A method for testing the maximum swimming ability of fish

Abstract

A method for testing the maximum swimming ability of fish, comprising the following steps: Step 1: Conduct a fish release experiment using an open flume device; Step 2: Obtain the swimming behavior of fish and the corresponding time under different factor conditions; Step 3: Determine the swimming speed of fish under different factor conditions in the open flume; Step 4: Establish a maximum swimming speed model of fish and a prediction model for the success rate of the maximum upstream distance of fish under different factor conditions in the open flume; the factors include the working flow rate, water temperature, and fish body length in the open flume device. The open flume device can better evaluate the maximum swimming speed of fish in a near-natural state, that is, in water flow environments with different temperatures, different body lengths, and different flow rates, under open conditions, and clarify the increase in the maximum swimming ability tested in the open flume compared to the closed environmental conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of ecology and fish protection, and particularly to a method for testing the maximum swimming ability of fish. Background Art

[0002] There are many methods for testing the swimming ability of fish. Currently, the widely used method is to use the fixed / increasing flow rate method in a closed square water tank for testing. This method was developed by Brett (1964) and is used to evaluate the movement of fish in a closed water tank. The estimation of the swimming ability of fish in a closed water tank is generally divided into three modes: the induced flow velocity, the critical (Ucrit), and the burst (Usprint), which helps the design criteria of fishway hydraulics.

[0003] However, recently, most researchers have questioned this testing method and testing device. They believe that the uniform water flow conditions in a closed water tank are quite different from the complex flow conditions in natural rivers, and the fish in the closed water tank swim passively. The testing space in the closed water tank is relatively small, which cannot meet the testing requirements of fish with a relatively large body length. Therefore, it restricts the free swimming behavior of fish and ignores the swimming behaviors that reduce energy consumption during the swimming process of fish at medium and low flow velocities, such as burst - glide behavior, bottom - or wall - adhering behavior, etc. As a result, it causes certain errors in some research results, leading to an overly conservative design of the fishway flow velocity, which may hinder effective passage. Therefore, the testing in a closed water tank cannot truly reflect the swimming ability and behavior of fish.

[0004] In recent years, researchers have realized that open water tanks can create hydraulic conditions that are closer to natural flow patterns, allowing for accurate analysis, and have begun to use open channels to explore fish behavior and swimming ability. In open water tanks, fish can exhibit autonomous, undisturbed upstream swimming, and can also exhibit richer swimming behaviors than in closed water tanks, such as changes in swimming posture, burst-gliding behavior, bottom- or wall-adhering behavior, fish swimming speed, and hydraulic preferences. These behavioral characteristics can provide useful information for fishway design and identify favorable situations where fish behavior and hydraulic conditions in fishways are integrated. In open water tanks, fish swimming performance and swimming behavior can be quantified by various indicators, and these indicators can also better reflect the actual upstream passage of fish, such as the maximum swimming speed of fish in open water tanks, fish upstream behavior, and comparison of the differences in swimming ability between closed and open water tanks. However, current research focuses on testing fish swimming behavior in closed water tanks or creating a larger test environment than closed water tanks. Understanding the behavioral data of swimming ability is of great scientific significance for determining the flow rate value of fish passing through fish facilities and defining the size design of key parts of fishways, such as rest pools, vertical seams, and entrances and exits. Compared with previous research conclusions, the test results of fish swimming ability in open tanks are greater than those in closed tanks. When testing the lunging swimming ability of fish in longer open tanks, fish can increase the frequency of using burst-gliding behavior, thereby showing greater lunging swimming ability than in closed tanks. In addition, combined with other research results, it is concluded that closed tanks are suitable for continuous-endurance testing of fish, and the micro-perturbation flow field in open tanks is more suitable for quantifying the swimming ability of fish.

[0005] In the prior art, for example, a patent application with publication number CN106577377A discloses a method for designing the water flow velocity of a fish-passing facility based on the swimming ability of fish. Specifically, the method includes selecting target fish and using a homemade water tank device to test the swimming ability of fish. However, the test environment is still in a closed and narrow space, which will restrict the swimming behavior of fish.

