Constant-temperature circulating flowing water artificial incubation and cultivation method for channel catfish

Abstract

The invention provides a constant-temperature circulating water artificial incubation and cultivation method for channel catfish, which comprises the following steps: introducing eyed eggs of channel catfish, building an indoor incubation device, and disinfecting the incubation device with potassium permanganate 7 days before incubation; the hatching device comprises a hatching tank and a hatching cylinder, the hatching tank is placed on the hatching cylinder, eyed eggs are uniformly spread at the bottom of the hatching tank, constant-temperature circulating water flow of 24.5-25.5 DEG C is filled 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 are broken and yolk sacs disappear, and the fries are successively transferred into a hatching tank in batches to be bred; the tenth day of transferring to the hatching tank is divided according to the size of the larvae, the larvae are divided once every 10 days, and the larvae are transferred to an indoor running water cement pond to be subjected to large-scale fingerling breeding until the average body length of each fish reaches 30 mm after 60 days. The method is suitable for breeding environments in Tibet regions, and has the advantages of high hatching rate and high survival rate.

Description

Technical Field

[0001] The invention belongs to the technical field of fish breeding, and particularly relates to a method for artificially hatching and cultivating channel catfish in constant-temperature circulating water. Background Art

[0002] Channel catfish is a common freshwater fish with a wide range of adaptability to living environments. It can survive in freshwater, ponds, rivers, lakes and other water environments. It grows rapidly and can reach the standard size for commercial farming in a relatively short period of time when the breeding conditions are good. Channel catfish is an omnivorous fish with good palatability to a variety of feeds, including pelleted feeds, artificial feeds and natural baits, which makes its breeding and management relatively easy. Under suitable environmental conditions, it has strong disease resistance and stress resistance, and has a certain tolerance to changes in water quality and environmental pressure.

[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 channel catfish into Tibet for breeding, carrying out artificial breeding of channel catfish, and improving its 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 artificial hatching and cultivation of channel catfish in constant temperature circulating water, which is suitable for the breeding environment in Tibet and 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 artificially hatching and cultivating channel catfish in constant temperature circulating water comprises the following steps:

[0007] A. Preparation before hatching

[0008] Introduce channel catfish eyed eggs and build indoor incubators to avoid exposing the fry to direct sunlight and prevent the effects of high temperatures and strong light on the fry; use potassium permanganate to disinfect the incubators for the first 7 days of incubation;

[0009] B. Incubation

[0010] The hatching device comprises a hatching tank and a hatching cylinder. The hatching tank is placed on the hatching cylinder so that the eyed eggs are evenly spread at the bottom of the hatching tank. The hatching cylinder is filled with a constant temperature circulating water flow of 24.5-25.5° C. to keep the hatching water body stirred and ventilated. The fry start to float up and eat after the yolk sac disappears after the fry membrane breaks. The fry are transferred to the hatching cylinder in batches for cultivation. Dead eggs and dead fish are picked out in time during the process.

[0011] C. Seedling cultivation

[0012] On the 10th day after being transferred to the hatching tank, the fry are separated according to their size. The larger fry are transferred to the nursery tank with a constant temperature circulating water flow of 24.5-25.5℃ for cultivation. The fry are separated every 10 days until the fry grow to an average body length of 30mm / tail after the 60th day, and then transferred to the indoor flowing water cement pool for large-scale fish seed cultivation;

[0013] D. Large-scale farming

[0014] The water temperature of the indoor flowing cement pool is 12-14℃, the nitrite content is less than 0.3mg / l, and the water flow rate is 0.008m 3 / s, pH value 7.68-8.31, stocking density 500-800 fish / ㎡, feeding three times a day, feeding appropriate caliber feed according to the size of the fry.

[0015] The water flow rate of the water inlet of the hatching tank and the seedling tank of the present invention is 0.001m 3 / s, daily water change>150%. If the flow rate is too large, the fry will swim weakly and the stress reaction will be too strong, which may easily cause the fry to die; if the flow rate is too small, the water filtration efficiency will be weakened, affecting the ammonia nitrogen content and pH of the water.

