An apparatus for testing fish target strength using a method of control of the overhang

Abstract

The application discloses a test device for testing fish target strength by using a suspension control method, which comprises a net cage, a winding wheel, an angle adjusting ruler, a transducer, a fish body suspension system and an underwater video monitoring system and an underwater camera arranged in the net cage from top to bottom in sequence, two equal-length first fish lines output by the winding wheel are connected with the upper and lower ends of the stainless steel rods of the fish body suspension system through the threading holes in the angle adjusting ruler; the lifting system is composed of the winding wheel and the two equal-length first fish lines, the first fish lines are connected with the winding wheel and the fish body suspension system respectively, the winding wheel is fixed to the top end of a fourth steel pipe, the fourth steel pipe is connected with a first steel pipe through a fourth fastener, and the first steel pipe is connected with the net cage through a first fastener. The test device is simple in structure and reasonable in design, can eliminate the influence of the fish body posture and the inclination angle on the fish target strength test, and can accurately measure the target strength of the fish body under different sound wave incident angles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fish target strength test in fishery resource assessment, and particularly relates to a test device for testing fish target strength by using a suspension control method. BACKGROUND

[0002] In the process of using hydroacoustics to assess fishery resources, fish target strength is a key parameter for converting echo signals into fish size and fish resource quantity estimation. Therefore, the accurate determination of target strength has a great influence on the reliability of acoustic assessment of fishery resources. One of the theoretical bases for acoustic assessment of fishery resources is that target strength is linearly positively correlated with fish size. However, target strength is not only related to fish size, but also closely related to factors such as fish swimbladder type (tube swimbladder or closed swimbladder), fish posture (bending degree), fish inclination angle (the angle between the incident sound wave and the main axis of the fish body), etc. For a specific fish, in order to accurately determine the target strength of individuals with different body lengths, the influence of fish posture and inclination angle must be excluded.

[0003] At present, in-situ determination of fish target strength mainly includes net cage determination method and suspension determination method. The net cage determination method is to place free-swimming fish in a net cage, and to read the target strength when the fish swims into the effective detection range of the echo sounder beam. The suspension method is to control the fish body in the effective detection range of the echo sounder beam by using a thin rope, and to measure the target strength of the fish. The net cage determination method is closer to the natural state of fish, but it takes a very long time to test due to the low probability of fish entering the effective detection range of the beam. In addition, since the influence of fish posture and inclination angle on target strength may exceed the body length in some cases, the target strength tested by the net cage method has no strong correlation with the fish size. The commonly used suspension method has good control over the spatial position of the fish body, but it is extremely difficult to suspend the fish body and adjust the inclination angle, and there is a problem of interference of the fish body suspension device with the target strength. SUMMARY

[0004] Based on the deficiencies of the prior art, the purpose of the present application is to provide a test device for testing fish target strength by using a suspension control method, which has a simple structure, a reasonable design, is easy to suspend the fish body to fully expand it, is convenient to control and adjust the inclination angle of the fish body, can effectively exclude the interference of the suspension device with the measurement of fish target strength, and can accurately determine the target strength of the fish body at different sound wave incidence angles.

[0005] To achieve the above purpose, the present application adopts the following technical measures:

[0006] An experimental device for testing fish target strength by using a suspension control method, comprising a net cage, characterized in that a winding reel, an angle adjusting ruler, a transducer, a fish body suspension system and an underwater video monitoring system are sequentially arranged from top to bottom in the net cage, two equal-length first fishing lines output by the winding reel are connected to the upper and lower ends of the stainless steel rods of the fish body suspension system through the threading holes in the angle adjusting ruler; the lifting system is composed of the winding reel and the two equal-length first fishing lines, and the first fishing lines are respectively connected to the winding reel and the upper and lower ends of the stainless steel rods of the fish body suspension system.

[0007] The winding reel is fixed to the top end of the fourth steel pipe, and the winding reel can control the equal-amplitude lifting of the two first fishing lines.

[0008] The fourth steel pipe is connected to the first steel pipe through a fourth fastener, and the first steel pipe is connected to the net cage through a first fastener.

[0009] The angle adjusting ruler is composed of a stainless steel strip and an angle ruler, the two ends of the stainless steel strip have threading holes, the center of symmetry of the two threading holes has a round hole, a fastening screw passes through the round hole to connect the angle adjusting ruler and the steel pipe, and the stainless steel strip rotates around the fastening screw to realize angle adjustment.

