A method for freshwater silver carp and bighead carp farming in large water surfaces

Abstract

This invention discloses a method for large-scale freshwater silver carp and bighead carp farming, comprising the following steps: S1: Selecting a large reservoir or lake surface; S2: Stocking fry weighing 0.15–0.25 kg from the current year's breeding period between late October and mid-December; wherein the ratio of silver carp to bighead carp is 7:3–6:4; S3: After a growth cycle of 1.5–4 years, the silver carp and bighead carp grow into adult fish, which are then harvested and marketed. Since silver carp primarily feed on phytoplankton, especially diatoms and green algae, and are typical filter-feeding fish, a higher proportion of silver carp is used, thus enhancing the water purification effect. Furthermore, the reservoirs in the Lianyungang area are mostly flatland reservoirs, where silver carp thrive in shallow water; therefore, this stocking ratio of bighead carp to silver carp is also suitable. This method achieves water purification through the farming of large-scale freshwater silver carp and bighead carp. First, put fish food outside the large mesh net; this will help avoid the impact of fishing on the growth of smaller fish.

Description

Technical Field

[0001] This invention relates to fish, specifically to a method for cultivating freshwater silver carp and bighead carp in large water bodies. Background Technology

[0002] Large water bodies refer to a general term for inland natural and semi-natural large water bodies such as lakes and reservoirs. my country's large water body fisheries have gone through four different development stages: natural fishing, fishing combined with propagation, aquaculture as the mainstay, and ecological fisheries. They have made significant contributions to meeting the animal protein needs of the Chinese people at different stages of social development. Large water bodies primarily use filter-feeding fish such as silver carp and bighead carp for water purification. Silver carp is also known as bighead carp, black carp, and big-headed carp; bighead carp is also known as white carp. Silver carp have comb-like gill rakers, enabling them to filter plankton larger than 50 μm in diameter, while white carp have spongy gill rakers, feeding on organisms ranging from 10 to 1000 μm. Ecological aquaculture of silver carp and bighead carp in large water bodies does not involve feeding or fertilization; the aim is to effectively utilize the productivity of natural water bodies to purify water quality. The fish mainly feed on plankton, humus, organic debris, and nutrients brought by floods. The production cycle is generally four years. In his paper "Summary of Key Technologies for Ecological and Healthy Aquaculture in Large Water Surfaces," published in the third issue of *Henan Fisheries* in 2023, Zhang Shuxian mentioned that bighead carp and silver carp have overlapping diets. Due to the higher economic benefits of bighead carp farming, the stocking ratio is generally 85:15 (bighead carp:silver carp). Years of practical experience have shown that bighead carp grow well in deep-water reservoirs in mountainous areas, while silver carp grow well in shallow-water reservoirs in plains areas. The stocking ratio of silver carp and bighead carp can be adjusted appropriately according to the actual conditions of the reservoir, such as its shape. Fish exhibit stress responses when startled, especially silver carp and bighead carp, which may experience a period of stagnation or slow growth. To ensure that the existing natural aquatic populations on large water surfaces have a sufficient breeding population to participate in reproductive activities, and to guarantee the replenishment and prosperity of the populations, a practical and feasible fishing plan must be formulated and fisheries control implemented. This involves using a combined fishing method of "driving, blocking, spearing, and setting" and automatic net placement in cages. The combined "driving, blocking, spearing, and setting" method should be carried out from October to May of the following year. During this period, the water temperature is low, fish activity and growth are slow, and fishing activities have minimal impact on fish growth. The automatic net placement method is used from mid-May to October. During this period, the water temperature is high, fish activity is high, and it is easy to achieve a good yield. Because this method allows fish to swim into the cages on their own according to their activity habits, the fish are not startled. This method mitigates the impact of fishing on fish growth by targeting periods when fish grow slowly (e.g., the combined "driving, blocking, spearing, and stretching" fishing method is conducted from October to May of the following year). In contrast, the fixed-net automated box fishing method requires fixed nets and automated equipment, which necessitates regular maintenance to ensure proper operation. Furthermore, this method uses different fishing methods and equipment at different times, making it both cumbersome and costly. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for large-scale freshwater silver carp and bighead carp farming. Since silver carp primarily feed on phytoplankton, especially diatoms and green algae, and are typical filter-feeding fish, a higher proportion of silver carp is desirable, thus enhancing water purification. Furthermore, the reservoirs in the Lianyungang area are mostly flatland reservoirs, where silver carp thrive in shallow waters; therefore, the stocking ratio of bighead carp and silver carp is also suitable. This method achieves water purification through the farming of large-scale freshwater silver carp and bighead carp.

