CN115720878B - Batch grading catching device for large-scale cage cultured fishes and using method - Google Patents

Abstract

The invention provides a batch and graded catching device for fish cultured in large cages, and relates to the technical field of fishery catching devices. It includes a large breeding cage and a small lifting fish cage, with a fishing port formed on the top and a fishing port on the bottom. It is equipped with an inflatable gravity sinking and floating structure, which drives the net clothing of the small lifting fish cage to float or sink; the fish passage is horizontally located between the large breeding cage and the small lifting fish cage, including The left channel and the right channel are detachably and fixedly connected; the left channel is sutured and connected to the small lifting fish cage, and a closing device is provided near the small lifting fish cage; the right channel is sutured and connected to the large breeding cage , a closing device is provided near the large breeding cage; the fish grading grille is arranged vertically in the left channel and is detachably and fixedly connected to the left channel. After the device of the present invention is operated according to the usage method, the fish-to-water ratio in the cage is greatly improved, making fishing easier.

Description

A batch and graded catching device for fish cultured in large cages and a method of using it

Technical field

The invention relates to the technical field of fishery catching devices, and in particular to a batch and graded catching device for fish cultured in large cages and a method of use.

Background technique

With the rapid development of my country's mariculture industry, large-scale offshore mariculture has brought about a series of problems such as industrial conflicts, ecological hazards, disease risks, and quality and safety. Therefore, the expansion of the mariculture industry from offshore to offshore and deep sea has become an inevitable trend in the development of my country's mariculture industry.

As cage farming becomes farther and farther offshore, water depth and sea state levels increase, and the cages used for farming become larger and larger, the technology for capturing farmed fish has become a matter of concern. At present, the fishing techniques for fish cultured in cages that are often used include casting net fishing, seining fishing in cages, pulling up nets, etc. The advantage of these fishing methods is that they are simple, but the disadvantage is that they require more manpower. The semi-submersible steel frame cage built by Wuchang Heavy Industry for Norway uses mechanical driving and mechanical lifting methods; my country's "Deep Blue No. 1" fully submersible cage uses floating cage fishing technology. The fishing technology of these latter two cages is too complicated. Moreover, in order to catch some fish, the entire fishing system needs to be activated, which will cause certain harm to farmed fish that are not planned to be caught.

At present, a simple mechanized batch fishing device is urgently needed at home and abroad. For example, the invention with the announcement number CN109221036B discloses a device for collecting and cultivating fish in batches in giant cages. It consists of four parts: a bottom pocket, a bottom pocket lifting rope, an upper cover and a guide rope. The bottom pocket consists of three parts: an extended wing net, a grading area, and a fish collecting box. Its main function is to accommodate the collected fish and enable small-sized fish to escape; the bottom pocket lifting rope is made of steel cables or ropes, and its main function is Lift or lift the bottom bag out of the water; the upper cover is composed of an upper cover frame and an upper cover net, its main function is to drive and gather farmed fish; the guide cable is composed of two or more steel cables, its main function is to collect fish during fishing Make sure the upper cover is properly buckled on the bottom pocket. This device solves the urgent need for daily multiple fishing, fishing in different specifications, and fishing in different water layers that are urgently needed in giant cage farming. It has the advantages of easy operation and labor saving.

This patent is used in giant cages. Similarly, the entire operation process is relatively complicated during use. Since fishing is mechanized and automatic, it may cause harm to the fish originally existing in the cage. In the above During the lowering process of the cover, the fish may be frightened and swim away, resulting in a smaller density of fish caught, and the space of the fish collection box is larger. The density of the fish when the fish is caught is even smaller, making it inconvenient to suck the fish pump or Net copying operation;

In addition, this device needs to move in the vertical direction when in use, so it requires enough space. It is generally only suitable for giant cages with very high heights. For giant cages with smaller heights, the applicability is poor. Moreover, once a school of fish enters the space formed by the upper cover and the bottom pocket, although the mesh size of the netting on the wing net and grading area is set as a standard to prevent the captured target fish from escaping, that is, smaller fish Small fish can get out of the net, but if the winch rolls up the fish collecting box in the bottom pocket at a faster speed, the duration will not be long, and the small fish entering the space formed by the upper cover and the bottom pocket will also have a longer escape time. Short, it is not easy for small fish to get out of the net under the obstruction of big fish, which leads to a greater possibility that the sizes of the fish caught in the end are not uniform. If the running speed is reduced, the fishing efficiency will be reduced and the consumption will be reduced. The energy will increase.

