Apparatus and method for testing light-avoidance behavior of fish

Abstract

This invention provides an experimental apparatus and method for testing the light avoidance behavior of fish. The experimental tank includes an outlet area, a testing area, and a drainage area. The outlet area contains multiple outlet pipes, and multiple drainage gates connect the outlet area and the testing area. The testing area contains a first experimental frame and a second experimental frame. Each of the first and second experimental frames has a fish-blocking net on one side, and multiple second fish lights on the other side. The second fish lights are mounted on a drive frame, which controls their movement within the testing area. The fish are kept within the testing area and monitored using monitoring equipment. Through this experimental apparatus and method, the light avoidance behavior of fish can be observed and recorded. This helps in studying the behavioral responses of fish and understanding their sensitivity to light and the mechanisms of their light-avoidance behavior.

Description

Technical Field

[0001] This invention relates to the field of fish experiments, and in particular to an experimental apparatus and method for testing the light avoidance behavior of fish. Background Technology

[0002] Light-induced fish repellency is considered a potential harmless directional guidance technology for fish, and has proven promising in assisting fish to cross dams. Specifically, it can be applied to fishway entrances, fish bypass systems, and downstream channels to attract or induce fish schools. In habitat restoration, this technology can be used to create a more suitable light environment for fish survival, improving the utilization rate of fish habitats and the suitability of the environment. Therefore, a thorough understanding of the behavioral responses of target fish to light environments is extremely important. Among reports on fish repellency technology and light environment creation, the phototaxis behavior of fish has received more attention due to its practical value in engineering. Fish phototaxis refers to the characteristic of fish's directional movement in response to light stimuli. Phototaxis behavior can be further divided into positive phototaxis and negative phototaxis based on the degree of fish preference and avoidance. In addition to the light environment, water flow is considered the dominant factor influencing fish behavior in natural rivers, stimulating the lateral line of fish and causing corresponding behavioral responses and swimming patterns. Current experimental devices for studying fish responses to light suffer from drawbacks such as limited functionality, low efficiency, and inability to perform multi-factor coupling analysis. Summary of the Invention

[0003] The main objective of this invention is to provide an experimental apparatus and method for testing the light avoidance behavior of fish, thereby solving the problems of single function, low efficiency, and inability to perform multi-factor coupling analysis in the experimental apparatus for studying the reaction of fish to light.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an experimental device for testing the light avoidance behavior of fish, wherein the experimental pool is provided with an outlet area, a test area and a drainage area, the outlet area is provided with multiple outlet pipes, and multiple drainage gates are provided between the outlet area and the test area.

[0005] The test area is equipped with a first test rack and a second test rack. Each of the first and second test racks has a fish-blocking net on one side and multiple second fish lights on the other side. The second fish lights are mounted on a drive frame, which controls the movement of the second fish lights within the test area.

[0006] In the preferred embodiment, multiple spotlights are installed on both sides of the test area, with the spotlights pointing towards the bottom of the test area;

[0007] The spotlight has a rectangular structure, and the light emitted by the spotlight is also rectangular in shape.

[0008] In the preferred embodiment, horizontal frames are provided on both sides of the test area, and multiple spotlights are set on the horizontal frames. The two ends of the horizontal frames are slidably connected to the top guardrails of the first and second test frames, and the spotlights are slidably connected to the horizontal frames through two sliding shafts.

[0009] In the preferred embodiment, the upper ends of the two sliding shafts are connected by a lifting plate, and an electric push rod is provided between the lifting plate and the transverse frame. The electric push rod controls the up and down movement of the spotlight.

[0010] In the preferred embodiment, at least one vertically arranged reinforcing rod is provided in the middle of the horizontal frame, and a roller is provided at the lower end of the reinforcing rod, with the roller resting against the bottom of the test area.

[0011] In the preferred embodiment, a light-shielding canopy is also provided on the top of the experimental pool, which covers the entire test area, and multiple motorized light-shielding curtains are provided around the canopy.

[0012] After the motorized blackout curtain is lowered, it covers the entire test area.

[0013] In the preferred embodiment, the interior of each shaded shed is equipped with multiple first fish lights and multiple first cameras.