[0004] To achieve the above objectives, the technical solution of this invention is to design a method for large-scale freshwater silver carp and bighead carp farming, comprising the following steps:

[0005] S1: Select the surface of a large reservoir or lake;

[0006] S2: From late October to mid-December, release seedlings weighing 0.15–0.25 kg that were bred that year; the ratio of silver carp to bighead carp should be 7:3 to 6:4.

[0007] S3: After a growth cycle of 1.5 to 4 years, the silver carp and bighead carp grow into adults and are then harvested and marketed. Since silver carp primarily feed on phytoplankton, especially diatoms and green algae, they are typical filter-feeding fish, resulting in a higher proportion of silver carp in the stock, thus enhancing the water purification effect. Furthermore, the reservoirs in the Lianyungang area are mostly flatland reservoirs, where silver carp thrive in shallow water, making the stocking ratio of silver carp and bighead carp suitable. This method of raising large-scale freshwater silver carp and bighead carp achieves water purification through fish farming.

[0008] A further technical solution is to use barrier nets with varying mesh sizes to separate large and small silver carp and bighead carp within a large water surface. In step S3, fish food or bait is placed away from the barrier nets before harvesting, and the adult fish are harvested immediately afterward. By placing fish food at the barrier nets, especially outside the large-mesh nets, smaller fish can be guided away before harvesting, thus reducing the impact of harvesting on the growth of smaller fish.

[0009] Another technical solution is to use barrier nets with varying mesh sizes to separate large and small silver carp and bighead carp within a large water surface. In step S3, before harvesting, fish feed is placed near the barrier nets with an initial velocity to move the feed away from the nets. Adult fish are then harvested immediately afterward. By placing fish feed at the barrier nets, especially outside the large-mesh nets, and directing the feed away from the large-mesh nets, a greater number of smaller fish can be guided away before harvesting, thus reducing the impact of harvesting on the growth of smaller fish.

[0010] Further technical solutions include using large-mesh nets with a mesh size of 3-5 cm and small-mesh nets with a mesh size of 1-2 cm.

[0011] A further technical solution is to deploy two large-mesh nets and two small-mesh nets in the large water area to separate large and small silver carp and bighead carp; the two small-mesh nets are set up upstream and downstream of the large water area, and the two large-mesh nets are set up between the two small-mesh nets.

[0012] A further technical solution is to install a fish food dispensing mechanism on the surface of a large body of water. The fish food dispensing mechanism includes a float, a base plate fixedly connected to the float, a fish food hopper fixedly installed on the base plate, a sealing cover on the fish food hopper, and a feeding pipe connected to the bottom of the fish food hopper. Part of the feeding pipe is located below the surface of the large body of water, and part is located above the surface of the large body of water. Several spaced branch pipes are integrally installed on the part of the feeding pipe located below the surface of the large body of water. The branch pipes are inclined downward and the openings of the branch pipes are away from the net. A blower is connected to the fish food hopper and fixedly connected to the base plate. A large portion of the feeding pipe is located below the water surface in the large water area; the branch pipes are inclined downwards with their openings facing away from the netting, meaning the openings of the branch pipes face the water area in the middle of the netting. This allows the fish food to be introduced with an initial velocity, moving it away from the netting. When the blower is activated, it blows a strong wind, and the fish food hopper has a sealed cover. This strong wind causes the fish food to be sprayed out from the openings of the branch pipes, ensuring that the fish food, when introduced near the netting before harvesting, has an initial velocity that moves it away from the netting. This method of feeding fish at depth, unlike existing technologies that place them on the water surface, avoids the crowding and negative impact on fish growth caused by them all swimming to the surface, and also provides a more even distribution of food. Furthermore, it guides the fish away from the netting at depth, reducing the impact on the fish during subsequent harvesting.