[0010] The angle ruler is aligned with the lower edge of the stainless steel strip, the center of symmetry of the two threading holes is aligned with the zero center of the angle ruler, the angle ruler and the stainless steel strip are welded to form a whole, and the angle ruler can rotate around the fastening screw with the stainless steel strip;

[0011] The angle adjusting ruler is provided with threading holes at both ends, and the two first fishing lines pass through the threading holes.

[0012] The threading hole diameter is adjustable, and the first fishing line can be locked by reducing the hole diameter.

[0013] The equal-amplitude winding and unwinding of the two first fishing lines by the winding reel realizes the lifting and lowering of the fish body suspension system connected to the lower end of the fishing line;

[0014] The angle adjusting ruler is welded by a stainless steel strip and an angle ruler, the zero center of the angle ruler coincides with the center of symmetry of the two threading holes, and a fastening screw fixes the angle adjusting ruler on the steel pipe through the center; the fastening screw can be loosened or locked; the stainless steel strip rotates around the fastening screw to realize the adjustment of the fish body inclination angle.

[0015] The upper and lower stainless steel rods of the fish body suspension system and the stainless steel strip of the angle adjusting ruler are always parallel. The fish body and the stainless steel rod in the fish body suspension system cannot overlap in the vertical direction to ensure that the fish body and the stainless steel rod can be clearly distinguished in the acoustic signal. The distance between the upper and lower stainless steel rods of the fish body suspension system cannot be too large, provided that the fish body signal can be clearly distinguished in the acoustic signal. The fish body suspension system includes a line tightener which can wind and lock the second fishing line tied to the fish body, and the position of the line tightener on the stainless steel rod can be adjusted and locked. The fish body can be fully unfolded by adjusting the position of the line tightener on the stainless steel rod and the length of the second fishing line.

[0016] The video monitoring system can adjust the position of the underwater camera in the horizontal and vertical directions by adjusting the relative position of the steel pipes and the position of the steel pipes on the net cage. The underwater camera of the video monitoring system cannot be located within the effective detection range of the acoustic wave beam. The underwater camera of the video monitoring system and the fish body cannot overlap in the vertical direction to ensure that the fish body and the underwater camera can be clearly distinguished in the acoustic signal. The video information collected by the underwater camera can be uploaded in real time through the cable.

[0017] Preferably, the distance between the threading holes and the distance between the first fishing line and the same stainless steel rod are completely equal.

[0018] The key components of the device are the lifting system, the angle adjusting ruler and the fish body suspension system. The equal amplitude output of the two fishing lines in the lifting system ensures that the stainless steel strip in the angle adjusting ruler and the stainless steel rods in the fish body suspension system are always parallel. In the fish body suspension system, a thin second fishing line is used to suspend the fish body between the two stainless steel rods, solving the problem of fish body bending in the traditional suspension method. The upper and lower stainless steel rods of the fish body suspension system are kept parallel and connected by a thin first fishing line, and the fish body and the two stainless steel rods do not overlap in the vertical direction, solving the problem of interference with the target strength caused by the suspension equipment in the traditional suspension method. The fish body main shaft and the stainless steel rods in the suspension system, as well as the stainless steel strip of the angle adjusting ruler, are always parallel, solving the problem of adjusting the angle of the incident sound wave and the fish body in the remote control.

[0019] Compared with the prior art, the test device for testing fish target strength by the suspension control method of the present application has the following beneficial effects and advantages:

[0020] 1. The key component of the device is the fish body suspension system, which connects the upper and lower stainless steel rods by two equal-length fishing lines and keeps them parallel, and the fish body is suspended between the two stainless steel rods by the stretching of the fishing lines. This solves the problem that the traditional suspension method cannot ensure that the fish body is fully unfolded, and solves the problem that the hard material used in the traditional suspension method overlaps with the fish body in the vertical direction, interfering with the target strength.

[0021] 2. The device has the advantages of simple structure, easy realization of fish body suspension and angle control, and elimination of fish body bending, unknown inclination angle, and interference of the suspension system on the accuracy of target strength determination.

[0022] 3. The device is mainly different from the prior art in that the fish body posture is controllable, and the fish body inclination angle is controllable and measurable.

[0023] 4. The device is mainly different from the prior art in that the fish body suspension system does not interfere with the target strength.

