Hybrid sturgeon constant-temperature circulating running water hatching and breeding method suitable for Tibet region

Abstract

The invention provides a hybrid sturgeon constant-temperature circulating running water hatching and breeding method suitable for Tibet regions. The method comprises the following steps that hybrid sturgeon eyed eggs which are bright in color and good in quality are introduced, the eggs are soaked in an iodine solution before hatching, and a hatching device is disinfected with potassium permanganate 7 days before hatching; the hatching device adopts a hatching tank and a hatching cylinder, eyed eggs are uniformly spread at the bottom of the hatching tank, constant-temperature circulating water flows in the hatching cylinder, and stirring and ventilation of a hatching water body are kept; the fries begin to float upwards to open for ingestion when membranes of the fries are broken and yolk sacs disappear, and the fries are successively transferred to a hatching tank in batches for centralized cultivation after floating for ingestion; separating the fish larvae according to different specifications on the tenth day after the fish larvae are transferred to the hatching tank, separating the fish larvae once every 10 days in the subsequent breeding process, and transferring the fish larvae to an indoor running water cement pond for large-scale breeding until the fish larvae grow to the average specification of 0.7 g per fish and the length of 5cm after the 50 days. The effects of hatching the eye eggs of the hybrid sturgeons and breeding the fries in the Tibet plateau area are remarkable.

Description

Technical Field

[0001] The invention belongs to the technical field of fish breeding, and in particular relates to a method for hatching and raising hybrid sturgeons in constant-temperature circulating water suitable for Tibet. Background Art

[0002] The Siberian sturgeon is a wide-temperature fish that grows in water temperatures between 15 and 25 degrees Celsius. It is good at surviving in cold waters and adapting to low-temperature environments. This sturgeon is resistant to low oxygen and pollution, and can adapt to different water conditions, including clear waters rich in oxygen and oxygen-deficient muddy bottoms. The spoonbill is highly tolerant to salt and can survive in freshwater and brackish water environments. It has strong adaptability and is also an excellent spawning fish with strong reproductive capacity, which is conducive to the sustainability of the population. Hybrid sturgeons may have a higher survival rate and better resistance to environmental changes and diseases, making them more suitable for breeding and protection. They usually have a faster growth rate than purebred sturgeons, which allows them to reach maturity and market availability faster.

[0003] Due to its special plateau geography and climate, the Tibetan Plateau has low temperatures throughout the year, a large temperature difference between day and night, a slow rise in water temperature in spring, and a rapid drop in water temperature in autumn. Introducing hybrid sturgeons of Siberian sturgeon and Chinese sturgeon into Tibet for breeding, carrying out artificial breeding of hybrid sturgeons and improving their survival rate are of great significance to the development of economic fish in Tibet. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a method for hybrid sturgeon constant temperature circulating water hatching and seedling raising suitable for the Tibet region, which has the advantages of high hatching rate and high survival rate.

[0005] The technical solution adopted by the present invention is:

[0006] A method for hatching and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet, comprising the following steps:

[0007] A. Preparation before hatching

[0008] Introduce bright-colored, high-quality hybrid sturgeon eyed eggs, soak the eggs in iodine solution before hatching, and rinse the eggs thoroughly with clean water after soaking to remove the residual iodine solution; use indoor hatching equipment, and disinfect the hatching equipment with potassium permanganate for the first 7 days of hatching to disinfect harmful pathogens;

[0009] B. Incubation

[0010] The hatching device uses a hatching trough and a hatching tank to evenly spread the eyed eggs at the bottom of the hatching trough to avoid accumulation, stacking, and dead corners. The hatching trough is placed on the hatching tank, and the hatching tank is filled with a constant temperature circulating water flow to keep the hatching water body stirred and ventilated to ensure that the fish eggs obtain sufficient oxygen and nutrients; the fry begin to float up and eat after the membrane breaks and the yolk sac disappears, and the fry are transferred to the hatching tank in batches for centralized cultivation after floating up and eating.