[0014] In the preferred embodiment, the drive frame is disposed on one side of the experimental frame. The drive frame includes a first sliding plate, which is laterally slidably connected to the experimental frame. A second motor on the first sliding plate is provided with a gear, which meshes with a second rack on the experimental frame.

[0015] The first sliding plate is provided with a second sliding plate that slides up and down, and the first motor on the second sliding plate meshes with the first rack on the side of the first sliding plate through a gear.

[0016] The second sliding plate is equipped with a mounting rod, and the second fish light is located at the lower end of the mounting rod.

[0017] Both the first and second experimental racks are equipped with at least two drive racks.

[0018] In the preferred embodiment, the bottom of the test area is an observation glass, and multiple second cameras are installed inside the observation slot at the bottom of the observation glass;

[0019] The water outlet area is equipped with multiple guide columns, and the water outlet pipe is located between two guide columns, with the lower end of the water outlet pipe near the bottom of the guide column;

[0020] An electric valve is installed on the outlet pipe. The drainage area is connected to the filtration system through the drain pipe. The filtration system is connected to the outlet pipe to form a circulating water supply.

[0021] The method includes:

[0022] S1. Prepare 200-400 fish for the experiment, with an average body length of 12-13cm and an average weight of 35-38g. The water level inside the experimental tank should reach the preset level. Slowly open the drainage gate in the drainage area and control the water flow speed at 0.1-0.2m / s. Place 40-50 fish in the test area. Put 40-50 fish in each experiment and conduct four experiments in total. A total of 200 fish will be used for the experiment.

[0023] S2. Control the electric light-blocking curtain of the light-blocking canopy. The electric light-blocking curtain covers the entire test area to ensure that the test area is in a dark state. The darkness is maintained for 40-50 minutes. The test flow rate is 0.1-0.2 m / s. Turn on the first and second cameras. Both the first and second cameras have infrared camera functions.

[0024] S3. Second fish lights are installed on the drive frames of the first and second experimental racks. Second fish lights are also installed in the four corners of the test area. The illumination of the second fish lights is different. The illumination of the four second fish lights is between 20-300 lx.

[0025] S4. Every 20-30 seconds, the distribution of the experimental fish in the four second fish lights in the test area is counted, and the illuminance of the second fish lights in the area is recorded.

[0026] S5. The distribution of fish at each location in the test area is statistically analyzed using the infrared imaging functions of the first and second cameras. The recorded data is used to describe the experimental fish's selection of light environment, tidal tendency and overall preference under different working conditions.

[0027] The expected light intensity value F is used as an index to represent the average selection of illuminance by the experimental fish under different working conditions. The formula is as follows:

[0028] F=∫0 n I(x)D(x)dx

[0029] In the formula: x is the distance from the experimental fish to the light source; I(x) is the light attenuation function; D(x) is the probability distribution function of the experimental group fish along the length direction of the test area (102);

[0030] To eliminate the influence of the baseline value of free swimming in the experimental tank, the environmental preference index P was used to represent the true preference of the grass carp in the experimental group for different locations in the experimental area. The distribution probability function was used to represent the intensity of preference for this area, and its formula is as follows:

[0031]

[0032] In the formula: C(x) is the probability distribution function of the experimental fish in the control group along the experimental area; P>0 indicates preference, P=0 indicates no preference, P<0 indicates avoidance, the absolute value of P indicates the strength of preference for the area, record the illuminance value K of the light source that the fish flees from in the opposite direction, and record the illuminance value M of the light source that the fish attracts.

[0033] S6. In step S1, the remaining 200 experimental fish are subjected to light channel testing. Repeat steps S1-S2 above. Push the horizontal frames on both sides of the test area. The horizontal frames on both sides are close together to form a narrow channel. Control the electric push rod to make the spotlight penetrate into the water. Adjust the light source illuminance of the spotlight to the light source illuminance K obtained in step S5 above, which is the light source illuminance that moves away from the fish. Control the second fish light to reach the front end of the horizontal frame through the drive frame.

[0034] S7. Spotlights form a light wall underwater. 40-50 fish are placed between the light channels. The second fish light is turned on. The water flow speed is measured by a flow meter to observe whether the fish swim between the two spotlights.