[0013] A square tube is fixedly installed on the outside of the fishing net used in the fishing process, covering four, nine, or sixteen mesh openings. The size of the square tube matches the size of the mesh openings being covered. Several square tubes are provided, and there is a gap between adjacent square tubes. The square tubes are made of the same material as the fishing net. A connecting ring is provided at the connection between the square tube and the fishing net. The upper half of the connecting ring is made of elastic plastic, and the lower half of the connecting ring is made of nylon or other non-elastic material.

[0014] A semi-circular float is fixedly installed at the lower end of the square tube, away from the fishing net.

[0015] A large mesh screen is topped with a fishing net of the same mesh count. One end of the fishing net is fixed to the lower surface of the large mesh screen, and the length of the fishing net is the same as that of the large mesh screen. After being folded once, the fishing net is hung at the middle height of the large mesh screen, with the free end of the fishing net close to the bottom of the water surface. Hooks for hanging the fishing nets are set on both large mesh screens. The fishing process involves lifting both large mesh screens a certain distance and bringing their bottom ends together a certain distance, then removing the fishing net from its hanging point and hanging it on the opposite large mesh screen. The large mesh screen that was not previously hung with a fishing net but is now hung with one is slightly higher than the other large mesh screen. Then, both large mesh screens are lifted simultaneously at the same speed to complete the fishing. A fish food dispensing mechanism is installed on the outer side of the large-mesh net. The fish food dispensing mechanism includes a conveying pipe fixedly connected to the net line of the large-mesh net, with outlets spaced apart on the conveying pipe. A square tube is fixedly installed on the outer side of the large-mesh net, covering four or nine mesh openings, with the middle of the square tube located at the outlet. The structure of the square tube is basically the same as in the previous embodiment, but an air bladder is also fixedly installed on the upper half of the connecting ring of the square tube. The air bladder has an opening that is connected to the conveying pipe. A filter screen can also be installed at the opening to prevent fish food from entering the air bladder. The fish food dispensing mechanism also includes a float and a base plate fixedly connected to the float. A fish food hopper is fixedly installed on the base plate, and a sealing cover is installed on the fish food hopper. A feeding pipe is connected to the bottom of the fish food hopper. A blower is fixedly connected to the base plate and connected to the fish food hopper. The feeding pipe and the conveying pipe are connected by a sealing connector.

[0016] (The size of the square tube matches the size of the several mesh openings to be covered; there are several square tubes and there is a gap between adjacent square tubes; the square tubes are made of the same material as the fishing net; there is a connecting ring at the connection between the square tube and the fishing net, the upper half of the connecting ring is made of elastic plastic, and the lower half of the connecting ring is made of nylon or other non-elastic material.)

[0017] (A square tube with a semi-circular float fixedly attached to its lower end, away from the fishing net)

[0018] The advantages and beneficial effects of this invention are as follows:

[0019] By feeding fish at the barrier net, especially outside the large-mesh barrier net, smaller fish can be guided away before harvesting, and then harvested in the waters inside the large-mesh barrier net, reducing the impact of the harvesting action on the growth of smaller fish.

[0020] By placing fish food at the barrier net, especially outside the large mesh barrier net, and directing the fish food away from the large mesh barrier net, a larger number of small-sized fish can be guided away before fishing, and then fished in the waters inside the large mesh barrier net, reducing the impact of fishing on the growth of small-sized fish.

[0021] Instead of feeding fish at the surface as with existing technologies, the feed is now distributed at depth. This avoids crowding at the surface and negatively impacts the fish's growth, while also distributing the feed more evenly. Furthermore, it guides the fish away from the net at depth, reducing the impact on subsequent harvesting operations. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the netting arrangement in a large water surface in Embodiment 1 of the present invention, which describes a method for raising silver carp and bighead carp in large water surfaces.

