A walleye fish hatching system and method

Abstract

The present application relates to a kind of Walsall Huang's catfish hatching system and method, belong to aquaculture technical field, solve the many technical problems of the existing Walsall Huang's catfish using traditional mesh suspension hatching method There are many deficiencies.In a kind of Walsall Huang's catfish hatching system, including inducing production fertilization module and hatching module;Inducing production fertilization module includes several inducing production barrels, first circulating water system, first oxygen supply device, first temperature control device, and several face basin;Hatching module includes several hatching barrels, several hatching plates, second circulating water system, second temperature control device and second oxygen supply device.The present application improves hatching efficiency and hatching rate, meets the needs of Walsall Huang's catfish artificial breeding industrialization.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, and specifically relates to a hatching system and method for yellow catfish. Background Technology

[0002] Yellow catfish (Pelteobagrus vachelli) is an important and high-quality economic fish species in my country, and its artificial breeding and seedling cultivation are key links in the industry's development. In the artificial breeding process, the hatching of fertilized eggs is a crucial step in seedling cultivation; the hatching efficiency and hatching rate directly affect the success or failure of production and economic benefits.

[0003] Currently, there is a general lack of dedicated and efficient hatching equipment in the hatching practices of yellow catfish and similar adhesive-egg fish. Existing technology mainly adopts the traditional net hanging hatching method. The specific operation is as follows: the fertilized fish eggs are evenly adhered to polyethylene netting or palm bark, and then the egg-carrying netting is suspended in the water of a pond, hatching pool or net cage, relying on the natural or slightly aerated water environment for still or slightly flowing water hatching.

[0004] However, this traditional incubation method has many inherent defects, which seriously restrict the improvement of incubation effect, such as: (1) complicated operation and high labor intensity: the process of hanging and collecting nets must be done manually. Especially in large-scale production, a large number of heavy egg-carrying nets need to be handled, which is inefficient and labor-intensive; (2) uneven water exchange: the suspended nets block each other, which can easily form dead corners in the water, resulting in uneven distribution of dissolved oxygen and water temperature at different positions of the nets. Eggs located in the inner or lower layers often suffocate and die due to insufficient dissolved oxygen supply; (3) egg accumulation and mold: when fish eggs adhere too densely on the nets, they are easy to accumulate, which not only affects water exchange, but also provides conditions for the growth of pathogenic bacteria such as water mold. (4) Inability to adjust the angle: The angle of the net after it is suspended is fixed and vertical. It is impossible to optimize the angle of the egg sheet according to the light, water temperature or water flow to create the best microenvironment for hatching. (5) Inconvenient management and difficult observation: The net is suspended in the water. It is difficult for the management personnel to observe the development of the fish eggs (such as the progress of embryo development, mold, etc.) at close range and clearly. It is impossible to find problems in time and take treatment measures, which increases the blind spots and risks of management. (6) Low space utilization efficiency: A certain distance needs to be maintained between the vertically suspended net sheets to ensure water flow. This method fails to make full use of the three-dimensional space of the water body, and the hatching capacity per unit water body is limited.

[0005] In summary, existing net-based hatching methods have become a technical bottleneck restricting the large-scale, intensive artificial breeding of *Pelteobagrus vachelli*. Therefore, there is an urgent need in this field for a device and method specifically designed for hatching *Pelteobagrus vachelli* to overcome these shortcomings and provide a hatching environment with sufficient water exchange, uniform dissolved oxygen, easy management, and effective prevention of saprolegniasis, thereby significantly improving hatching efficiency and hatching rate. Summary of the Invention

[0006] To address the above-mentioned technical problems, this invention provides a hatching system and method for yellow catfish (Pelteobagrus vachelli), which can solve many shortcomings of the existing traditional net hanging hatching method for yellow catfish, improve hatching efficiency and hatching rate, and thus meet the needs of the industrialization of artificial breeding of yellow catfish.

[0007] The objective of this invention is mainly achieved through the following technical solutions:

[0008] On the one hand, the present invention provides a hatching system for yellow catfish, including a spawning and fertilization module and a hatching module;

[0009] The labor induction and fertilization module includes several labor induction tanks, a first circulating water system, a first oxygen supply device, a first temperature control device, and several basins;

[0010] The incubation module includes several incubation buckets, several incubation boards, a second circulating water system, a second temperature control device, and a second oxygen supply device.

[0011] Furthermore, the bottom of the spawning tank is equipped with a first oxygen supply device for compressed air with a relative pressure of 0.12~0.20 bar; the bottom of the incubation tank is equipped with a second oxygen supply device for compressed air with a relative pressure of 0.12~0.20 bar.