[0035] S8. Turn on the second fish light. The illuminance value of the second fish light is M. The second fish light starts to attract fish. Observe whether the fish swim towards the second fish light in the channel between the two spotlights. Observe the swimming direction of the fish according to different flow rates.

[0036] The experiment data recorded whether fish could not pass through the spotlight wall and whether fish swam between the spotlight channels.

[0037] This invention provides an experimental apparatus and method for testing the light-avoidance behavior of fish. It employs a zoned approach to achieve different water flow velocities in different environments, with partitions in the drainage zone creating different water outlet patterns. This allows the water flow in various locations within the test area to simulate a river channel, keeping the fish confined within the test area. Monitoring equipment is used to monitor the fish population within the test area. Through this experimental apparatus and method, the light-avoidance behavior of fish can be observed and recorded. This helps in studying the behavioral responses of fish and understanding their sensitivity to light and the mechanisms of their light-avoidance behavior. Attached Figure Description

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0039] Figure 1 This is a left-side view of the overall structure of the experimental cell of the present invention;

[0040] Figure 2 This is a view of the overall structure of the experimental cell on the right side of the present invention;

[0041] Figure 3 This is a structural diagram showing the distribution of the water outlet test area and the drainage area of ​​this invention;

[0042] Figure 4 This is a front sectional view of the present invention;

[0043] Figure 5 This is a structural diagram of the internal structure of the shading canopy of the present invention;

[0044] Figure 6 This is a diagram of the internal structure of the drive frame of the present invention;

[0045] Figure 7 This is a diagram of the spotlight installation structure of the present invention;

[0046] Figure 8 This is a diagram of the walkway structure illuminated by the spotlight of the present invention.

[0047] In the diagram: Experimental pool 1; Outlet area 101; Test area 102; Drainage area 103; Walkway 2; Shading canopy 3; First camera 301; First fish light 302; Electric shading curtain 4; Guide pipe 5; Outlet pipe 6; Electric valve 601; Observation trough 7; Drainage pipe 8; Drainage gate 9; Fish barrier net 10; First experimental frame 11; Spotlight 12; Observation glass 13; Second fish light 14; Drive frame 15; First sliding plate 1501; First rack 1502; First motor 1503; Second sliding plate 1504; Second motor 1505; Mounting rod 1506; Gear 1507; Second rack 1508; Second experimental frame 16; Second camera 17; Horizontal frame 18; Lifting plate 19; Electric push rod 20; Sliding shaft 21; Reinforcing rod 22. Detailed Implementation

[0048] Example 1

[0049] like Figures 1-8 As shown, an experimental apparatus for testing the light avoidance behavior of fish is provided. The experimental pool 1 is provided with an outlet area 101, a test area 102 and a drainage area 103. The outlet area 101 is provided with multiple outlet pipes 6, and multiple drainage gates 9 are provided between the outlet area 101 and the test area 102. The water flow speed in different environments is achieved by using a partition method. The partitions 105 of the drainage area 103 form different water outlet modes, so that the water flow in various positions of the test area 102 forms a simulated river channel, thereby controlling the fish in the test area 102. The fish in the test area 102 are monitored by monitoring equipment.

[0050] The test area 102 is equipped with a first experimental frame 11 and a second experimental frame 16. Each of the first and second experimental frames 11 and 16 has a fish-blocking net panel 10 on one side and multiple second fish lights 14 on the other side. The second fish lights 14 are mounted on a drive frame 15, which controls their movement within the test area 102. The fish-blocking net panels 10 of the first and second experimental frames 11 and 16 enclose the fish within the test area 102. By controlling the movement of the second fish lights 14 within the test area 102, it is possible to test whether the fish follow the fish lights as they move.

[0051] In the preferred embodiment, multiple spotlights 12 are provided on both sides of the test area 102, with the spotlights 12 facing the bottom of the test area 102; this is mainly to form a spotlight walkway, such as... Figure 8 As shown.

[0052] Spotlight 12 has a rectangular structure, and the light emitted by spotlight 12 is also rectangular. The rectangular shape of the light emitted by spotlight 12 is primarily for creating a spotlight walkway, such as... Figure 8 As shown.