[0023] Figure 2 This is a schematic diagram of the working state when fish food is released on a large water surface according to Embodiment 2 of the present invention;

[0024] Figure 3 yes Figure 2 Diagram showing the layout of the central blocking net;

[0025] Figure 4 yes Figure 2 A schematic diagram of a fish feed distribution system;

[0026] Figure 5 yes Figure 2 A schematic diagram showing the deployment of a fishing net used for fishing in the waters within a two-mesh barrier net;

[0027] Figure 6 yes Figure 5 A schematic diagram of the decomposition process;

[0028] Figure 7 yes Figure 5 Side view;

[0029] Figure 8 yes Figure 7 An enlarged schematic diagram of the square tube;

[0030] Figure 9 yes Figure 8 The left view;

[0031] Figure 10 yes Figure 4 A three-dimensional schematic diagram;

[0032] Figure 11 This is a schematic diagram of Embodiment 3 of the present invention;

[0033] Figure 12 yes Figure 11 A schematic diagram of two large mesh nets used for blocking the nets;

[0034] Figure 13 yes Figure 11 A partially enlarged schematic diagram of the fish feeding mechanism and its surrounding components;

[0035] Figure 14 yes Figure 12 Another schematic diagram of the working state;

[0036] Figure 15 yes Figure 13 A partially enlarged schematic diagram of the square tube and its surrounding components;

[0037] Figure 16 yes Figure 15 A magnified view of a portion of the image.

[0038] In the diagram: 1. Small mesh barrier net; 2. Large mesh barrier net; 3. Float; 4. Bottom plate; 5. Fish feed hopper; 6. Sealing cover; 7. Feed pipe; 8. Branch pipe; 9. Blower; 10. Fishing net; 11. Square tube; 12. Connecting ring; 13. Semi-square annular float; 14. Feed pipe; 15. Discharge port; 16. Airbag; 17. Opening. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0040] Example 1: As Figure 1 As shown, this invention is a method for cultivating silver carp and bighead carp in large-scale freshwater environments, comprising the following steps:

[0041] S1: Select the surface of a large reservoir or lake;

[0042] S2: From late October to mid-December, release seedlings weighing 0.15–0.25 kg that were bred that year; the ratio of silver carp to bighead carp should be 7:3 to 6:4.

[0043] S3: After a growth cycle of 1.5 to 4 years, bighead carp and silver carp grow into adult fish, which are then harvested and sold on the market.

[0044] Different mesh sizes of nets are arranged at intervals in the large water surface to separate large and small silver carp and bighead carp; in step S3, fish food or bait is put in a place away from the nets before fishing, and adult fish are caught immediately after being put in; adult fish are caught from August of the current year to mid-April of the following year when the growth cycle is reached; the mesh size of the large mesh nets is 3-5 cm; the mesh size of the small mesh nets is 1-2 cm; two large mesh nets and two small mesh nets are arranged in the large water surface to separate large and small silver carp and bighead carp; two small mesh nets 1 are set up upstream and downstream of the large water surface, and two large mesh nets 2 are set up between the two small mesh nets.

[0045] First, fish food is placed outside the large-mesh net, causing smaller fish that are not originally within the two large-mesh nets to move away from the large-mesh nets (while larger fish cannot pass through the mesh of the large-mesh nets). The smaller fish that were originally within the two large-mesh nets leave the water between the two large-mesh nets due to the placement of fish food, thus reducing the number of smaller fish within the large-mesh nets; this avoids the impact of fishing on the growth of smaller fish in terms of quantity.

[0046] Although some bait is used, it is only used during the fishing process, so the amount is small and the impact on the water is minimal. Although the fish are startled during the fishing process (which can affect their growth), the fish caught are silver carp and bighead carp that meet market size requirements, so there is no issue of affecting the growth of fish that are about to be sold. When pulling up the fishing net, care should be taken to avoid startling the smaller silver carp and bighead carp in the large mesh net.