[0012] Furthermore, the incubation board includes a frame and a mesh. The frame is rectangular, 70-80cm long and 30-40cm wide. The mesh is round or square with a diameter of 1-2mm. The mesh is evenly distributed on the mesh, and the total area of ​​the mesh is 69-83% of the area of ​​the mesh. The mesh is 1-2mm thick and made of nylon.

[0013] On the other hand, the present invention also provides a method for hatching yellow catfish, comprising the following steps:

[0014] Step 1, Artificial spawning and fertilization: Select female Yellow Catfish with red anus and a weight of over 180g from the parent stock for spawning induction injection. After injection, transfer all parent fish to the spawning induction tank of the spawning and fertilization unit. The circulating water temperature is controlled at 24~26℃. After 10~12 hours, observe the development of the female fish regularly. Squeeze the female fish eggs that have reached the effect time into a basin, and squeeze the male fish sperm into it at the same time. After fertilization, put the fertilized eggs into yellow mud water for de-adhesion treatment.

[0015] Step 2, incubation of fertilized eggs: Place the de-adhesive fertilized eggs into the incubation plate of the incubation module, then place the incubation plate into the incubation bucket and incubate for 48-72 hours. After the fry detach from the mold and swim horizontally in the incubation bucket, remove the incubation plate and incubate for another 48-72 hours until the fry start to eat.

[0016] Step 3, Initial feeding: After the fry start to eat, feed them with live food such as cladocerans and copepods. Continue feeding them in the hatching tank for 3-5 days, then transfer them out of the hatching tank to enter the fry rearing stage.

[0017] Furthermore, in step 1, the drugs used for spawning induction injection are a mixture of three agents: dopamine antagonist dioxone (DOM), luteinizing hormone-releasing hormone analog (LRH-A2), and human chorionic gonadotropin (HCG). The dosage for female fish is as follows: DOM: 2-4 mg / kg, LRH-A2: 15-30 μg / kg, HCG: 1000-2000 units / kg, administered twice. For parent fish, the dosage of the prepared drug is 1-3 mL each time. Male fish are injected twice, with each injection being half the dosage of the female fish. The interval between the two injections is 8-10 hours. The injection site is the base of the pectoral fin.

[0018] Furthermore, in step 2, several incubation boards are fixedly installed in parallel on an incubation board rack, with each incubation board facing downwards and forming an angle α with the vertically placed incubation board rack column, 30°≤α≤45°. The distance between two adjacent incubation boards on an incubation board rack is 10~15cm. Then, the incubation board rack with the incubation boards installed is fixed in an incubation bucket.

[0019] Furthermore, in step 2, time-sequential temperature control is carried out during incubation. The water temperature is controlled at 23.0℃±1℃ for 0~12 hours, and then increased by 1℃ every 8 hours after 12 hours until it reaches 26.0℃±0.5℃ and is maintained.

[0020] Furthermore, in step 3, the water temperature in the incubation tank is always controlled at 24~26℃.

[0021] Furthermore, in step 3, before feeding, cladocerans and copepods need to be disinfected by soaking in 5% saline for 5 minutes to remove impurities and predators. Before feeding live animals, they are sieved to select individuals with a size of 0.5~1.5mm.

[0022] Furthermore, in steps 1 through 3, the ammonia nitrogen in the water... ≤0.5mg / L, nitrite The water quality index is ≤0.2mg / L, pH value is 6.5~8.0, dissolved oxygen is >6mg / L, transparency is >50cm, and other water quality indicators comply with the relevant provisions of GB11607 "Fishery Water Quality Standard".

[0023] Compared with the prior art, the present invention can achieve at least one of the following technical effects:

[0024] (1) The mesh size of the incubation board of the present invention is slightly smaller than the diameter of the fertilized egg. The distribution density of the mesh on the net and the nylon net material can prevent the fertilized egg from falling out of the mesh and facilitate the attachment of the fertilized egg. At the same time, it allows water circulation and can ensure that each fertilized egg is in full contact with the water. The angle α between the plane of the incubation board and the vertically placed incubation board frame and the distance between two adjacent incubation boards not only facilitates the rolling off of dead eggs, but also facilitates the sliding off of the fry hatched from the fertilized eggs.

[0025] (2) By using the induced labor injection and controlling the appropriate time for artificial insemination in this invention, the fertilization rate of yellow catfish is improved.

