Fish welfare type method for improving breeding efficiency of wild snakehead

Abstract

The invention provides a fish welfare type method for improving the breeding efficiency of wild snakehead, and belongs to the technical field of aquaculture, the method has significant advantages in the aspect of wild snakehead breeding, when parent fish is caught, specific water areas and opportunities are selected, the parent fish is transported with water by gently taking and releasing, parent fish injury is reduced, and the survival rate is increased. According to parent fish cultivation, different aquatic plants are cultivated, the vegetation area proportion and the reasonable stocking density are controlled, a suitable environment is provided for parent fishes, special treatment is conducted in the wintering period in the northern area to guarantee survival of the parent fishes, specification and age requirements are defined in the spawning induction link, cost reduction and efficiency improvement are promoted, and the spawning induction rate is increased in a specific spawning induction agent injection and matching mode; the weight ratio of male and female parent fishes is controlled to facilitate mating and spawning, the parent fishes are timely recovered for continuous breeding after delivery, the loss of the wild parent fishes is further reduced, water changing and oil film removing are achieved through an innovative egg collecting method, fertilized egg development is facilitated, the method is friendly to the parent fishes, and the breeding efficiency is comprehensively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and in particular relates to a fish welfare method for improving the reproduction efficiency of wild snakehead fish. Background Art

[0002] Wild black snakehead has important value in preserving original fine breeds, purifying and strengthening germplasm, cultivating new varieties and meeting other production needs. Therefore, it is very necessary to carry out research on efficient and fish-welfare-oriented wild black snakehead breeding.

[0003] There are currently many problems in the breeding process of wild snakehead. On the one hand, through comparative tests, it was found that the mortality rate of snakehead broodstock directly caught from the wild environment was very high, usually 40% to 60%, and the fertilized eggs produced were generally 310 to 330 per gram, and the eggs were small and of low quality. On the other hand, in the current breeding process of snakehead, foam boxes and net cages are often used to separate different pairs of broodstock to prevent them from killing each other. The following examples are usually used to collect fertilized eggs: one method is to manually use foam boxes or net cages to scoop up fertilized eggs one by one to separate fish and eggs, and carry out centralized incubation; the other method is to manually use foam boxes or net cages to collect fertilized eggs one by one to separate fish and eggs, and carry out centralized incubation. In the former method, it is inevitable that some fertilized eggs will fall during the operation, resulting in waste. If the spawning system is continued to be used, the fallen fertilized eggs may be mixed into the next batch, causing the next batch of fertilized eggs to hatch asynchronously, and then the fry to grow asynchronously, resulting in serious cannibalism; the latter method greatly increases the probability of operational damage to the broodstock, affecting its next spawning. In addition, the father and mother of the black snakehead generally do not excrete sperm and eggs at one time. Frequent operations cause greater stress to the black snakehead broodstock, affecting their continued spawning. It can be seen that no matter which method is commonly used in the past, the collection process of fertilized eggs is time-consuming and laborious, and it is impossible to effectively separate the large amount of oil film and mucus accompanying the black snakehead spawning, and the broodstock are seriously damaged and the breeding efficiency is low.

[0004] In order to solve the above-mentioned problems that restrict the reproductive efficiency and survival rate of wild snakehead fish and promote the large-scale utilization of wild snakehead fish resources, this project team started from the aspects of broodstock catching, cultivation, spawning, and egg collection method upgrading and transformation, and developed and integrated a series of methods in order to provide a fish welfare-oriented method to improve the reproductive efficiency of wild snakehead fish. Summary of the invention

[0005] The object of the present invention is to provide a fish welfare type method for improving the reproduction efficiency of wild Channa argus, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A fish welfare method for improving the breeding efficiency of wild Channa argus includes the following steps:

[0008] Fishing process: Collect wild snakehead fish from ditches, puddles or small reservoirs in the wild. If the place is suitable for drainage, drain the water and then use a scoop net to catch it. Ground traps should be used for catching in large water areas. The whole process requires gentle handling and transportation with water. The best time to catch wild broodstock is October to November of the year before breeding work is carried out. The cooler temperature at this time can significantly reduce the damage that may be caused to wild broodstock during the fishing process, thereby increasing the survival rate of broodstock.

[0009] Broodstock cultivation: After the wild adult snakehead fish are caught and treated with about 3% salt water for 5 to 10 minutes, they are placed in a special broodstock cultivation pond. The pond should be planted with benthic aquatic plants, such as Vallisneria, Dermatophyta, etc.; emergent plants, such as reeds and lotus, etc.; and floating plants, such as water hyacinth, etc. The vegetation area at the bottom of the pond should account for 1 / 10 to 1 / 3 of the total area of ​​the pond bottom. The stocking density of snakehead broodstock should be set at 1 kg per 4 to 7 square meters to ensure that there is enough space for the broodstock in the pond to move around and avoid mutual interference. Fresh wild fish should be artificially added to keep the pond with abundant and palatable live bait. In northern regions, the water level needs to be raised to more than 2 meters before wintering. During the ice period, the dirt on the ice surface should be cleaned and it should be ensured that there are more than 2 ice eyes per 667 square meters.

