Freshwater shellfish culture device and use method

Abstract

The invention discloses a freshwater shellfish culture device and a use method, and relates to the technical field of aquaculture, a floating bottle and a fixing rope are connected through a connecting rope, and one end of the connecting rope is fixed on the fixing rope in a knotting manner, so that the friction between the connecting rope and the fixing rope in the culture process is reduced, and the rope breaking probability is reduced; the net cage is integrally formed and made of PPC degradable environment-friendly materials, so that the net cage has the advantage of being light in weight. The side walls of the net cage are obliquely arranged and the bottom of the net cage is arc-shaped, so that a plurality of net cages can be overlapped, and the net cage has the advantages of convenience in operation, transportation and storage, low cost, reusability and the like; the bottom of the net cage protrudes downwards in an arc shape, when the shellfishes are small in specification, the bottom structure facilitates gathering of the freshwater shellfishes to the middle, the fry escape probability is reduced, water permeable holes are not formed in the positions, 4-5 cm above the bottom, of the periphery of the net cage, the substrate can be prevented from being washed away, a sheltering place is provided for the freshwater shellfishes, and shellfish growth is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture, and in particular to a freshwater shellfish culture device and a use method thereof. Background Art

[0002] Freshwater shellfish play an important role in the food web structure, water quality regulation and material circulation of the ecosystem. They also have high economic value, such as edible value, pearl cultivation and extraction of anti-tumor ingredients. They are also used as indicator organisms to monitor and evaluate heavy metal pollution in water bodies.

[0003] Shellfish farming is an efficient, environmentally friendly and sustainable farming method, suitable for promotion and application in a variety of freshwater areas. my country's freshwater economic shellfish are mainly freshwater clams, cockles, etc., which are mostly raised in a hanging manner, using fixed piles, fixed ropes, cages, floats and other facilities to hang shellfish in ponds or open water bodies for farming. The hanging method can make full use of the water space and increase the yield per unit area. Based on the filter-feeding characteristics of shellfish, the hanging process can filter suspended particles and organic matter in the water, which helps to purify the water quality. In the process of growth, it will absorb a large amount of carbon to form calcium carbonate, which has a positive effect on carbon fixation and reducing greenhouse gas emissions.

[0004] At present, most freshwater shellfish farming cages are made of wood, bamboo strips, etc. as frame materials. The bottom and sides of the frame are sewn with plastic film, and the outside is wrapped with polyethylene mesh. The farming floats are mostly cola bottles. The general operation steps of this type of cage and floating bottle farming are: (1) Tie one end of the nylon rope to the cola bottle and the other end to the four corners of the cage. One cage requires four cola bottles; (2) Wrap the nylon ropes of the four bottles around the fixed rope to fix the cage; (3) Cut the sealing line of the cage, put in the mussel seedlings, and seal it with nylon line; (4) After the farming is completed, the bottles need to be unwound from the fixed rope and removed from the cage to take out the shellfish.