[0011] C. Seedling cultivation

[0012] On the 10th day after being transferred to the hatching tank, the fry are separated according to different sizes. The larger fry are transferred to the nursery tank with constant temperature circulating water flow for cultivation. During the subsequent cultivation process, the fry are separated every 10 days until the fry grow to an average size of 0.7g / tail and 5cm long after the 50th day, and then transferred to the indoor flowing water cement pool for large-scale breeding;

[0013] The method of dividing the fry into tanks according to specifications is adopted to reduce the density of fry, increase the dissolved oxygen content in the water, and ensure the hatching rate of eyed eggs and the survival rate of fry.

[0014] D. Large-scale farming

[0015] The water temperature of the indoor flowing cement pool is controlled at 12-14℃, the nitrite content is less than 0.25mg / l, and the water flow rate is 0.005m 3 / s, pH value 7.98-8.24, stocking density 1000-1200 fish / ㎡, feeding three times a day, feeding appropriate caliber feed according to the size of the fry.

[0016] The water flow rate at the water inlet of the hatching tank and the seedling tank of the present invention is 0.001m 3 / s, daily water exchange>150%. If the flow rate exceeds 0.001m 3 / s, the fry swim weakly and the stress response is too strong, which may easily cause the fry to die; if the flow rate is less than 0.001m 3 / s, the water filtration efficiency is weakened, affecting the ammonia nitrogen content and pH of the water quality.

[0017] The stocking density of fry in the hatching tank of the present invention is 20,000 fry / ㎡, and dead eggs and dead fish are picked out in time.

[0018] The invention soaks the fish eggs with 5 mg / L iodine solution for 10-15 minutes before hatching to kill pathogens that may exist on the surface and prevent disease transmission.

[0019] The dissolved oxygen content in the hatching tank and the seedling raising tank of the invention is 5.16-6.28 mg / L, the water temperature is 17.5-18.5°C, the pH value is 7.6-8.2, the salinity is 172-206 mg / L, the ammonia nitrogen content is 0.05-0.2 mg / L, and the nitrite content is 0.01-0.05 mg / L.

[0020] Hybrid sturgeons are sensitive to water temperature and nitrite content. The water temperature for incubating sturgeon eyed eggs should be controlled at 17.5-18.5℃. Water temperature that is too high or too low is not conducive to the hatching of fry. When the nitrite content is higher than 0.05, the fry will eat less.

[0021] The step C of the present invention comprises feeding a microparticle compound feed specially used for sturgeon fry produced by Shandong Shengsuo Feed Technology Co., Ltd. to train the fry to start eating, wherein the feed particle size is 0.6 mm, and the fry are fed 6-8 times a day, and the fry can finish eating the feed within 10-20 minutes each time; at the initial stage of feeding, the feed is mixed with water and formed into a ball shape, the ball diameter is 2 cm, and the feeding amount each time is 0.35 g / 1,000 fish tails; after the fry grow to an average weight of 0.3 g / tail, the feeding amount each time is adjusted to 0.5 g / 1,000 fish tails, and as the fry grow, the feed is gradually converted from microparticle feed to granular feed.

[0022] The hatching device of the present invention comprises a hatching trough and a hatching cylinder. The bottom of the hatching trough is a mesh surface and is placed on the hatching cylinder. Water inlet pipes are arranged on opposite sides of the hatching cylinder. The water outlet of the water inlet pipe is arranged along the cylinder wall, and the water outlet direction is clockwise or counterclockwise. A drainage pipe is arranged on the upper part of the hatching cylinder. The two water inlet pipes are connected to an external water supply pipe, and the water supply pipe is connected to a water inlet pump. A hot water pipe is coiled around the inner wall of the hatching cylinder, and the hot water pipe is connected to an external heat exchanger. A temperature sensor is arranged in the hatching cylinder. An air inlet pipe is arranged at the bottom of the hatching cylinder, and the air inlet pipe is connected to an external oxygenation device, and an aeration stone is arranged in the air inlet pipe.

[0023] Preferably, the hot water pipe and the air inlet pipe are provided on the inner wall of the seedling raising tank, the drain pipe is provided at the upper part of the tank body, and the water inlet pipe is provided at the lower part on the opposite side of the drain pipe; the water inlet and outlet of the hatching tank and the seedling raising tank are provided with 3-4 layers of filter screens to filter impurities and aquatic organisms and control the flow rate of the water body, and the drain pipes are provided with filter screens to prevent the fry from escaping.