[0024] 5. The device can realize remote control and adjustment of the angle of the incident wave relative to the fish body, and can meet the testing requirements of fish target strength under different incident wave angles. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a structural schematic view of a test device for testing fish target strength by a suspension control method.

[0026] Figure 2 It is a structural schematic view of a lifting system and an angle adjusting ruler.

[0027] Figure 3 It is a structural schematic view of a fish body suspension system.

[0028] In the figure: 1 - net cage; 2 - first steel pipe; 3 - second steel pipe; 4 - stainless steel strip; 5 - third steel pipe; 6 - fourth steel pipe; 7 - first fastener; 8 - second fastener; 9 - third fastener; 10 - fourth fastener; 11 - winding wheel; 12 - angle ruler; 13 - threading hole; 14 - fastening screw; 15 - transducer; 16 - first fishing line; 17 - stainless steel rod; 18 - second fishing line; 19 - line tightener; 20 - underwater camera; 21 - lead hammer. DETAILED DESCRIPTION

[0029] Example 1: According to Figure 1 、 Figure 2 、 Figure 3 It can be known that a test device for testing fish target strength by a suspension control method comprises a net cage 1, characterized in that a winding wheel 11, an angle adjusting ruler, a transducer 15, a fish body suspension system, an underwater video monitoring system, and an underwater camera 20 are sequentially arranged from top to bottom in the net cage 1. Two equal-length first fishing lines 16 output by the winding wheel 11 are connected to a stainless steel rod 17 at the upper end of the fish body suspension system after passing through the threading holes 13 on the angle adjusting ruler. The first fishing lines 16 are retracted and released by the winding wheel 11, so as to adjust the rising and falling of the fish body suspension system.

[0030] The lifting system is composed of a reel 11 and two equal-length first fishing lines 16, the first fishing lines 16 are connected with the reel 11 and the fish body suspension system respectively, and the water depth of the fish body suspension system is adjusted by winding and unwinding the first fishing lines 16 through the reel 11.

[0031] The reel 11 is fixed to the top end of the fourth steel pipe 6.

[0032] The fourth steel pipe 6 is connected with the first steel pipe 2 through the fourth fastener 10.

[0033] The first steel pipe 2 is connected with the net cage 1 through the first fastener 7.

[0034] The reel 11 can control the equal-amplitude lifting of the two first fishing lines 16.

[0035] The angle adjusting ruler is composed of a stainless steel strip 4 and an angle ruler 12, the two ends of the stainless steel strip 4 have threading holes 13, the center of symmetry of the two threading holes 13 has a circular hole, a fastening screw 14 passes through the circular hole to connect the angle adjusting ruler with the fourth steel pipe 6, and the stainless steel strip 4 rotates around the fastening screw 14 to realize angle adjustment.

[0036] The angle ruler 12 is aligned with the lower edge of the stainless steel strip 4, the center of symmetry of the two threading holes 13 is aligned with the zero center of the angle ruler, the angle ruler 12 and the stainless steel strip 4 are welded to form a whole, and the angle ruler 12 can rotate around the fastening screw 14 with the stainless steel strip 4.

[0037] The two ends of the stainless steel strip 4 are provided with threading holes 13, and the two first fishing lines 16 pass through the threading holes 13.

[0038] The diameter of the threading hole 13 is adjustable, and the first fishing line 16 can be locked by reducing the diameter.

[0039] The fish body suspension system is composed of two parallel stainless steel rods 17, a line tightener 19, a lead sinker 21, and first fishing lines 16 and second fishing lines 18 connected in sequence. Two equal-length first fishing lines 16 are connected with the two ends of the upper and lower stainless steel rods 17 respectively, and the fish body is connected with the line tightener 19 through the second fishing line 18.

[0040] The position of the line tightener 19 on the stainless steel rod 17 can be adjusted and locked.

[0041] One end of the second fishing line 18 is connected with the line tightener 19, and the other end is tied to the dorsal side or ventral side of the fish body, and the fish body is fully unfolded and suspended in the center of the two stainless steel rods 17 by tightening the second fishing line 18 through the line tightener 19.

[0042] The top end of the lead sinker 21 is a circular ring, the first fishing lines 16 connected with the two ends of the lower stainless steel rod 17 pass through the circular ring, and the lead sinker 21 can freely slide on the first fishing lines 16.

[0043] The lower end of the stainless steel rod 17 is connected with a first fishing line 16, and the plumb bob 21 can freely slide on the first fishing line 16.