It can be seen that large-scale cage culture in the deep sea is the development direction of marine fish farming, which can expand new breeding space and use high-quality water sources in the deep sea to breed high-quality aquatic products. Large-scale breeding cages have a large scale and high output at a time. The fish grown are large and small, and they need to be caught in batches and put on the market. Large cages are troublesome to operate due to their relatively large structures. Therefore, it is necessary to design a catching device that is convenient for catching large cages and releasing small cages, and adopt correct catching methods to adapt to the development needs of intensive breeding in large and super-large cages. Therefore, the present invention provides a batch and graded catching device for fish cultured in large cages and a method of use.

Contents of the invention

In view of the shortcomings of the existing technology in the cages in which the density of fish captured by fish suction pumps or dip nets is small, the purpose of the present invention is to propose a batch and graded catching device for fish cultured in large cages and a method of use. Specifically, The plan is as follows:

A device for batch and graded catching of fish cultured in large cages, including large cages, and also includes:

A small lift-type fish cage has a fishing port formed on the top, and an inflatable gravity sinking and floating structure is provided at the bottom. The inflatable gravity sinking and floating structure drives the netting of the small lift-type fish cage to float or sink;

The fish passing channel is horizontally located between the large breeding cage and the small lifting fish cage, including a left channel and a right channel that are detachably and fixedly connected;

The left channel is sutured and connected to the small lift-type fish cage, and a closing device is provided near the small lift-type fish cage;

The right channel is sutured and connected to the large breeding cage, and there is also a closing device near the large breeding cage;

The fish grading grille is arranged vertically in the left channel and is removably and fixedly connected to the left channel.

Through the above technical solution, when it is necessary to raise a fish group, the inflatable gravity sinking and floating structure is not inflated. Under the action of gravity, the net clothing of the small lifting fish cage floats down until it is vertically formed, maintaining the ability of the small lifting fish cage to pass fish. Channels and large-scale breeding cages are connected. Bait is put into the small lift-type fish cage, and the fish enter the small lift-type fish cage from the large breeding cage through the fish channel. When the number reaches the required value, the closing device is controlled to quickly move the fish through the channel. The communication port between the two cages is closed, and fish are prohibited from being transferred. Since the left channel and the right channel are detachably and fixedly connected, the left channel and the right channel are then separated, and the fish are A similar graded grille is installed on the left channel, and then the left channel and the right channel are reconnected, and restored to the small lifting fish cage, the fish passing channel, and the large breeding cage.

Bait is put into the large breeding cage. Under the action of the fish grading grid, small-sized fish can return to the large breeding cage to continue breeding, while large-sized fish remain in the small lifting fish cage. By inflating the inflatable gravity sinking and floating structure until the inflatable gravity sinking and floating structure floats up, the net clothing is lifted to the water surface. At this time, the water volume in the small lifting fish cage is greatly reduced, and the fish-to-water ratio in the cage is greatly improved, making it easier to copy. Net fishing or fish suction pump suction fishing.

Further, the small lift-type fish cage includes a frame structure and a conical net structure from top to bottom, and the frame structure floats on the water;

The inflatable gravity sinking and floating structure is configured as a gravity hollow steel pipe, with a drainage port at the bottom and an air inlet at the top, and the air inlet passes through a hose to the water surface;

The hose is connected with a stop valve, which cooperates with each other to transport compressed gas to the gravity hollow steel pipe;

When the stop valve is opened, the compressed gas enters the gravity hollow steel pipe through the hose and discharges the seawater in the gravity hollow steel pipe. When the buoyancy reaches or exceeds the net weight of the gravity hollow steel pipe and the tapered netting structure, the stop valve closes. The gravity hollow steel pipe floats on the water.