[0053] In the preferred embodiment, horizontal frames 18 are provided on both sides of the test area 102, and multiple spotlights 12 are mounted on the horizontal frames 18. The two ends of the horizontal frames 18 are slidably connected to the top guardrails of the first test frame 11 and the second test frame 16. The spotlights 12 are slidably connected to the horizontal frames 18 via two sliding shafts 21. The horizontal frames 18 are used to install the spotlights 12, and the distance between the spotlights 12 on both sides can be adjusted.

[0054] In the preferred embodiment, the upper ends of the two sliding shafts 21 are connected by a lifting plate 19. An electric push rod 20 is provided between the lifting plate 19 and the transverse frame 18. The electric push rod 20 controls the up and down movement of the spotlight 12. The electric push rod 20 adjusts the height of the spotlight 12 in the water.

[0055] In the preferred embodiment, the transverse frame 18 is further provided with at least one vertically arranged reinforcing rod 22 in the middle, and the lower end of the reinforcing rod 22 is provided with a roller, which abuts against the bottom of the test area 102. The reinforcing rod 22 ensures the support strength of the middle part of the transverse frame 18.

[0056] In the preferred embodiment, the top of the experimental pool 1 is also equipped with a light-shielding canopy 3, which covers the entire test area 102. Multiple motorized light-shielding curtains 4 are arranged around the perimeter of the light-shielding canopy 3. When the motorized light-shielding curtains 4 are lowered, they cover the entire test area 102. The motorized light-shielding curtains 4 of the light-shielding canopy 3 are used to cover the entire test area 102, making the test area 102 dark.

[0057] In the preferred embodiment, the shaded enclosure 3 is equipped with multiple first fish lights 302, and also with multiple first cameras 301. The first fish lights 302 enable the experimental method of opening fish passages on the shore.

[0058] In the preferred embodiment, the drive frame 15 is disposed on one side of the experimental frame. The drive frame 15 includes a first sliding plate 1501, which is laterally slidably connected to the experimental frame. A second motor 1505 on the first sliding plate 1501 is equipped with a gear 1507, which meshes with a second rack 1508 on the experimental frame. A second sliding plate 1504 is disposed on the first sliding plate 1501, which slides up and down. A first motor 1503 on the second sliding plate 1504 meshes with a first rack 1502 on the side of the first sliding plate 1501 via a gear. A mounting rod 1506 is disposed on the second sliding plate 1504, and a second fish light 14 is disposed at the lower end of the mounting rod 1506. At least two drive frames 15 are disposed on both the first experimental frame 11 and the second experimental frame 16. The drive frames 15 drive the fish lights to move within the test area 102.

[0059] In the preferred embodiment, the bottom of the test area 102 is an observation glass 13, and the observation groove 7 at the bottom of the observation glass 13 is equipped with multiple second cameras 17; the observation glass 13 observes the bottom of the test area 102.

[0060] The water outlet area 101 is equipped with multiple guide columns 5, and the water outlet pipe 6 is located between two guide columns 5, with the lower end of the water outlet pipe 6 close to the bottom of the guide column 5; the guide columns 5 make the water outlet more stable.

[0061] An electric valve 601 is installed on the outlet pipe 6. The drainage area 103 is connected to the filtration system through the drain pipe 8. The filtration system and the outlet pipe 6 are connected to form a circulating water supply. The circulating water supply ensures the continuity of water supply and saves water resources.

[0062] Example 2

[0063] Further explanation in conjunction with Example 1, such as Figure 1-8 The structure shown is used to prepare 200-400 fish for the experiment, with an average body length of 12-13cm and an average weight of 35-38g. The water level inside the experimental pool 1 reaches the preset horizontal line. The drainage gate 9 of the drainage area 103 is slowly opened, and the water flow speed is controlled at 0.1-0.2m / s. 40-50 fish are placed in the test area 102. 40-50 fish are put in each experiment, and the experiment is repeated four times, with a total of 200 fish used in the experiment.