[0016] Preferably, the water inlet pipes of the hatching tank and the seedling tank are provided with 3-4 layers of filter screens to filter impurities and aquatic organisms, and at the same time help control the water flow rate at 0.001m 3 / s,The drainage pipe is equipped with a filter to prevent the fry from escaping.

[0017] The stocking density of fry in the hatching tank of the present invention is 20,000 fry / ㎡, and the stocking density of the nursery tank is gradually reduced as the fry grow after the tanks are divided.

[0018] The dissolved oxygen content in the hatching tank and the seedling raising tank of the present invention is 3.2-4.5 mg / L, the water temperature is 24.5-25.5°C, the pH value is 7.6-8.0, the salinity is 178-247 mg / L, the ammonia nitrogen content is 0.05-0.2 mg / L, and the nitrite content is 0.01-0.15 mg / l.

[0019] Channel catfish fry are very sensitive to water temperature. The water temperature for hatching and fry cultivation should be controlled at 24.5-25.5℃. Too high or too low water temperature is not conducive to the hatching and cultivation of fry. When the nitrite content is higher than 0.15, the fry will eat less.

[0020] In step C of the present invention, channel catfish is a carnivorous fish, and Artemia and sturgeon fry special microparticle compound feed of Shandong Shengsuo Feed Technology Co., Ltd. are selected to be mixed and fed in a mass ratio of 4:6 for opening feeding training, the feed particle size is 0.6mm, and the feed is fed 6-8 times a day, and the fry can finish eating 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 2cm, and the feeding amount each time is 0.35g / 1000 fish tails; after the fry grows to an average body length of 23mm / tail, the feeding amount each time is adjusted to 0.5g / 1000 fish tails, and as the fry grow, the feed is gradually converted from microparticle feed to granular feed.

[0021] The incubation device of the present invention comprises an incubation cylinder and an annular incubation groove. The annular structure is conducive to occupying the surface area of ​​the incubation cylinder with maximum efficiency, and the middle space is more conducive to operating the incubation cylinder than the arrangement of multiple parallel grooves. The bottom of the incubation tank is a mesh surface and is placed on the incubation cylinder. A water inlet pipe is arranged at the lower part of one side of the incubation cylinder, and a drain pipe is arranged at the upper part of the other side. The water inlet pipe is connected to an external heater, and a temperature sensor is arranged in the incubation cylinder; an aeration and stirring mechanism is arranged at the bottom of the incubation cylinder, and the aeration and stirring mechanism comprises a hollow stirring paddle, an air supply pipe and a protective mesh cover. The stirring paddle is arranged at the bottom of the incubation cylinder, and the protective mesh cover is arranged on the outer side of the stirring paddle. A plurality of air inlet holes are arranged on the paddle of the stirring paddle. The rotating rod of the stirring paddle extends out of the bottom of the incubation cylinder and is connected to the incubation cylinder through a sealed bearing. The rotating rod is circumferentially provided with rotating teeth. A rotating motor is arranged below the incubation cylinder. The output rod of the rotating motor is connected to a transmission gear, and the rotating teeth are meshed with the transmission gear. The air supply pipe is inserted from the bottom end opening of the rotating rod, and the air supply pipe is connected to an oxygenation device; the outer wall of the incubation cylinder is provided with a thermal insulation layer, and the thermal insulation layer is thermal insulation asbestos or fiber felt.