[0026] (3) The sequential temperature control process used in this invention during incubation can shorten the incubation time of fertilized eggs compared with traditional incubation methods, significantly reducing the incubation time of fertilized eggs of yellow catfish from 60-72 hours to 54-60 hours.

[0027] (4) This invention controls the dissolved oxygen content in the water to be greater than 6 mg / L, the water transparency to be greater than 50 cm, and the ammonia nitrogen content to be lower than 50 cm. ≤0.5mg / L, nitrite With a concentration of ≤0.2mg / L, a temperature control accuracy of ±0.5℃, a pH value within the range of 6.5~8.0, and other water quality indicators meeting the relevant provisions of GB11607 "Fishery Water Quality Standard", an excellent environment suitable for the hatching of yellow catfish is created, improving the hatching rate and fry emergence rate.

[0028] (5) The incubation system and method of the present invention have a fertilization rate of 85-96%, a hatching rate of 90-95%, and a seedling emergence rate of 70-85%, which is an improvement over traditional incubation facilities and methods and meets the needs of the artificial breeding industry of yellow catfish. Attached Figure Description

[0029] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0030] Figure 1 This is a schematic diagram of the main structure of the incubation system of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure and installation of the incubation board;

[0032] Figure 3 for Figure 2 A magnified view of the area shown;

[0033] Figure 4 This is a schematic diagram of the incubation board's modular assembly.

[0034] In the diagram, A1-Induced labor and fertilization module; A10-Induced labor tank; A11-First oxygen supply device; A12-First temperature control device; A13-First circulating water system; A2-Incubation module; A20-Incubation tank; A21-Second oxygen supply device; A22-Second temperature control device; A23-Second circulating water system; 1-Incubation board; 10-Frame; 11-Mesh cloth; 12-Handle; 2-Incubation board frame; 20-Screw; α-Angle between the incubation board plane facing downwards and the upright of the incubation board frame. Detailed Implementation

[0035] The following detailed description of a hatching system and method for yellow catfish (Pelteobagrus vachelli) is provided in conjunction with specific embodiments. These embodiments are for comparative and illustrative purposes only, and the present invention is not limited to these embodiments.

[0036] First, the present invention provides a hatching system for yellow catfish (Pelteobagrus vachelli), comprising a spawning and fertilization module and a hatching module. The spawning and fertilization module includes several spawning tanks, a first circulating water system, a first oxygen supply device, a first temperature control device, and several basins; the hatching module includes several hatching tanks, several hatching plates, a second circulating water system, a second temperature control device, and a second oxygen supply device. Figure 1 This is a schematic diagram of the main structure of the incubation unit of the present invention.

[0037] The induced labor tank is cylindrical, with a diameter of 2-3m and a depth of 1-1.5m (e.g., 2m diameter × 1.2m depth). The bottom of the tank is equipped with a primary oxygen supply device using compressed air at a relative pressure of 0.12-0.20 bar. The tank also has a built-in primary temperature control device to adjust the water temperature, with a heating power of 1kW or higher (e.g., 3kW). The basin is approximately 30cm in diameter and 15cm in height. The circulation cycle of the water in each induced labor tank unit is 4-6 hours. For example, with five Φ3m × 1.5m induced labor tanks, the maximum total water volume is approximately 53m³, with a circulation cycle of 4 hours. When the main pipeline specification is DN250-DN300, the flow rate is approximately 13.3m³ / h.

[0038] The hatching tank is cylindrical, with a diameter of 1-2m and a depth of 1-1.5m (e.g., 1.5m diameter and 1.2m depth). A second oxygen supply device with compressed air at a relative pressure of 0.12-0.20 bar is installed at the bottom of the tank. The tank also has a built-in second temperature control device to adjust the water temperature, with a heating power of 1kW or higher (e.g., 3kW). The water circulation cycle for each hatching tank unit is 9-12 hours. For example, with 30 Φ2m×1.5m hatching tanks, the maximum total water volume is approximately 141m³, with a circulation cycle of 12 hours. When the main pipeline specification is DN250-DN300, the flow rate is approximately 11.8m³ / h.

[0039] Figure 2 This is a schematic diagram of the structure and installation of the incubation board. The incubation board 1 is a flat plate, including a frame 10 and a mesh 11. The frame 10 is rectangular, 70-80cm long, 30-40cm wide, and about 1-2cm thick. The mesh 11 has round or square meshes with a diameter of 1-2mm. The meshes are evenly distributed on the mesh 11, and the total area of ​​the meshes is about 69-83% of the area of ​​the mesh. The mesh 11 is 1-2mm thick. The frame 10 is made of PVC or wood, and the mesh 11 is made of nylon fabric to ensure a stable structure and good water permeability.