[0064] Before the experiment, the water temperature in the tank was checked to ensure it matched the holding water temperature, and the water depth was controlled at 0.1m. Five juvenile fish were then randomly selected from the holding tank and placed in the experimental area of ​​the tank for acclimatization. After 30 minutes of darkness acclimatization, the flow rate was adjusted according to the operating conditions, and the illuminance of the light source was uniformly increased to the experimental treatment value within 2 minutes. The infrared camera was then turned on, and the experiment officially began, with each group lasting 60 minutes. To avoid the influence of natural light, the experiment was conducted from 20:00 on the first day to 06:00 the next day. After the experiment, the acquired video data was processed and analyzed. The distribution of the experimental fish and their head orientation in the experimental area were recorded every 10 seconds, and the illuminance of the entire area was also recorded.

[0065] Control the electric light-blocking curtain 4 of the light-blocking canopy 3. The electric light-blocking curtain 4 covers the entire test area 102 to ensure that the test area 102 is in a dark state. The darkness is maintained for 40-50 minutes. The test flow rate is 0.1-0.2 m / s. Turn on the first camera 301 and the second camera 17. Both the first camera 301 and the second camera 17 have infrared camera functions.

[0066] Second fish lights 14 are installed on the drive frame 15 on the first experimental frame 11 and the second experimental frame 16. Second fish lights 14 are installed at the four corners of the test area 102. The illumination of the second fish lights 14 is different. The illumination of the four second fish lights 14 is between 20-300 lx.

[0067] The distribution of the experimental fish in the four second fish lights 14 in the test area 102 was statistically analyzed every 20-30 seconds, and the illuminance of the second fish lights 14 in the area was recorded.

[0068] The distribution of fish at 102 locations in the test area was statistically analyzed using the infrared imaging functions of the first camera 301 and the second camera 17. The recorded data was used to describe the experimental fish's selection of light environment, tidal tendency, and overall preference under different working conditions.

[0069] The expected light intensity value F is used as an index to represent the average selection of illuminance by the experimental fish under different working conditions. The formula is as follows:

[0070] F=∫0 n I(x)D(x)dx

[0071] In the formula: x is the distance from the experimental fish to the light source; I(x) is the light attenuation function; D(x) is the probability distribution function of the experimental group fish along the length direction of the test area (102).

[0072] To eliminate the influence of the baseline value of free swimming in the experimental tank, the environmental preference index P was used to represent the true preference of the grass carp in the experimental group for different locations in the experimental area. The distribution probability function was used to represent the intensity of preference for this area, and its formula is as follows:

[0073]

[0074] In the formula: C(x) is the probability distribution function of the experimental fish in the control group along the experimental area; P>0 indicates preference, P=0 indicates no preference, P<0 indicates avoidance, the absolute value of P indicates the strength of preference for the area, record the illuminance value K of the light source that the fish flees from, and record the illuminance value M of the light source that the fish attracts.

[0075] The phototactic behavior of the experimental fish was studied under different flow rates (0, 0.1, and 0.2 m / s) at an illuminance of 300 lx, with a dark, still water condition serving as a control group. The results showed that a flow rate of 0.2 m / s could fully stimulate the fish's tropism, causing them to swim in a direction mostly ±20° to the upstream direction. Based on the distribution of the fish within the tank under different flow rates and the decrease in illuminance, the expected light intensity values ​​for the fish under the three flow rate conditions were calculated. When the illuminance was 300 lx, the experimental fish in still water exhibited a distribution pattern of "high at both ends and low in the middle" in experimental pond 1, without showing any preference for a particular light intensity range. At low flow velocities below the sensing value, the distribution trend of grass carp juveniles was similar to that under still water conditions, but they were more concentrated further away from the light source, mostly exhibiting "backward movement against the current." When the flow velocity exceeded the sensing velocity, the fish's aggregation at the tail end decreased significantly due to the influence of tropism, and their distribution in the tank became more uniform, weakening the effect of the original light environment. This study preliminarily demonstrates that tropism induced by a small flow velocity slightly above the sensing value can influence the experimental fish's response to the light environment.

[0076] The experimental fish species selected were silver carp (Hypophthalmichthys nobilis) and common carp (Cyprinus carpio). The fish were sourced from artificially aquaculture ponds in the middle reaches of the Yangtze River. They were transported from the ponds to the Experimental Base for Aquatic Ecology and Biological Resources Research of the Ministry of Water Resources for temporary holding. Dissolved oxygen levels in the holding water were measured using a dissolved oxygen meter, and an oxygenation pump was used to maintain the dissolved oxygen level in the holding water at 7.0 mg / L.