[0022] Preferably, the outer side of the seedling raising cylinder is provided with the insulation layer, and does not contain the aeration and stirring mechanism. The bottom of the cylinder body is provided with an air inlet pipe, and the air inlet pipe is provided with an aeration stone; the seedling raising cylinder and the hatching cylinder are 0.45-0.5m high, and both are provided with a separate cylinder cover, and the inner side of the cylinder cover is provided with an adjustable LED lamp. When the spotted catfish eggs are hatched and cultivated indoors, when the light is insufficient, it is necessary to supplement with appropriate light to help maintain the ecological balance of the water body and prevent the growth of mold. Therefore, a separate cylinder cover with an LED lamp is added for indoor hatching and supplementary lighting, which is convenient for managing light to simulate the natural environment or provide appropriate lighting. Limiting the height of the seedling raising cylinder to 0.45-0.5m is conducive to the stirring paddle at the bottom of the cylinder to stir the water body and prevent the deposition and formation of water mold at the bottom of the hatching frame.

[0023] Preferably, one of the incubation devices and six 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 heater, the heater 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.

[0024] Preferably, the speed of the stirring paddle is 15-20 rpm. If the speed is too high, it will cause stress response of the fry, and if the speed is too low, the water body cannot be stirred to prevent the deposition of fish eggs.

[0025] The beneficial effects of the present invention are:

[0026] 1. In the process of hatching channel catfish eggs and cultivating fry, the present invention strictly controls the key factors of healthy growth of fish, such as water temperature, water change amount, stocking density, feed feeding, disease prevention and control, etc., except that individual dead eggs are not picked out in time and produce Saprolegnia, no obvious Saprolegnia disease and other diseases occur, and a high hatching rate and survival rate are successfully guaranteed. The hatching of channel catfish eggs and cultivation of fry in the Tibetan Plateau area have remarkable results.

[0027] 2. Use the method of separating fry into tanks to reduce the density of fry, increase the dissolved oxygen content in the water, and ensure the survival rate of fry. Timely distinguish the fry of different sizes, and cultivate the fry in tanks according to size every 10 days. The consistent size is conducive to the healthy growth and scientific management of fry, and improves the growth rate and survival rate of fry.

[0028] 3. In view of the low temperature throughout the year and the large temperature difference between day and night in the Tibetan Plateau, the spotted catfish fry are very sensitive to water temperature. Improvements are made to the hatching tank and seedling tank. Not only are the water temperature controlled in real time through temperature sensors and heaters, but an insulation layer is also set on the outside of the tank body to extend the insulation time of the tank body, slow down the cooling of the water body, and make it easier for the water temperature to be constant at around 25°C.

[0029] 4. An aeration and stirring mechanism is set at the bottom of the cylinder body, and the rotating gear meshing is used to drive the stirring paddle to rotate, so that the air supply pipe can stably supply air to the stirring paddle, and then discharge the gas into the cylinder from the air inlet. At the same time, the stirring is coordinated to keep the water body agitated, ensure the nutrition of the water body, avoid the deposition of fish eggs, prevent the formation of water mold, and improve the hatching rate. A protective net cover is added to the outside of the stirring paddle to prevent the fry from entering the stirring paddle range and causing a stress reaction.

[0030] 5. The hatching and cultivating method of the present invention adopts an integrated constant temperature circulating water system for hatching and cultivating channel catfish. The circulating water system integrates one hatching device and six seedling raising tanks, which meets the cultivation requirements of the entire hatching process of channel catfish from hatching to tank separation. It is a complete production line for channel catfish breeding and is suitable for large-scale promotion and application of channel catfish breeding in Tibet. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a cross-sectional view of a channel catfish constant temperature circulating water incubation device.

[0032] Figure 2 The present invention is a cross-sectional view of a channel catfish constant temperature circulating water seedling raising tank.

[0033] Figure 3 This is a cross-sectional view of the constant temperature circulating water incubation device for channel catfish in Example 6.

[0034] Figure 4 The schematic diagram of the channel catfish constant temperature circulating water incubation system of the present invention is shown.