[0006] For another example, the patent application with announcement number CN111642449A discloses a variable slope fish swimming ability test tank, which includes an open tank body, one end of which is connected to the energy dissipation tank, and the other end of the outlet is equipped with a flip-open and closable tailgate, and the bottom surface of the middle part of the tank body, both ends of the tank body and the bottom of the tank body are supported by T-shaped reversing supports. This device can test large fish and can test swimming ability in a state close to natural pressure-free flow. However, this invention only provides a swimming space slightly larger than that of a closed tank, but does not evaluate the swimming behavior of fish in a variety of water environments such as different flow rates, water temperatures and salinity.

[0007] In summary, in the research on testing the swimming behavior of fish, there is no relevant research technical solution to compare the differences in the results of swimming ability tested in closed tanks and open tanks respectively. Summary of the Invention

[0008] The main object of the present invention is to propose a method for testing the maximum swimming ability of fish. The testing device is under open conditions, which can better evaluate the maximum swimming speed of fish in a near-natural state, and clarify the increase in the maximum swimming ability tested by the open flume device compared to the closed environmental conditions, so as to solve the problems existing in the prior art.

[0009] To achieve the above object, the present invention proposes a method for testing the maximum swimming ability of fish, including the following steps:

[0010] Step.1: Conduct a fish release experiment using an open flume device;

[0011] Step.2: Obtain the swimming behaviors of fish and the corresponding times under different factor conditions;

[0012] Step.3: Determine the swimming speeds of fish under different factor conditions in the open flume device;

[0013] Step.4: Establish a maximum swimming speed model of fish and a prediction model for the success rate of the maximum upstream distance of fish under different factor conditions in the open flume device;

[0014] The factors include the working flow rate, water temperature in the open flume device, and the body length of the fish.

[0015] Preferably, the open flume device includes a test flume, a water pump, a monitoring device, and a water delivery pipe; an inlet is provided at the upstream end of the test flume, a flume tail gate is provided at the downstream end, and a reservoir is provided at the flume tail gate; one end of the water delivery pipe is arranged in the reservoir, and the other end is connected to the inlet; the water pump is installed on the water delivery pipe; a test area is arranged in the test flume; the monitoring device is arranged at a position close to the test area for monitoring the behaviors of fish inside the test area.

[0016] Preferably, a flow controller is arranged on the water delivery pipe.

[0017] Preferably, a slope adjusting device is arranged at the bottom of the test flume.

[0018] Preferably, a control board is arranged on the inner surface of one side wall of the test area in the test flume, and the control board is used to adjust the lateral width W 试验区 of the test area, and a diversion inclined surface is arranged at the upstream end of the control board.

[0019] Preferably, the lateral width W 试验区 of the test area is 1.5 to 3.0 times the tail swing amplitude of the test fish; the water depth of the test area ≥ 30 cm, and the length L of the test area试验区 ≥6.0 m.

[0020] Preferably, the tail gate of the water tank is a folding door; a downstream net and an adaptation net are arranged near the tail gate of the water tank. The downstream net and the adaptation net are arranged at intervals to form a fish adaptation area. During the fish release experiment, the test fish are first adapted in the fish adaptation area, and the adaptation time T 适应 = 30 - 60 min.

[0021] Preferably, a rectifying grid is arranged at the upstream end of the test water tank.

[0022] Preferably, in Step.3, the swimming speed of the fish is calculated by the following formula:

[0023] D max =(U max -U s )*E,

[0024] where D max : the upstream distance of the test fish relative to the ground, m;

[0025] U max : the maximum upstream swimming speed of the test fish under the open water tank device, m / s;

[0026] U s : the average water flow speed in the test area, m / s;

[0027] E: the upstream time of the test fish in the test area, s.