Through the above technical solution, only the working status of the stop valve is controlled, and with the cooperation of the stop valve, hose and gravity hollow steel pipe, the cone-shaped netting structure can be raised and lowered.

Further, the stop valve and hose are installed on the water surface through floats and traction ropes.

Further, the left channel is connected to the middle position of the small lifting fish cage;

The left channel and the right channel are connected by a snap suture rope.

Through the above technical solution, the setting of the movable suture rope can realize the rapid separation of the left channel and the right channel.

Further, starting from the position of the closing device, the distances from the left channel and the right channel to the snap suture rope are not less than their heights above the water surface.

Through the above technical solution, it is ensured that the net clothing of the fish passage can be pulled to the water surface after being closed, which is convenient for operation.

Further, the closing device includes a plurality of rope loops arranged in a circumferential array on the outside of the fish passage, and a lead rope passing through the rope rings, with a lead rope between the lead rope and the rope ring. Thin ropes are connected with a spacing equal to the distance between two adjacent rope loops.

Further, the number of the rope loops is consistent with the number of nets on the fish passage, and is no less than four.

Further, the shape and size of the outer ring of the fish grading grid are consistent with the net box of the fish passage.

A method of using the batch grading catching device for fish cultured in large cages is to install a small lifting fish cage in a preset position, connect the fish passage, and do not install a fish grading grille in advance. The small lifting fish cage, the large breeding cage and the fish passage are interconnected to ensure that the fish passage is open;

Using the bait method, after the large-scale breeding cages are fasted for a period of time, bait is thrown at the small lifting fish cages, and the cultured fish are lured from the large cages to the small lifting fish cages through the fish passage. When the number of transfers reaches After the number of fish needs to be caught, control the two closing devices on the left and right to quickly close the fish, then separate the left channel and the right channel, pull the closed left channel to the water surface, and then connect the fish grading grille to the left according to the predetermined position. In the side channel, reconnect the left channel and the right channel and restore them to their original positions to ensure smooth fish passage. Small lift-type fish cages are forbidden, and large breeding cages are fed with bait to induce small lift-type fish cages. Small-sized fish in fish cages are transferred to large breeding cages through grids;

After the small-sized fish are transferred to the large-scale breeding cage, the two closing devices on the left and right are controlled from the water surface to quickly close the mouth again, so that the left channel and the right channel are closed again, and then the left channel and the right channel are separated again. Separate the small lifting fish cage and the large breeding cage, and by controlling the inflatable gravity sinking and floating structure, lift the bottom netting of the small lifting fish cage to the water surface, reducing the water volume of the small lifting fish cage, and finally Fish with a dip net or fish suction pump.

Further, the specific operation of controlling the closing device to close quickly is as follows: pulling the hoisting rope from the water surface. After the hoisting rope is stressed, the thin rope connecting the hoisting rope and the rope loop is broken, and all the rope rings are gathered, and then Close the left channel and right channel;

The specific steps to separate the left channel and the right channel are: start from the water surface and untie the snap suture rope;

The specific operation to control the inflatable gravity sinking and floating structure is: open the stop valve to control the compressed air to enter the gravity hollow steel pipe, and gradually discharge the water in the gravity hollow steel pipe.