[0047] Example 2: The difference from Example 1 is that, as shown in Example 2... Figures 2 to 10 As shown (for ease of illustration), Figure 5 Only one square tube is shown; Figure 10 (The structure on the bottom plate is not shown). Different mesh sizes of nets are arranged at intervals in the large water surface to separate large and small silver carp and bighead carp. In step S3, when fish food is put into the vicinity of the net before fishing, the fish food is given a certain initial velocity so that the fish food is away from the net. After the fish food is put into the net, the adult fish are caught immediately.

[0048] Different mesh sizes of nets are used to separate large and small silver carp and bighead carp. During fishing, the larger silver carp and bighead carp are "lured": fish food or bait is placed away from the large mesh nets (furthermore, when placed near the nets, the fish food is given an initial velocity in a certain direction to move it away from the large mesh nets 2), and then the larger silver carp and bighead carp are caught in time to avoid affecting the growth of the smaller silver carp and bighead carp (because if the large silver carp and bighead carp are of market size, they must be caught in time, otherwise it will affect the growth of the smaller silver carp and bighead carp). In this way, when the fishing net is pulled up, there are almost no small silver carp and bighead carp near the large mesh nets 2, minimizing the impact of the fishing action on the growth of the smaller fish, and avoiding the impact of the fishing action on the growth of the smaller fish in a specific area.

[0049] A fish food dispensing mechanism is set up on the surface of a large body of water. The fish food dispensing mechanism includes a float 3, a base plate 4 fixedly connected to the float 3, a fish food hopper 5 fixedly installed on the base plate, a sealing cover 6 installed on the fish food hopper 5, and a feeding pipe 7 connected to the bottom of the fish food hopper. Part of the feeding pipe 7 is located below the surface of the large body of water, and part of it is located above the surface of the large body of water. Several spaced branch pipes 8 are integrally installed on the part of the feeding pipe located below the surface of the large body of water. The branch pipes are inclined downward and the openings of the branch pipes are away from the net. A blower 9 is connected to the fish food hopper and fixedly connected to the base plate.

[0050] A square tube 11 is fixedly installed on the outside of the fishing net 10 (i.e., the fishing net used for fishing), covering four, nine, or sixteen net openings. The size of the square tube 11 matches the size of the net openings being covered. There are several square tubes and a gap is provided between adjacent square tubes. The square tube 11 is made of the same material as the fishing net. A connecting ring 12 is provided at the connection between the square tube 11 and the fishing net. The upper half of the connecting ring is made of elastic plastic, and the lower half of the connecting ring 12 is made of nylon or other non-elastic material.

[0051] A semi-circular float 13 is fixedly wrapped around the lower end of the tube opening 11, which is away from the fishing net;

[0052] The spacing between the square tubes is preferably the size of the covered net opening, which avoids the problem of adjacent square tubes bumping into each other when the net is retrieved. When retrieving the net, because the square tubes are set on the outside of the fishing net, the square tubes will gradually leave the water surface and gradually float to the surface. After the net is set, water is "stored" in the square tubes due to liquid flow (and because of the semi-circular float 13 at its lower end, the square tube 11 is buoyed by the float after the net is set, and combined with its "similar hinge" setting near the fishing net end, the square tube is basically in a horizontal state or tends to be horizontal). As the square tube gradually floats to the surface, because the upper half of the connecting ring 12 is retractable, the square tube is similar to being "hinged" to the fishing net line. Therefore, as the square tube gradually floats to the surface, the end of the square tube away from the fishing net tilts downward, so more water in the square tube tends to flow outward, creating a local downstream water flow environment for small fish in the fishing net near the square tube; small silver carp The silver carp float downstream out of the fishing net; minimizing the impact of the fishing action (i.e., the impact on the growth of small-sized fish within the large-mesh net when the net is pulled up) on the growth of small-sized fish; compared to existing technologies that directly bait the fishing area (e.g., fishing within the waters of two large-mesh nets in this embodiment) to attract fish before catching them, this embodiment first baits the outside of the large-mesh nets (but close to the large-mesh nets), attracting and "guiding" the small-sized silver carp and bighead carp close to the large-mesh nets out of the two large-mesh nets, and then catching them in the waters between the two large-mesh nets. This reduces the impact of the fishing operation on the growth of small-sized fish. In contrast, when fishing directly baits the fish, a considerable number of small-sized fish experience the process of the net being pulled up (although they can pass through the mesh of the net and leave the net, they still experience the fishing process), which affects the growth of small-sized silver carp and bighead carp.