[0040] Secondly, this invention provides a method for hatching yellow catfish (Pelteobagrus vachelli), comprising the following steps:

[0041] Step 1, Artificial spawning and fertilization: Select female Yellow Catfish with red anus and a weight of over 180g from the parent stock for spawning induction injection. After injection, transfer all parent fish to the spawning induction tank of the spawning and fertilization unit. The circulating water temperature is controlled at 24~26℃. After 10~12 hours, observe the development of the female fish regularly. Squeeze the female fish eggs that have reached the effect time into a basin, and squeeze the male fish sperm into it at the same time. After fertilization, put the fertilized eggs into yellow mud water for de-adhesion treatment.

[0042] Step 2, incubation of fertilized eggs: Place the de-adhesive fertilized eggs into the incubation plate of the incubation module, then place the incubation plate into the incubation bucket and incubate for 48-72 hours. After the fry detach from the mold and swim horizontally in the incubation bucket, remove the incubation plate and incubate for another 48-72 hours until the fry start to eat.

[0043] Step 3, Initial feeding: After the fry start to eat, feed them with live food such as cladocerans and copepods. Continue feeding them in the hatching tank for 3-5 days, then transfer them out of the hatching tank to enter the fry rearing stage.

[0044] In step 1, the spawning-inducing injection uses a mixture of three drugs: dopamine antagonist domperidone (DOM), luteinizing hormone-releasing hormone analogue (LRH-A2), and human chorionic gonadotropin (HCG). The dosage for female fish is as follows: DOM: 2-4 mg / kg, LRH-A2: 15-30 μg / kg, HCG: 1000-2000 units / kg, administered twice. For the parent fish, each injection is 1-3 mL of the prepared drug. Male fish receive two injections, each half the dosage given to the female. The interval between the two injections is generally 8-10 hours; this interval can be extended when the water temperature is low. The injection site is the base of the pectoral fin. Artificial insemination requires precise timing; otherwise, the fertilization rate will be reduced. The effect time is approximately 10-12 hours. Before the effect time, the dynamics of the parent fish in the spawning pond should be monitored. When the parent fish begin to show signs of estrus but have not yet reached climax, a net should be used for inspection. During the examination, the female fish should be examined first. Place the female fish belly-down and gently press on the abdomen until eggs flow out. Cover the genital opening, dry the fish's body, and wrap it with a towel. Gently hold the fish, head up and belly down, and repeatedly squeeze gently from top to bottom to allow the eggs to flow into a clean, dry basin. Simultaneously, squeeze in male semen. After thorough stirring, add a small amount of physiological saline, stir again, and let stand for 1 minute. Then, place the fertilized eggs in muddy water for de-adhesion treatment. Male semen is obtained by dissecting the male fish and extracting its gonads. To prevent poor quality semen from a single male from affecting the fertilization rate, it is best to use semen from at least three males to fertilize the female eggs in one basin. Usually, one female fish can be fertilized 2-3 times, pausing briefly after each fertilization. After induced spawning, pay attention to the female fish's postpartum care to reduce postpartum mortality.

[0045] It should be noted that the luteinizing hormone-releasing hormone analogue (LRH-A2) and human chorionic gonadotropin (HCG) comply with the provisions of SC1012 "Lluteinizing Hormone-Releasing Hormone Analogue for Fish" and SC1011 "Human Choroid Gonadotropin for Fish", respectively, and the dopamine antagonist dioxone (DOM) meets the effective quality standards declared by the manufacturer.

[0046] In step 2, Figure 2 This is a schematic diagram of the structure and installation of the incubation board. Figure 3 for Figure 2The image shows a magnified view of the area shown. The fertilized eggs of *Pelteobagrus vachelli* are approximately 1-2 mm in diameter. The mesh size of the hatching plate is slightly smaller than the diameter of the fertilized eggs. The mesh density and the nylon material of the mesh prevent the fertilized eggs from falling out while allowing water circulation, ensuring that each fertilized egg has sufficient contact with the water. Specifically, several hatching plates 1 are fixedly installed in parallel on a hatching plate frame 2, such as 4-6 hatching plates 1 combined on one frame. Each hatching plate 1, with its plane facing downwards, forms an angle α with the vertically placed column of the frame 2, 30°≤α≤45°. The distance between two adjacent hatching plates 1 on a frame 2 is 10-15 cm. Then, the hatching plate frames 2 with the installed hatching plates 1 are fixed in a hatching container, such as two frames in one container. Each hatching plate holds 40,000-50,000 fertilized eggs, with a density of approximately 15-19 eggs / cm². 2 .