[0010] Selection of broodstock: The appropriate size is 1.0 to 2.2 kg per fish, and the age must be more than 2 winters old. Females are preferably 2 to 3 winters old, and males are preferably 3 to 4 winters old.

[0011] Induced spawning of broodstock: The best time is from June to July, and the water temperature of the breeding environment can be stabilized at 27 to 29 degrees Celsius. The method of inducing spawning is to use one injection and supplementary injections depending on the actual situation of sperm and egg discharge. The type and dosage of oxytocin injected into female broodstock per kg body weight is 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 mg of DOM. The type and dosage of oxytocin injected into male broodstock are the same as those of female broodstock, and the injection dosage is 1 / 2 of that of female broodstock. The timing of supplementary injection is described in the section "Timing of postpartum broodstock recovery" below. The method of supplementary injection is the same as the first injection. Male and female broodstock are paired at a ratio of 1:1, and the spawning grids of the small water body in the special spawning pool are used to separate them to prevent mutual cannibalism. The weight specifications of the paired male and female broodstock are controlled between 1:1 and 1:2.

[0012] The timing of postpartum broodstock recovery is any of the following: 3 fertilized eggs; no fertilized eggs within 36 hours after 2 fertilized eggs; no fertilized eggs within 36 hours after 1 fertilized eggs; no fertilized eggs after 55 hours of artificial injection of oxytocin and 2 fertilized eggs after oxytocin injection; no fertilized eggs after 55 hours of artificial injection of oxytocin and 24 hours after 1 fertilized eggs after oxytocin injection; no fertilized eggs after 55 hours of artificial injection of oxytocin and 24 hours after 1 fertilized eggs after oxytocin injection. The recovered broodstock are returned to the broodstock breeding pond and given sufficient palatable fresh wild bait fish for further breeding.

[0013] Special spawning pool: including a water pool, the water pool is divided into a plurality of spawning grids, the height of the spawning grid is 100 to 120 cm, the length and width are both 120 to 150 cm, each of the spawning grids is provided with an extension edge at the junction, the width of the extension edge is 15 cm, each of the spawning grids is provided with a water grid at the end close to each other, the vertical plate interval of each water grid is 1 to 2 cm, the thickness is 10 to 15 cm, each of the spawning grids is connected with a shuttle-shaped foam float to simulate an ovary, the area of ​​each shuttle-shaped foam float accounts for about 1 / 4 of the area of ​​the spawning grid, a water inlet pipe is provided on one side of the water pool, and a plurality of water jet holes are provided on the side of the water inlet pipe close to the water pool. Two drain pipes are arranged on the other side of the pool away from the water inlet pipe. The two drain pipes are respectively arranged at the side ends of the two rightmost egg-laying grids and connected to the outside. The height of one end of each drain pipe immersed in the egg-laying grid is 40 to 45 cm, and the height of the other end is 2 to 3 cm lower than the aforementioned height. An egg-collecting net cage is arranged on the side of the drain pipe connected to the outside of the pool. Water stop valves are arranged at the ends of the drainage outlets of the two drain pipes. The drainage outlets of the two drain pipes are arranged in the egg-collecting net cage. The upper part of the egg-collecting net cage is a 60-mesh nylon net, and the lower part is a watertight basin. The height of the watertight basin in the egg-collecting net cage is 10 to 12 cm lower than the end of the drain pipe. The pipe diameter of the water inlet pipe and the two drain pipes is 11 cm.

[0014] Egg collection method: When the water inlet pipe is working, water is ejected from one side of the rectangular pool to push the water in the spawning pool to flow. The water jetting intensity of the water inlet pipe is adjusted to control the flow rate of the water in the spawning pool at 0.2 to 0.4 meters per second. At this time, the water flow can push the floating fertilized eggs of black snakehead together with the oil film to flow to the side with the drain pipe. During this period, the fertilized eggs together with the oil film can smoothly pass through the gap between the spawning grids and the obstacles of the shuttle-shaped foam floats, and flow into the egg collection cage through the drain pipe connected to the overflow port. The vertical pipe of the drain pipe in the spawning grid is lower than the grid, and the vertical pipe of the drain pipe outside the spawning pool is slightly lower than the vertical pipe in the spawning grid. A water stop valve is set at the end of the drain pipe outlet to control the speed of collecting fertilized eggs or stop collecting.

[0015] As a preferred solution of the present invention, wild broodstock are suitable for collection from October to November, and are collected by draining water, fishing with a scoop net or trapping on a large water surface, and transporting with water. This method causes less damage to the collected broodstock.

[0016] As a preferred scheme of the present invention, the reasonable area of ​​vegetation in the broodstock breeding pond is about 1 / 10 to 1 / 3 of the bottom area of ​​the pond. Such vegetation configuration can create an environment suitable for the survival of broodstock and provide reasonable feeding. The specifications of the fertilized eggs produced by this method are 270 to 290 grains per gram, while the specifications of the fertilized eggs produced by broodstock not bred according to this method are usually 310 to 330 grains per gram. This method can improve the quality of fertilized eggs.

