Quantitative survey device for resource density of mangrove forest swimming animals

Abstract

The invention relates to the technical field of animal resource density survey, in particular to a mangrove forest swimming animal resource density quantitative survey device which comprises a net opening, mounting supports are mounted on two sides of the lower end of the net opening through detachable connectors, a net is fixedly connected to one side end face of the net opening, the net is conical, and a collecting bag is mounted at the tail end of the net. A second fixing sleeve and a first fixing sleeve are fixedly connected to the middle of the netting and the side, close to the net opening, of the netting correspondingly, an anti-escape assembly is arranged in the second fixing sleeve and used for preventing the swimming animals entering the netting from escaping from the net opening, a fixing support is fixedly connected to the inner wall of the first fixing sleeve, and the fixing support is fixedly connected to the inner wall of the first fixing sleeve. A servo motor is arranged on the end face of one side of the fixing support. Compared with the prior art, the method solves the problems that a trawl method cannot be used due to plant obstruction during quantitative investigation of the nekton in the mangrove forest, the trawl method damages the collected nekton, the sampling efficiency is low, and the error is large.

Description

Technical Field

[0001] The invention relates to the technical field of animal resource density investigation, in particular to a device for quantitative investigation of mangrove swimming animal resource density. Background Art

[0002] As a unique ecosystem, mangroves not only provide habitats for many organisms, but also play an important role in maintaining ecological balance and promoting biodiversity. As an important part of the mangrove ecosystem, swimming animals, such as population size, distribution and ecological habits, are of great significance for assessing the health status and ecological function of mangroves. Therefore, it is particularly important to develop an efficient and accurate quantitative sampling device for swimming animals.

[0003] At present, quantitative surveys of swimming animals mostly use the trawling method, but this method cannot be used because mangrove plants are standing. Although this method can cover a larger area of ​​water, it causes great damage to the collected swimming animals, which is not conducive to the subsequent research and analysis work. In addition, the trawling method also has the problems of low sampling efficiency and large errors.

[0004] Furthermore, we disclose a device for quantitative investigation of the density of swimming animals in mangroves to solve the problems of being unable to use the trawl method due to plant obstruction, damaging the collection of swimming animals by the trawl method, and having low sampling efficiency and large errors when conducting quantitative investigations of swimming animals in mangrove waters. Summary of the invention

[0005] In view of this, the purpose of the present invention is to propose a quantitative survey device for the density of swimming animal resources in mangroves, so as to solve the problems of being unable to use the trawl method due to plant obstruction during the quantitative survey of swimming animals in mangrove waters, the trawl method damaging the collection of swimming animals, and the low sampling efficiency and large errors.

[0006] Based on the above purpose, the present invention provides a quantitative investigation device for the density of swimming animals in mangrove forests, including a net port, both sides of the lower end of the net port are installed with mounting brackets through disassembly joints, one end face of the net port is fixedly connected with a net, the net is conical and a collecting bag is installed at the tail end, the middle part of the net and one side close to the net port are respectively fixedly connected with a second fixing sleeve and a first fixing sleeve, the interior of the second fixing sleeve is provided with an anti-escape component, the anti-escape component is used to prevent swimming animals entering the net from escaping from the net port, and the inner wall of the first fixing sleeve is fixedly connected to the first fixing sleeve. A fixed bracket is provided, a servo motor is arranged on one end face of the fixed bracket, an impeller is arranged on the side of the fixed bracket away from the servo motor, the output end of the servo motor is transmission-connected to the impeller, a speed change assembly is arranged at the connection between the output end of the servo motor and the fixed bracket, the speed change assembly is used to detect the internal water flow velocity and thus adjust the rotation speed of the impeller, a plurality of through holes are evenly spaced on the outer side of the middle part of the fixed bracket, an anti-curling mesh cover is fixedly connected to the outer side of the middle part of the end face of one side of the impeller of the fixed bracket, and the impeller is located inside the anti-curling mesh cover.

[0007] Preferably, the anti-escape component includes an anti-escape net fixedly connected to the inner wall of the second fixed sleeve, the anti-escape net is conical and the end with a smaller diameter is located on the side away from the net mouth, and the end with a smaller diameter of the anti-escape net is evenly spaced and fixedly connected with a plurality of spring pieces, the spring pieces are made of elastic material, are arc-shaped and protrude toward one side of the collection bag.