[0053] Since the breeding season for silver carp and bighead carp is usually from late April to July, fishing during this period is avoided. This is to prevent affecting their reproduction and because freshwater fish tend to swim upstream during the breeding season and downstream at other times, the current created during fishing will carry smaller silver carp and bighead carp downstream out of the net (since the net catches adult fish, a larger mesh size is used, such as the same as the large mesh size of the barrier net, 3-5 cm). This minimizes the impact of the fishing action (i.e., the impact on the growth of smaller fish in the large mesh barrier net when the net is pulled up) on the growth of smaller fish, thus avoiding the impact of the fishing action on the growth of smaller fish to a certain extent.

[0054] This method does not require automated equipment, the fishing method is simple, and only requires appropriate technical modifications to the existing fishing nets. The fishing equipment is simple and the cost is low. Moreover, this method minimizes the impact of fishing on the growth of small-sized silver carp and bighead carp.

[0055] Example 3: The difference from Example 2 is that, as shown in Example 3... Figures 11 to 16 As shown (for clarity, the feeding pipe and conveying pipe in the fish feeding mechanism are separate), a layer of fishing net 10 with the same mesh count as the large mesh screen 2 is also installed on top of it. One end of the fishing net 10 is fixedly connected to the lower surface of the large mesh screen 2, and the length of the fishing net is the same as that of the large mesh screen 2. After folding once, the fishing net 10 is hung at the middle height of the large mesh screen 2, with the free end of the fishing net 10 close to the bottom of the large water surface. Hooks for hanging fishing nets are installed on both large mesh screens 2. The fishing process involves appropriately raising the two large mesh screens 2 a certain distance and bringing their bottom ends together a certain distance, then removing the fishing net 10 from its hanging position and hanging it on the corresponding large mesh screen. Then, the large mesh screen 2 that was not originally hung with the fishing net 10 but is now hung with it is slightly higher than the other large mesh screen. Then, both large mesh screens are raised simultaneously while maintaining the same upward speed. It can complete the fishing; a fish food delivery mechanism is set on the outside of the large mesh net. The fish food delivery mechanism includes a feed pipe 14 fixedly connected to the net line of the large mesh net. The feed pipe has outlets 15 set at intervals. A square tube 11 is fixedly set on the outside of the large mesh net. The square tube 11 covers four or nine net openings and the middle of the square tube 11 is located at the outlet 15. The structure of the square tube is basically the same as the previous embodiment, but an air bag 16 is also fixedly set on the upper half of the connecting ring 12 of the square tube. The air bag has an opening 17, which is connected to the feed pipe 14. A filter screen can also be set at the opening to prevent fish food from entering the air bag. The fish food delivery mechanism also includes a float 3, a bottom plate 4 fixedly connected to the float, a fish food hopper 5 fixedly set on the bottom plate, a sealing cover 6 set on the fish food hopper, and a feeding pipe 7 connected to the bottom of the fish food hopper. A blower 9 is fixedly connected to the bottom plate and connected to the fish food hopper. The feeding pipe 7 and the feed pipe 14 are connected by a sealing connector.

[0056] (The size of the square tube matches the size of the several net openings to be covered; there are several square tubes and there is a gap between adjacent square tubes; the square tubes are made of the same material as the fishing net; there is a connecting ring 12 at the connection between the square tube and the fishing net, the upper half of the connecting ring is made of elastic plastic, and the lower half of the connecting ring is made of nylon or other non-elastic material.)