[0017] As a preferred solution of the present invention, the suitable stocking density of the snakehead broodstock is 1 kg per 4 to 7 square meters, which can ensure that the broodstock have enough space and sufficient food.

[0018] As a preferred solution of the present invention, the specific method for inducing spawning of male and female fish is to inject 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 milligrams of DOM per kg body weight of female fish, and inject the same type of oxytocin as that of female fish into male fish, with a dosage of 1 / 2 of that of female fish, and perform additional injections depending on the actual situation of sperm and egg ovulation. This method can effectively reduce the input of manpower and material resources and operations that cause stress reactions to broodstock, and significantly improve the induced spawning rate.

[0019] As a preferred solution of the present invention, the pairing method for induced spawning of broodstock is 1 female:1 male, and small water bodies are used to separate spawning grids to prevent mutual cannibalism, and the weight ratio of male and female broodstock is controlled between 1:1 and 1:2, which is conducive to mating and spawning.

[0020] As a preferred solution of the present invention, the recovery of broodstock after birth needs to be based on a specific time to maximize the preservation of the broodstock and improve the breeding efficiency. The survival rate of broodstock recovered by this method can be increased from the original 40% to 60% to more than 90%, saving a lot of manpower and reducing the interference of poor quality fertilized eggs on later hatching work.

[0021] As a preferred solution of the present invention, the egg collection method uses reasonable water flow circuit design and egg collection cage setting to push water from one side in a rectangular cement pool so that the fertilized eggs can flow smoothly into the egg collection cage. This method is friendly to parent fish, the fertilized eggs can be freed from oil film interference, and the fertilized eggs of the same period and batches can be collected simultaneously and incubated on a large scale, thereby improving the breeding efficiency.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] First, in the broodstock fishing stage, it is important to select specific fishing waters and times, and to use the method of gentle handling and water transportation, especially to use scoop nets in places with drainage conditions or ground cages in large water surfaces, which can greatly reduce the damage to wild broodstock and improve the survival rate of broodstock, thus providing a healthy broodstock foundation for subsequent breeding work. Secondly, in the broodstock cultivation process, different types of aquatic plants are cultivated in earthen ponds to create an environment suitable for broodstock survival. At the same time, the vegetation area at the bottom of the broodstock cultivation pond is controlled to be approximately 1 / 10 to 1 / 3 of the pond bottom area, which not only provides a hiding place for broodstock, but also improves the water quality. A stocking density of 1 kg of broodstock is adopted for every 4 to 7 square meters to ensure that the broodstock have enough space and sufficient food, which is conducive to the growth and development of the broodstock. Special treatment measures in northern regions, such as raising the water level before wintering, cleaning dirt on the ice surface during the ice-covered period, and ensuring the number of ice eyes, further guarantee the survival conditions of the broodstock. Furthermore, in the broodstock induction stage, it is important to clarify the regulations for broodstock. The invention relates to a method for spawning fish, a method for spawning fish and a method for spawning fish. The invention relates to a method for spawning fish, ... BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a three-dimensional schematic diagram of the intermediate water pool of the present invention;

[0025] Figure 2 It is a cross-sectional schematic diagram of the intermediate water tank of the present invention;

[0026] Figure 3 It is a schematic diagram of the middle drainage pipe of the present invention.

[0027] In the figure: 1, water pool; 2, spawning grid; 5, extension edge; 6, shuttle-shaped foam float; 7, water inlet pipe; 8, drainage pipe; 9, egg collecting cage. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figure 1-Figure 3 The present invention provides a fish welfare method for improving the breeding efficiency of wild Channa argus, comprising the following steps:

[0030] Fishing process: Collect wild snakehead fish from ditches, puddles or small reservoirs in the wild. If the place is suitable for drainage, drain the water and then use a scoop net to catch it. Ground traps should be used for catching in large water areas. The whole process requires gentle handling and transportation with water. The best time to catch wild broodstock is October to November of the year before breeding work is carried out. The cooler temperature at this time can significantly reduce the damage that may be caused to wild broodstock during the fishing process, thereby increasing the survival rate of broodstock.

[0031] Broodstock cultivation: After the wild adult snakehead fish are caught and treated with about 3% salt water for 5 to 10 minutes, they are placed in a special broodstock cultivation pond. The pond should be planted with benthic aquatic plants, such as Vallisneria, Dermatophyta, etc.; emergent plants, such as reeds and lotus, etc.; and floating plants, such as water hyacinth, etc. The vegetation area at the bottom of the pond should account for 1 / 10 to 1 / 3 of the total area of ​​the pond bottom. The stocking density of snakehead broodstock should be set at 1 kg per 4 to 7 square meters to ensure that there is enough space for the broodstock in the pond to move around and avoid mutual interference. Fresh wild fish should be artificially added to keep the pond with abundant and palatable live bait. In northern regions, the water level needs to be raised to more than 2 meters before wintering. During the ice period, the dirt on the ice surface should be cleaned and it should be ensured that there are more than 2 ice eyes per 667 square meters.