[0005] However, this type of cage and floating bottle has the following disadvantages: (1) The cages are handmade with non-uniform specifications, poor firmness, short service life, and high labor costs; (2) The cages cannot be placed on top of each other, making them difficult to transport and store and occupying a large space; (3) Due to insufficient structural strength and production process problems, they are prone to falling apart, resulting in a reduction in the space for shellfish to move around; (4) During the breeding process, the nylon line connecting the Coke bottle and the fixed rope is prone to breakage due to long-term friction with the fixed rope, causing the cage to tip over; (5) The operation procedures of the breeding cages and floating bottles are very cumbersome, the ropes are inconvenient to install and remove, the labor intensity is high, and the work efficiency is low. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a freshwater shellfish culture device, comprising two fixed ropes arranged in parallel in the horizontal direction, the two ends of the fixed ropes are fixed to the river bank or the edge of the river, a plurality of sealed floating bottles are arranged at intervals above the fixed ropes, and the floating bottles on the two fixed ropes are arranged symmetrically along the spacing direction of the fixed ropes; the floating bottles are fixed to the fixed ropes by connecting ropes; a plurality of integrally formed net cages are connected between the two fixed ropes, each two net cages are arranged as a group between adjacent floating bottles on the same fixed rope, and the two net cages are arranged at intervals along the length direction of the fixed ropes, and when the entire culture device is placed in water, all the floating bottles are inverted, and a part of the floating bottles is exposed above the water surface; The upper end of the net box is open, and the edge of the opening protrudes downward with buckles located on the outside of the net box. The buckles are arranged at intervals along the circumference of the opening, and the buckles on one side of the net box along the length direction of the fixed rope are connected to the fixed rope on the corresponding side; the upper end of the net box is provided with a mesh that completely covers the opening, and the buckles correspond to the mesh holes passing through the mesh around the mesh; the side walls around the net box are inclined, and the bottom of the side walls is closer to the center of the net box, and a number of water-permeable holes are opened on the side walls around the net box; the bottom of the net box protrudes downward in an arc shape.

[0007] The technical solution further defined in the present invention is: Furthermore, one end of the connecting rope is fixed to the fixing rope by tying a knot.

[0008] As described above, in a freshwater shellfish culture device, the floating bottle comprises a bottle body and a bottle cap threadedly connected to the bottle mouth, a connecting portion protrudes outward from the bottle cap, and a connecting hole for connecting a connecting rope is provided on the connecting portion.

[0009] As described above, in a freshwater shellfish breeding device, the cross-section of the bottle body along the vertical direction is set to be circular, and the radius of the cross-section gradually increases and then gradually shortens from the bottle mouth to the bottle bottom, and the cross-section radius of the bottle mouth is smaller than the cross-section radius of the bottle bottom.

[0010] As described above, a freshwater shellfish culture device has a plurality of annular grooves spaced apart on the outer wall of the bottle body along the direction from the bottle mouth to the bottle bottom, and the annular grooves are opened along the circumference of the bottle body.

[0011] As described above, in the freshwater shellfish culture device, the bottom of the bottle body is provided with an inwardly concave arc groove.

[0012] As described above, in a freshwater shellfish culture device, the opening edge of the net cage is provided with an outwardly folded-outwards everted portion, and a plurality of buckles are fixed to the end of the outwardly folded portion.

[0013] As described above, in a freshwater shellfish breeding device, the buckles are arranged along the vertical direction, the spacing between adjacent buckles is set to be equal, and the buckles located on the symmetrical two sides are also symmetrically arranged.

[0014] In the above-mentioned freshwater shellfish culture device, the inclination angle of the side wall of the cage is set to 15-20 degrees.

[0015] The present invention also provides a method for using a freshwater shellfish culture device, comprising the following steps: S1. Tie one end of the connecting rope to the connecting hole of the floating bottle, and fix the other end of the connecting rope to the fixing rope by tying a knot; S2. Connect all the floating bottles to two fixed ropes respectively by the method in step S1. The floating bottles on the two fixed ropes are symmetrically arranged along the spacing direction of the fixed ropes. The floating bottles on the same fixed rope are distributed at equal intervals. S3. After placing the freshwater shellfish inside the cage, completely cover the opening at the upper end of the cage with the mesh, tighten the mesh, and fix the four sides of the mesh to the cage by passing buckles through the mesh holes on the mesh; S4, clamping all the buckles on one side of the net box opening onto a fixing rope, the fixing rope being located between the buckles and the corresponding side wall of the net box, and the upper end of the fixing rope being in contact with the outward-turned portion; S5. All the buckles on the other symmetrical side of the cage opening are clamped onto another fixing rope, the fixing rope is located between the buckles on the other side and the corresponding side wall of the cage, and the upper end of the fixing rope is in contact with the outer eversion portion on the other side; S6, installing two cages between two adjacent floating bottles using the method of steps S3 to S5, with the two cages spaced apart along the length direction of the fixed rope; S7, repeat step S6 until all cages are arranged; S8. Place the entire freshwater shellfish culture device in the river, with both ends of each fixed rope fixed to the river bank or the edge of the river. At this time, the net cages are completely located in the river. Due to buoyancy, all the floating bottles are inverted, and a part of the floating bottles is exposed above the water surface.