[0047] In addition, the incubation board is composed of a frame 10 and a mesh 11 that can be freely combined separately. When the frame 10 and the incubation board frame 2 are fixed, the mesh 11 can be separated from the frame 10 by the handle 12, or it can be inserted into the frame 10 for easy incubation operation. At the same time, the included angle α can also be adjusted by the screw 20 on the incubation board frame 2. Figure 4 This is a schematic diagram of the incubation board's modular assembly.

[0048] It should be noted that the nylon fabric used for hatching and the mesh size of the mesh not only facilitate the attachment of fertilized eggs but also provide a larger contact area between the fertilized eggs and the water. The angle α between the hatching board's plane facing downwards and the vertically placed hatching board frame's uprights, as well as the spacing between adjacent hatching boards, not only facilitate the rolling off of dead eggs but also allow the hatched fry to slide off easily.

[0049] Maintain a micro-flow water environment to prevent fertilized eggs from absorbing oxygen. Control the water circulation cycle to 9-12 hours, and maintain the relative pressure range of the second oxygen supply device at 0.12-0.20 bar. Ensure the dissolved oxygen content in the water is greater than 6 mg / L. Use an internal circulation aquaculture system in the hatching unit for incubation, and promptly remove dead eggs to ensure good water quality.

[0050] During incubation, temperature is controlled sequentially. The water temperature is maintained at 23.0℃±1℃ for 0-12 hours, and then increased by 1℃ every 8 hours after 12 hours until it reaches 26.0℃±0.5℃ and is maintained. Compared with traditional incubation methods, this method can shorten the incubation time of fertilized eggs, significantly reducing the incubation time of fertilized eggs of yellow catfish from 60-72 hours to 54-60 hours.

[0051] Eight to twelve hours after fertilization, the embryo reaches mid-gastrulosum. At this time, dead eggs are removed, and the fertilization rate is calculated as the percentage of fertilized eggs out of the total number of eggs, i.e., fertilization rate = number of fertilized eggs / total number of eggs × 100%. Specifically, 3 to 5 egg clusters from the hatching plate are randomly selected, each cluster containing ≥200 eggs. After removing adherent eggs, the total number of eggs is counted. The cleavage morphology is observed under a dissecting microscope to confirm the number of fertilized eggs. The fertilization rate of this invention is 85-96%.

[0052] Hatching rate is calculated within 12-24 hours after hatching. The hatching rate is the percentage of hatched fry out of the number of fertilized eggs, i.e., hatching rate (%) = number of hatched fry / number of fertilized eggs × 100%. The hatching rate of this invention is 90-95%.

[0053] After approximately 72 hours of incubation, the fry swim horizontally within the incubation tank, and the hatching rate is calculated. The hatching rate is the percentage of healthy, viable fry suitable for stocking in a pond out of the total number of fertilized eggs, calculated as: Hatching Rate (%) = Number of swimming fry / Number of fertilized eggs × 100%. Specifically, dead and weak fry are removed, and the number of viable, healthy fry is counted. The hatching rate of this invention can reach 70-85%.

[0054] Once the yellow catfish fry are swimming horizontally in the hatching tank, remove the hatching plate. Keep them in the hatching tank until the yolk sac is almost completely used up, then they are ready to be fed. During this period, it is necessary to constantly monitor water quality changes.

[0055] In step 3, before feeding, cladocerans and copepods need to be soaked in 5% saline solution for 5 minutes for disinfection to remove impurities and predators. Before feeding live animals, they are sieved to select individuals with a size of 0.5~1.5mm. The hatching tank has a built-in second temperature control device to maintain the water temperature at 24~26℃.

[0056] It should be noted that in steps 1-3, the ammonia nitrogen in the water... ≤0.5mg / L, nitrite The water quality parameters are: ≤0.2mg / L, pH value is 6.5~8.0, dissolved oxygen >6mg / L, transparency >50cm; other water quality indicators comply with the relevant provisions of GB11607 "Fishery Water Quality Standard".

[0057] Example

[0058] A hatching system for yellow catfish (Pelteobagrus vachelli) includes a spawning and fertilization module and a hatching module. The spawning and fertilization module includes three spawning tanks, a first circulating water system, a first oxygen supply device, a first temperature control device, and ten basins; the hatching module includes five hatching tanks, forty hatching plates, a second circulating water system, a second temperature control device, and a second oxygen supply device.