[0035] The markings in the figure are: 1. Incubation device; 2. Water storage tank; 3. Ecological pool; 4. Ultraviolet disinfection device; 5. Heater; 6. Filter device; 7. Oxygenation device; 8. Water inlet pump; 9. Water supply main pipe; 10. LED lamp; 11. Incubation tank; 12. Incubation trough; 13. Insulation layer; 14. Air supply pipe; 15. Hook; 16. Air inlet pipe; 17. Seedling tank; 18. Drainage main pipe; 19. Water supply branch; 20. Aeration and stirring mechanism; 21. Stirring paddle; 22. Rotating motor; 23. Protective mesh cover; 24. Transmission gear; 25. Rotating gear; 26. Rotating rod; 30. Cylinder cover; 111. Water inlet pipe; 112. Drain pipe; 211. Air inlet hole. DETAILED DESCRIPTION

[0036] 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.

[0037] Example 1

[0038] A method for artificially hatching and cultivating channel catfish in constant temperature circulating water comprises the following steps:

[0039] A. Preparation before hatching

[0040] Introduce channel catfish eyed eggs, build indoor incubators, and disinfect the incubators with potassium permanganate during the first 7 days of incubation;

[0041] B. Incubation

[0042] The hatching device comprises a hatching tank and a hatching cylinder. The hatching tank is placed on the hatching cylinder so that the eyed eggs are evenly spread at the bottom of the hatching tank. The hatching cylinder is filled with a constant temperature circulating water flow of 24.5-25.5° C. to keep the hatching water body stirred and ventilated. The fry start to float up and eat after the yolk sac disappears after the fry membrane breaks. The fry are transferred to the hatching cylinder in batches for cultivation. Dead eggs and dead fish are picked out in time during the process.

[0043] C. Seedling cultivation

[0044] On the 10th day after being transferred to the hatching tank, the fry are separated according to their size. The larger fry are transferred to the nursery tank with a constant temperature circulating water flow of 24.5-25.5℃ for cultivation. The fry are separated every 10 days until the fry grow to an average body length of 30mm / tail after the 60th day, and then transferred to the indoor flowing water cement pool for large-scale fish seed cultivation;

[0045] D. Large-scale farming

[0046] The water temperature of the indoor flowing cement pool is 12-14℃, the nitrite content is less than 0.3mg / l, and the water flow rate is 0.008m 3 / s, pH value 7.68-8.31, stocking density 500-800 / m2, to meet the breeding needs of spotted catfish, feed three times a day, feed appropriate caliber feed according to the size of the fry.

[0047] Example 2

[0048] This embodiment is based on embodiment 1:

[0049] 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%.

[0050] The water inlet pipes of the hatching tank and the seedling tank are provided with 3-4 layers of filter screens to filter impurities and aquatic organisms, and at the same time help control the water flow rate at 0.001m 3 / s,The drainage pipe is equipped with a filter to prevent the fry from escaping.

[0051] Example 3

[0052] This embodiment is based on embodiment 1:

[0053] The dissolved oxygen content in the hatching tank and the seedling tank is 3.2-4.5 mg / L, the water temperature is 24.5-25.5° C., the pH value is 7.6-8.0, the salinity is 178-247 mg / L, the ammonia nitrogen content is 0.05-0.2 mg / L, and the nitrite content is 0.01-0.15 mg / l.

[0054] Channel catfish fry are very sensitive to water temperature. The water temperature for hatching and fry cultivation should be controlled at 24.5-25.5℃. Too high or too low water temperature is not conducive to the hatching and cultivation of fry. When the nitrite content is higher than 0.15, the fry will eat less.

[0055] Example 4

[0056] This embodiment is based on embodiment 1:

[0057] In the step C, Artemia and sturgeon fry-specific microparticle compound feed of Shandong Shengsuo Feed Technology Co., Ltd. are selected and mixed in a mass ratio of 4:6 for feeding 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, and the fry can finish eating 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 body length of 23 mm / 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.