[0032] Selection of broodstock: The appropriate size is 1.0 to 2.2 kg per fish, and the age must be more than 2 winters old. Females are preferably 2 to 3 winters old, and males are preferably 3 to 4 winters old.

[0033] Induced spawning of broodstock: The best time is from June to July, and the water temperature of the breeding environment can be stabilized at 27 to 29 degrees Celsius. The method of inducing spawning is to use one injection and supplementary injections depending on the actual situation of sperm and egg discharge. The type and dosage of oxytocin injected into female broodstock per kg body weight is 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 mg of DOM. The type and dosage of oxytocin injected into male broodstock are the same as those of female broodstock, and the injection dosage is 1 / 2 of that of female broodstock. The timing of supplementary injection is described in the section "Timing of postpartum broodstock recovery" below. The method of supplementary injection is the same as the first injection. Male and female broodstock are paired at a ratio of 1:1, and the spawning grids of the small water body in the special spawning pool are used to separate them to prevent mutual cannibalism. The weight specifications of the paired male and female broodstock are controlled between 1:1 and 1:2.

[0034] The timing of postpartum broodstock recovery is any of the following: 3 fertilized eggs; no fertilized eggs within 36 hours after 2 fertilized eggs; no fertilized eggs within 36 hours after 1 fertilized eggs; no fertilized eggs after 55 hours of artificial injection of oxytocin and 2 fertilized eggs after oxytocin injection; no fertilized eggs after 55 hours of artificial injection of oxytocin and 24 hours after 1 fertilized eggs after oxytocin injection; no fertilized eggs after 55 hours of artificial injection of oxytocin and 24 hours after 1 fertilized eggs after oxytocin injection. The recovered broodstock are returned to the broodstock breeding pond and given sufficient palatable fresh wild bait fish for further breeding.

[0035] Special spawning pool: including a pool 1, the pool 1 is divided into a plurality of spawning grids 2, the height of the spawning grid 2 is 100 to 120 cm, the length and width are both 120 to 150 cm, each spawning grid 2 is provided with an extension edge 5 at the joint, the width of the extension edge 5 is 15 cm, each spawning grid 2 is provided with a water grid at the end close to each other, the vertical plate interval of each water grid is 1 to 2 cm, the thickness is 10 to 15 cm, each spawning grid 2 is connected with a shuttle-shaped foam floating plate 6 to simulate an ovary, and the area of ​​each shuttle-shaped foam floating plate 6 accounts for about 1 / 4 of the area of ​​the spawning grid 2, a water inlet pipe 7 is provided on one side of the pool 1, and a plurality of water injection holes are provided on the side of the water inlet pipe 7 close to the pool 1, and the pool 1 is away from Two drain pipes 8 are provided on the other side of the water inlet pipe 7. The two drain pipes 8 are respectively arranged at the side ends of the two rightmost spawning grids 2 and connected to the outside. The height of one end of each drain pipe 8 immersed in the spawning grid 2 is 40 to 45 cm, and the height of the other end is 2 to 3 cm lower than the aforementioned height. An egg collecting net cage 9 is provided on one side of the drain pipe 8 connected to the outside of the pool 1. Water stop valves are provided at the ends of the drainage outlets of the two drain pipes 8. The drainage outlets of the two drain pipes 8 are both arranged in the egg collecting net cage 9. The upper part of the egg collecting net cage 9 is a 60-mesh nylon net, and the lower part is a watertight basin. The height of the watertight basin in the egg collecting net cage 9 is 10 to 12 cm lower than the end of the drain pipe. The pipe diameter of the water inlet pipe 7 and the two drain pipes 8 is 11 cm.

[0036] Egg collection method: When the water inlet pipe is working, water is ejected from one side of the rectangular pool to push the water in the spawning pool to flow. The water jetting intensity of the water inlet pipe is adjusted to control the flow rate of the water in the spawning pool at 0.2 to 0.4 meters per second. At this time, the water flow can push the floating fertilized eggs of black snakehead together with the oil film to flow to the side with the drain pipe. During this period, the fertilized eggs together with the oil film can smoothly pass through the gap between the spawning grids and the obstacles of the shuttle-shaped foam floats, and flow into the egg collection cage through the drain pipe connected to the overflow port. The vertical pipe of the drain pipe in the spawning grid is lower than the grid, and the vertical pipe of the drain pipe outside the spawning pool is slightly lower than the vertical pipe in the spawning grid. A water stop valve is set at the end of the drain pipe outlet to control the speed of collecting fertilized eggs or stop collecting.