Compared with the prior art, the beneficial effects of the present invention are as follows:

(1) The entire catching device is distributed in the horizontal direction, and the small lift-type fish cage and fish passage are set outside the large breeding cage. The small lift-type fish cage and fish passage actually play the role of catching. , a small lift-type fish cage is used for fish suction pumps or net fishing. The fish passage provides space for fish to go back and forth between the two cages. In the actual fishing process, various operations will not If it harms the fish inside the large-scale breeding cages, usually small lift-type fish cages and fish passages can be left on one side of the large-scale breeding cages, and it will not affect the breeding work inside the large-scale breeding cages. Moreover, small The specifications of lifting fish cages, fish passages and the space required for operation will not be restricted by large-scale breeding cages, nor will they occupy the space of large-scale breeding cages. Therefore, compared with the setting of mechanized batch fishing devices, Inside the giant cage, the device in the prior art is applicable to either a giant cage with a smaller height or a larger cage.

(2) The setting of the small lifting fish cage, as long as the fish enters the small lifting fish cage, the connection between the fish passage and the small lifting fish cage is quickly cut off through the closing device, so that the fish cannot escape even if they are frightened, ensuring The density of fish in the small lift-type fish cage is relatively high; although the small lift-type fish cage also performs lifting movements, its stroke is shorter. After setting up an inflatable gravity sinking and floating structure, the net clothing is lifted up, further increasing the density of the cage. The density of fish is convenient for dip net fishing or fish suction pump suction.

(3) Therefore, compared with the mechanized batch fishing device used in the prior art, the small lift-type fish cage of the present invention is based on the existing large-scale breeding cage and only needs to make small changes in the mechanical structure. Improvement: An inflatable gravity sinking and floating structure is set up at the bottom, and a purely mechanical fish passage is set up between the two cages. Together with the purely mechanical closing device and the fish grading grille, the fish can be completed efficiently and conveniently. Classified arrests.

(4) The suturing operation, the unbuckling suture rope unbuckling operation and the closing operation of the present invention can all be completed manually or operated by mechanical external force. Because the operation is relatively simple, even if it is done manually, the time and energy consumed when operating by mechanical external force are smaller than that of the existing technology.

Description of the drawings

Figure 1 is a top view of the catching device of the present invention;

Figure 2 is a front view of the catching device of the present invention;

Figure 3 is an overall schematic diagram of the inflatable gravity sinking and floating structure;

Figure 4 is a schematic diagram of the netting of a small lift-type fish cage rising to the water surface;

Figure 5 is a schematic diagram showing the live-buckle suture rope between the left channel and the right channel;

Figure 6 is a schematic diagram showing the closing device;

Figure 7 is a schematic diagram of a fish grading grid.

Reference symbols: 1. Large-scale breeding cage; 2. Small lift-type fish cage; 21. Frame structure; 22. Conical net structure; 23. Inflatable gravity sinking and floating structure; 3. Fish passage; 31. Left Side channel; 32, right channel; 33, live buckle suture rope; 331, live rope end; 34, force frame; 4, drain outlet; 5, air inlet; 6, hose; 7, stop valve; 8, Closing device; 81. Rope ring; 82. Leading rope; 821. Annular mouth; 9. Fish grading grid; 10. Float; 11. Towing rope.

Detailed ways

The present invention will be further described in detail below with reference to the examples and drawings, but the implementation of the present invention is not limited thereto.

As shown in Figure 1, the present invention proposes a batch and graded catching device for fish cultured in large cages, which includes a large culture cage 1 for cultivating fish, a small lift-type fish cage 2 that can be easily operated, Quickly sew the fish passage 3 connecting the two cages and the fish grading grille 9 provided in the fish passage 3.

With reference to Figures 2 to 4, the small lift-type fish cage 2 is a frame-type gravity cage. The top is a frame structure 21 that can float on the water surface. It is used to form a fishing port for operating fishing groups. The middle box The body is a cone-shaped mesh structure 22, and the bottom is an inflatable gravity sinking and floating structure 23. The inflatable gravity sinking and floating structure 23 is set as a gravity hollow steel pipe, and the internal space can carry water. When the small lift-type fish cage 2 is arranged in the water, the frame structure 21 floats on the water surface, and under the action of the gravity hollow steel pipe, the conical net structure 22 is formed vertically. After inflating to a certain amount, the net clothing of the small lift-type fish cage 2 can also be driven to float.