[0058] Example 5

[0059] This embodiment is based on embodiment 1:

[0060] like Figure 1 As shown, the incubation device 1 comprises an incubation cylinder 11 and an annular incubation tank 12, the bottom of the incubation tank 12 is a mesh surface and is placed on the incubation cylinder 11, a water inlet pipe 111 is arranged at the lower part of one side of the incubation cylinder 11, and a drain pipe 112 is arranged at the upper part of the other side, the water inlet pipe 111 is connected to an external heater, and a temperature sensor is arranged in the incubation cylinder 11; an aeration stirring mechanism 20 is arranged at the bottom of the incubation cylinder 11, and the aeration stirring mechanism 20 comprises a hollow stirring paddle 21, an air supply pipe 14 and a protective mesh cover 23, the stirring paddle 21 is arranged at the bottom of the incubation cylinder 11, and the outer side of the stirring paddle 21 is provided with the protective mesh cover 23. A protective net cover 23, a plurality of air inlet holes 211 are arranged on the blades of the stirring paddle 21, a rotating rod 26 of the stirring paddle 21 extends out of the bottom of the hatching cylinder 11 and is connected to the hatching cylinder 11 through a sealed bearing, the rotating rod 26 is circumferentially provided with rotating teeth 25, a rotating motor 22 is arranged below the hatching cylinder 11, an output rod of the rotating motor 22 is connected to a transmission gear 24, the rotating teeth 25 are meshed with the transmission gear 24, the air supply pipe 14 is inserted from the bottom end opening of the rotating rod 26, and the air supply pipe 14 is connected to an oxygenation device; an outer wall of the hatching cylinder 11 is provided with a thermal insulation layer 13, and the thermal insulation layer 13 is thermal insulation asbestos or fiber felt.

[0061] Due to the low temperature throughout the year in the Tibetan Plateau, the temperature difference between day and night is large, and a heat preservation layer is arranged outside the hatching cylinder, which is conducive to reducing the heat dissipation speed. The temperature can be monitored and controlled in real time by connecting the temperature sensor and the heater to the controller. The addition of the heat preservation layer is more conducive to the maintenance of constant temperature under low temperature conditions in the Tibetan region. An aeration and stirring mechanism is arranged at the bottom of the cylinder body, and the rotating gear meshing is adopted to drive the stirring paddle 21 to rotate, so that the air supply pipe 14 can stably supply air to the stirring paddle 21, and then discharge the gas from the air inlet 211 into the cylinder, and the stirring is coordinated at the same time, so that the water body is continuously stirred, to ensure that the fish eggs obtain enough oxygen and guarantee the water body nutrition, and the deposition of the fish eggs can be avoided, and no water mold is produced, so as to improve the hatching rate. A protective net cover is added outside the stirring paddle to prevent the fry from entering the stirring paddle range and causing a stress reaction.

[0062] Example 6

[0063] This embodiment is based on Embodiment 5:

[0064] like Figure 2-3 As shown, the outer side of the seedling raising cylinder 17 is provided with the insulation layer 13, and does not contain the aeration and stirring mechanism 20. An air inlet pipe 16 is provided at the bottom of the cylinder body, and an aeration stone is provided in the air inlet pipe 16. The seedling raising cylinder 17 and the hatching cylinder 11 are 0.45-0.5m high, and both are provided with a separate cylinder cover 30, and an adjustable LED lamp 10 is provided on the inner side of the cylinder cover 30.

[0065] The rotation speed of the stirring blade 21 is 18 rpm.

[0066] Example 7

[0067] This embodiment is based on Embodiment 5:

[0068] like Figure 4 As shown, one incubation device 1 and five seedling raising cylinders 17 integrate a constant temperature circulating water incubation system, the drainage pipes of the incubation cylinder 11 and the seedling raising cylinder 17 are connected to the filter device 6 through the drainage main pipe 18, the filter device 6 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 heater 5, the heater 5 is connected to the water supply main pipe 9, and the water supply main pipe 9 is connected to the corresponding water inlet pump 8 through the water supply branch 19; the ecological pool 3 uses aquatic plants and microorganisms to remove ammonia nitrogen and nitrify.

[0069] The rotation speed of the stirring blade 21 is 20 rpm.