[0016] The beneficial effects of the present invention are: (1) In the present invention, the floating bottle and the fixed rope are connected by a connecting rope, and one end of the connecting rope is fixed to the fixed rope by tying a knot. This connection method between the floating bottle and the fixed rope reduces the friction between the connecting rope and the fixed rope during the breeding process, and reduces the probability of rope breakage; the net cage has the advantage of being lightweight by integrated molding and using PPC degradable and environmentally friendly materials; the net cage also has the advantages of being able to overlap and place several net cages by setting the side wall inclined and the bottom in an arc shape, which has the advantages of being easy to operate, convenient to transport and store, low cost, and reusable; (2) In the present invention, the bottom of the cage is convex downward in an arc shape. When the shellfish are small in size, this bottom structure is conducive to the gathering of freshwater shellfish in the middle, reducing the probability of escape. There are no water holes at the bottom of the cage, and there are no water holes around the cage from the bottom to the top 4-5 cm, which can prevent the bottom sediment from being washed away, provide a shelter for freshwater shellfish, and is conducive to the growth of shellfish. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a structural schematic diagram of the floating bottle in the present invention; Figure 3 It is a structural schematic diagram of the net box in the present invention; Figure 4 It is a schematic diagram of the shape of the net box in the present invention.

[0018] Among them: 1. fixing rope; 2. floating bottle; 3. connecting rope; 4. net box; 5. buckle; 6. mesh; 7. water-permeable hole; 8. bottle body; 9. bottle cap; 10. connecting part; 11. connecting hole; 12. annular groove; 13. arc groove; 14. eversion part. DETAILED DESCRIPTION

[0019] This embodiment provides a freshwater shellfish breeding device, such as Figure 1 As shown, it includes two fixed ropes 1 arranged in parallel along the horizontal direction, both ends of the fixed ropes 1 are fixed to the river bank or the edge of the river, a number of sealed floating bottles 2 are arranged at intervals above the fixed ropes 1, and the floating bottles 2 on the two fixed ropes 1 are symmetrically arranged along the spacing direction of the fixed ropes 1, the floating bottles 2 and the fixed ropes 1 are fixed by connecting ropes 3, one end of the connecting rope 3 is fixed to the fixed rope 1 by knotting, this connection method of the floating bottles 2 and the fixed ropes 1 reduces the friction between the connecting ropes 3 and the fixed ropes 1 during the breeding process, and reduces the probability of rope breaking.

[0020] like Figure 2 As shown, the floating bottle 2 includes a bottle body 8 and a bottle cap 9 threadedly connected to the bottle mouth, a connecting portion 10 protrudes outward from the bottle cap 9, the connecting portion 10 is arranged in a triangular shape, a connecting hole 11 for connecting the connecting rope 3 is opened on the connecting portion 10 along its own thickness direction, and the connecting hole 11 is arranged in a circular shape for easy tying.

[0021] The bottle body 8 is hollow inside, and the cross section of the bottle body 8 along the vertical direction is circular, and the radius of the cross section gradually increases and then gradually shortens from the bottle mouth to the bottle bottom, and the radius of the cross section of the bottle mouth is smaller than the radius of the cross section of the bottle bottom. The outer wall of the bottle body 8 is provided with a plurality of annular grooves 12 at equal intervals from the bottle mouth to the bottle bottom, and the annular grooves 12 are provided along the circumferential direction of the bottle body 8. An inwardly concave arc groove 13 is provided at the bottom of the bottle body 8, and the arc groove 13 is provided in a semicircular shape, which increases the stability of the floating bottle 2, and makes the entire floating bottle 2 easy to operate, large buoyancy, and low price.