A drainage port 4 is provided at the bottom of the gravity hollow steel pipe, and an air inlet 5 is provided at the upper part. The air inlet 5 reaches the water surface through a hose 6, and a stop valve 7 is connected to the hose 6. The two cooperate with each other to compress the gravity hollow steel pipe. gas. The stop valve 7 and the hose 6 are stabilized on the water surface by setting the float 10 and the traction rope 11 to facilitate monitoring and operation by the staff. Since the weight of the gravity hollow steel pipe plus the weight of the water carried can make it sink into the water, when the air inlet 5 continues to deliver compressed gas into the gravity hollow steel pipe, at the same time, the water inside will be discharged from the drain outlet 4, thereby reducing the gravity hollow steel pipe. The total weight of the steel pipe.

The lifting and lowering of the cone-shaped netting structure 22 is realized through the above-mentioned lifting system. The stop valve 7 is opened to control the compressed air entering the gravity hollow steel pipe, and the water in the gravity hollow steel pipe is discharged. When the buoyancy reaches or exceeds the gravity hollow steel pipe and the cone-shaped netting structure 22 When there is a net weight in the water, the gravity hollow steel pipe will float to the water surface and float together with the cone-shaped net clothing structure 22 to reduce the net volume of the small lifting fish cage 2. When the gravity hollow steel pipe completely floats to the water surface, close the stop valve 7 . At this time, the fish in the small lift-type fish cage 2 will be concentrated, increasing the fish density in the space and making it easier to catch.

Secondly, the fish passage 3 is generally elongated and cylindrical, and is horizontally located between the large breeding cage 1 and the small lift-type fish cage 2. The height position is in the middle of the small lift-type fish cage 2, and the fish passage The direction of the channel 3 is consistent with the direction of the tide. The direction of the tide is the direction pointed by the double arrow in the figure. The tide is a periodic horizontal movement phenomenon of the water body when the sea level rises and falls. Under the inertia of the sea water movement, the flow can be ensured. The netting of fish channel 3 is opened.

Combining Figure 2 and Figure 5, the fish crossing channel 3 is sewn with mesh clothing and is divided into a left channel 31 and a right channel 32. A live buckle suture rope 33 is used in the middle to achieve a detachable fixed connection. As shown in the figure, based on the live buckle The principle is similar to the snap thread on the existing packaging bag. The snap suture rope 33 is specifically a rope body that passes through the netting on the left channel 31 and the right channel 32 through a specific threading path to achieve knotting. Finally, a live rope end 331 is left. By pulling the live rope end 331, the entire live fastening suture rope 33 is pulled out from the left channel 31 and the right channel 32, thereby separating the left channel 31 and the right channel 32.

The left channel 31 is sutured and connected to the middle position of the small lift-type fish cage 2, and the two do not need to be separated when unnecessary. The left channel 31 is provided with a closing device 8 near the connection with the small lifting fish cage 2 . The right channel 32 is similarly sutured to the large breeding cage 1, and its position is not limited. It is determined according to the actual situation. The right channel 32 is also provided with a closing device 8 at the connection close to the large breeding cage 1. By setting the closing device 8, when it is necessary to prevent fish from swimming out of the large breeding cage 1, or to prohibit fish from swimming into the small lifting fish cage 2, you only need to control the closing device 8 and move the fish passage 3 The connection port between the two cages is closed.