[0008] Preferably, the speed shift assembly includes a fixed seat fixedly connected to one side of the lower end of the second fixed sleeve, a rotating seat is fixedly connected to the middle of the upper end of the fixed seat, a rotating plate is rotatably connected to the upper end of the rotating seat, a first spring is fixedly connected to the middle of the lower end surface of the rotating plate, and the lower end of the first spring is fixedly connected to the inner wall of the second fixed sleeve.

[0009] Preferably, a steel wire rope is fixedly connected to the middle of one end surface of the rotating plate close to the fixed bracket, a connecting frame is fixedly connected to the middle of one end surface of the rotating seat close to the fixed bracket, an end of the connecting frame away from the rotating seat is rotatably connected to a roller, and the end of the steel wire rope away from the fixed connection with the rotating plate passes through the lower end of the roller and contacts the roller.

[0010] Preferably, the speed shift assembly also includes a limit block fixedly connected to the lower end of the inner wall of the first fixed sleeve, the upper end of the limit block is slidably connected to a sleeve rod, one end of the steel wire rope passes through the roller and is fixedly connected to the middle part of the sleeve rod, the inner upper end of the sleeve rod is slidably connected to a sliding rod, the upper end of the sliding rod passes through the sleeve rod and is fixedly connected to a connecting plate, the upper end surface of the connecting plate is fixedly connected to a second spring on both sides, the upper end surfaces of the two second springs are fixedly connected to a slide plate, a sliding groove is provided in the middle part of the lower end of the outer wall of the anti-rolling suction net cover, and the slide plate is slidably connected to the sliding groove.

[0011] Preferably, a connecting shaft is fixedly connected to the middle part of the upper end surface of the connecting plate, the upper end of the connecting shaft passes through the slide plate, extends into the interior of the anti-rolling suction mesh cover and is fixedly connected to a rotating bracket, the upper end of the rotating bracket is engaged and rotatably connected to a driven wheel, and the driven wheel is conical and the end with a smaller diameter is located on the side away from the fixed bracket.

[0012] Preferably, a spline shaft is slidably connected to the middle of the driven wheel, one end of the spline shaft is fixedly connected to a second rotating shaft, and a plurality of lower blades are fixedly connected to the outer wall of the second rotating shaft at even intervals.

[0013] Preferably, the end of the spline shaft away from the second rotating shaft is fixedly connected to the optical axis, a rectangular groove is opened at the lower end of the middle part of the fixing bracket, and one end of the optical axis extends into the interior of the rectangular groove and is slidably engaged therein.

[0014] Preferably, the speed change assembly also includes a driving wheel rotatably connected to the middle part of the fixed bracket, the output end of the servo motor is fixedly connected to the driving wheel, the driving wheel is conical and the end with a smaller diameter is close to the fixed bracket, the driving wheel is in contact with the driven wheel and is transmission-connected, the inner middle part of the driving wheel is engaged and rotatably connected with a first rotating shaft, one end of the first rotating shaft passes through the driving wheel and is fixedly connected to the impeller.

[0015] Preferably, a plurality of upper blades are evenly and fixedly connected to the outer wall of the first rotating shaft between the driving wheel and the impeller, and the upper blades are staggered with the lower blades.

[0016] Beneficial effects of the present invention:

[0017] 1. The quantitative investigation device for the density of swimming animals in mangroves simulates the process of trawl surveys, captures swimming animals at fixed points, and converts the density of swimming animals in mangroves by filtering water, effectively realizing the quantitative investigation of swimming animals in the complex ecological environment of mangroves. It adopts a conical net design, combined with a collection bag and anti-escape components, to ensure that swimming animals are difficult to escape once they enter the net, while reducing the physical damage to animals caused by the capture process. This design not only improves the accuracy of the survey data, but also reflects the respect and protection awareness for the ecological environment, ensuring the sustainability and eco-friendliness of the survey activities.