[0022] A number of net cages 4 are connected between the two fixed ropes 1, and each two net cages 4 are set as a group between adjacent floating bottles 2 on the same fixed rope 1, and the two net cages 4 are spaced apart along the length direction of the fixed rope 1. When the entire breeding device is placed in water, all the floating bottles 2 are inverted, and a part of the floating bottles 2 is exposed above the water surface. The distance between the bottle cap 9 and the fixed rope 1 is 10-20 cm, and the distance between adjacent floating bottles 2 on the same fixed rope 1 is set to 100-120 cm.

[0023] like Figures 3 to 4 As shown, the net box 4 is basket-shaped, and the entire net box 4 is integrally formed and can be factory-automatically manufactured on a large scale, which significantly improves production efficiency and ensures product quality; the material of the net box 4 is PPC degradable and environmentally friendly material, which has the advantages of corrosion resistance and high strength; the size of the net box 4 is set to 418×418×125mm.

[0024] The upper end of the net box 4 is open, and the opening edge of the net box 4 is turned outward by 2 cm to form an outward-turned portion 14. A number of buckles 5 are fixed to the end of the outward-turned portion 14. The buckles 5 protrude downward from the outside of the net box 4 in the vertical direction. The length of the buckles 5 is set to 2 cm, and the spacing between adjacent buckles 5 is set to be equal, both 5 cm, and the buckles 5 located on the symmetrical two sides are also symmetrically arranged. The buckles 5 on one side of the net box 4 along the length direction of the fixing rope 1 are connected to the fixing rope 1 on the corresponding side.

[0025] A mesh 6 that completely covers the opening is provided at the upper end of the net box 4. The mesh 6 is a square polyethylene mesh 6 with a pore size of 1-2 cm, and the buckles 5 correspond to the mesh holes passing through the mesh 6. The side walls around the net box 4 are inclined, and the inclination angle is set to 15 degrees, and the bottom of the side wall is closer to the center of the net box 4. A number of water-permeable holes 7 are opened on the side walls around the net box 4, and two rows of water-permeable holes 7 are symmetrically opened on each side wall. The water-permeable holes 7 in each row are arranged at equal intervals, and the water-permeable holes 7 are set to be squares with a side length of 2 cm; the bottom of the net box 4 is arc-shaped and protrudes downward. When the shellfish is small in size, this bottom structure is conducive to the gathering of freshwater shellfish to the middle, reducing the probability of escape. There are no water-permeable holes 7 at the bottom of the net box 4, and there are no water-permeable holes 7 around the net box 4 from the bottom to the top 4-5 cm. It can prevent the bottom sediment from being washed away, provide a shelter for freshwater shellfish, and is conducive to the growth of shellfish.

[0026] Since the side walls of the net box 4 are inclined, the bottom is arc-shaped and protrudes downward, and the overall material of the net box 4 is lightweight, the overall weight of the net box 4 is relatively light and can be stacked. Each box costs only 8-10 yuan, and has the characteristics of convenient operation, convenient transportation and storage, low cost, and reusability.