With reference to Figures 2 and 6, the closing device 8 specifically includes a plurality of rope loops 81 arranged in a circumferential array on the outside of the fish passage 3 and a lead rope 82 passing through the rope loops 81. The rope loops 81 are circular in shape. The number of force lines 34 of the net clothing passing through the fish channel 3 is consistent. The force level 34 refers to the ropes in the middle of the net clothing or its seams to bear the force and prevent the rupture and expansion of the net clothing, and the number of rope loops 81 is not less than 4 indivual. The lead rope 82 is a commonly used "lead rope" in this field. It refers to the lead rope that is usually installed between the sleeve end of the net and the net bag and is used to pull the net when raising the net. Since the inner diameter of the rope ring 81 is much larger than the diameter of the hoisting rope 82, in order to improve the structural stability between the two, the hoisting rope 82 and the rope ring 81 are tied with thin ropes with a spacing of two adjacent ones. The distance between the two rope loops 81 refers to the netting of the hoisting rope 82 and the rope loop 81 fixed by the thin rope, that is, the circumferential arc length of the netting of two adjacent rope loops 81, further making the rope loop 81 Stably connected to the lead cable 82. As shown in Figure 6 , an annular opening 821 is formed at one end of the hoisting rope 82 . The number of the annular openings 821 is not limited. When the number of the annular openings 821 exceeds one, the annular openings 821 are bundled in sequence, and the hoisting rope 82 is After the other end passes through the rope loop 81 in sequence, it passes out from the annular opening 821 at the edge.

In order to facilitate the control of the hoisting rope 82, its length is not limited. After the free end of the hoisting rope 82 passes through the water, its length must be sufficient to extend to a position accessible to the staff. The staff pulls the hoisting rope 82 82, the hoisting rope 82 gradually emerges from the water, and the rope rings 81 gradually converge with each other, thereby tightening the fish passage 3.

In addition, the lengths of the left channel 31 and the right channel 32 are not less than the height above the water surface. Furthermore, starting from the position of the closing device 8, the left channel 31 and the right channel 32 are connected to the loop suture The distance of the rope 33 is not less than its height from the water surface to ensure that it can be pulled to the water surface after the fish passage 3 net clothing is closed for easy operation.

As shown in Figures 2 and 7, secondly, the fish grading grille 9 is vertically arranged in the left channel 31, and is detachably and fixedly connected to the left channel 31, and its position is close to the live buckle suture rope 33. The shape and size of the outer ring of the fish grading grille 9 are consistent with the net clothing box of the fish passage 3, and are sutured and connected to the net clothing of the fish passage 3. Since the sutures are detachable, the fish grading grille 9 and the fish passage 3 mesh are quickly connected and are replaceable devices. The fish grading grille 9 device is a fish size grading device, and includes multiple parallel rods inside. There are rods with a certain spacing, and changing the fish grading grids 9 with different spacings determines the ability to catch fish of different sizes, which is not limited in this embodiment.

When the fish cultured in large-scale breeding cages 1 reach marketable specifications, they need to be sold in batches according to market demand. Therefore, it is necessary to catch the fish in batches and levels to achieve catching the big ones and releasing the small ones on demand. It is necessary to use the above-mentioned large-scale fish cage culture fish batch and graded catching device, and its specific usage method is as follows:

After installing the small lifting fish cage 2 at the preset position, connect the fish passage 3, and do not install the fish grading grille 9 in advance. The small lifting fish cage 2, the large breeding cage 1 and the fish passage 3 are are interconnected to ensure that the fish passage 3 is open;

Using the bait method, after the large-scale breeding cage 1 is fasted for a period of time, bait is thrown at the small lift-type fish cage 2, and the cultured fish are lured from the large cage to the small lift-type fish cage 2 through the fish passage 3. When the transferred quantity reaches the amount to be caught, the lead rope 82 on the fish channel 3 is pulled simultaneously from the water surface. After the lead rope 82 is stressed, the thin rope connecting the lead rope 82 and the rope ring 81 is broken. , all the rope loops 81 are gathered, and then the left channel 31 and the right channel 32 are closed. Then, untie the hook suture rope 33 between the left channel 31 and the right channel 32 from the water surface, separate the two channels, pull the closed left channel 31 to the water surface, and then move the fish grading grille 9 according to The predetermined position is connected to the left channel 31, and the left channel 31 and the right channel 32 are reconnected and returned to the original position to ensure the smooth flow of the fish passage 3.

