A device for conducting fish taxis experiments

Abstract

The application relates to a device for carrying out fish tropism experiment, belonging to fish behavior research in fishway engineering, and comprising the following contents: a water tank experiment part, a water tank control part and a camera recording device; the water tank experiment part comprises branch water tanks and a ring-shaped central pool, and the branch water tanks are arranged in axial symmetry around the ring-shaped central pool; the water tank control part comprises a water inlet pipe, a water stabilizing weir, a tail door, a water outlet pipe, a water return tank, a water return pump, a water inlet pipe, an overflow tank and a water supply pipe; and the camera recording device comprises a top camera and a normal calibration grid; the device has the beneficial effects that one-way physiological stimulation can be separated to stimulate fish, behavior response of the fish under various stimulation conditions can be analyzed, various stimulations can be provided to the fish uniformly or separately, and tropism preference of the fish can be analyzed.

Description

Technical Field

[0001] This invention relates to an apparatus for conducting fish tropism experiments, specifically an apparatus for analyzing fish responses to different physiological stimuli by placing fish in environments with different tropism characteristics, belonging to the field of fish behavior research in fishway engineering. Background Technology

[0002] In fish, tropism refers to the directional behavioral response of an animal to a unidirectional environmental stimulus. Examples include fish's phototaxis (positive phototaxis) or aversion to light (negative phototaxis), tidal behavior, target stability, and attraction or avoidance of odors or highly oxygenated water. Tropicism is a type of stereotyped behavior and is the simplest form of instinctive behavior. While foraging behavior in fish is also a directional behavioral response, its complex nature involves a significant amount of learned behavior and is therefore not considered tropism.

[0003] CN114223583A discloses an interactive experimental method and detection system for simultaneously testing the phototaxis and mesotropism of fish. The method includes the following steps: water is introduced into two test channels and then flows into a confluence zone; fish with PIT tags implanted in the confluence zone are guided to swim towards the test channels; different light sources are placed on the upper part of the test channels; induction antenna coils are arranged at both ends of the channels; the fish are placed in the confluence zone; then, in a dark environment, the light sources are turned on to create water flow; the time of processing the PIT signal generated by the same PIT tag is recorded; the proportion of the fish's residence time in each test channel is recorded; then the light sources are swapped, and the above steps are repeated. Data on the phototaxis and mesotropism of different fish species can be analyzed.

[0004] CN205848361U discloses an experimental apparatus for studying the phototaxis of fish. The apparatus includes a water tank divided into two channels by a baffle. Multiple underwater illuminometers are arranged at equal intervals at the bottom of one channel, while the other channel serves as a fish passageway. A light source is located on the left end of the water tank. All inner walls of the water tank, except those near the light source, are covered with black cloth. Marking strips are evenly spaced on the bottom of the water tank. Multiple support frames are arranged along the side of the water tank in the direction of fish passage. An infrared camera is fixedly mounted at the end of the horizontal arm of each support frame, positioned directly above the water tank. This apparatus enables the study of the phototaxis of fish. Based on the preferences of different fish for different light colors and their optimal light intensity ranges, it can provide valuable references for technologies such as light-induced fish attraction and safe fish passage through dams.

[0005] CN206895569U Fish Phototaxis Measurement Device discloses a fish phototaxis measurement device, including an experimental water tank (1), characterized in that: a baffle (2) is movably inserted into one end of the experimental water tank (1), the baffle (2) divides the experimental water tank (1) into a temporary storage chamber (3) and a measurement chamber (4), a plurality of parallel dividing lines (5) are drawn on the bottom of the measurement chamber (4), an plexiglass plate (6) is provided at one end of the measurement chamber (4), a cylindrical light shield (7) is connected to the plexiglass plate (6), the other end of the light shield (7) is connected to a lampshade (8), a light source (9) is provided inside the lampshade (8), the light source (9) is connected to a power supply through a dimming switch (10), a camera (11) is provided above the experimental water tank (1), and all parts of the experimental water tank (1) except for the plexiglass plate (6) are black, and the baffle (2) is also black.