[0018] 2. The mangrove swimming animal resource density quantitative survey device is equipped with a speed change component, which can intelligently adjust the rotation speed of the impeller according to the actual flow velocity of the water. This function not only ensures that under different water flow conditions, the water flow velocity inside the device can be maintained in a relatively stable state, thereby optimizing the capture conditions of swimming animals and improving the capture efficiency, but more importantly, it avoids the fluctuation of the capture effect caused by changes in water flow velocity, ensuring the stability and reliability of the survey results. This adaptive adjustment mechanism provides technical guarantee for efficient and accurate swimming animal resource surveys in complex and changeable water environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0021] Figure 2 It is a schematic diagram of a partial three-dimensional structure of the present invention;

[0022] Figure 3 It is a schematic diagram of the partial three-dimensional structure inside the speed change assembly of the present invention;

[0023] Figure 4 This is a schematic diagram of the three-dimensional structure of the anti-escape component of the present invention;

[0024] Figure 5 It is a schematic diagram of the three-dimensional structure of the speed change assembly of the present invention;

[0025] Figure 6 It is a schematic diagram of a partial three-dimensional structure of a speed change assembly of the present invention;

[0026] Figure 7 for Figure 2 Enlarged view of point A in the middle.

[0027] The markings in the figure are:

[0028] 1. Mounting bracket; 2. Net mouth; 3. First fixing sleeve; 4. Net; 5. Second fixing sleeve; 6. Collecting bag; 7. Limit block; 8. Anti-rolling and suction net cover; 9. Impeller; 10. Fixed bracket; 11. Servo motor; 12. Driving wheel; 13. First rotating shaft; 14. Slide plate; 15. Connecting plate; 16. Sliding rod; 17. Sleeve rod; 18. Shrapnel; 19. Anti-escape net; 20. First spring; 21. Fixed seat; 22. Turn plate; 23. Rotating seat; 24. Connecting frame; 25. Roller; 26. Spline shaft; 27. Wire rope; 28. Connecting shaft; 29. ​​Rotating bracket; 30. Lower blade; 31. Upper blade; 32. Driven wheel; 33. Sliding groove; 34. Through hole; 35. Optical axis; 36. Second rotating shaft; 37. Second spring; 38. Rectangular groove. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0030] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] like Figures 1 to 7As shown, a quantitative investigation device for the density of swimming animals in mangrove forests comprises a net port 2, both sides of the lower end of the net port 2 are installed with mounting brackets 1 through disassembly joints, one end face of the net port 2 is fixedly connected with a net 4, the net 4 is conical and a collecting bag 6 is installed at the tail end, the middle part of the net 4 and one side close to the net port 2 are respectively fixedly connected with a second fixing sleeve 5 and a first fixing sleeve 3, an anti-escape component is arranged inside the second fixing sleeve 5, and the anti-escape component is used to prevent swimming animals entering the net 4 from escaping from the net port 2, and the inner wall of the first fixing sleeve 3 is fixedly connected with a fixing bracket 10, and the fixing bracket 10 is fixedly connected with the inner wall of the first fixing sleeve 3. A servo motor 11 is provided on one end face of the bracket 10, an impeller 9 is provided on one side of the fixed bracket 10 away from the servo motor 11, the output end of the servo motor 11 is connected to the impeller 9 by transmission, a speed change assembly is provided at the connection between the output end of the servo motor 11 and the fixed bracket 10, the speed change assembly is used to detect the internal water flow velocity and then adjust the rotation speed of the impeller 9, a plurality of through holes 34 are evenly spaced outside the middle part of the fixed bracket 10, an anti-curling net cover 8 is fixedly connected to the outer middle part of the end face of one side of the fixed bracket 10 located at the impeller 9, and the impeller 9 is located inside the anti-curling net cover 8;

[0032] The device for quantitatively investigating the density of swimming animals in mangroves achieves low-damage quantitative investigation of swimming animals in the complex environment of mangroves through the innovative design of conical net 4 and anti-escape components. At the same time, the integrated speed-changing component can intelligently adjust the speed of the impeller 9 according to the water flow rate to ensure the stability of the water flow, thereby improving the capture efficiency and the stability of the investigation results, and providing efficient and accurate technical support for the scientific management and protection of mangrove swimming animal resources.

[0033] Further, such as Figure 4 As shown, the anti-escape assembly includes an anti-escape net 19 fixedly connected to the inner wall of the second fixing sleeve 5, the anti-escape net 19 is conical and the end with a smaller diameter is located on the side away from the net opening 2, and the end with a smaller diameter of the anti-escape net 19 is evenly spaced and fixedly connected with a plurality of spring pieces 18, the spring pieces 18 are made of elastic material, are arc-shaped and protrude toward one side of the collection bag 6;