[0059] The induced labor tank is circular, with a diameter of 3m and a depth of 1.5m. A primary oxygen supply device with compressed air at a relative pressure of 0.12~0.20 bar is installed at the bottom of the tank. The tank also has a built-in primary temperature control device for adjusting the water temperature, with a heating power of 3kW. The basin is 30cm in diameter and 15cm in height. The water circulation cycle in the induced labor tank unit is 4~6 hours.

[0060] The hatching tank is circular, with a diameter of 2m and a depth of 1.5m. A second oxygen supply device with compressed air at a relative pressure of 0.12~0.20 bar is installed at the bottom of the tank. A second temperature control device with a heating power of 3kW is also built into the tank to adjust the water temperature. The water circulation cycle in the hatching tank unit is 9~12 hours.

[0061] Figure 2 This is a schematic diagram of the structure and installation of the incubation board. The incubation board 1 is a flat plate, including a frame 10 and a mesh 11. The frame 10 is rectangular, 75cm long, 35cm wide, and 2cm thick. The mesh 11 has square meshes with a diameter of 2mm. The meshes are evenly distributed on the mesh 11, and the total area of ​​the meshes is approximately 75% of the area of ​​the mesh. The mesh 11 is 1mm thick. The frame 10 is made of PVC, and the mesh 11 is made of nylon.

[0062] A method for hatching yellow catfish (Pelteobagrus vachelli) includes the following steps:

[0063] Step 1, Artificial spawning and fertilization: Select female Yellow Catfish with red anus and a weight of over 180g from the parent stock for spawning induction injection. After injection, transfer all parent fish to the spawning induction tank of the spawning and fertilization unit. The circulating water temperature is controlled at 24~26℃. After 10 hours, observe the development of the female fish regularly. Squeeze the female fish eggs that have reached the effect time into a basin, and squeeze the male fish sperm into it at the same time. After fertilization, put the fertilized eggs into yellow mud water for de-adhesion treatment.

[0064] The spawning-inducing injection uses a mixture of three drugs: dopamine antagonist domperidone (DOM), luteinizing hormone-releasing hormone analogue (LRH-A2), and human chorionic gonadotropin (HCG). The dosage for female fish is as follows: DOM: 3 mg / kg, LRH-A2: 25 μg / kg, HCG: 1500 units / kg, administered twice. For parent fish, the dosage is 2 mL per injection. Male fish receive two injections, each half the dosage given to females. The interval between the two injections is 9 hours. The injection site is the base of the pectoral fin. The effect lasts 10-12 hours. Before the effect time, observe the parent fish in the spawning tank. When the parent fish begin to spawn but have not yet reached climax, check them with a net. Check the female first. With the female abdomen down, gently press the abdomen; if eggs flow out, cover the genital opening, dry the fish's body, and wrap it with a towel. Gently hold the fish head up and belly down, and repeatedly squeeze gently from top to bottom to allow the eggs to flow into a clean basin. Simultaneously, squeeze in male fish sperm. After thorough stirring, add a small amount of saline solution, stir again, and let stand for 1 minute. Then, place the fertilized eggs in muddy water for de-adhesion. Male fish sperm is obtained by killing the male fish and extracting its gonads. For female eggs in one basin, use sperm from at least three male fish to fertilize them. Squeeze the eggs from one female fish 2-3 times, pausing briefly after each squeezing before squeezing again.

[0065] ammonia nitrogen in water ≤0.5mg / L, nitrite The water quality parameters are: ≤0.2mg / L, pH value is 6.5~8.0, dissolved oxygen >6mg / L, transparency >50cm; other water quality indicators comply with the relevant provisions of GB11607 "Fishery Water Quality Standard".

[0066] Step 2, incubation of fertilized eggs: Place the de-adhesive fertilized eggs into the incubation plate of the incubation unit, and then place the incubation plate into the incubation bucket. Incubate for 48-72 hours. After the fry detach from the mold and swim horizontally in the incubation bucket, remove the incubation plate. Incubate for another 48-72 hours after removing the incubation plate until the fry start to eat.

[0067] Specifically, five hatching boards are fixed parallel to each other on a hatching board rack, with each hatching board facing downwards at a 45° angle to the vertically placed rack's uprights. The distance between any two adjacent hatching boards on a rack is 15cm. Then, two racks with the hatching boards installed are fixed into an incubation container, for a total of 40 hatching boards fixed in four incubation containers. Each hatching board holds 40,000 to 50,000 fertilized eggs, with a density of approximately 15 to 19 eggs / cm². 2 .