[0044] The fish body suspension system is composed of two parallel stainless steel rods 17, a line tightener 19 and a second fishing line 18. The second fishing line 18 connected to the output end of the line tightener 19 is tied to the fin or skin on the dorsal or ventral side of the fish body. The position of the line tightener 19 on the stainless steel rod 17 can be adjusted and locked. By adjusting the position of the line tightener 19 and tightening the second fishing line 18, the fish body can be fully stretched, and the main axis of the fish body can be parallel or at a certain angle to the stainless steel rod 17. Since the stainless steel rod 17 is always parallel to the stainless steel strip 4, when the angle adjustment ruler is rotated at a small angle around the fastening screw 14 (-30 degrees to 30 degrees, positive for the fish head upward and negative for the fish head downward), the fish body will also produce the same angle change. When it is required to make the incident sound wave have an angle less than 60 degrees or greater than -60 degrees with the main axis of the fish body, only the angle between the main axis of the fish body and the stainless steel rod 17 needs to be adjusted to the required complementary angle, and then the angle adjustment ruler is kept horizontal.

[0045] The underwater video monitoring system is composed of a second steel pipe 3, a third steel pipe 5 and an underwater camera 20. The underwater camera 20 is fixed to the bottom end of the third steel pipe 5. The second steel pipe 3 is connected with the third steel pipe 5 through a third fastener 9, and the second steel pipe 3 is connected with the net cage 1 through a second fastener 8. The relative position of the second steel pipe 3 and the third steel pipe 5 and the position of the second steel pipe 3 on the net cage 1 are adjusted to realize the horizontal and vertical position adjustment of the underwater camera 20. The video information collected by the underwater camera 20 can be uploaded in real time through the cable.

[0046] The upper edge of the net cage 1 is connected with the first steel pipe 2 through the first fastener 7. The fourth steel pipe 6 is vertically downward, and is connected with the first steel pipe 2 through a fourth fastener 10.

[0047] The lower end of the fourth steel pipe 6 is connected with a transducer 15, and the beam of the transducer 15 is vertically downward.

[0048] The materials of the first fishing line 16 and the second fishing line 18 are nylon or polyethylene fiber, which are thin enough to avoid interference with the target strength test caused by echo signals under the premise of ensuring strength.

[0049] As Figure 1As shown, during the test, the live fish is connected with the second fishing line 18 and the fish line tightener 19 on the shore, and then the position of the fish line tightener on the stainless steel rod 17 is adjusted, the second fishing line 18 is tightened by the fish line tightener 19, the fish body is fully stretched and unfolded, and the main axis of the fish body is adjusted to be parallel to the stainless steel rod 17. The acoustic device is turned on, the test parameters are adjusted, and the transducer 15 is vertically emitted to the underwater sound wave. Then the fish body suspension system is gently put into the net cage 1, the angle adjusting ruler is kept perpendicular to the fourth steel pipe 6, and the fish body suspension system is slowly lowered to the water depth to be tested (the water depth of the fish body is read in real time by the acoustic device). The aperture of the threading hole 13 is reduced to lock the first fishing line 16. The position of the underwater camera is adjusted to be opposite to the side of the fish body, and the posture of the fish body can be observed in real time on the water surface. At this time, the angle between the incident sound wave and the main axis of the fish body is 90 degrees, and the target strength of the fish body tested by the acoustic device is the target strength when the sound wave is 90 degrees to the back of the fish body.

[0050] When the target strength of the incident sound wave and the main axis of the fish body is needed to be tested in the range of 60 degrees to 90 degrees and -90 degrees to -60 degrees, the angle between the 90 degree scale line of the angle ruler 12 and the fourth steel pipe 6 is the complementary angle of the required angle.

[0051] When the fish body needs to be at an angle of -60 degrees to 60 degrees with the incident sound wave, the fish body is hung on the shore, the fish line tightener 19 is adjusted so that the angle between the main axis of the fish body and the stainless steel rod 17 is the complementary angle of the required angle, and then the angle adjusting ruler is kept horizontal.

[0052] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can understand the transformation or replacement within the technical range disclosed by the present application, which should be covered in the inclusive scope of the present application.

[0053] In the embodiment 1:

[0054] When the target strength of the sound wave vertically incident from the back of the fish body is needed to be tested, the fish body is hung on the shore first, the main axis of the fish body is parallel to the stainless steel rod 17, and then the fish body is adjusted to the target water depth by the lifting system, and the angle between the 90 degree scale line of the angle ruler and the fourth steel pipe 6 is 0 degree.