[0006] CN210157860U discloses an aquarium for testing fish phototaxis. This utility model relates to the field of aquarium technology, comprising a feeding tank, a transition tank, and a living tank connected in sequence. The feeding tank and living tank are filled with water, while the transition tank is dry. The feeding tank and living tank are connected by a transition tube inside the transition tank. The front and rear sides of the transition tank and its connection with the living tank are opaque. A feed box is located inside the feeding tank, at the opening of the transition tube within the feeding tank. The upper end of the feed box is fixed to the top of the feeding tank by a bracket, and the feed box has holes that match the feed. This device provides two independent spaces for observing organisms, connected by a passageway. The brightness of light in one space does not affect the illuminance of the other, thus enabling indoor observation of fish phototaxis. This allows researchers and science educators to conduct safe, time- and location-independent teaching and research on fish phototaxis, unrestricted by natural environment or time constraints.

[0007] The above-mentioned prior art is the closest to this application. In summary, the above prior art all share two common shortcomings:

[0008] The above devices cannot accurately determine the relationship between fish behavior and different unidirectional physiological stimuli, especially when multiple physiological stimuli act together, it is impossible to determine which stimulus has the greatest impact on the fish.

[0009] Providing fish with multiple stimuli, either in a unified manner or separately, to analyze their tropism and preference has been a problem that researchers in this field have been trying to solve. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a device that can separately provide different tropism effects to fish, thus providing an experimental device for determining fish tropism.

[0011] The aforementioned experimental device for determining fish tropism includes: a water tank experimental section, a water tank control section, and a video recording device;

[0012] The above-mentioned water tank experiment includes: branch water tanks and an annular central pool, with the branch water tanks arranged symmetrically around the annular central pool.

[0013] The aforementioned water tank control system includes: inlet pipe, stabilizing weir, tailgate, drain pipe, return water tank, upper reservoir, return water pump, water supply pipe, overflow tank, and water supply pipe.

[0014] There are four branch water channels, arranged in a cross shape, spaced 90° apart from each other. The four branch water channels point to the east, south, west, and north respectively. Each branch water channel is connected to an inlet pipe and a water stabilizing weir at the beginning and a tail gate at the end, with the tail gate connected to the annular central pool at the end.

[0015] At the end of the aforementioned branch water channel, after the branch water channel enters the annular central pool, the lengths of the two side walls of the water channel are unequal. One side wall is directly connected to the annular pool, while the other side wall extends into the annular pool and approaches the central guide gate near the annular central pool. The distance between the two is equal to three times the body width of the fish. The aforementioned central guide gate is a cylindrical surface, which is composed of multiple adjustable-angle rotating blades.

[0016] The bottom of the circular central pool is connected to a drain pipe, which is connected to a return water tank. The end of the return water tank is connected to a return water pump, which is connected to an upper water pipe. The upper water pipe is connected to an upper reservoir. An overflow tank is installed in the upper reservoir. The upper reservoir is connected to a water supply pipe. The overflow portion of the overflow tank is connected to a return water pipe, which is connected to the return water tank. The water supply pipe is connected to an inlet water pipe.

[0017] A valve is installed on the water inlet pipe to control the flow rate.

[0018] The aforementioned video recording device includes: a top camera and an orthogonal calibration grid;

[0019] Before conducting the experiment, the orthogonal calibration grid was placed in the water tank experimental section, and the top camera was used to take pictures to calibrate the position of the water tank plane corresponding to the camera image.

[0020] During the experiment, the return water tank is filled with water, the return water pump is turned on, and the water in the return water tank is pumped into the upper reservoir. When the water level is too high, the water overflows through the overflow tank and enters the return water pipe, returning to the return water tank. The water that does not overflow enters the inlet pipe through the supply pipe, enters the stabilizing weir through the valve, then flows through the branch water tank and the tail gate, enters the annular central pool, flows into the drain pipe, and then enters the return water tank to complete the entire process.

[0021] When water bodies require aeration, aeration devices are installed in the upper reservoir.

[0022] When the water body needs to regulate its temperature, a temperature control device is installed in the upper reservoir.

[0023] The experimental subjects were placed in the water tank experimental section, and the external environment was adjusted to generate stimulation. The movement process of the experimental subjects was recorded by a camera on the top.

[0024] 1. This invention provides a tank device capable of conducting fish tropism experiments, which can separate unidirectional physiological stimuli to stimulate fish and analyze the behavioral responses of fish under multiple stimulus conditions;

[0025] 2. Provide multiple stimuli to fish, either in a unified manner or separately, and then analyze the fish's tropism and preference.