[0028] Preferably, in Step.4, the maximum swimming speed model of the fish is:

[0029] U max =β 1 Q + β 2 T + β 3 FL + ε,

[0030] where Q: the working condition flow rate of the test area, L / s; T: the water temperature of the test area, °C; FL: the body length of the test fish, cm; β i : the weight coefficient, i = 1, 2, 3; ε: the error coefficient; U max : the maximum upstream swimming speed of the test fish under the open water tank device, m / s;

[0031] The prediction model of the maximum upstream distance success rate of the fish is:

[0032] y = (A 1 -A 2 ) / [1 + (D max / x 0 )^p)] + A2 ,

[0033] Among them, A 1 : represents the starting value, close to 1; A 2 : represents the final value, which is the coefficient value when the function fitting approaches stability; x 0 : represents the central value of the function fitting; p: exponent, that is, the degree of the function; y: upstream success rate; D max : the upstream distance of the test fish relative to the ground, m.

[0034] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0035] (1) Compared with the traditional fish swimming ability test method, by using an open flume device and adopting different hydraulic conditions, the autonomous swimming ability and behavior of the target fish are studied in the open flume device. The relationship between water flow velocity - swimming distance and water flow velocity - swimming speed under different hydraulic conditions can be analyzed by statistically counting indexes such as the maximum upstream distance, swimming speed, passing rate, and passing time, and the differences in the attempt rate, upstream success rate, attempt time, and successful upstream time of the test fish under different hydraulic conditions can be analyzed. The relationship between the swimming speed of fish in a nearly natural open flow state and flow rate, water temperature, and body length can be obtained by multiple linear regression fitting, which serves as the basis for the swimming ability database or swimming ability prediction model of different species of fish under the open flume device.

[0036] (2) The open flume device in the present invention can better evaluate the maximum swimming speed of fish in a nearly natural state, that is, evaluate the maximum swimming speed of fish in the water flow environment with different temperatures, different body lengths, and different working condition flow rates, and clarify the increase in the maximum swimming ability tested by the open flume device compared with the closed environment conditions.

[0037] (3) Based on this model, suggestions are provided for the flow velocity design of the key parts of the fishway, including suggestions for the inlet flow velocity, the flow velocity of the vertical seams in the fishway, and the length of the fishway chambers, etc. When building a fish passage facility for a water retaining structure with fish passage requirements, such as a fishway, after determining the fish passage target for the water retaining structure, relevant parameters (Q - flow rate, T - temperature, and FL - body length) are selected and brought into the maximum swimming speed (U max ) prediction model and the upstream distance (D max ) - success rate (y) prediction model. By substituting the values of relevant factors into the model, the maximum swimming speed and swimming distance of the target fish can be predicted, providing a design reference for the fishway with the target fish as the fish passage object. Description of the Drawings

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0039] Figure 1 Flowchart of the method steps for testing the maximum swimming ability of fish provided by the present invention;

[0040] Figure 2 Schematic diagram of the open flume device in the present invention;

[0041] Figure 3 Floor plan of the open flume device in the present invention;

[0042] Figure 4 Behavior diagram of fish, where the length of the arrow represents the magnitude of fish body fatigue F or upstream motivation M;

[0043] Figure 5 Diagram of fish tail swing amplitude;

[0044] Figure 6 Prediction model diagram of the relationship between upstream distance - success rate of grass carp under different flow rates;

[0045] Figure 7 Prediction model diagram of the relationship between upstream distance - success rate of Opsariichthys bidens under different flow rates;

[0046] Figure 8 Prediction model diagram of the relationship between upstream distance - success rate of silver carp under different flow rates;

[0047] Figure 9 Three behavior event frequencies of grass carp under different flow rates;

[0048] Figure 10 Three behavior event frequencies of silver carp under different flow rates;

[0049] Figure 11 Three behavior event frequencies of Opsariichthys bidens under different flow rates;

[0050] Figure 12 Schematic diagram of the swimming ability test flume in a closed environment in the prior art.