After that, the small lifting fish cage 2 is fasted, and the large breeding cage 1 is fed, so as to induce the small size fish in the small lifting fish cage 2 to be transferred to the large breeding cage 1 through the grille.

After the small-sized fish are transferred to the large breeding cage 1, the closing device 8 is controlled from the water surface to quickly close the mouth again, so that the left channel 31 and the right channel 32 are closed again, and then the left channel 31 and the right channel 32 are closed. Separate again, separate the small lifting fish cage 2 and the large breeding cage 1, and by controlling the inflatable gravity sinking and floating structure 23, open the stop valve 7 to control the compressed air to enter the gravity hollow steel pipe, and gradually discharge the water in the gravity hollow steel pipe. Lift the bottom netting of the small lift-type fish cage 2 to the water surface, reduce the water volume of the small lift-type fish cage 2, and finally catch fish with a dip net or a fish suction pump.

On the basis of the existing technology, the most we can think of is setting up different forms of graded catching devices in large-scale breeding cages 1. Even if a graded catching device with more automated operation and better structure is installed, there will still be an impact on the large-scale breeding cages 1. Internal conditions, and even if you think of setting up a graded catching device outside the large breeding cage 1, you will only install a graded catching device that relies on mechanical automation.

According to the bait method, the present invention additionally sets up a small cage outside the large breeding cage 1 for luring fish of qualified specifications, which is the core improvement of the present invention, and the small cage can also be changed. Its own shape can lift the fish to the water surface and facilitate fishing, which is also one of the core improvements of the present invention. On the basis of the large-scale breeding cage 1, combined with the improvements in the above content, the large-scale cage of the present invention is formed. Batch and graded catching device for farmed fish.

The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above-mentioned embodiments. All technical solutions that fall under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications may be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (9)

1. The batch grading catching device for the large-scale net cage cultured fishes comprises a large-scale net cage (1) and is characterized by further comprising:

the small lifting fish lifting net cage (2) is characterized in that a fishing opening is formed in the top of the small lifting fish lifting net cage (2), an inflatable gravity floating structure (23) is arranged at the bottom of the small lifting fish lifting net cage, the inflatable gravity floating structure (23) drives a net of the small lifting fish lifting net cage (2) to float or sink, the small lifting fish lifting net cage (2) comprises a frame structure (21) and a conical net structure (22) from top to bottom, the frame structure (21) floats on the water surface, the inflatable gravity floating structure (23) is arranged as a gravity hollow steel pipe, a water outlet (4) is formed in the bottom of the inflatable gravity floating structure, an air inlet (5) is formed in the upper portion of the inflatable gravity floating structure, the air inlet (5) is connected to the water surface through a hose (6), a stop valve (7) is connected to the hose (6), the pneumatic gravity hollow steel pipe is mutually matched to convey compressed air, when the stop valve (7) is opened, the compressed air enters the gravity hollow steel pipe through the hose, seawater in the gravity hollow steel pipe is discharged, and when the buoyancy reaches and exceeds the gravity hollow steel pipe and the gravity hollow steel pipe (22), and the stop valve (7) is closed on the water surface;

the fish passing channel (3) is horizontally arranged between the large-scale cultivation net cage (1) and the small-scale lifting fish lifting net cage (2) and comprises a left side channel (31) and a right side channel (32) which are detachably and fixedly connected;

the left channel (31) is connected with the small lifting fish lifting net cage (2) in a sewing way, and a closing device (8) is arranged at a position close to the small lifting fish lifting net cage (2);

the right side channel (32) is connected with the large-scale cultivation net cage (1) in a sewing way, and a closing device (8) is arranged at a position close to the large-scale cultivation net cage (1);

the fish grading grid (9) is vertically arranged in the left channel (31) and is detachably and fixedly connected with the left channel (31).

2. The batch grading catching device for large-scale cage farmed fish according to claim 1, characterized in that the stop valve (7), the hose (6) are arranged on the water surface through a float (10) and a hauling rope (11).