[0026] 3. The design method of multiple branch water tanks surrounding the annular central pool of the device of the present invention can adjust the relationship between Coriolis force and centrifugal force in the bend by changing the drainage angle of the branch water tanks and the opening angle of the central guide gate. This can fully simulate the external force situation of fish in different bend environments, so that the device can eliminate or enhance potential fluid external force stimulation when stimulating the environment. Attached Figure Description

[0027] Figure 1 A schematic diagram of an experimental device for determining fish tropism according to the present invention;

[0028] Figure 2 A schematic diagram of a modified branch tank experimental device for determining fish tropism, according to the present invention, is shown in the figure below;

[0029] Figure 3 A schematic diagram of the phototaxis experimental apparatus of the present invention after being covered by a light-shielding cloth.

[0030] Figure 4 This invention Figure 1 A top view schematic diagram of an experimental device for determining fish tropism;

[0031] Figure 5 This invention Figure 4 A partially enlarged schematic diagram of the annular central pool of an experimental device for determining fish tropism;

[0032] Figure 6 A three-dimensional schematic diagram of an experimental device for determining fish tropism according to the present invention;

[0033] Figure 7 Schematic diagram of the underwater lighting arrangement in the phototaxis experiment tank;

[0034] Figure 8 A partial schematic diagram of the central guide gate of the annular central pool of the present invention.

[0035] Branch water tank 1, circular central pool 2, central guide gate 3, inlet pipe 4, water stabilizing weir 5, tail gate 6, drain pipe 7, return water tank 8, upper reservoir 9, water pump 10, water pipe 11, overflow tank 12, water supply pipe 13, return water pipe 14, rotating blade 15, fish barrier net 16. Detailed Implementation

[0036] The present invention will now be further described with reference to the accompanying drawings. Example

[0037] Water flow tropism experiment: A reservoir project mainly consists of water-retaining structures and spillway structures, with a dam height of 70m. Fish passage facilities are planned for its construction. In order to maintain ecological characteristics as much as possible and to provide a continuous and uninterrupted passageway for upstream migratory fish, the fish passage targets are *Schizothorax longibrachiatus* and *Schizothorax rubiginosa*, collectively referred to as *Schizothorax* in this embodiment.

[0038] An experimental device for determining fish tropism includes: a water tank experimental part, a water tank control part, and a video recording device;

[0039] The above-mentioned water tank experiment includes: branch water tank 1, annular central pool 2, central guide gate 3, rotating blade 15, and fish barrier net 16. The branch water tank 1 is arranged symmetrically around the annular central pool 2.

[0040] The above-mentioned water tank control section includes: inlet pipe 4, water stabilizing weir 5, tail gate 6, drain pipe 7, return water tank 8, upper reservoir 9, return water pump 10, water supply pipe 11, overflow tank 12, water supply pipe 13.

[0041] There are four branch water channels 1, arranged in a cross shape, spaced 90° apart from each other. The four branch water channels 1 point to the east, south, west and north respectively. Each branch water channel 1 is connected to an inlet pipe 4 and a water stabilizing weir 5 at the beginning and a tail gate 6 at the end. The end of the tail gate is connected to the ring-shaped central pool 2.

[0042] The bottom of the annular central pool is connected to the drain pipe 7, the drain pipe 7 is connected to the return water tank, the end of the return water tank 8 is connected to the return water pump 10, the return water pump 10 is connected to the water supply pipe 11, the water supply pipe 11 is connected to the upper reservoir 9, the upper reservoir 9 is installed with an overflow tank, the upper reservoir 9 is connected to the water supply pipe 13, the overflow part of the overflow tank 12 is connected to the return water pipe 14, the return water pipe 14 is connected to the return water tank 8, the water supply pipe 13 is connected to the inlet pipe 4;

[0043] A valve is installed on water inlet pipe 4 to control the flow rate.

[0044] The aforementioned video recording device includes: a top camera C1 and an orthogonal calibration grid; the orthogonal calibration grid is a white background with black square grids drawn on it, and the side length of each grid is 2~5cm;

[0045] Before conducting the experiment, the orthogonal calibration grid was placed in the water tank experimental section, and the top camera C1 was used to take pictures to calibrate the position of the water tank plane corresponding to the camera image.

[0046] When conducting the experiment, the return water tank 8 is filled with water, and the return water pump 10 is turned on. The water in the return water tank 8 is pumped into the upper reservoir 9. When the water level is too high, the water overflows through the overflow tank 12 and enters the return water pipe 14, returning to the return water tank 8. The water that does not overflow enters the inlet pipe 4 through the supply pipe 13, enters the stabilizing weir 5 through the valve, and then flows through the branch water tank 1, the tail gate 5, and enters the annular central pool 2. It then flows into the drain pipe 7 through the central guide gate 3 and then enters the return water tank 8 to complete the entire process.