[0034] When swimming animals are caught by the net 4 and move toward the collection bag 6 with the water flow, they will first contact the anti-escape net 19 located inside the second fixed sleeve 5. The anti-escape net 19 is designed in a conical shape, with the end with a smaller diameter facing the collection bag 6, forming a natural barrier. More importantly, this end is also evenly distributed with a plurality of arc-shaped spring pieces 18 made of elastic material, which protrude toward the collection bag 6, forming a dynamic blocking mechanism. When swimming animals try to pass through the anti-escape net 19 in the reverse direction, the elasticity of the spring pieces 18 will make it close to the net surface, increasing the difficulty of escape. At the same time, the arc-shaped design of the spring pieces 18 can also guide the animals to continue to move toward the collection bag 6. Therefore, the anti-escape component effectively prevents swimming animals from escaping from the net opening 2 through its unique conical structure and the cooperation of the elastic spring pieces 18, thereby ensuring the accuracy of the survey results.

[0035] Further, such as Figures 2 to 7As shown, the speed change assembly includes a fixed seat 21 fixedly connected to one side of the lower end of the second fixed sleeve 5, a rotating seat 23 is fixedly connected to the middle of the upper end of the fixed seat 21, a rotating plate 22 is rotatably connected to the upper end of the rotating seat 23, a first spring 20 is fixedly connected to the middle of the lower end surface of the rotating plate 22, the lower end of the first spring 20 is fixedly connected to the inner wall of the second fixed sleeve 5, a steel wire rope 27 is fixedly connected to the middle of the end surface of the rotating plate 22 close to the fixed bracket 10, a connecting frame 24 is fixedly connected to the middle of the end surface of the rotating seat 23 close to the fixed bracket 10, a roller 25 is rotatably connected to the connecting frame 24 at one end away from the rotating seat 23, and the steel wire rope 27 is away from the end fixedly connected to the rotating plate 22. The end passes through the lower end of the roller 25 and contacts with the roller 25. The speed change assembly also includes a limit block 7 fixedly connected to the lower end of the inner wall of the first fixed sleeve 3. The upper end of the limit block 7 is slidably connected to the sleeve rod 17. The wire rope 27 passes through one end of the roller 25 and is fixedly connected to the middle part of the sleeve rod 17. The inner upper end of the sleeve rod 17 is slidably connected to the slide rod 16. The upper end of the slide rod 16 passes through the sleeve rod 17 and is fixedly connected to the connecting plate 15. The upper end surface of the connecting plate 15 is fixedly connected to the second spring 37 on both sides. The upper end surfaces of the two second springs 37 are fixedly connected to the slide plate 14. A slide groove 33 is opened in the middle of the lower end of the outer wall of the anti-rolling suction net cover 8. The slide plate 14 is slidably connected to the slide groove 33. The connecting plate 15 A connecting shaft 28 is fixedly connected to the middle of the upper end surface of the sliding plate 14, and the upper end of the connecting shaft 28 penetrates the slide plate 14 and extends into the interior of the anti-rolling suction net cover 8 and is fixedly connected to a rotating bracket 29. The upper end of the rotating bracket 29 is engaged and rotatably connected to a driven wheel 32. The driven wheel 32 is conical and the end with a smaller diameter is located on the side away from the fixed bracket 10. The middle part of the driven wheel 32 is slidably connected to a spline shaft 26, and one end of the spline shaft 26 is fixedly connected to a second rotating shaft 36. The outer wall of the second rotating shaft 36 is evenly spaced and fixedly connected to a plurality of lower blades 30. The end of the spline shaft 26 away from the second rotating shaft 36 is fixedly connected to an optical axis 35. A rectangular groove 38 is provided at the lower end of the middle part of the fixed bracket 10. The optical axis One end of 35 extends into the interior of the rectangular groove 38 and slides and engages therein, the speed change assembly also includes a driving wheel 12 rotatably connected to the middle of the fixed bracket 10, the output end of the servo motor 11 is fixedly connected to the driving wheel 12, the driving wheel 12 is conical and the end with a smaller diameter is close to the fixed bracket 10, the driving wheel 12 is in contact with the driven wheel 32 and is transmission-connected, the inner middle part of the driving wheel 12 is engaged and rotatably connected with a first rotating shaft 13, one end of the first rotating shaft 13 passes through the driving wheel 12 and is fixedly connected to the impeller 9, the outer wall of the first rotating shaft 13 is located between the driving wheel 12 and the impeller 9 and is evenly spaced and fixedly connected with a plurality of upper blades 31, and the upper blades 31 and the lower blades 30 are staggered;