3. The batch grading fishing device for large-scale cage farmed fish according to claim 1, characterized in that the left side channel (31) is connected with the middle position of the small-scale lifting fish cage (2);

the left side channel (31) and the right side channel (32) are connected through a loose knot sewing rope (33).

4. A batch grading catching device for large-scale cage farmed fish according to claim 3, characterized in that the distance from the left side channel (31) and the right side channel (32) to the living buckle sewing rope (33) is not less than the height from the water surface by taking the position of the closing device (8) as the starting point.

5. The batch grading catching device for large-scale cage farmed fish according to claim 1, characterized in that the closing device (8) comprises a plurality of rope rings (81) arranged outside along the circumferential array of the fish passage (3), and a lifting rope (82) passing through the rope rings (81), wherein the lifting rope (82) is connected with the rope rings (81) by strings, and the interval is the distance between two adjacent rope rings (81).

6. The batch grading catching device for large-scale cage farmed fish according to claim 5, characterized in that the number of rope loops (81) is consistent with the number of net lacing lines (34) on the fish passage (3) and not less than four.

7. The batch grading catching device for large-scale cage farmed fish according to claim 1, characterized in that the shape and size of the outer ring of the fish grading grating (9) are consistent with the cage body of the fish passage (3).

8. A method for using the batch grading fishing device for large-scale cage farmed fish according to any one of claims 1-7, characterized in that after the small-scale lifting fish cage (2) is installed at a preset position, a fish passing channel (3) is connected, a fish grading grid (9) is not installed in advance, and the small-scale lifting fish lifting cage (2), the large-scale fish farmed cage (1) and the fish passing channel (3) are mutually communicated so as to ensure that the fish passing channel (3) is opened;

after a large-scale aquaculture net cage (1) is fasted for a period of time by using a bait method, bait is thrown at a small-scale lifting type aquaculture net cage (2), cultured fishes are induced to turn from the large-scale net cage to the small-scale lifting type aquaculture net cage (2) through a fish passing channel (3), after the transfer quantity reaches the quantity required to be caught, two left and right closing devices (8) are controlled to quickly close, then a left channel (31) and a right channel (32) are separated, the closed left channel (31) is pulled to the water surface, then a fish grading grid (9) is connected in the left channel (31) according to a preset position, the left channel (31) and the right channel (32) are reconnected, the normal position is restored, the smoothness of the fish passing channel (3) is ensured, the small-scale lifting type aquaculture net cage (2) is fasted, and the small-scale lifting type aquaculture net cage (2) is induced to be transferred to the large-scale aquaculture net cage (1) through the grid;

after the small-size fish is transferred to the large-size aquaculture net cage (1), the left closing device and the right closing device (8) are controlled to close quickly from the water surface again, so that the left channel (31) and the right channel (32) are closed again, then the left channel (31) and the right channel (32) are separated again, the small-size lifting fish lifting net cage (2) and the large-size aquaculture net cage (1) are separated, the bottom netting of the small-size lifting fish lifting net cage (2) is lifted to the water surface by controlling the inflatable gravity sinking and floating structure (23), the water volume of the small-size lifting fish lifting net cage (2) is reduced, and finally fishing or sucking is carried out by using a landing net fishing or sucking pump.

9. The method for using the batch grading catching device for large-scale cage farmed fish according to claim 8, wherein the specific operation of controlling the rapid closing of the left closing device (8) and the right closing device (8) is as follows: lifting the lifting rope (82) from the water surface, and breaking the string connecting the lifting rope (82) with the string ring (81) after the lifting rope (82) is stressed, wherein all the string rings (81) are gathered, so that the left side channel (31) and the right side channel (32) are closed;

the specific steps of separating the left side channel (31) from the right side channel (32) are as follows: starting to unwind the loose-buckle suture rope (33) from the water surface;

the specific operation of controlling the inflatable gravity floating structure (23) is as follows: and (3) opening a stop valve (7) to control compressed air to enter the gravity hollow steel pipe, and gradually discharging water in the gravity hollow steel pipe.