[0068] Maintain a micro-flow water environment to prevent fertilized eggs from hypoxia. Control the water circulation cycle to 9-12 hours. The relative air pressure range of the second oxygen supply device is 0.12-0.20 bar. The dissolved oxygen content in the water is greater than 6 mg / L.

[0069] During incubation, temperature is controlled sequentially. The water temperature is maintained at 23.0℃±1℃ for 0-12 hours, and then increased by 1℃ every 8 hours after 12 hours until it reaches 26.0℃±0.5℃ and is maintained thereafter.

[0070] Eight to twelve hours after fertilization, the embryo reaches mid-gastrulosum. At this time, dead eggs are removed, and the fertilization rate is calculated. Egg clusters of 3 to 5 random cells from the hatching plate are selected, with each cluster containing ≥200 eggs. After removing adherent eggs, the total number of eggs is counted. Cleavage morphology is observed under a dissecting microscope to confirm the number of fertilized eggs. The average fertilization rate in this embodiment is 90%.

[0071] Hatching rate was calculated within 12 to 24 hours after hatching. The average hatching rate in this example was 92%.

[0072] After about 72 hours of incubation, the fry swim horizontally in the incubation tank, and the hatching rate is counted. The hatching rate is the percentage of healthy fry that can be released into the pond out of the number of fertilized eggs. The average hatching rate of this invention is 80%.

[0073] After the yellow catfish fry have swum horizontally in the hatching tank, remove the hatching plate and release the fry into the hatching tank. Keep them in the hatching tank until the yolk sac is almost completely used up, then they are ready to be fed. During this period, it is necessary to constantly monitor water quality changes.

[0074] ammonia nitrogen in water ≤0.5mg / L, nitrite The water quality parameters are: ≤0.2mg / L, pH value is 6.5~8.0, dissolved oxygen >6mg / L, transparency >50cm; other water quality indicators comply with the relevant provisions of GB11607 "Fishery Water Quality Standard".

[0075] Step 3, Initial feeding: After the fry start to eat, feed them with live food such as cladocerans and copepods. Continue feeding them in the hatching tank for 3-5 days, then transfer them out of the hatching tank to enter the fry rearing stage.

[0076] Before feeding, cladocerans and copepods should be disinfected by soaking in 5% saline solution for 5 minutes to remove impurities and predators. Live animals should be sieved before feeding, selecting individuals with a diameter of 0.5-1.5 mm. The water temperature in the hatching tank should always be controlled at 24-26℃.

[0077] ammonia nitrogen in water ≤0.5mg / L, nitrite The water quality parameters are: ≤0.2mg / L, pH value is 6.5~8.0, dissolved oxygen >6mg / L, transparency >50cm; other water quality indicators comply with the relevant provisions of GB11607 "Fishery Water Quality Standard".

[0078] In this embodiment, 125 male and 25 female catfish were raised as parents, resulting in a total of approximately 1.043 million fry.

[0079] Comparative Example

[0080] The oxygen supply device used in this comparative example is a common aerator, and the water quality and temperature are uncontrollable.

[0081] Step 1, Artificial Induction of Labor and Fertilization: Except for differences in water quality, temperature and dissolved oxygen levels, this step is exactly the same as the example.

[0082] Step 2, Fertilized Egg Incubation: This step uses a different incubation board than the conventional incubation board in the previous embodiment. Specifically, it has an aluminum wire frame and a 60-mesh silk screen in the middle, and is vertically suspended in the incubation bucket for incubation. Because sequential temperature control was not performed during incubation as in the previous embodiment, the incubation time for the fertilized eggs was 70 hours.

[0083] The average fertilization rate of this comparative example was 72%, the average hatching rate was 76%, and the average emergence rate was 68%.

[0084] Step 3, Initial Feeding: Except for differences in water quality, temperature, and dissolved oxygen levels, this step is exactly the same as the example.

[0085] This comparative study used approximately 125 male and 25 female catfish parents, producing a total of about 586,000 fry.

[0086] As can be seen from the above, the embodiment is superior to the comparative example in terms of fertilized egg incubation time, fertilization rate, hatching rate and seedling emergence rate. The hatching efficiency is 1.8 times that of the comparative example, which improves the hatching efficiency and hatching rate and realizes the large-scale artificial breeding industry of yellow catfish.