[0036] First, the servo motor 11 drives the driving wheel 12 to rotate. The driving wheel 12 contacts and is connected to the driven wheel 32 through its conical design, and transmits power to the driven wheel 32. At the same time, the spline shaft 26 that is slidably connected inside the driving wheel 12 rotates synchronously. The spline shaft 26 rotates the first rotating shaft 13 to rotate synchronously and the lower blade 30 rotates accordingly. The rotation of the lower blade 30 can drive the first rotating shaft 13 to rotate through the upper blade 31. The rotation of the first rotating shaft 13 drives the impeller 9 to rotate, thereby generating a water flow in the direction of the net 4, pushing the swimming animals into the collection bag 6. In this process, the flowing The water flow produces a certain resistance to the rotating plate 22, causing it to rotate around the rotating seat 23. The rotation of the rotating plate 22 is converted into a pulling force on the sleeve rod 17 through the connection between the wire rope 27 and the sleeve rod 17. The sliding rod 16 and the connecting plate 15 structure sliding inside the sleeve rod 17, as well as the elastic force of the second spring 37, ensure the smooth transmission of this pulling force, and make the slide plate 14 slide on the slide groove 33, driving the connecting shaft 28 and the rotating bracket 29 to move horizontally inside the anti-rolling suction net cover 8. Since the driven wheel 32 is engaged and rotatably connected with the rotating bracket 29, the driven wheel 32 also moves horizontally on the driving wheel 12. Since both are conical in design and the ends with smaller diameters are facing each other, this horizontal movement causes the contact point between the driven wheel 32 and the driving wheel 12 to change, thereby changing the transmission ratio and realizing the adjustment of the rotation speed of the impeller 9. When the flow rate is low, the rotating plate 22 rotates clockwise through the action of the first spring 20, so that the rotation speed of the impeller 9 increases, thereby increasing the flow speed of the water flow. When the flow rate is high, the rotating plate 22 rotates counterclockwise to reduce the flow speed of the water flow.

[0037] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0038] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A quantitative survey device for the density of mangrove swimming animals, characterized by: The invention comprises a net opening (2), both sides of the lower end of the net opening (2) are installed with mounting brackets (1) through disassembly joints, one end face of the net opening (2) is fixedly connected with a net (4), the net (4) is conical and a collecting bag (6) is installed at the tail end, the middle part of the net (4) and the side close to the net opening (2) are respectively fixedly connected with a second fixing sleeve (5) and a first fixing sleeve (3), the interior of the second fixing sleeve (5) is provided with an anti-escape component, the anti-escape component is used to prevent swimming animals entering the net (4) from escaping from the net opening (2), the inner wall of the first fixing sleeve (3) is fixedly connected with a fixing bracket (10), one end face of the fixing bracket (10) is fixedly connected with a net (4), and the second fixing sleeve (5) is fixedly connected with a first fixing sleeve (3) and a second fixing sleeve (5) is fixedly connected with a second fixing sleeve (5), and the second fixing sleeve (5) is fixedly connected with a first fixing sleeve (3) and a second fixing sleeve (10) is fixedly connected with a second fixing sleeve (10) and a second fixing sleeve (10) is fixedly connected with a second fixing sleeve (5) and a second fixing sleeve (10) is fixedly connected with a second fixing sleeve (10 ... A servo motor (11) is provided, an impeller (9) is provided on a side of the fixed bracket (10) away from the servo motor (11), an output end of the servo motor (11) is transmission-connected to the impeller (9), a speed change assembly is provided at the connection between the output end of the servo motor (11) and the fixed bracket (10), the speed change assembly is used to detect the flow velocity of the internal water flow and thus adjust the rotation speed of the impeller (9), a plurality of through holes (34) are evenly spaced apart on the outer side of the middle part of the fixed bracket (10), an anti-curling mesh cover (8) is fixedly connected to the outer side of the middle part of the end surface of one side of the fixed bracket (10) located on the impeller (9), and the impeller (9) is located inside the anti-curling mesh cover (8).

2. The device for quantitatively investigating the density of mangrove swimming animals according to claim 1, characterized in that: The anti-escape component comprises an anti-escape net (19) fixedly connected to the inner wall of the second fixing sleeve (5); the anti-escape net (19) is conical and the end with a smaller diameter is located on a side away from the net opening (2); a plurality of spring pieces (18) are evenly spaced and fixedly connected to the end with a smaller diameter of the anti-escape net (19); the spring pieces (18) are made of elastic material, are arc-shaped and protrude toward one side of the collection bag (6).