[0057] The lower end of the square tube, away from the fishing net, is fixedly covered with a semi-square annular float 13)

[0058] The barrier net and fishing net are combined into one unit, with a fish feed dispensing mechanism also installed on the barrier net. This integration of the fishing net, barrier net, and fish feed dispensing mechanism avoids the previous embodiment's modification of the fishing net by adding square tubes. Since the fishing net needs to be frequently deployed and retracted, placing square tubes on it could easily lead to tangling problems. Therefore, the modification is made on the relatively "rigid" barrier net to prevent the net cable from getting tangled in the square tubes when the barrier net is retracted. Before harvesting, fish feed is placed in the fish feed hopper, the sealing cover is closed, and then the blower is started. The fish feed is dispensed from the feeding pipe. The feed is delivered to the feed pipe and flows rapidly towards the outlet due to the wind. Since the airbag is connected to the feed pipe, it expands during this process, and the square tube is no longer horizontal but tilted downwards. Therefore, the fish food sprayed at the outlet is guided away from the square tube and sprayed obliquely downwards, which plays the role of "guiding" the direction of the fish flow. After the fish food is delivered and the blower is turned off, the airbag returns to its original position due to elastic contraction. The square tube also returns to a near-horizontal position because the airbag no longer expands. In this way, a local downstream water flow environment is still created during the final harvest.

[0059] To better implement this embodiment, the technical solution in the applicant's previous patent application number 202410508614.4 can be adopted. The fishing net also adopts an adjustable mesh size (similar to the adjustable mesh size barrier net in the aforementioned application number) to ensure that small-mesh nets are not damaged when passing through multiple layers of fishing nets and a single barrier net, and to facilitate passing through large-mesh barrier nets (including large-mesh fishing nets hung on large-mesh barrier nets). In addition, a more preferable solution for the height of the fishing net is to prevent the free end of the fishing net from directly contacting the bottom of the water after folding, thus avoiding easy wear and damage.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for cultivating silver carp and bighead carp in large-scale freshwater environments, characterized in that, It consists of the following steps: S1: Select the surface of a large reservoir or lake; S2: From late October to mid-December, release seedlings weighing 0.15–0.25 kg that were bred that year; the ratio of silver carp to bighead carp should be 7:3 to 6:

4. S3: After a growth cycle of 1.5 to 4 years, bighead carp and silver carp grow into adult fish, which are then harvested and sold. Large-mesh nets and small-mesh nets are arranged at intervals within the large water surface to separate large and small silver carp and bighead carp. In step S3, when fish food is put into the vicinity of the nets before fishing, the fish food is given a certain initial velocity to move the fish food away from the large-mesh nets, so as to guide the small-sized fish away before fishing, and then fishing is carried out in the waters within the large-mesh nets, reducing the impact of fishing on the growth of small-sized fish. A square tube is fixedly installed on the outside of the fishing net used for fishing, covering four, nine, or sixteen mesh openings. The size of the square tube matches the size of the mesh openings being covered. There are several square tubes, and there is a gap between adjacent square tubes. The square tubes are made of the same material as the fishing net. A connecting ring is provided at the connection between the square tube and the fishing net. The upper half of the connecting ring is made of elastic plastic, while the lower half of the connecting ring is made of non-elastic material. The lower end of the square tube, away from the fishing net, is fixedly covered with a semi-square ring-shaped float.

2. The method for large-scale freshwater silver carp and bighead carp farming according to claim 1, characterized in that, The large-mesh barrier has a mesh size of 3-5 cm; the small-mesh barrier has a mesh size of 1-2 cm.

3. The method for large-scale freshwater silver carp and bighead carp farming according to claim 2, characterized in that, Two small-mesh nets are set up upstream and downstream of the large water surface, and two large-mesh nets are set up between the two small-mesh nets.

4. A method for large-scale freshwater silver carp and bighead carp farming according to claim 3, characterized in that, A fish food dispensing mechanism is installed on the surface of a large body of water. The fish food dispensing mechanism includes a float, a base plate fixedly connected to the float, a fish food hopper fixedly installed on the base plate, a sealing cover on the fish food hopper, and a feeding pipe connected to the bottom of the fish food hopper. Part of the feeding pipe is located below the surface of the large body of water, and part of it is located above the surface of the large body of water. Several spaced branch pipes are integrally installed on the part of the feeding pipe located below the surface of the large body of water. The branch pipes are inclined downward and the openings of the branch pipes are away from the net. A blower is connected to the fish food hopper and fixedly connected to the base plate.

Images