[0027] This embodiment also provides a method for using a freshwater shellfish culture device, comprising the following steps: S1, tie one end of the connecting rope 3 to the connecting hole 11 of the floating bottle 2, and fix the other end of the connecting rope 3 to the fixing rope 1 by tying a knot; S2, connecting all the floating bottles 2 to the two fixed ropes 1 respectively through the method of step S1, the floating bottles 2 on the two fixed ropes 1 are symmetrically arranged along the spacing direction of the fixed ropes 1, and the floating bottles 2 on the same fixed rope 1 are distributed at equal intervals; S3, after placing the freshwater shellfish inside the net box 4, the mesh 6 is completely covered at the opening at the upper end of the net box 4, and the mesh 6 is tightened, and the four sides of the mesh 6 are fixed to the net box 4 by passing the buckle 5 through the mesh hole on the mesh 6; S4, all the buckles 5 on one side of the opening of the net box 4 are clipped onto a fixing rope 1, the fixing rope 1 is located between the buckle 5 and the corresponding side wall of the net box 4, and the upper end of the fixing rope 1 is in conflict with the outward-turned portion 14; S5, clamp all the buckles 5 on the other symmetrical side of the opening of the net box 4 to another fixing rope 1, the fixing rope 1 is located between the buckle 5 on the other side and the corresponding side wall of the net box 4, and the upper end of the fixing rope 1 is in conflict with the outer eversion portion 14 on the other side; S6, installing two net boxes 4 between two adjacent floating bottles 2 by the method of steps S3 to S5, and the two net boxes 4 are spaced apart along the length direction of the fixing rope 1; S7, repeat step S6 until all cages 4 are arranged; S8. Place the entire freshwater shellfish culture device in the river, with both ends of each fixed rope 1 fixed to the river bank or the edge of the river. At this time, the net cages 4 are completely located in the river. Due to the buoyancy, all the floating bottles 2 are inverted, and a part of the floating bottles 2 is exposed above the water surface.

[0028] In actual use, on May 10, 2024, two skilled clam farmers were invited to culture the cumbria clams using traditional net cages 4 and cola bottles. The operation steps are as follows: (1) Tie one end of the nylon rope to the cola bottle and the other end to the four corners of the net cage 4; (2) Wrap the four bottles around the fixed rope 1 to fix the net cage 4; (3) After adding the bottom material to the net cage 4, put in the clam seedlings with a size of 1.2-1.5 cm. Because the clam seedlings are smaller than the aperture of the polyethylene mesh 6, the clam seedlings are put in through the 6 holes of the polyethylene mesh. The two skilled workers put a total of 322 clam culture boxes in one day. According to statistics in June 2024, the survival rate was 98%-99%, and the average shell length of the cumbria clams increased by about 1.8 cm. According to statistics in July 2024, the survival rate was 98%-99%, and the average shell length of the cumbria clams increased by about 2.3 cm.

[0029] On May 11, 2024, two skilled workers used the breeding device and breeding method of this embodiment to breed the cumbria clams. The operation steps are as follows: (1) Use a nylon rope to pass through the bottle cap 9, tie the floating bottle 2 to the two fixed ropes 1, align the floating bottles 2 on the two fixed ropes 1, and the distance between the bottle cap 9 and the fixed rope 1 is about 10 cm, and the distance between the floating bottles 2 is 100-120 cm; (2) Tighten the square polyethylene mesh 6 with a hole diameter of 2 cm and hang it on the four-side buckles 5, hang the net box 4 on the two fixed ropes 1 in the middle of the floating bottle 2, and hang two net boxes 4 between the two floating bottles 2; (3) After adding the bottom material into the net box 4, the clam seedlings with a specification of 1.2-1.5 cm are put in. Because the clam seedlings are smaller than the hole diameter of the polyethylene mesh 6, the clam seedlings are put in through the holes of the polyethylene mesh 6. The two skilled workers put a total of 824 clam breeding boxes in one day. According to statistics in June 2024, the survival rate was 98%-99%, and the average shell length of the cuming fan clams increased by about 1.8 cm. According to statistics in July 2024, the survival rate was 98%-99%, and the average shell length of the cuming fan clams increased by about 2.3 cm.