3. The device for quantitatively investigating the density of mangrove swimming animals according to claim 1, characterized in that: The speed change assembly comprises a fixed seat (21) fixedly connected to one side of the lower end of the second fixed sleeve (5); a rotating seat (23) is fixedly connected to the middle of the upper end of the fixed seat (21); a rotating plate (22) is rotatably connected to the upper end of the rotating seat (23); a first spring (20) is fixedly connected to the middle of the lower end surface of the rotating plate (22); and the lower end of the first spring (20) is fixedly connected to the inner wall of the second fixed sleeve (5).

4. The device for quantitatively investigating the density of mangrove swimming animals according to claim 3, characterized in that: A steel wire rope (27) is fixedly connected to the middle of the end surface of one side of the rotating plate (22) close to the fixed bracket (10), a connecting frame (24) is fixedly connected to the middle of the end surface of one side of the rotating seat (23) close to the fixed bracket (10), an end of the connecting frame (24) away from the rotating seat (23) is rotatably connected to a roller (25), and an end of the steel wire rope (27) away from the fixed connection with the rotating plate (22) passes through the lower end of the roller (25) and contacts the roller (25).

5. The device for quantitatively investigating the density of mangrove swimming animals according to claim 4, characterized in that: The speed change assembly also includes a limit block (7) fixedly connected to the lower end of the inner wall of the first fixed sleeve (3), the upper end of the limit block (7) is slidably connected to a sleeve rod (17), one end of the steel wire rope (27) passes through the roller (25) and is fixedly connected to the middle part of the sleeve rod (17), the inner upper end of the sleeve rod (17) is slidably connected to a slide rod (16), the upper end of the slide rod (16) passes through the sleeve rod (17) and is fixedly connected to a connecting plate (15), both sides of the upper end surface of the connecting plate (15) are fixedly connected to second springs (37), the upper end surfaces of the two second springs (37) are fixedly connected to a slide plate (14), a slide groove (33) is provided in the middle part of the lower end of the outer wall of the anti-rolling suction net cover (8), and the slide plate (14) is slidably connected to the slide groove (33).

6. The device for quantitatively investigating the density of mangrove swimming animals according to claim 5, characterized in that: A connecting shaft (28) is fixedly connected to the middle of the upper end surface of the connecting plate (15); the upper end of the connecting shaft (28) penetrates the slide plate (14) and extends into the interior of the anti-rolling suction net cover (8) and is fixedly connected to a rotating bracket (29); the upper end of the rotating bracket (29) is engaged and rotatably connected to a driven wheel (32); the driven wheel (32) is conical and the end with a smaller diameter is located on a side away from the fixed bracket (10).

7. The device for quantitatively investigating the density of mangrove swimming animals according to claim 6, characterized in that: The middle part of the driven wheel (32) is slidably connected to a spline shaft (26), one end of the spline shaft (26) is fixedly connected to a second rotating shaft (36), and the outer wall of the second rotating shaft (36) is evenly spaced and fixedly connected to a plurality of lower blades (30).

8. The device for quantitatively investigating the density of mangrove swimming animals according to claim 7, characterized in that: An end of the spline shaft (26) away from the second rotating shaft (36) is fixedly connected to an optical axis (35), a rectangular groove (38) is provided at the lower end of the middle portion of the fixed bracket (10), and one end of the optical axis (35) extends into the interior of the rectangular groove (38) and is slidably engaged therein.

9. The device for quantitatively investigating the density of mangrove swimming animals according to claim 1, characterized in that: The speed change assembly further comprises a driving wheel (12) rotatably connected to the middle part of the fixed bracket (10); the output end of the servo motor (11) is fixedly connected to the driving wheel (12); the driving wheel (12) is conical and the end with a smaller diameter is close to the fixed bracket (10); the driving wheel (12) is in contact with and transmission-connected to the driven wheel (32); the inner middle part of the driving wheel (12) is engaged and rotatably connected with a first rotating shaft (13); one end of the first rotating shaft (13) passes through the driving wheel (12) and is fixedly connected to the impeller (9).

10. The device for quantitatively investigating the density of mangrove swimming animals according to claim 9, characterized in that: The outer wall of the first rotating shaft (13) is located between the driving wheel (12) and the impeller (9) and is evenly and fixedly connected with a plurality of upper blades (31), and the upper blades (31) and the lower blades (30) are arranged in an alternating manner.

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