[0047] When water bodies require aeration, aeration devices are installed in the upper reservoir.

[0048] When the water body needs to regulate its temperature, a temperature control device is installed in the upper reservoir.

[0049] The experimental subjects were placed in the water tank experimental section, and the external environment was adjusted to generate stimulation. The movement process of the experimental subjects was recorded by the top camera C1.

[0050] At the start of the experiment, the fish were placed between the central guide gate 3 and the tail gate 6. Different flow velocities were released into the four branch tanks 1, and the angles of the vane 15 and tail gate 6 were adjusted to create a clockwise vortex at the drain pipe 7. When the fish swam upstream against the current, they initially swam to the left, but were deflected to the right by a Coriolis force, requiring them to expend more energy. They also tended to leave the circulation area as quickly as possible and enter one of the four branch tanks 1, with the following flow velocities: 1.0 m / s to the east, 0.8 m / s to the north, 0.6 m / s to the west, and 0.4 m / s to the south. The number of fish entering each branch tank was used to determine which flow velocity the fish preferred.

[0051] The following record table was obtained in this experiment, so it can be known that 0.6 m / s is the tactic velocity of the schizothorax 'Schizothorax'.

[0052] Table 1 Distribution of Experimental Subjects

[0053] Sink location East-facing branch water tank North-facing branch water tank Westward branch water tank South-facing branch water tank Flume flow rate 1.0m / s 0.8m / s 0.6m / s 0.4m / s Number of experimental subjects 2 tails 5 tails 12 tails 6 tails Example

[0054] Phototaxis experiment: One branch tank 1 of the device of the present invention was selected;

[0055] The full-spectrum light source L2 is arranged in a branch tank as follows: along the length of the two side walls, it is divided into a first section, a middle section, and a last section, with a segmented grid G1 set in the middle between the two sections; in the elevation direction, it is divided into three elevations, with the highest height being right below the water surface in the tank, the lowest height being 3 times the height of the fish, and the middle height being between the highest and lowest heights; the angle of each light source can be adjusted independently via a gimbal.

[0056] In this embodiment, the water level in the tank is 1m, the height of the fish (3 times the height of the fish) is 36cm, and the height of the middle section is 68cm.

[0057] The top of the experimental tank was covered with a completely opaque cloth NL1, and a top camera C1 was set up to capture the behavioral trajectory of the schizothorax; a dual camera group C2 was set up according to the focal length of the fish's eyes to capture changes in the light source.

[0058] Fill the experimental water tank with water using a water pump, maintaining the tank at full capacity. Then, stop the water pump, close all segmented grids G1, turn on all lights, maintaining the lowest possible brightness, and ensure all light illuminates the bottom of the first section. At this minimum brightness, the illuminance at the bottom of the first section of the experimental water tank is 2 × 10⁻⁶. -5 Lux; Place the experimental schizothorax in a fish container, place the fish container at the bottom of the first section of the experimental tank, open the hatch of the fish container, turn on the fish-attracting water pump, attract the fish into the first section of the experimental tank, turn off and remove the fish-attracting water pump and the fish container to allow the fish to fully adapt to the first section of the experimental tank; the fish-attracting water pump is an electric water-pushing propeller.

[0059] Using the top camera C1 to determine that the experimental fish have begun to relax, the segmented grid between the first and middle sections is opened, and the segmented grid between the middle and last sections is opened;

[0060] Adjust the light brightness in the following order to obtain the relationship between the fish's movement path and reaction time and the light brightness. The entire fish behavior path is recorded by the top camera C1:

[0061] (1) When the experimental subject begins to swim randomly within the first section, increase the brightness of the light on the right side of the middle section until the experimental subject fish begins to swim towards the light. Stop increasing the brightness and wait for the experimental subject to approach the light on the right side of the middle section.

[0062] (2) When the experimental subject begins to swim randomly at the right light in the middle section, turn up the brightness of the left light in the middle section until the experimental subject fish begins to swim towards the light, and wait for the experimental subject to approach the left light in the middle section.

[0063] (3) When the experimental subject begins to swim randomly at the left side of the middle section of the last section, turn up the brightness of the right side of the middle section of the last section until the experimental subject fish begins to swim towards the light, and wait for the experimental subject to approach the right side of the middle section of the last section.

[0064] (4) When the experimental subject begins to swim randomly at the right light in the middle of the last section, turn up the brightness of the left light in the middle section until the experimental subject fish begins to swim towards the light, and wait for the experimental subject to approach the left light in the middle section.