[0030] In another actual use, on April 13, 2023, traditional cages 4 and cola bottles were used to culture olive razor clams and pearl oysters. On May 15, 2024, two skilled clam farmers were asked to take the triangular fan clams cultured in traditional cages 4 and cola bottles. The skilled workers unhooked the bottles from the fixed rope 1 and then took out the cages 4 and the clams. The two skilled workers sorted out a total of 454 breeding cages in one day, of which 489 cages were broken, accounting for 19.6% of the total cages 4, and 25 cages 4 overturned due to the wear and tear of the nylon rope connecting the cola bottle and the cage 4, accounting for 5.5% of the total cages 4.

[0031] On April 14, 2023, the culture device and culture method of this embodiment were used to culture olive clams and pearl clams. On May 16, 2024, two skilled workers were invited to culture the triangular fan clams using the culture device and culture method of this embodiment. The skilled workers directly moved the net cage 4 to take out the clams. The two skilled workers sorted out a total of 1,468 culture boxes in one day. The culture boxes did not overturn or fall apart.

[0032] In another practical use, in May 2024, the floating bottle 2 was tied to two fixed ropes 1 with a nylon line, the distance between the screw cap and the fixed rope 1 was about 10 cm, the distance between the two floating bottles 2 was about 100-120 cm, and the floating bottles 2 on the two fixed ropes 1 corresponded. The square polyethylene mesh 6 with an aperture of 1 cm was tightened and hung on the four-side buckles 5, and the net box 4 was hung on the two fixed ropes 1 in the middle of the floating bottle 2. Two net boxes 4 can be hung between the two floating bottles 2. Put 2-3 cm thick yellow mud in the net box 4, and put 1 jin of river clam seedlings (specification 0.3g-0.8g) into the net box 4. According to statistics in June 2024, the survival rate was 97%-99%, and the average weight increase of river clams was about 0.6g. According to statistics in July 2024, the survival rate was 97%-99%, and the average weight increase of river clams was about 0.9g.

[0033] The net cage 4 and the floating bottle 2 in the freshwater shellfish breeding device of this embodiment can be used for freshwater bivalves such as triangular fan clams, olive clams, and river clams. The floating bottle 2 can also be used in fishing nets, etc., and has the advantage of strong applicability. The freshwater shellfish breeding device and the use method of this embodiment have been promoted and used in an area of ​​3,000 acres. Due to its high convenience, economy and effective reduction of labor costs, it is highly accepted by fishermen.

[0034] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A freshwater shellfish culture device, characterized in that: The invention comprises two fixing ropes (1) arranged in parallel along the horizontal direction, the two ends of the fixing ropes (1) are fixed to the river bank or the edge of the river, a plurality of sealed floating bottles (2) are arranged at intervals above the fixing ropes (1), and the floating bottles (2) on the two fixing ropes (1) are arranged symmetrically along the spacing direction of the fixing ropes (1); the floating bottles (2) and the fixing ropes (1) are fixed by connecting ropes (3); a plurality of integrally formed net cages (4) are connected between the two fixing ropes (1), and each two net cages (4) are arranged as a group between adjacent floating bottles (2) on the same fixing rope (1), and the two net cages (4) are arranged at intervals along the length direction of the fixing rope (1); when the entire aquaculture device is placed in water, all the floating bottles (2) are inverted, and a part of the floating bottles (2) is exposed above the water surface; The upper end of the net box (4) is open, and a buckle (5) is protruding downward from the edge of the opening and is located outside the net box (4). The buckles (5) are arranged at intervals along the circumference direction of the opening. The buckles (5) on one side of the net box (4) along the length direction of the fixing rope (1) are snapped onto the fixing rope (1) on the corresponding side. A mesh sheet (6) that completely covers the opening is provided at the upper end of the net box (4), and the buckles (5) correspond to mesh holes passing through the mesh sheet (6) on all sides. The side walls of the net box (4) are inclined, and the bottom of the side walls is closer to the center of the net box (4). A plurality of water-permeable holes (7) are provided on the side walls of the net box (4). The bottom of the net box (4) protrudes downward in an arc shape.