[0051] Description of the attached reference numerals: 1. Water pump; 2. Flow controller; 3. Gradient adjustment device; 4. Water inlet; 5. Test water tank; 6. Tail gate of the water tank; 7. Test area; 8. Reservoir; 9. Rectifying grid; 10. Control panel; 11. Downstream net; 12. Adaptation net; 13. Water delivery pipe; 14. Monitoring device; 1401. First camera; 1402. Second camera; 15. Test fish inlet; 16. Fish adaptation area; 17. Water flow inlet. Detailed implementation mode

[0052] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0053] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0054] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0055] Embodiment

[0056] Combined with Figure 1 As shown, a method for testing the maximum swimming ability of fish includes the following steps:

[0057] Step.1: Conduct a fish release experiment using an open water tank device;

[0058] Step.2: Obtain the swimming behaviors of fish and the corresponding time under different factor conditions;

[0059] Step.3: Determine the swimming speed of fish under different factor conditions in the open water tank device;

[0060] Step.4: Establish a maximum swimming speed model for fish and a prediction model for the success rate of the maximum upstream distance under different factor conditions in the open flume device;

[0061] The factors include the working flow rate, water temperature, and fish body length in the open flume device.

[0062] Combined with Figure 2 、 Figure 3 As shown, the open flume device includes a test flume 5, a water pump 1, a monitoring device 14, and a water delivery pipe 13; an inlet 4 is provided at the upstream end of the test flume 5, a flume tail gate 6 is provided at the downstream end, and a reservoir 8 is provided at the flume tail gate 6; one end of the water delivery pipe 13 is arranged in the reservoir 8, and the other end is connected to the inlet 4; the water pump 1 is installed on the water delivery pipe 13; a test area 7 is arranged in the test flume 5; the monitoring device 14 is arranged near the test area 7 for monitoring the fish behavior inside the test area 7. By using the water pump 1 and the water delivery pipe 13, a circulating water supply structure is formed in the whole test flume 5.

[0063] Combined with Figure 2 As shown, in this embodiment, in order to control the water flow rate introduced into the test flume 5 by the water pump 1, a flow controller 2 is arranged on the water delivery pipe 13. The flow controller 2 can remotely control the opening degree of the gate inside through the PC terminal to achieve the purpose of controlling the flow rate. In the present invention, the flow controller 2 is an electromagnetic flow valve. Further, in this embodiment, a slope adjusting device 3 is arranged at the bottom of the test flume 5 for adjusting the slope of the test flume 5. The whole open flume device is placed under open-air conditions, and the flow rate and water temperature are controllable, and the light is ambient light. Therefore, the environmental factors of the whole open flume device are close to the natural state.

[0064] Combined with Figure 3 As shown, a control board 10 is arranged on the inner surface of one side wall of the test area 7 in the test flume 5, and the control board 10 is used to adjust the transverse width W of the test area 7 试验区 , a guide inclined plane is arranged at the upstream end of the control board 10. Further, the transverse width W of the test area 7 试验区 is 1.5 - 3.0 times the tail-swing amplitude of the test fish; different fish will show different tail-swing amplitudes S when moving 摆尾幅度 ; Combined with Figure 5 As shown in the diagram of the tail-swing amplitude, when the fish moves forward, it will be subjected to the thrust of the tail, from position a 1 to position a 2 , and then from position a 2 restore to position b 1 after swimming a certain distance L (b 1Position a before the swimming distance L 1 Position), that is, at this time, it is a complete tail - wagging cycle for the fish to complete the swimming distance L.

[0065] The water inlet end of the test area 7 is the water flow inlet 17, and the water outlet end is the test fish inlet 15. The width of the test area 7 between the water flow inlet 17 and the test fish inlet 15 can be adjusted by the control board 10 in the direction perpendicular to the water flow, by adjusting the lateral width W 试验区 , and thus the water flow velocity V in the test area 7 can be indirectly controlled 水 .