[0065] (5) When the experimental subject begins to swim randomly at the left side of the middle section light, turn up the brightness of the right side of the middle section light until the experimental subject fish begins to swim towards the light, and wait for the experimental subject to approach the right side of the middle section light.

[0066] (6) When the experimental subject begins to swim randomly at the right light in the middle of the first section, increase the brightness of the left light in the middle of the first section until the experimental subject fish begins to swim towards the light. Wait for the experimental subject to approach the left light in the middle of the first section. Repeat the above steps until the experimental subject no longer moves due to changes in light brightness or the light brightness reaches its maximum.

[0067] The full-spectrum light source was filtered using a [200,400]nm bandpass optical filter, and steps (1)-(6) were repeated.

[0068] The full-spectrum light source was filtered using a [390,770]nm bandpass optical filter, and steps (1)-(6) were repeated.

[0069] The full-spectrum light source was filtered using a [770, 1500] nm bandpass optical filter, and steps (1)-(6) were repeated.

[0070] The path of the experimental subjects during their movement was recorded using a top-mounted camera.

[0071] The aforementioned phototaxis experimental water tank, based on the phototaxis experimental device, adds a light adjustment system;

[0072] The aforementioned light adjustment system includes: a lighting adjustment system and a natural light adjustment system; the aforementioned lighting adjustment system includes: a surface lighting adjustment system and an underwater lighting adjustment system.

[0073] The above-mentioned underwater lighting adjustment system includes: a light shield NL1, a light shield bracket NL2, a filter plate NL3, a lamp holder L11, a lamp holder rail L12, a lamp L1, an underwater filter plate L13, and an underwater filter plate slot L14.

[0074] The aforementioned light shield NL1 encloses the entire water tank experimental section, with all sides completely sealed and an opening at the top for installing different light filters.

[0075] The lamp L1 is mounted on the lamp holder L11, the lamp holder L11 is mounted on the lamp holder guide rail L12, and the lamp holder guide rail L12 is laid along both sides of the branch water tank 1.

[0076] Preferably, the lamp L1 described above moves up and down along the lamp holder L11;

[0077] Preferably, there are multiple lamps L1, and their wavelength range covers [200, 1500] nm;

[0078] Preferably, the lamp L1 mentioned above is an angle-adjustable directional spotlight;

[0079] The aforementioned underwater lighting adjustment system includes: underwater light L2, and underwater light bracket;

[0080] The underwater light L2 mentioned above is an angle-adjustable directional spotlight. The underwater light bracket mentioned above is fixed on the side wall of the water tank experimental section. The underwater light L2 mentioned above is mounted on the underwater light bracket.

[0081] The aforementioned underwater lights L2 are arranged in the upper, middle and lower parts, respectively. The lower light is three times the height of the fish body from the bottom of the tank, the upper L2 is arranged below the water surface, and the middle L2 is arranged between the bottom and the upper part.

[0082] Table 2. Analysis of the range of light intensity and wavelength when fish are attracted.

[0083] time Behavior Light intensity (Lux) in the left eye Light intensity (Lux) in the right eye Wavelength range (nm) 00:02.5 Moving towards the light source 0.5 1 390-770 00:05.3 Moving towards the light source 0.9 12 390-770 00:06.2 Moving towards the light source 10 17 390-770 00:08.5 Moving towards the light source 16 2 390-770 00:10.6 Moving towards the light source 18 2 390-770 00:13.4 Moving towards the light source 19 6 390-770 00:23.1 Moving towards the light source 69 23 390-770 00:25.6 Moving towards the light source 36 65 390-770 00:31.6 Moving towards the light source 75 23 390-770 00:32.5 Moving towards the light source 42 96 390-770 00:35.3 Moving towards the light source 65 35 390-770 00:37.2 Moving towards the light source 78 42 390-770 00:39.2 Moving towards the light source 96 53 390-770 00:41.6 Moving towards the light source 53 62 390-770 00:42.6 Moving towards the light source 68 68 390-770 00:45.7 Moving towards the light source 94 72 390-770 00:46.8 Moving towards the light source 69 81 390-770 00:51.2 Moving towards the light source 110 93 390-770 00:53.4 Moving towards the light source 115 135 390-770 00:54.5 Moving towards the light source 126 165 390-770 00:55.6 Moving towards the light source 131 217 390-770 Example

[0084] Stimulation tropism analysis of multiple environmental characteristic parameters: The four branch water tanks 1 of this experimental device were set as follows: The flow velocity of the three branch water tanks 1 in the north, west and south was set to 0.1 m / s, which is lower than the sensing flow velocity of the experimental fish, but the preferred environmental stimuli can be transferred to the initial residence area of ​​the fish, that is, the annular central pool 2.