[0087] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for hatching yellow catfish using a yellow catfish hatching system, characterized in that, The system includes an induced labor and fertilization module and an incubation module; The labor induction and fertilization module includes several labor induction tanks, a first circulating water system, a first oxygen supply device, a first temperature control device, and several basins; the labor induction tank is cylindrical, with a diameter of 2-3m and a depth of 1-1.5m; the bottom of the labor induction tank is equipped with the first oxygen supply device, which supplies compressed air with a relative pressure of 0.12-0.20 bar; the circulation cycle of the water in the labor induction tank unit is 4-6 hours; The incubation module includes several incubation tanks, several incubation plates, a second circulating water system, a second temperature control device, and a second oxygen supply device; the incubation tank is cylindrical, with a diameter of 1~2m and a depth of 1~1.5m; the bottom of the incubation tank is equipped with the second oxygen supply device, which supplies compressed air with a relative pressure of 0.12~0.20 bar; the circulation cycle of the water in the incubation tank unit is 9~12 hours. The incubation board includes a frame and a mesh. The frame is rectangular, 70-80cm long and 30-40cm wide. The mesh has circular mesh openings with a diameter of 1-2mm, evenly distributed across the mesh. The total area of ​​the mesh openings is 69-83% of the mesh area. The mesh is 1-2mm thick and made of nylon. Several incubation boards are fixedly installed in parallel on an incubation board frame. Each incubation board, with its plane facing downwards, forms an angle α with the vertically placed column of the incubation board frame. The angle α is adjusted by screws on the incubation board frame, with a range of 30°≤α≤45°. The distance between two adjacent incubation boards on an incubation board frame is 10-15cm. Then, the incubation board frames with the incubation boards installed are fixed in an incubation bucket. The method includes the following steps: Step 1: Artificial spawning and fertilization: Female *Pelteobagrus vachelli* broodstock with red anus and a weight of over 180g were selected for spawning induction injection. After injection, all broodstock were transferred to the spawning induction tank of the spawning induction unit. The circulating water temperature was controlled at 24-26℃, and the effect time was 10-12 hours. After 10-12 hours, the development of the female fish was observed regularly. Eggs from the female fish that had reached the effect time were squeezed into a basin, along with male semen. After fertilization, the fertilized eggs were placed in muddy water for de-adhesion treatment. The spawning induction injection... The medication used is a mixture of three agents: dopamine antagonist diorone, luteinizing hormone-releasing hormone analog A2, and human chorionic gonadotropin (hCG). The dosage for female fish is as follows: dopamine antagonist diorone: 2-4 mg / kg, luteinizing hormone-releasing hormone analog A2: 25-30 μg / kg, and hCG: 1000-1500 units / kg. Two injections are given. Parent fish are injected with 1-3 mL of the prepared medication each time. Male fish are injected twice, each time with half the dosage given to female fish. The interval between the two injections is 8-10 hours. Step 2, incubation of fertilized eggs: Place the de-adhesive fertilized eggs into the incubation plate of the incubation module, then place the incubation plate into the incubation bucket and incubate for 48-72 hours. After the fry detach from the mold and swim horizontally in the incubation bucket, remove the incubation plate and incubate for another 48-72 hours until the fry start to eat. Step 3, Initial feeding: After the fry start to eat, feed them cladocerans and copepods as live food. Continue feeding them in the hatching tank for 3-5 days, then transfer them out of the hatching tank to enter the fry rearing stage.

2. The method according to claim 1, characterized in that, In step 1, the injection site for the labor-inducing injection is the base of the pectoral fin.

3. The method according to claim 1, characterized in that, In step 2, temperature is controlled sequentially during incubation. The water temperature is controlled at 23.0℃±1℃ for 0-12 hours, and then increased by 1℃ every 8 hours after 12 hours until it reaches 26.0℃±0.5℃ and is maintained thereafter.

4. The method according to claim 1, characterized in that, In step 3, the water temperature in the incubation tank is always controlled at 24~26℃.

5. The method according to claim 1, characterized in that, In step 3, before feeding, the cladocerans and copepods need to be disinfected by soaking in 5% saline for 5 minutes to remove impurities and harmful organisms. Before feeding, the live animals are sieved to select individuals with a size of 0.5~1.5mm.

6. The method according to any one of claims 1 to 5, characterized in that, In steps 1 to 3, the ammonia nitrogen (NH3-N) in the water is ≤0.5 mg / L, and the nitrite (NO2) content is ≤0.5 mg / L. - ≤0.2mg / L, pH value 6.5~8.0, dissolved oxygen >6mg / L, transparency >50cm.

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