzed, and the specific results are shown in Table 1.

[0147] Table 1

[0148]

[0149] Example 4

[0150] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0151] In step 2), the rotifer density is 5 / mL.

[0152] Example 5

[0153] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0154] In step 2), when the body length of the newly hatched fry is not less than 0.7 cm, no flow generation treatment is performed.

[0155] Example 6

[0156] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0157] In step 4), the stocking density without hidden cultivation is 4500 fish / m 3 The stocking density of hidden culture is 3500 fish / m 3 .

[0158] Example 7

[0159] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0160] In step 4), the feed does not contain manno-oligosaccharides.

[0161] Example 8

[0162] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0163] In step 4), the aquaculture water does not include biological bait.

[0164] Example 9

[0165] The method for large-scale cultivation of seedlings provided in this embodiment is basically the same as that provided in Example 1, except that:

[0166] In step 4), the flow rate of the aquaculture water during the non-hidden cultivation stage is 0.05 m / s.

[0167] Comparative Example 1

[0168] The method for large-scale cultivation of seedlings provided in this comparative example is basically the same as that in Example 1, except that:

[0169] In step 2), the temperature of the culture water is maintained at 22°C during the period from 1 to 25 days of age.

[0170] Test Case

[0171] The fry cultured by the methods provided in all the embodiments and comparative examples were recorded, and the relevant data are shown in Table 2.

[0172] Table 2

[0173]

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for large-scale cultivation of naked Heterocystis nativus seedlings, characterized in that: The following steps are involved: 1) Incubate the fertilized eggs to be incubated at 18°C ​​and a water intake of 0.15 L / min to obtain newly hatched fry; 2) The newly hatched fry are cultured in static water at staged temperatures, with a temperature increase rate of 0.5-1°C / d at 1-4 days old, the temperature is raised to 22°C and maintained for 6 days, and a temperature increase rate of 0.27-0.4°C / d at 10-25 days old, the temperature is raised to 26-28°C, to obtain juvenile fish; 3) transferring the juvenile fish to a pond for cultivation to obtain released fry; The transfer pond cultivation process includes non-hidden cultivation and hidden cultivation.

2. The method for large-scale cultivation of seedlings according to claim 1, characterized in that: The incubation process also includes a pretreatment, which includes the following steps: The fertilized eggs are stirred to obtain the fertilized eggs to be hatched with an egg diameter of 0.2 cm.

3. The method for large-scale cultivation of seedlings according to claim 1 or 2, characterized in that: In step 1), the dissolved oxygen concentration in the hatching water is not less than 6 mg / L, the ammonia nitrogen concentration is less than 0.5 mg / L, and the nitrite concentration is less than 0.1 mg / L.

4. The method for large-scale cultivation of seedlings according to claim 3, characterized in that: In step 1), the incubation water includes nitrifying bacteria and Bacillus subtilis, and the concentration of the nitrifying bacteria is 1.5*10 7 / L or more, the concentration of Bacillus subtilis is 1.5*10 7 Pieces / L or more.

5. The method for large-scale cultivation of seedlings according to any one of claims 1 to 4, characterized in that: In step 2), rotifers are fed to fry aged 4 to 10 days, and the density of the rotifers is not less than 10 / mL; the feeding frequency is 4 to 5 times / day; and / or, feeding Artemia nauplii of 400 μm to 500 μm to fry of 10-day-old to 25-day-old fish at a feeding frequency of 4 to 5 times per day, wherein the density of Artemia nauplii is 10,000 per L; And / or, during the static water temperature raising cultivation, when the average body length of the newly hatched fry is not less than 0.7 cm, flow treatment is carried out, the flow rate is 0.04-0.06 m / s, the flow is created twice a day, the time interval is 10 hours, the flow is created for 2 hours each time, and it lasts for 10 days.

6. The method for large-scale cultivation of seedlings according to any one of claims 1 to 5, characterized in that: The breeding density of the non-hidden culture is 3000-4000 tails / m 3 ; And / or, the breeding density of the hidden culture is 2000-3000 fish / m 3 ; And / or, during the hidden cultivation process, flow is created twice a day, the flow rate is 0.2 m / s, the time interval is 10 hours, and the flow is created for 2 hours each time.

7. The method for large-scale cultivation of seedlings according to any one of claims 1 to 6, characterized in that: The particle size of the feed cultivated in the transfer pond is 0.32-0.42 mm, and the feed includes manno-oligosaccharide with a mass content of 0.2%-0.3%; And / or, the aquaculture water for the transfer pond cultivation includes biological bait, and the density of the biological bait is 3-4 / mL.

8. The method for large-scale cultivation of seedlings according to claim 7, characterized in that: The ammonia nitrogen concentration of the aquaculture water in the transfer pond cultivation is <0.5mg / L, the nitrite concentration is <0.1mg / L, and the dissolved oxygen is not less than 6mg / L.

9. The method for large-scale cultivation of seedlings according to any one of claims 1 to 8, characterized in that: In the non-hidden cultivation stage, the flow rate of the aquaculture water is 0.06-0.08 m / s; And / or, during the hidden cultivation stage, the flow rate of the aquaculture water is 0.09-0.14 m / s.

10. The method for large-scale cultivation of seedlings according to claim 1, characterized in that: In step 4), the seedling transfer process is also included before the transfer pond cultivation; The seedling rotation process is achieved by a seedling rotation device; the seedling rotation device includes a plastic box and a screen; The plastic box comprises two long sides, two short sides and a box bottom, the long sides and / or the short sides comprise a plurality of hole structures, and the shortest distance between the hole structures and the box bottom is 40-50 cm; The mesh covers the hole structure.

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