[0077] The remaining experimental fish 200 were subjected to a light channel test. The above steps were repeated. The horizontal frames 18 on both sides of the test area 102 were pushed together to form a narrow channel. The electric push rod 20 was controlled to make the spotlight 12 penetrate into the water. The illuminance of the spotlight 12 was adjusted to the illuminance K of the light source that was away from the fish obtained in step S5 above. The second fish light 14 was controlled to reach the front end of the horizontal frame 18 through the drive frame 15.

[0078] Spotlight 12 forms a light wall underwater. 40-50 fish are placed between the light channels. The second fish light 14 is turned on. The water flow speed is measured by a flow meter to observe whether the fish swim between the two spotlights 12.

[0079] Turn on the second fish light 14. The illuminance value of the light source of the second fish light 14 is M. The second fish light 14 begins to attract fish. Observe whether the fish swim towards the second fish light 14 in the channel between the two spotlights 12. Observe the swimming direction of the fish according to different flow rates.

[0080] The experiment data recorded whether fish could not pass through the spotlight wall and whether fish swam between the spotlight channels.

[0081] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. An experimental apparatus for testing the light avoidance behavior of fish, characterized in that: the experiment... The pool (1) is equipped with an outlet area (101), a test area (102) and a drainage area (103). The outlet area (101) is equipped with multiple outlet pipes (6), and multiple drainage gates (9) are provided between the outlet area (101) and the test area (102). The test area (102) is equipped with a first experimental frame (11) and a second experimental frame (16). Each of the first experimental frame (11) and the second experimental frame (16) has a fish-blocking net plate (10) on one side. Each of the first experimental frame (11) and the second experimental frame (16) has multiple second fish lights (14) on the other side. The second fish lights (14) are mounted on a drive frame (15). The drive frame (15) controls the movement of the second fish lights (14) within the test area (102). Multiple spotlights (12) are provided on both sides of the test area (102), with the spotlights (12) facing the bottom of the test area (102); The spotlight (12) has a rectangular structure, and the light emitted by the spotlight (12) is a rectangular beam shape. The spotlight (12) forms a light wall underwater. The test area (102) is equipped with horizontal frames (18) on both sides, and multiple spotlights (12) are set on the horizontal frames (18). The two ends of the horizontal frames (18) are slidably connected to the top guardrails of the first test frame (11) and the second test frame (16). The spotlights (12) are slidably connected to the horizontal frames (18) through two sliding shafts (21). The upper ends of the two sliding shafts (21) are connected by a lifting plate (19). An electric push rod (20) is provided between the lifting plate (19) and the horizontal frame (18). The electric push rod (20) controls the spotlight (12) to move up and down. The top of the experimental pool (1) is also equipped with a light-blocking canopy (3), which covers the entire test area (102). Multiple electric light-blocking curtains (4) are installed around the light-blocking canopy (3). After the electric blackout curtain (4) is lowered, it covers the entire test area (102). The shading shed (3) is equipped with multiple first fish lights (302) and multiple first cameras (301) inside the shading shed (3). The bottom of the test area (102) is an observation glass (13), and the observation slot (7) at the bottom of the observation glass (13) is equipped with multiple second cameras (17). The water outlet area (101) is provided with multiple guide columns (5), and the water outlet pipe (6) is located between two guide columns (5), with the lower end of the water outlet pipe (6) close to the bottom of the guide column (5); An electric valve (601) is installed on the outlet pipe (6). The drainage area (103) is connected to the filtration system through the drain pipe (8). The filtration system is connected to the outlet pipe (6) to form a circulating water supply.

2. The experimental apparatus for testing the light avoidance behavior of fish according to claim 1, characterized in that: The horizontal frame (18) is also provided with at least one vertically arranged reinforcing rod (22) in the middle, and the lower end of the reinforcing rod (22) is provided with a roller, which abuts against the bottom of the test area (102).