[0024] Further preferably, the hatching tank and the seedling tank are 0.4-0.5m high, the hatching tank is provided with a tank cover, and an adjustable LED lamp is provided inside the tank cover. Although strong sunlight is not required for hatching sturgeon eggs, moderate light helps to maintain the ecological balance of the water body and prevent mold growth. The installation of LED lamps is conducive to indoor hatching light supplement. The hatching tank is 0.4-0.5m high, which is conducive to aeration and stirring of the water body at the bottom of the tank, and prevents the deposition of water mold at the bottom of the hatching frame.

[0025] Further preferably, one of the incubation devices and five seedling raising tanks are integrated into a constant temperature circulating water incubation system, the drainage pipes of the incubation tank and the seedling raising tank are connected to the filtering device through the main drainage pipe, the filtering device is connected to the water storage tank, the water storage tank is connected to the ecological pool, the ecological pool is connected to the ultraviolet sterilization device, the ultraviolet sterilization device is connected to the water supply main pipe, and the water supply main pipe is connected to the corresponding water inlet pump through the water supply branch; the ecological pool uses aquatic plants and microorganisms to remove ammonia nitrogen and nitrify.

[0026] The beneficial effects of the present invention are:

[0027] 1. When hatching sturgeon eggs, avoid exposing the eggs to direct sunlight to prevent the influence of too high temperature and too strong light on the eggs. Therefore, the present invention adopts indoor hatching. In the process of hatching sturgeon eyed eggs and fry cultivation, the key to the healthy growth of fish, such as water temperature, water change amount, breeding density, feed feeding, disease prevention and control, is strictly controlled. Except for individual dead eggs that are not picked out in time and produce water mold, no obvious water mold disease and other diseases occur, successfully ensuring a high hatching rate and survival rate, and the hatching of hybrid sturgeon eyed eggs and fry cultivation in the Tibetan Plateau area have achieved remarkable results.

[0028] 2. During the fry cultivation process, different sizes of fry should be distinguished in time, and the fry should be cultivated in different tanks according to different sizes every 10 days. Consistent sizes are conducive to the healthy growth and scientific management of the fry, and improve the growth rate and survival rate of the fry.

[0029] 3. In view of the low temperature throughout the year and the large temperature difference between day and night in the Tibetan Plateau, the hatching tank is improved. The water is indirectly heated by a heat exchanger to heat the hot water pipe, making it easier to control the water temperature at around 18°C. At the same time, the water is stirred by rotating water inlet and bottom aeration to ensure water nutrition and prevent water mold from forming, thereby improving the hatching rate.

[0030] 4. The constant temperature circulating water incubation system of the present invention integrates an incubation tank, an incubation tank and a cultivation tank, which can meet the cultivation requirements of hybrid sturgeons from incubation to separation in the entire incubation process. It is a complete production line suitable for hybrid sturgeon breeding in Tibet and is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a longitudinal cross-sectional view of the hybrid sturgeon constant temperature circulating water incubation device of the present invention.

[0032] Figure 2 It is a transverse cross-sectional view of the hybrid sturgeon constant temperature circulating water incubation device of the present invention.

[0033] Figure 3 The present invention is a transverse cross-sectional view of a hybrid sturgeon constant temperature circulating water breeding tank.

[0034] Figure 4 This is a longitudinal cross-sectional view of the hybrid sturgeon constant temperature circulating water incubation device in Example 5.

[0035] Figure 5 The schematic diagram of the hybrid sturgeon constant temperature circulating water incubation system of the present invention is shown in FIG.

[0036] The markings in the figure are: 1. Incubation device; 2. Water storage tank; 3. Ecological pool; 4. Ultraviolet disinfection device; 5. Filter device; 6. Heat exchanger; 7. Oxygenation device; 8. Water inlet pump; 9. Water outlet; 10. Air inlet pipe; 11. Incubation tank; 12. Incubation trough; 13. Drain pipe; 14. Hook; 15. LED light; 16. Seedling tank; 17. Water inlet pipe; 20. Hot water pipe; 21. Air supply pipe; 22. Water inlet pipe; 23. Water supply pipe; 24. Drainage main pipe; 25. Water supply main pipe; 26. Water supply branch; 30. Tank cover. DETAILED DESCRIPTION

[0037] In order to more clearly and in detail illustrate the technical solution of the present invention, the present invention is further described below through relevant embodiments. The following embodiments are only for specific explanation of the implementation method of the present invention, and do not limit the protection scope of the present invention.