[0066] To ensure that the test fish can choose different water layers to swim upstream at a sufficient water depth, and to simulate the conditions found under natural and artificial velocity barriers, the water depth of the test area 7 ≥ 30 cm, and the length L of the test area 7 试验区 ≥ 6.0 m. The swimming distance of fish in the burst - swimming mode (U sprint ) is the longest. Some research shows that the burst - swimming speed of cyprinid fish measured in a closed water tank is between 1.5 m / s and 2.0 m / s, that is, L 测试min = 3 - 4 m. Therefore, in order to better facilitate the fish to have enough swimming space to display swimming behaviors, the length of the test area 7 is set to L 试验区 ≥ 6.0 m.

[0067] Combined with Figure 3 shown, in this embodiment, the water tank tail gate 6 is a folding gate, and the water depth in the test water tank 5 is adjusted by controlling the opening degree of the tail - water folding gate; a downstream net 11 and an adaptation net 12 are arranged near the position of the water tank tail gate 6. The downstream net 11 and the adaptation net 12 are arranged at intervals to form a fish adaptation area 16. When conducting the fish - releasing experiment, the test fish are first adapted in the fish adaptation area 16, and the adaptation time T 适应 = 30 - 60 min. Further, a flow - straightening grid 9 is arranged at the upstream end of the test water tank 5, and its purpose is to make the water flow at the water inlet 4 enter the test area 7 smoothly.

[0068] Combined with Figure 3 shown, in order to better distinguish the upstream distance D max and behaviors of the test fish, the monitoring device 14 uses multiple cameras for monitoring, namely the first camera 1401 and the second camera 1402. The first camera 1401 is used to monitor the upstream section of the test area 7, and the second camera 1402 is used to monitor the downstream section of the test area 7, Figure 3 The letter B in it represents the monitoring range of the camera.

[0069] By using the monitoring device 14, the upstream distance of the test fish relative to the ground and the upstream time E in the test area 7 are observed in the open flume device to obtain its swimming speed at different flow rates:

[0070] D max =(U max -U s )*E (1)

[0071] Where, D max : The upstream distance of the test fish relative to the ground, m;

[0072] U max : The maximum upstream swimming speed of the test fish under the open flume device, m / s;

[0073] U s : The average water flow velocity in the test area 7, m / s;

[0074] E: The upstream time of the test fish in the test area 7, s.

[0075] The swimming ability of fish is affected by physiological factors such as body length, gender and species, and environmental factors such as water temperature and flow rate. In this embodiment, combined with multivariate analysis of variance, the effects of different factors on the swimming ability of fish are identified, and the maximum swimming speed model of fish under different environmental factors is constructed as:

[0076] U max =β 1 Q+β 2 T+β 3 FL+ε (2)

[0077] Where, Q: The working condition flow rate of the test area 7, L / s; T: The water temperature of the test area 7, °C; FL: The body length of the test fish, cm; β i : The weight coefficient, i = 1, 2, 3; ε: The error coefficient; U max : The maximum upstream swimming speed of the test fish under the open flume device, m / s.

[0078] Combining the above formula (1) and formula (2), the maximum upstream distance model and the maximum swimming speed model of different fish can be established, and the maximum swimming speed database of fish under the open flume device and the platform of the maximum upstream distance database under the influence of different factors can be built to guide and diagnose the design of fish passage chambers such as fishways.

[0079] In this embodiment, the prediction model of the success rate of the maximum upstream distance of fish is:

[0080] y=(A 1 -A 2 ) / [1+(D max / x0 )^p)]+A 2 (3)

[0081] Among them, A 1 : represents the starting value, close to 1;

[0082] A 2 : represents the final value, which is the coefficient value when the function fitting approaches a steady state;

[0083] x 0 : represents the central value of the function fitting;

[0084] p: exponent, that is, the degree of the function;

[0085] y: upstream success rate;

[0086] D max : the upstream distance of the test fish relative to the ground, m.