[0085] The flow velocity in the eastward branch channel 1 was set to 0.6 m / s, which is the preferred flow velocity for the long-whiskered schizothorax.

[0086] North-facing branch tank 1 is a phototactic tank, with the light intensity set to 100 Lux and the wavelength bandpass 390-770 nm.

[0087] The west-facing branch water tank 1 is an olfactory tactical stimulus, dissolving the bait's odor substances in the south-facing branch water tank;

[0088] The south-facing branch water tank is a dissolved oxygen and acoustic branch water tank. The aeration in the branch water tank reaches 100%, and the jet water sound is set, with a large number of bubbles flowing down with the water.

[0089] After the physicochemical conditions of each branch tank stabilized, the experimental subjects were placed in the annular central pool 2, which is the position between the central guide gate 3 and the fish-blocking net 16. The behavioral characteristics of the experimental subjects were recorded over time, and the following table was finally obtained:

[0090] Table 3. Distribution of experimental subjects under different unidirectional stimuli

[0091] Sink location East-facing branch water tank North-facing branch water tank Westward branch water tank South-facing branch water tank Stimulation methods Water flow stimulation Light stimulation Sense of smell Dissolved oxygen and acoustics Number of experimental subjects 5 tails 1 tail 4 tails 4 tails

Claims

1. An apparatus for conducting fish tropism experiments, characterized in that: Includes the following: The water tank experimental section, the water tank control section, and the video recording device; the water tank experimental section includes: branch water tanks and an annular central pool, with the branch water tanks arranged symmetrically around the annular central pool. The water tank control system includes: an inlet pipe, a stabilizing weir, a tailgate, a drain pipe, a return water tank, an upper reservoir, a return water pump, an inlet pipe, an overflow tank, and a water supply pipe. There are four branch water channels arranged in a cross shape, spaced 90° apart from each other. The four branch water channels point to the east, south, west, and north respectively. Each branch water channel is connected to an inlet pipe and a water stabilizing weir at the beginning and a tail gate at the end, with the tail gate connected to the annular central pool at the end. The branch water channel ends at the point where it enters the annular central pool. The lengths of the two side walls of the branch water channel are unequal. One side wall is directly connected to the annular central pool, while the other side wall extends into the annular central pool and approaches the central guide gate. The distance between the two is equal to three times the body width of the fish being transported. The central guide gate is cylindrical in shape, and the cylindrical surface is composed of multiple adjustable-angle rotating blades. The bottom of the annular central pool is connected to a drain pipe, which is connected to a return water channel. The end of the return water channel is connected to a return water pump, which is connected to an upper water pipe. The upper water pipe is connected to an upper reservoir, where an overflow channel is installed. The upper reservoir is connected to a water supply pipe, and the overflow portion of the overflow channel is connected to a return water pipe, which is connected to the return water channel. The water supply pipe is connected to an inlet water pipe. A valve is installed on the water inlet pipe to control the flow rate.

2. The apparatus for conducting fish tropism experiments according to claim 1, characterized in that: The video recording device includes: a top camera and an orthogonal calibration grid; Before conducting the experiment, the orthogonal calibration grid was placed in the water tank experimental section, and the top camera was used to take pictures to calibrate the position of the water tank plane corresponding to the camera image.

3. The apparatus for conducting fish tropism experiments according to claim 1, characterized in that: During the experiment, the return water tank is filled with water, the return water pump is turned on, and the water in the return water tank is pumped into the upper reservoir. When the water level is too high, the water overflows through the overflow tank and enters the return water pipe, returning to the return water tank. The water that does not overflow enters the inlet pipe through the supply pipe, enters the stabilizing weir through the valve, then flows through the branch water tank and the tail gate, enters the annular central pool, flows into the drain pipe, and then enters the return water tank to complete the entire process. When water bodies require aeration, aeration devices are installed in the upper reservoir. When the water body needs to regulate its temperature, a temperature control device is installed in the upper reservoir. The experimental subjects were placed in the water tank experimental section, and the external environment was adjusted to generate stimulation. The movement process of the experimental subjects was recorded by a camera on the top.

Images