[0038] Example 1

[0039] A method for hatching and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet, comprising the following steps:

[0040] A. Preparation before hatching

[0041] Introduce bright-colored, high-quality hybrid sturgeon eyed eggs, soak the eggs in iodine solution before hatching, and rinse the eggs thoroughly with clean water after soaking; use indoor hatching equipment, and disinfect the hatching equipment with potassium permanganate for the first 7 days of hatching;

[0042] B. Incubation

[0043] The hatching device adopts a hatching tank and a hatching cylinder, and the eyed eggs are evenly spread at the bottom of the hatching tank. The hatching tank is placed on the hatching cylinder. The hatching cylinder is a constant temperature circulating water flow to keep the stirring and ventilation of the hatching water body; the fry start to float up and eat after the membrane breaks and the yolk sac disappears, and the fry are transferred to the hatching cylinder in batches for centralized cultivation after floating up and eating.

[0044] C. Seedling cultivation

[0045] On the 10th day after being transferred to the hatching tank, the fry are separated according to different sizes. The larger fry are transferred to the nursery tank with constant temperature circulating water flow for cultivation. During the subsequent cultivation process, the fry are separated every 10 days until the fry grow to an average size of 0.7g / tail and 5cm long after the 50th day, and then transferred to the indoor flowing water cement pool for large-scale breeding;

[0046] D. Large-scale farming

[0047] The water temperature of the indoor flowing cement pool is controlled at 12-14℃, the nitrite content is less than 0.25mg / l, and the water flow rate is 0.005m 3 / s, pH value 7.98-8.24, stocking density 1000-1200 fish / ㎡, feeding three times a day, feeding appropriate caliber feed according to the size of the fry.

[0048] Example 2

[0049] This embodiment is based on embodiment 1:

[0050] The water flow rate at the water inlet of the hatching tank and the seedling tank is 0.001m 3 / s, daily water change volume>150%.

[0051] The stocking density of fry in the hatching tank and the nursery tank is 20,000 fry / m2, and dead eggs and dead fish are picked out in time.

[0052] Before hatching, soak the fish eggs in 5 mg / L iodine solution for 10-15 minutes.

[0053] The dissolved oxygen content in the hatching tank and seedling tank is 4.16-4.98 mg / L, the water temperature is 17.5-18.5℃, the pH value is 7.6-8.2, the dissolved oxygen content in the water body is greater than 5 mg / L, the salinity is 172-206 mg / L, the ammonia nitrogen content is 0.05-0.2 mg / L, and the nitrite content is 0.01-0.05.

[0054] Example 3

[0055] This embodiment is based on embodiment 1:

[0056] In the step C, the fry are fed with a microparticle feed specially made for sturgeon fry produced by Shandong Shengsuo Feed Technology Co., Ltd. to train the fry to start eating. The feed particle size is 0.6 mm, and the fry are fed 6-8 times a day. The fry can finish eating within 10-20 minutes each time.

[0057] At the beginning of feeding, mix the feed with water and make it into balls with a diameter of 2 cm. The amount of feed each time is 0.35 grams per thousand fish. After the fry grow to an average weight of 0.3g per fish, the amount of feed each time is adjusted to 0.5 grams per thousand fish. As the fry grow, gradually convert the feed from micro-particle feed to granular feed.

[0058] Example 4

[0059] This embodiment is based on embodiment 1:

[0060] like Figure 1-2 As shown, the hatching device 1 includes a hatching trough 12 and a hatching cylinder 11. The bottom of the hatching trough 12 is a mesh surface and is placed on the hatching cylinder 11. Water inlet pipes 22 are arranged on opposite sides of the hatching cylinder 11. The water outlet 9 of the water inlet pipe 22 is arranged along the cylinder wall, and the water outlet direction is clockwise or counterclockwise. A drain pipe 13 is arranged on the upper part of the hatching cylinder 11. The two water inlet pipes 22 are connected to an external water supply pipe 23, and the water supply pipe 23 is connected to a water inlet pump 8; a hot water pipe 20 is coiled around the inner wall of the hatching cylinder 11, and the hot water pipe 20 is connected to an external heat exchanger 6. A temperature sensor is arranged in the hatching cylinder 11. An air inlet pipe 10 is arranged at the bottom of the hatching cylinder 11, and the air inlet pipe 10 is connected to an external oxygenation device 7, and an aeration stone is arranged in the air inlet pipe 10.