[0037] In a specific embodiment of the present invention, in the fishing process, the specific fishing location and time, as well as the method of gentle handling and water transportation, especially the catching with a scoop net and the catching with a ground cage, greatly reduce the damage to wild broodstock and improve the survival rate of broodstock. In the breeding of broodstock, the cultivation of different types of aquatic plants in the earth pond creates a suitable living environment. The reasonable vegetation area and stocking density ensure that the broodstock have enough space and food. The special treatment in the northern region ensures the wintering conditions of the broodstock. The specific injection method and the matching method in the induced labor process improve the induced labor rate and are conducive to mating and spawning. The egg collection method is friendly to the broodstock, ensures the quality of the fertilized eggs and the breeding water environment, and realizes efficient breeding. The shuttle-shaped foam float 6 is set to simulate the ovary of the wild black snakehead to prevent the fertilized eggs from silting up. In addition, it can float up and down with the water level and will not move easily due to the setting of the traction rope. The top width of the extended edge 5 has an umbrella edge of 15 cm to prevent the fish from jumping and escaping, and the extended edge 5 is higher than the drain pipe 8. The drain pipe 8 can be used to control the water level, and the fertilized eggs flow out from here into the collection cage 9 outside the pond.

[0038] Specifically, wild broodstock are suitable for collection from October to November. They should be collected by draining the water, catching with scoop nets or trapping with large water surfaces, or transporting with water. This method causes less damage to the collected broodstock.

[0039] Specifically, the reasonable area of ​​vegetation in the broodstock breeding pond is about 1 / 10 to 1 / 3 of the bottom area of ​​the pond. This vegetation configuration can create an environment suitable for the survival of broodstock, and with reasonable feeding, the specifications of the fertilized eggs produced by this method are 270 to 290 grains per gram, while the specifications of the fertilized eggs produced by broodstock not bred according to this method are usually 310 to 330 grains per gram. This method can improve the quality of fertilized eggs.

[0040] In this embodiment: On the one hand, benthic aquatic plants such as dead grass and duckweed provide a habitat and foraging place for broodstock, and emergent plants such as reeds and lotus and floating plants such as water hyacinth together constitute a complex ecological environment, which increases the stability and self-purification ability of the water body. This vegetation configuration can not only provide a hiding place for broodstock and reduce their stress response, but also improve water quality, absorb harmful substances in the water, release oxygen, and create good living conditions for broodstock. At the same time, a reasonable vegetation area avoids problems such as water hypoxia caused by excessive growth, ensuring that broodstock grow in a comfortable environment and their gonads are fully developed, while enjoying the welfare of fish and laying the foundation for improving reproductive efficiency.

[0041] Specifically, the suitable stocking density of snakehead broodstock is 1 kg per 4 to 7 square meters, which can ensure that the broodstock have enough space and sufficient food.

[0042] In this embodiment: firstly, it ensures that the broodstock have enough space for activities, avoids fighting and injuries caused by overcrowding, and reduces the stress response of the broodstock; secondly, the appropriate stocking density enables the food resources to be reasonably distributed, ensuring that the abundant and palatable fresh wild bait fish in the pond can meet the needs of the broodstock and promote the growth and development of the broodstock; at the same time, this stocking density is also conducive to maintaining the ecological balance of the water body and reducing the risk of water quality deterioration; during the breeding period, sufficient space and food help the broodstock maintain a good physical condition, improve the success rate of mating and spawning, and thus improve the breeding efficiency of wild snakehead.

[0043] Specifically, the specific method for inducing spawning of male and female fish is to inject 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 milligrams of DOM per kg body weight of female fish, and the male fish is injected with the same type of oxytocin as the female fish and 1 / 2 of the dosage of the female fish, and additional injections are given depending on the actual sperm and egg ovulation situation. This method can effectively reduce the input of manpower and material resources and operations that cause stress responses to broodstock, and significantly improve the induced spawning rate.

[0044] In this embodiment, the specific injection method for male and female fish during induced labor of broodstock is to inject 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 milligrams of DOM per kg body weight of female fish, and the injection dose of male fish is 1 / 2 of that of female fish. This method has significant advantages. This specific drug combination and dose can effectively stimulate the reproductive system of broodstock, promote gonadal development and maturation, and improve the induced labor rate. HCG human chorionic gonadotropin can promote the maturation and discharge of eggs, LHRH-A2 luteinizing hormone releasing hormone analog 2 can stimulate the pituitary gland to release gonadotropin, and DOM dioxinone has a synergistic effect and enhances the induced labor effect. The halved dose of male fish not only ensures the stimulation of its reproductive function, but also avoids the side effects of excessive medication. Through this precise injection method, the breeding success rate of wild snakehead can be improved, providing strong support for the protection and utilization of germplasm resources.

[0045] Specifically, the broodstock are paired in a 1:1 ratio of female to male for induced spawning, and small water bodies are used to separate spawning grids to prevent mutual cannibalism. The weight ratio of male and female broodstock is controlled between 1:1 and 1:2, which is conducive to mating and spawning.