[0070] The filtering device, heater, oxygenating device, ecological pool and ultraviolet sterilizing device of the present invention are all conventional equipment in the art.

[0071] The experimental site of the present invention is a constant temperature circulating warm 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 incubation and cultivation is the local underground constant temperature cold water, the water quality is clear and transparent without pollution, and 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 within an appropriate range: dissolved oxygen content is 3.2-4.5mg / L, water temperature is 24.5-25.5℃, pH value is 7.6-8.0, salinity is 178-247mg / L, ammonia nitrogen content is 0.05-0.2mg / L, and nitrite content is 0.01-0.15mg / l.

[0072] 60,000 eyed eggs of channel catfish that passed quarantine were introduced to carry out hatching experiments and cultivation. The eyed eggs were divided into three batches for experiments. The hatching tank of the first batch used a nursery tank without a thermal insulation layer, the hatching tank of the second batch used a nursery tank with a thermal insulation layer of the present invention, and the third batch used the hatching tank of Example 6. The speed of the stirring paddle was 15 rpm. The three batches all used the hatching and seedling raising method of the present invention, and the feed was Artemia and the microparticle compound feed for sturgeon fry of Shandong Shengsuo Feed Technology Co., Ltd.

[0073] The hatching time of eyed eggs is 4-5 days, calculated from the day when the eyed eggs enter the hatching site. The fry start to float and eat from the day when the yolk sac disappears. The fry float to eat on the 7-10th day. After the fry float to eat, they are transferred to the constant temperature circulating warm water nursery tank for centralized cultivation in batches. They are transferred to the nursery tank every 10 days. Around the 60th day, the fry grow to an average body length of 30mm / tail. The specific experimental situation is shown in Table 1:

[0074] Table 1 Artificial hatching of channel catfish

[0075]

[0076] During the process of hatching eyed eggs and cultivating fry of spotted catfish, 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 26°C, the mortality rate of eyed eggs and hatched fry increases significantly. The water temperature at the test site is generally constant at around 25°C. After the fry are transferred to the indoor cement pool, the water temperature is controlled at 12-14°C. The nitrite content in the water quality for cultivating spotted catfish must not be higher than 0.3. If it is higher than 0.3, the spotted catfish will stop eating.

[0077] As can be seen from Table 1, the hatching rate of the third batch of experiments is as high as 87.5%, and the survival rate is as high as 90.29%. By using the incubator of the present invention, the insulation layer can make the water temperature of the incubation water body under the low temperature conditions in Tibet more stable, and stirring air is adopted in the cylinder body to keep the water body in a continuous stirring state. In the experiment, except that individual dead eggs were not picked out in time and produced water mold, no obvious water mold disease and other diseases occurred.

[0078] On the basis of the third batch of experiments, the present invention adjusts the rotation speed of the stirring paddle and finds that when the rotation speed is 12 rpm, the water body is not stirred obviously, the hatching rate is reduced to 78.13%, when the rotation speed is increased to 25 rpm, the survival rate is reduced to 80.69%, and when the rotation speed is maintained at 15-20 rpm, the hatching rate and the survival rate are both maintained at more than 85%.

[0079] 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 circulating water artificial hatching and cultivation method for channel catfish fry, characterized in that: include: A. Preparation before hatching Introduce channel catfish eyed eggs, build indoor incubators, and disinfect the incubators with potassium permanganate during the first 7 days of incubation; B. Incubation The hatching device comprises a hatching tank and a hatching cylinder. The hatching tank is placed on the hatching cylinder, and the eyed eggs are evenly spread at the bottom of the hatching tank. The hatching cylinder is filled with a constant temperature circulating water flow of 24.5-25.5° C. to keep the hatching water body stirred and ventilated. The fry start to float up and eat after the yolk sac disappears after the fry membrane breaks. The fry are transferred to the hatching cylinder in batches for cultivation, and dead eggs and dead fish are picked out in time during the process. C. Seedling cultivation On the 10th day after being transferred to the hatching tank, the fry are separated according to their size. The larger fry are transferred to the nursery tank with a constant temperature circulating water flow of 24.5-25.5℃ for cultivation. The fry are separated every 10 days until the fry grow to an average body length of 30mm / tail after the 60th day, and then transferred to the indoor flowing water cement pool for large-scale fish seed cultivation; D. Large-scale farming The water temperature of the indoor flowing cement pool is 12-14℃, the nitrite content is less than 0.3mg / l, and the water flow rate is 0.008m 3 / s, pH value 7.68-8.31, stocking density 500-800 fish / ㎡, feeding three times a day, feeding appropriate caliber feed according to the size of the fry.

2. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 1, characterized in that: 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 circulating water artificial hatching and cultivation method of channel catfish fry according to claim 2, characterized in that: The water inlet and outlet of the hatching tank and the seedling raising tank are both provided with 3-4 layers of filter screens, and the drainage pipe is provided with a filter screen.

4. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 1, characterized in that: The stocking density of the fry in the hatching tank is 20,000 fry / ㎡. After the tanks are divided, the stocking density of the nursery tank is gradually reduced as the fry grow.

5. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 1, characterized in that: The dissolved oxygen content in the hatching tank and the seedling tank is 3.2-4.5 mg / L, the water temperature is 24.5-25.5° C., the pH value is 7.6-8.0, the salinity is 178-247 mg / L, the ammonia nitrogen content is 0.05-0.2 mg / L, and the nitrite content is 0.01-0.15 mg / l.

6. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 1, characterized in that: In the step C, Artemia and sturgeon fry-specific microparticle compound feed of Shandong Shengsuo Feed Technology Co., Ltd. are selected and mixed in a mass ratio of 4:6 for feeding to train the fry to open their mouth to eat, the feed particle size is 0.6 mm, and the fry are fed 3-4 times a day, and the fry can finish eating 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 body length of 23 mm / 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.

7. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 1, characterized in that: The incubation device comprises an incubation cylinder and an annular incubation tank, the bottom of the incubation tank is a mesh surface and is placed on the incubation cylinder, a water inlet pipe is arranged at the lower part of one side of the incubation cylinder, and a drain pipe is arranged at the upper part of the other side, the water inlet pipe is connected to an external heater, and a temperature sensor is arranged in the incubation cylinder; an aeration and stirring mechanism is arranged at the bottom of the incubation cylinder, the aeration and stirring mechanism comprises a hollow stirring paddle, an air supply pipe and a protective mesh cover, the stirring paddle is arranged at the bottom of the incubation cylinder, the outer side of the stirring paddle is provided with the protective mesh cover, a plurality of air inlet holes are arranged on the paddle of the stirring paddle, a rotating rod of the stirring paddle extends out of the bottom of the incubation cylinder and is connected to the incubation cylinder through a sealed bearing, the rotating rod is circumferentially provided with rotating teeth, a rotating motor is arranged below the incubation cylinder, an output rod of the rotating motor is connected to a transmission gear, the rotating teeth are meshed with the transmission gear, the air supply pipe is inserted from the bottom end opening of the rotating rod, and the air supply pipe is connected to an oxygenation device; an insulation layer is arranged on the outer wall of the incubation cylinder, and the insulation layer is insulation asbestos or fiber felt.

8. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 7, characterized in that: The outer side of the seedling raising cylinder is provided with the insulation layer, but does not contain the aeration and stirring mechanism. The bottom of the cylinder body is provided with an air inlet pipe, and an aeration stone is provided in the air inlet pipe. The seedling raising cylinder and the hatching cylinder are 0.45-0.5m high, and both are provided with separate cylinder covers, and an adjustable LED lamp is provided on the inner side of the cylinder cover.

9. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 7, characterized in that: One incubation device and six 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 heater, the heater 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.

10. The circulating water artificial hatching and cultivation method of channel catfish fry according to claim 7, characterized in that: The rotation speed of the stirring paddle is 15-20 rpm.

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