[0061] Since the temperature in the Tibetan Plateau is relatively low throughout the year and the temperature difference between day and night is large, installing hot water pipes on the inner wall of the hatching tank is conducive to maintaining a constant temperature of about 18°C. The hot water pipes heat more evenly and gently. The heat exchanger heats the hot water pipes to adjust the temperature, which makes the temperature easier to control and more accurate. Two water inlets in a clockwise or counterclockwise direction are set on the tank wall. Water is pumped through the water inlet pump. The upper drainage pipe controls the water level, which can make the water in the hatching tank rotate clockwise or counterclockwise. At the same time, the air is exploded below to keep the water body stirred to ensure that the fish eggs get enough oxygen and nutrients, while avoiding the formation of water mold.

[0062] Example 5

[0063] This embodiment is based on Embodiment 4:

[0064] The inner wall of the seedling raising cylinder 16 is provided with a hot water pipe 20 and an air inlet pipe 10 which are the same as those of the hatching cylinder. The water inlet is not in a rotary mode, but in a conventional water flow mode. Figure 3 As shown, the inner wall of the seedling raising cylinder 16 is provided with the hot water pipe 20 and the air inlet pipe 10, the drain pipe 13 is provided at the upper part of the cylinder body, and the water inlet pipe 22 is provided at the lower part on the opposite side of the drain pipe 13; the water inlet and outlet of the hatching cylinder 11 and the seedling raising cylinder 16 are provided with 3-4 layers of filter screens to filter impurities and aquatic organisms and control the flow rate of the water body, and the drain pipes are provided with filter screens to prevent the fry from escaping.

[0065] like Figure 4 As shown, the hatching tank 11 and the seedling raising tank 16 are 0.4-0.5 m high, the hatching tank 11 is provided with a tank cover 30 , and an adjustable LED lamp 15 is provided inside the tank cover 30 .

[0066] Example 6

[0067] This embodiment is based on Embodiment 5:

[0068] like Figure 5 As shown, one incubation device 1 and five seedling raising cylinders 16 integrate a constant temperature circulating water incubation system, the drainage pipes of the incubation cylinder 11 and the seedling raising cylinder 16 are connected to the filtering device 5 through the drainage main pipe 24, the filtering device 5 is connected to the water storage tank 2, the water storage tank 2 is connected to the ecological pool 3, the ecological pool 3 is connected to the ultraviolet disinfection device 4, the ultraviolet disinfection device 4 is connected to the water supply main pipe 25, and the water supply main pipe 25 is connected to the corresponding water inlet pump 8 through the water supply branch pipe 26; the ecological pool 3 uses aquatic plants and microorganisms to remove ammonia nitrogen and nitrify.

[0069] The filtering device, ecological pool, heat exchanger, oxygenation device and ultraviolet sterilization device of the present invention are all conventional equipment in the art.

[0070] The experimental site of the present invention is a constant temperature circulating cold water incubation workshop of the Institute of Fisheries Science of the Tibet Autonomous Region Academy of Agricultural and Animal Husbandry Sciences. The water source for hatching and cultivation is the local underground constant temperature cold water, the water quality is clear and transparent without pollution, meets the national fishery water quality standard (GB11607-1989), and the water body is weakly saline and alkaline. A water quality detector is used to regularly detect water quality parameters to ensure that the water quality is stable in an appropriate range: dissolved oxygen content is 4.16-4.98 mg / L, water temperature is 17.5-18.5°C, pH value is 7.6-8.2, dissolved oxygen content of water body is greater than 5 mg / L, salinity is 172-206 mg / L, ammonia nitrogen content is 0.05-0.2 mg / L, and nitrite content is 0.01-0.05.