[0046] In this embodiment, the pairing method for induced spawning of broodstock is 1:1 pairing of male and female, and small water bodies are used to separate them to prevent mutual injure. The weight ratio of male and female is controlled between 1:1 and 1:2, which has many positive effects. First, the 1:1 pairing of male and female ensures that there are enough male and female broodstock to participate in mating during the breeding process, thereby increasing the chance of fertilization. The establishment of a separate breeding area separated by a small water body can effectively prevent the broodstock from injuring each other, reduce the injury and mortality of the broodstock, and at the same time, controlling the weight ratio of male and female to between 1:1 and 1:2 is conducive to the smooth progress of mating and spawning. Broodstock with similar weights are more likely to coordinate actions during mating, thereby increasing the success rate of fertilization. In addition, a suitable weight ratio also helps to maintain the health of the broodstock, avoid breeding difficulties or bites caused by excessive weight differences, thereby improving the breeding efficiency of wild snakeheads.

[0047] Specifically, the recovery of broodstock after birth needs to be based on a specific time to maximize the preservation of the broodstock and improve the breeding efficiency. The survival rate of broodstock recovered by this method can be increased from the original 40% to 60% to more than 90%, saving a lot of manpower and reducing the interference of poor-quality fertilized eggs on later hatching work.

[0048] In this embodiment: the postpartum broodstock recovery is based on a specific time, which is of great significance for improving the breeding efficiency and protecting the broodstock. The broodstock are recovered when they have laid sperm and eggs 3 times, have laid sperm and eggs 2 times and have no sperm and eggs within 36 hours, etc., which can preserve the broodstock to the greatest extent. Timely recovery of broodstock can avoid excessive fatigue and injury of broodstock during the breeding process, and prepare for the next breeding. The recovered broodstock are put back into the broodstock breeding pond, and given sufficient palatable fresh wild bait fish for continued breeding, which helps the broodstock to restore their physical strength and reproductive ability. This scientific choice of recovery time not only ensures the effect of this breeding, but also provides sustainable broodstock resources for subsequent breeding work, and improves the overall sustainable breeding efficiency of wild snakehead.

[0049] Specifically, the egg collection method uses a reasonable water flow circuit design and an egg collection cage 9 to push water from one side in a rectangular cement pool so that the fertilized eggs can flow smoothly into the egg collection cage. This method is friendly to parent fish, and the fertilized eggs can be freed from oil film interference. Fertilized eggs of the same period and batches can be collected at the same time and incubated on a large scale to improve breeding efficiency.

[0050] In this embodiment: the egg collection method uses a reasonable water flow circuit design and egg collection cage setting. Water is introduced and pushed from one side in a rectangular cement pool so that the fertilized eggs flow smoothly into the egg collection cage. This method has many advantages. This method is friendly to parent fish and avoids harm and excessive stress to parent fish. The flow stimulation can simulate the natural environment, which is more conducive to parent fish breeding and improves the quality and quantity of fertilized eggs. Water is changed during the process of collecting fertilized eggs, ensuring the freshness of the water quality of the breeding water environment, removing most of the oil film, and creating good conditions for the further development of the fertilized eggs. The setting of the egg collection cage enables the fertilized eggs to be collected smoothly, reduces waste and loss, and improves breeding efficiency.

[0051] The working principle and use process of the present invention:

[0052] Collect wild black snakeheads from ditches, puddles or small reservoirs in the wild. If the area is drained, use a scoop net to catch it. Use a ground trap to catch it on large water surfaces. The entire fishing process requires gentle handling and transportation with water. The best time to catch broodstock is from October to November of the year before breeding. At this time, the temperature gradually cools down, the stress response of black snakeheads is weak, and the resistance is small, which can reduce damage to the broodstock and increase the survival rate of the broodstock. The captured wild black snakeheads are immersed in about 3% salt water for 5 to 10 minutes and then placed in a special earthen pond for broodstock cultivation. The earthen pond is planted with benthic aquatic plants such as dead grass and goldfish. The vegetation area accounts for 1 / 10 to 1 / 3 of the total area of ​​the pond bottom. The stocking density of black snakehead broodstock is 1 kg of broodstock per 4 to 7 square meters to ensure that there are abundant and palatable fresh wild bait fish in the pond. In the northern region, the water level should be raised to more than 2 meters before wintering. During the ice period, the dirt on the ice surface should be cleaned and 2 ice eyes should be ensured for every 667 square meters to provide a good living environment for black snakehead and fresh wild bait fish. The size of the broodstock should be 1.0 to 2.2 kg / tail, and the age should be more than 2 winters. Females are preferred. Select 2 to 3 winter-olds, preferably 3 to 4 winter-olds for males. Parent fish are injected with one needle and supplemented with injections depending on the actual sperm and egg ovulation situation. The type and dosage of oxytocin injected into female parent fish per kg body weight is 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 milligrams of DOM. The injection dose of male fish is 1 / 2 of that of female fish. Male and female fish are paired in a ratio of 1:1, separated by multiple spawning grids 2 to prevent mutual injury, and the weight ratio of male and female fish is controlled between 1:1 and 1:2. Postpartum parent fish are recovered according to specific timing, such as when sperm and eggs have been ovulated 3 times, and the recovered parent fish are put back into the parent fish breeding pond for continued breeding. Water is introduced into one side of the spawning pool to push water, so that the water flow pushes the floating fertilized eggs to flow to the side with drainage and overflow outlets. The fertilized eggs pass through the grille smoothly and flow into the egg collecting cage through the drainage pipe connected to the overflow outlet. The upper part of the egg collecting cage 9 is a 60-mesh nylon net, and the lower part is a watertight basin. The height of the watertight basin in the egg collecting cage 9 is lower than the end of the drainage pipe, and the edge of the water basin is lower than the egg collecting cage so that excess water and mucus overflow to leave the fertilized eggs. This egg collection method is friendly to parent fish, can realize water change while collecting fertilized eggs, ensure fresh water quality, remove oil film, and is beneficial to the development of fertilized eggs and improve breeding efficiency.