3. The experimental apparatus for testing the light avoidance behavior of fish according to claim 1, characterized in that: The drive frame (15) is set on one side of the experimental frame. The drive frame (15) includes a first sliding plate (1501). The first sliding plate (1501) is laterally slidably connected to the experimental frame. The second motor (1505) on the first sliding plate (1501) is equipped with a gear (1507). The gear (1507) meshes with the second rack (1508) on the experimental frame. The first sliding plate (1501) is provided with a second sliding plate (1504) that slides up and down. The first motor (1503) on the second sliding plate (1504) meshes with the first rack (1502) on the side of the first sliding plate (1501) through gears. The second sliding plate (1504) is provided with a mounting rod (1506), and the second fish light (14) is located at the lower end of the mounting rod (1506); Both the first experimental frame (11) and the second experimental frame (16) are equipped with at least two drive frames (15).

4. The experimental method for testing the light avoidance behavior of fish according to any one of claims 1-3, characterized in that: The method includes: S1. Prepare 200-400 fish for the experiment, with an average body length of 12-13cm and an average weight of 35-38g. The water level inside the experimental pool (1) reaches the preset horizontal line. Slowly open the drainage gate (9) of the drainage area (103) and control the water flow speed at 0.1-0.2m / s. Place 40-50 fish in the test area (102). Put 40-50 fish in each experiment. The experiment is repeated four times. A total of 200 fish are used for the experiment. S2. Control the electric light-blocking curtain (4) of the light-blocking canopy (3). The electric light-blocking curtain (4) covers the entire test area (102) to ensure that the test area (102) is in a dark state. The darkness is maintained for 40-50 minutes. The test flow rate is 0.1-0.2 m / s. Turn on the first camera (301) and the second camera (17). Both the first camera (301) and the second camera (17) have infrared imaging functions. S3. The drive frame (15) on the first experimental frame (11) and the second experimental frame (16) are equipped with second fish lamps (14). The four corners of the test area (102) are equipped with second fish lamps (14). The illumination of the second fish lamps (14) is different. The illumination of the light source of the four second fish lamps (14) is between 20-300 lx. S4. Every 20-30 seconds, the distribution of the experimental fish in the four second fish lamps (14) in the test area (102) is counted, and the illuminance of the second fish lamps (14) in the area is recorded. S5. The distribution of fish in each location of the test area (102) is statistically analyzed using the infrared imaging function of the first camera (301) and the second camera (17). The recorded data is used to describe the experimental fish's selection of light environment, tidal behavior and overall preference under different working conditions. The expected light intensity value F is used as an index to represent the average selection of illuminance by the experimental fish under different working conditions. The formula is as follows: In the formula: x is the distance from the experimental fish to the light source; I(x) is the light attenuation function; D(x) is the probability distribution function of the experimental group fish along the length direction of the test area (102); To eliminate the influence of the fish's baseline swimming performance in the experimental tank, the environmental preference index P was used to represent the true preference of the experimental group fish for different locations in the experimental area. A probability distribution function was used to represent the intensity of this preference, and its formula is as follows: In the formula: C(x) is the probability distribution function of the experimental fish in the control group along the length of the experimental area; P>0 indicates preference, P=0 indicates no preference, P<0 indicates avoidance, the absolute value of P indicates the strength of preference for the area, record the illuminance value K of the light source that the fish flees from, and record the illuminance value M of the light source that the fish attracts. S6. In step S1, the remaining experimental fish are subjected to light channel testing. Repeat steps S1-S2 above. Push the horizontal frames (18) on both sides of the test area (102). The horizontal frames (18) on both sides approach each other to form a narrow channel. Control the electric push rod (20) to make the spotlight (12) penetrate into the water. Adjust the light source illuminance of the spotlight (12) to the light source illuminance K of the fish obtained in step S5 above. Control the second fish light (14) to reach the front end of the horizontal frame (18) through the drive frame (15). S7. The spotlights (12) form a light wall underwater. 40-50 fish are placed between the light channels. The second fish light (14) is turned on. The water flow speed is tested by the flow meter. It is observed whether the fish swim between the two spotlights (12). S8. Turn on the second fish lamp (14). The illuminance value of the second fish lamp (14) is M. The second fish lamp (14) starts to attract fish. Observe whether the fish swim towards the second fish lamp (14) in the channel between the two spotlights (12). Observe the swimming direction of the fish according to different flow rates. Record whether the fish cannot pass through the light-illuminated wall according to the experimental data, and also record whether the fish swim between the light channels.

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