[0071] 60,000 hybrid sturgeon eyed eggs that have passed quarantine were introduced to carry out hatching tests and cultivation. The introduction time is May 23, 2024. The average egg diameter of the eyed eggs is about 5mm, the egg weight is 0.05g, the color is bright, and the quality is good. The hybrid sturgeon eyed eggs were divided into three batches for experiments. The first batch of hatching tanks adopted a conventional flow mode, without a hot water pipe in the tank, and adopted a temperature control method of uniform water heating. The second batch of hatching tanks adopted a conventional flow mode with a hot water pipe in the tank. The third batch used the hatching tank of Example 5 for hatching. All three batches adopted the hatching and seedling raising method of the present invention, and the feed was a microparticle compound feed specially designed for sturgeon fry produced by Shandong Shengsuo Feed Technology Co., Ltd.

[0072] The hatching time of eyed eggs is 2-4 days, calculated from the day when the eyed eggs enter the hatching site. The fry start to float up and start to eat from the 6th to 9th day after the fry break the membrane and the yolk sac disappears. After the fry float up and eat, they are transferred to the constant temperature circulating cold water hatching tank for centralized cultivation in batches. They are transferred to the nursery tank every 10 days. Around the 50th day, the fry grow to an average size of 0.7g / tail. The specific experimental situation is shown in Table 1:

[0073] Table 1 Artificial hatching of sturgeon

[0074]

[0075] During the process of sturgeon eyed eggs hatching and fry cultivation, water temperature, water change volume, stocking density, feed feeding, and disease prevention and control are key control points for the healthy growth of fish. Water temperature that is too high or too low is not conducive to the hatching of fry. When the water temperature exceeds 20°C, the mortality rate of eyed eggs and hatched fry increases significantly. The water temperature at the test site is generally constant at around 18°C. After the fry are transferred to the indoor cement pool, the water temperature is controlled at 12-14°C. In the water quality for cultivating sturgeons, the nitrite content must not be higher than 0.25. If it is higher than 0.25, the sturgeons will not eat.

[0076] As shown in Table 1, the hatching rate of the third batch of experiments is as high as 88.1%, and the survival rate is as high as 86.19%. With the incubation device of the present invention, the water temperature can be kept constant by heating the incubation water body with the hot water pipe, and after the rotary water inlet is adopted, except for the occurrence of water mold due to the failure to pick up individual dead eggs in time, no obvious water mold disease and other diseases occurred in the experiment. The invention has remarkable results in hatching sturgeon eyed eggs and cultivating fry in the plateau environment of constant temperature circulating water.

[0077] The above-mentioned embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for incubating and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet, characterized in that: The following steps are involved: A. Preparation before hatching Introduce bright-colored, high-quality hybrid sturgeon eyed eggs, soak the eggs in iodine solution before hatching, and rinse the eggs thoroughly with clean water after soaking; use indoor hatching equipment, and disinfect the hatching equipment with potassium permanganate for the first 7 days of hatching; B. Incubation The hatching device adopts a hatching tank and a hatching cylinder, and the eyed eggs are evenly spread at the bottom of the hatching tank. The hatching tank is placed on the hatching cylinder. The hatching cylinder is a constant temperature circulating water flow to keep the stirring and ventilation of the hatching water body; the fry start to float up and eat after the membrane breaks and the yolk sac disappears, and the fry are transferred to the hatching cylinder in batches for centralized cultivation after floating up and eating. C. Seedling cultivation On the 10th day after being transferred to the hatching tank, the fry are separated according to different sizes. The larger fry are transferred to the nursery tank with constant temperature circulating water flow for cultivation. During the subsequent cultivation process, the fry are separated every 10 days until the fry grow to an average size of 0.7g / tail and 5cm long after the 50th day, and then transferred to the indoor flowing water cement pool for large-scale breeding; D. Large-scale farming The water temperature of the indoor flowing cement pool is controlled at 12-14℃, the nitrite content is less than 0.25mg / l, and the water flow rate is 0.005m 3 / s, pH value 7.98-8.24, stocking density 1000-1200 fish / ㎡, feeding three times a day, feeding appropriate caliber feed according to the size of the fry.