[0053] The electronic components and modules used in the invention can be parts commonly used in the market and can realize the specific functions in this case, and the specific models and sizes can be selected and adjusted according to actual needs.

[0054] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A fish welfare method for improving the breeding efficiency of wild Channa argus, characterized in that: The following steps are covered: Fishing process: Collect wild snakehead fish from ditches, puddles or small reservoirs in the wild. If the place is suitable for drainage, drain the water and then use a scoop net to catch it. Ground traps should be used for catching in large water areas. The whole process requires gentle handling and transportation with water. The best time to catch wild broodstock is October to November of the year before breeding work is carried out. The cooler temperature at this time can significantly reduce the damage that may be caused to wild broodstock during the fishing process, thereby increasing the survival rate of broodstock. Broodstock cultivation: After the wild adult snakehead fish are caught and treated with about 3% salt water for 5 to 10 minutes, they are placed in a special broodstock cultivation pond. The pond should be planted with benthic aquatic plants, such as Vallisneria, Dermatophyta, etc.; emergent plants, such as reeds and lotus, etc.; and floating plants, such as water hyacinth, etc. The vegetation area at the bottom of the pond should account for 1 / 10 to 1 / 3 of the total area of ​​the pond bottom. The stocking density of snakehead broodstock should be set at 1 kg per 4 to 7 square meters to ensure that there is enough space for the broodstock in the pond to move around and avoid mutual interference. Fresh wild fish should be artificially added to keep the pond with abundant and palatable live bait. In northern regions, the water level needs to be raised to more than 2 meters before wintering. During the ice period, the dirt on the ice surface should be cleaned and it should be ensured that there are more than 2 ice eyes per 667 square meters. Selection of broodstock: The appropriate size is 1.0 to 2.2 kg per fish, and the age must be over 2 winters old. Females are preferably 2 to 3 winters old, and males are preferably 3 to 4 winters old. Induced spawning of broodstock: The best time is from June to July, and the water temperature of the breeding environment can be stabilized at 27 to 29 degrees Celsius. The method of inducing spawning is one injection and supplementary injections are used depending on the actual situation of sperm and egg discharge. The type and dosage of oxytocin injected into female broodstock per kg body weight is 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 mg of DOM. The type and dosage of oxytocin injected into male broodstock are the same as those of female broodstock, and the injection dosage is 1 / 2 of that of female broodstock. The timing of supplementary injection is described in the section "Timing of postpartum broodstock recovery" below. The method of supplementary injection is the same as the first injection. Male and female broodstock are paired at a ratio of 1:1, and the spawning grids of the small water body of the special spawning pool are used to separate them to prevent mutual cannibalism. The weight specifications of the paired male and female broodstock are controlled between 1:1 and 1:

2. The timing of postpartum broodstock recovery is any of the following: 3 fertilized eggs; no fertilized eggs within 36 hours after 2 fertilized eggs; no fertilized eggs within 36 hours after 1 fertilized eggs; no fertilized eggs after 55 hours of artificial injection of oxytocin and 2 fertilized eggs after oxytocin injection; no fertilized eggs after 55 hours of artificial injection of oxytocin and 24 hours after 1 fertilized eggs after oxytocin injection; no fertilized eggs after 55 hours of artificial injection of oxytocin and 24 hours after 1 fertilized eggs after oxytocin injection. The recovered broodstock are returned to the broodstock breeding pond and given sufficient palatable fresh wild bait fish for further breeding. A special spawning pond comprises a water pond (1), wherein the water pond (1) is divided into a plurality of spawning grids (2), wherein the height of the spawning grids (2) is 100 to 120 cm, and the length and width are both 120 to 150 cm. An extension edge (5) is provided at the joint of each spawning grid (2), and the width of the extension edge (5) is 15 cm. A water-passing grid is provided at the mutually close ends of each spawning grid (2), and the vertical plate interval of each water-passing grid is 1 to 2 cm, and the thickness is 10 to 15 cm. A shuttle-shaped foam floating plate (6) is connected to each spawning grid (2) to simulate an ovary, and the area of ​​each shuttle-shaped foam floating plate (6) is about 1 / 4 of the area of ​​the spawning grid (2). A water inlet pipe (7) is provided on one side of the water pond (1), and a plurality of water jet holes are provided on the side of the water inlet pipe (7) adjacent to the water pond (1). Two drain pipes (8) are arranged on the other side of the pool (1) away from the water inlet pipe (7). The two drain pipes (8) are respectively arranged at the side ends of the two rightmost egg-laying grids (2) and connected to the outside. The height of one end of each drain pipe (8) immersed in the egg-laying grid (2) is 40 to 45 cm, and the height of the other end is 2 to 3 cm lower than the aforementioned height. An egg-collecting net box (9) is arranged on the side of the drain pipe (8) connected to the outside of the pool (1). The ends of the drainage outlets of the two drain pipes (8) are both provided with water stop valves. The drainage outlets of the two drain pipes (8) are both arranged in the egg-collecting net box (9). The upper part of the egg-collecting net box (9) is a 60-mesh nylon net, and the lower part is a watertight basin. The height of the watertight basin in the egg-collecting net box (9) is 10 to 12 cm lower than the end of the drain pipe. The pipe diameters of the water inlet pipe (7) and the two drain pipes (8) are 11 cm. Egg collection method: When the water inlet pipe is working, water is ejected from one side of the rectangular pool to push the water in the spawning pool to flow. The water jetting intensity of the water inlet pipe is adjusted to control the flow rate of the water in the spawning pool at 0.2 to 0.4 meters per second. At this time, the water flow can push the floating fertilized eggs of black snakehead together with the oil film to flow to the side with the drain pipe. During this period, the fertilized eggs together with the oil film can smoothly pass through the gap between the spawning grids and the obstacles of the shuttle-shaped foam floats, and flow into the egg collection cage through the drain pipe connected to the overflow port. The vertical pipe of the drain pipe in the spawning grid is lower than the grid, and the vertical pipe of the drain pipe outside the spawning pool is slightly lower than the vertical pipe in the spawning grid. A water stop valve is set at the end of the drain pipe outlet to control the speed of collecting fertilized eggs or stop collecting.

2. A fish welfare method for improving the breeding efficiency of wild Channa argus according to claim 1, characterized in that: Wild broodstock are suitable for collection from October to November. They should be collected by draining the water, catching with scoop nets, catching with traps on large water surfaces, or transporting with water. This method causes less damage to the collected broodstock.

3. A fish welfare method for improving the breeding efficiency of wild Channa argus according to claim 2, characterized in that: The reasonable area of ​​vegetation in the broodstock breeding pond is about 1 / 10 to 1 / 3 of the pond area. This vegetation configuration can create an environment suitable for the survival of broodstock, and with reasonable feeding, the specifications of the fertilized eggs produced by this method are 270 to 290 grains per gram, while the specifications of the fertilized eggs produced by broodstock not bred according to this method are usually 310 to 330 grains per gram. This method can improve the quality of fertilized eggs.

4. A fish welfare method for improving the breeding efficiency of wild Channa argus according to claim 3, characterized in that: The appropriate stocking density for snakehead broodstock is 1 kg per 4 to 7 square meters, which ensures that the broodstock have enough space and food.

5. A fish welfare method for improving the reproduction efficiency of wild Channa argus according to claim 4, characterized in that: The specific method for inducing spawning for male and female fish is to inject 1000 units of HCG + 6 micrograms of LHRH-A2 + 6 milligrams of DOM per kg body weight of female fish, and inject male fish with the same type of oxytocin as female fish and 1 / 2 of the dosage of female fish, and additional injections are given depending on the actual sperm and egg ovulation situation. This method can effectively reduce the input of manpower and material resources and operations that cause stress responses to broodstock, and significantly improve the induced spawning rate.

6. A fish welfare method for improving the reproduction efficiency of wild Channa argus according to claim 5, characterized in that: The broodstock are paired in groups of 1 female:1 male, and small water bodies are used to separate spawning grids to prevent mutual cannibalism. The weight ratio of male and female broodstock is controlled between 1:1 and 1:2, which is conducive to mating and spawning.

7. A fish welfare method for improving the reproduction efficiency of wild Channa argus according to claim 6, characterized in that: Post-natal broodstock recovery needs to be based on specific timing to maximize the preservation of broodstock and improve reproductive efficiency. The survival rate of broodstock recovered by this method can be increased from the original 40% to 60% to more than 90%, saving a lot of manpower and reducing the interference of poor-quality fertilized eggs on later hatching work.

8. A fish welfare method for improving the reproduction efficiency of wild Channa argus according to claim 7, characterized in that: The egg collection method uses a reasonable water flow circuit design and an egg collection cage (9) to push water from one side of a rectangular cement pool so that the fertilized eggs can flow smoothly into the egg collection cage. The method is friendly to parent fish, and the fertilized eggs can be freed from oil film interference. Fertilized eggs of the same period and batches can be collected at the same time and incubated on a large scale, thereby improving the breeding efficiency.

Images