[0055] When the target strength of the sound wave and the main axis of the fish body is needed to be tested at an angle of 70 degrees, the fish body is hung on the shore first, the main axis of the fish body is parallel to the stainless steel rod 17, and then the fish body is adjusted to the target water depth by the lifting system, and the angle between the 90 degree scale line of the angle ruler and the fourth steel pipe 6 is 20 degrees.

[0056] When the target intensity of the angle between the sound wave and the main axis of the fish head side is 45 degrees, first, the fish body is hung on the shore, and the angle between the main axis of the fish head side and the stainless steel rod 17 is 45 degrees. Then, the fish body is adjusted to the target water depth through the lifting system, and the angle between the 90-degree scale line of the angle ruler 90 and the fourth steel pipe 6 is 45 degrees.

Claims

1. A test apparatus for testing the strength of fish targets using a suspension control method, comprising a net cage (1), characterized in that, Inside the net cage (1), from top to bottom, a winding wheel (11), an angle adjustment ruler, a transducer (15), a fish suspension system, and an underwater video monitoring system are arranged in sequence. The two equal-length first fishing lines (16) output by the winding wheel (11) are connected to the stainless steel rod (17) at the upper end of the fish suspension system after passing through the threading hole (13) on the angle adjustment ruler. The lifting system consists of a winding wheel (11) and two first fishing lines (16) of equal length. The first fishing lines (16) are connected to the winding wheel (11) and the stainless steel rods (17) at the upper and lower ends of the fish suspension system, respectively. The winding wheel (11) is fixed to the top of the fourth steel pipe (6); The fourth steel pipe (6) is connected to the first steel pipe (2) via the fourth fastener (10); The first steel pipe (2) is connected to the wire mesh cage (1) by the first fastener (7); The fish suspension system consists of two parallel stainless steel rods (17), a line tensioner (19), a plumb bob (21), a first fishing line (16), and a second fishing line (18) connected in sequence. The two equal-length first fishing lines (16) are connected to the two ends of the upper and lower stainless steel rods (17), and the fish is connected to the line tensioner (19) through the second fishing line (18). The angle adjustment ruler is composed of a stainless steel strip (4) and an angle ruler (12). The stainless steel strip (4) has wire holes (13) at both ends. There is a round hole at the center of the symmetry of the two wire holes (13). The fastening screw (14) passes through the round hole to connect the angle adjustment ruler to the fourth steel pipe (6). The two equal-length first fishing lines (16) in the lifting system ensure that the stainless steel strip (4) in the angle adjustment ruler and the stainless steel rod (17) in the fish suspension system are always parallel. The angle between the incident sound wave and the fish body is controlled and adjusted at the remote end. The first fishing line (16) and the second fishing line (18) are made of nylon or polyethylene fiber.

2. The test apparatus for testing the strength of fish targets using the suspension control method according to claim 1, characterized in that: The angle ruler (12) is aligned with the lower edge of the stainless steel strip (4), and the center of symmetry of the two threading holes (13) is aligned with the zero-degree center of the angle ruler (12). The angle ruler (12) and the stainless steel strip (4) are welded together. The stainless steel strip (4) has threading holes (13) at both ends, and the two first fishing lines (16) pass through the threading holes (13).

3. The test apparatus for testing the strength of fish targets using the suspension control method according to claim 1, characterized in that: The top of the plumb bob (21) is a ring, and the first fishing line (16) tied to both ends of the stainless steel rod (17) below passes through the ring.

4. The test apparatus for testing the strength of fish targets using the suspension control method according to claim 1, characterized in that: The underwater video monitoring system consists of a second steel pipe (3), a third steel pipe (5) and an underwater camera (20). The camera (20) is fixed to the bottom of the third steel pipe (5). The second steel pipe (3) and the third steel pipe (5) are connected by a third fastener (9). The second steel pipe (3) and the net cage (1) are connected by a second fastener (8).

5. The test apparatus for testing the strength of fish targets using the suspension control method according to claim 1, characterized in that: The upper edge of the cage (1) is connected to the first steel pipe (2) via the first fastener (7); the fourth steel pipe (6) is vertically downward and is connected to the first steel pipe 2 via the fourth fastener (10); the lower part of the fourth steel pipe (6) is connected to the transducer (15).

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