2. The method for incubating and raising hybrid sturgeon seedlings in a constant temperature circulating water according to claim 1, wherein: The water flow rate at the water inlet of the hatching tank and the seedling tank is 0.001m 3 / s, daily water change volume>150%.

3. The method for incubating and raising hybrid sturgeon seedlings in a constant temperature circulating water according to claim 1, wherein: The stocking density of fry in the hatching tank and the nursery tank is 20,000 fry / m2, and dead eggs and dead fish are picked out in time.

4. The method for hatching and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet according to claim 1, characterized in that: Before hatching, soak the fish eggs in 5 mg / L iodine solution for 10-15 minutes.

5. The method for incubating and raising hybrid sturgeon seedlings in a constant temperature circulating water according to claim 1, wherein: The dissolved oxygen content in the hatching tank and the seedling tank is 5.16-6.28 mg / L, the water temperature is 17.5-18.5° C., the pH value is 7.6-8.2, the salinity is 172-206 mg / L, the ammonia nitrogen content is 0.05-0.2 mg / L, and the nitrite content is 0.01-0.05 mg / l.

6. The method for incubating and raising hybrid sturgeon seedlings in a constant temperature circulating water according to claim 1, wherein: The step C comprises feeding the sturgeon fry special microparticle compound feed prepared by Shandong Shengsuo Feed Technology Co., Ltd. to train the fry to open their mouth to eat, the feed particle size being 0.6 mm, feeding 6-8 times a day, and each feeding enabling the fry to finish eating within 10-20 minutes; at the initial stage of feeding, mixing the feed with water and forming it into a ball shape, the ball diameter being 2 cm, and feeding the feed at a rate of 0.35 g / 1,000 fish tails each time; after the fry grow to an average weight of 0.3 g / tail, adjusting the feeding rate at each time to 0.5 g / 1,000 fish tails, and gradually converting the feed from microparticle feed to granular feed as the fry grow.

7. The method for incubating and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet according to claim 1, characterized in that: The hatching device comprises a hatching trough and a hatching cylinder. The bottom of the hatching trough is a mesh surface and is placed on the hatching cylinder. Water inlet pipes are arranged on opposite sides of the hatching cylinder. The water outlet of the water inlet pipe is arranged along the cylinder wall, and the water outlet direction is clockwise or counterclockwise. A drainage pipe is arranged on the upper part of the hatching cylinder. The two water inlet pipes are connected to an external water supply pipe, and the water supply pipe is connected to an inlet pump. A hot water pipe is coiled around the inner wall of the hatching cylinder, and the hot water pipe is connected to an external heat exchanger. A temperature sensor is arranged in the hatching cylinder. An air inlet pipe is arranged at the bottom of the hatching cylinder, and the air inlet pipe is connected to an external oxygenation device, and an aeration stone is arranged in the air inlet pipe.

8. The method for incubating and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet according to claim 7, characterized in that: The inner wall of the seedling raising cylinder is provided with the hot water pipe and the air inlet pipe, the drain pipe is provided at the upper part of the cylinder body, and the water inlet pipe is provided at the lower part opposite to the drain pipe; the water inlet and outlet of the hatching cylinder and the seedling raising cylinder are both provided with 3-4 layers of filter screens, and the drain pipes are both provided with filter screens.

9. The method for incubating and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet according to claim 8, characterized in that: The hatching tank and the seedling raising tank are 0.4-0.5m high, the hatching tank is provided with a tank cover, and an adjustable LED lamp is provided on the inner side of the tank cover.

10. The method for incubating and raising hybrid sturgeon seedlings in constant temperature circulating water suitable for Tibet according to claim 8, characterized in that: One incubation device and five seedling raising tanks are integrated into a constant temperature circulating water incubation system. The drainage pipes of the incubation tank and the seedling raising tank are connected to the filtering device through the drainage main pipe, the filtering device is connected to the water storage tank, the water storage tank is connected to the ecological pool, the ecological pool is connected to the ultraviolet sterilization device, the ultraviolet sterilization device is connected to the water supply main pipe, and the water supply main pipe is connected to the corresponding water inlet pump through the water supply branch. The ecological pool uses aquatic plants and microorganisms to remove ammonia nitrogen and nitrify.

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