2. A freshwater shellfish culture device according to claim 1, characterized in that: One end of the connecting rope (3) is fixed to the fixing rope (1) by tying a knot.

3. A freshwater shellfish culture device according to claim 1, characterized in that: The floating bottle (2) comprises a bottle body (8) and a bottle cap (9) threadedly connected to the bottle mouth, a connecting portion (10) protruding outward from the bottle cap (9), and a connecting hole (11) for connecting the connecting rope (3) is provided on the connecting portion (10).

4. A freshwater shellfish culture device according to claim 3, characterized in that: The cross section of the bottle body (8) along the vertical direction is arranged to be circular, and the radius of the cross section gradually increases and then gradually decreases from the bottle mouth to the bottle bottom, and the radius of the cross section of the bottle mouth is smaller than the radius of the cross section of the bottle bottom.

5. A freshwater shellfish culture device according to claim 4, characterized in that: The outer wall of the bottle body (8) is provided with a plurality of annular grooves (12) spaced apart from each other in a direction from the bottle mouth to the bottle bottom, and the annular grooves (12) are provided along the circumferential direction of the bottle body (8).

6. A freshwater shellfish culture device according to claim 5, characterized in that: The bottom of the bottle body (8) is provided with an inwardly recessed arc-shaped groove (13).

7. A freshwater shellfish culture device according to claim 1, characterized in that: The opening edge of the net box (4) is provided with an outwardly folded-back portion (14), and a plurality of buckles (5) are fixed to the end of the outwardly folded portion (14).

8. A freshwater shellfish culture device according to claim 7, characterized in that: The buckles (5) are arranged along the vertical direction, the spacing between adjacent buckles (5) is arranged to be equal, and the buckles (5) located on the two symmetrical sides are also arranged symmetrically.

9. A freshwater shellfish culture device according to claim 1, characterized in that: The inclination angle of the side wall of the net box (4) is set to 15-20 degrees.

10. A method for using a freshwater shellfish culture device, characterized in that: The freshwater shellfish culture device according to any one of claims 1 to 9 comprises the following steps: S1. Tie one end of the connecting rope (3) to the connecting hole (11) of the floating bottle (2), and fix the other end of the connecting rope (3) to the fixing rope (1) by tying a knot; S2. Connect all the floating bottles (2) to the two fixed ropes (1) respectively by the method of step S1. The floating bottles (2) on the two fixed ropes (1) are symmetrically arranged along the spacing direction of the fixed ropes (1). The floating bottles (2) on the same fixed rope (1) are evenly spaced and distributed; S3, after placing the freshwater shellfish inside the net box (4), completely cover the opening at the upper end of the net box (4) with the mesh (6), tighten the mesh (6), and fix the four sides of the mesh (6) to the net box (4) by passing the buckle (5) through the mesh hole on the mesh (6); S4. All the buckles (5) on one side of the opening of the net box (4) are clipped onto a fixing rope (1), the fixing rope (1) being located between the buckle (5) and the corresponding side wall of the net box (4), and the upper end of the fixing rope (1) being in contact with the outward-turned portion (14); S5. All the buckles (5) on the other symmetrical side of the opening of the net box (4) are clipped onto another fixing rope (1), the fixing rope (1) being located between the buckles (5) on the other side and the corresponding side wall of the net box (4), and the upper end of the fixing rope (1) being in contact with the outer-turned portion (14) on the other side; S6. Install two net cages (4) between two adjacent floating bottles (2) using the method of steps S3 to S5, with the two net cages (4) being spaced apart along the length direction of the fixing rope (1); S7, repeat step S6 until all cages (4) are arranged; S8. Place the entire freshwater shellfish culture device in the river, with both ends of each fixing rope (1) fixed to the river bank or the edge of the river. At this time, the net cage (4) is completely located in the river. Due to buoyancy, all the floating bottles (2) are inverted, and a part of the floating bottles (2) is exposed above the water surface.

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