[0087] While solving the maximum swimming ability of fish under the open flume device through the above formulas (1) to (3), it is also clear that the swimming behavior of fish plays an equally important role in the flow velocity design of fish passage facilities. Therefore, to quantify the upstream behavior of fish under a single obstacle, it is necessary to obtain the indicators characterizing the upstream behavior of fish, such as the attempt time, attempt rate, successful upstream time, and upstream success rate, etc. However, this kind of behavior can have important reference value for the hydraulic and structural optimization inside the fishway and the diagnosis of existing fishway chambers, and can achieve the improvement of the passing rate of fish in the actual fishway project.

[0088] In this embodiment, an attempt is defined as that after the fish adapts to the fish adaptation area 16 and successfully passes through the test fish inlet 15 in the downstream section of the test area 7, it is considered that the fish has completed the attempt motivation, indicating that the water flow conditions at the test fish inlet 15 are suitable for the upstream of the test fish. The upstream attempt time of the test fish is defined as the time interval t 1 (s).

[0089] The successful upstream time is defined as the time interval t from the start of the attempt to the successful upstream 2 (s). The attempt rate is defined as the ratio (%) of the number N 进口 of fish entering the test fish inlet 15 under a certain flow condition to the total number N 总 of test fish under this flow, so as to characterize the number of fish attracted into the fishway at the fishway inlet, that is, the attempt rate of entering the fishway inlet.

[0090] The upstream success rate is defined as the ratio (%) of the number of fish that completely pass through the test area 7 to the number of fish that complete the attempt under a certain flow condition.

[0091] By playing back the test video, extract the time and frequency of the following behaviors.

[0092] "Completing the upstream section" is defined as: the fish swims upstream from the field of view of the second camera 1402 to the field of view of the first camera 1041 and leaves the field of view of the first camera 1041, and the behavior is continuous until it passes through the test area 7, thereby characterizing the passing rate of the test fish successfully passing through the fishway.

[0093] "Not completing the upstream section" is defined as: the fish enters the field of view of the first camera 1401 from downstream but does not completely pass through the entire test area 7. Instead, the fish leaves the line of sight in the downstream direction, rushes downstream, and does not reach upstream, thereby characterizing that the test fish successfully enters the fishway inlet but does not ascend to the fishway outlet.

[0094] "Completing the downstream section" is defined as: after the fish enters the field of view of the second camera 1042 from downstream but does not reach the field of view of the first camera 1401, a turning-back behavior occurs immediately after it enters the monitoring screen of the second camera 1042, and it is washed downstream by the water flow until it reaches the test fish inlet 15, thereby characterizing the turning-back behavior that occurs after the test fish enters the fishway inlet.

[0095] "Not completing the downstream section" is defined as: after the fish enters the field of view of the first camera 1401 from the test fish inlet 15, it passes through the test area 7 but does not reach downstream. Instead, the fish leaves the line of sight in the upstream direction or is interpreted as the fish staying in the middle of the test area 7 for more than 20 s, that is, it passes through the test area 7 but does not reach downstream, and there is no ascending motivation throughout the test, that is, it stays at the end.

[0096] Experimental example

[0097] When conducting a fish release experiment using an open flume device, it is necessary to check whether the flow system of the open flume device is normal before releasing the fish. That is, after adjusting the flow rate of the open flume device to the specified flow rate, the test flume 5 continuously discharges water for 5 min, and the fish release test starts after the water depth is stable. Before the formal test starts, a single healthy and highly active target test fish is placed in the fish adaptation area 16 between the downstream net 11 and the adaptation net 12 for 60 min. After the adaptation ends, while raising the adaptation net 12 in front of the fish adaptation area 16, the monitoring device 14 is turned on to start recording the autonomous ascending behavior of the test fish in the test area 7. If the test fish completely passes through the entire test area 7, it is recorded that the test fish has successfully ascended, that is, the test of this fish ends; if the test fish still has not successfully ascended within the test time of 1 h, it is recorded that the fish has failed to ascend, and the next test fish is replaced.

[0098] The water temperature was recorded before the test, 30 minutes after the test, and at the end of the test, and the average value was taken. If the test fish failed to swim upstream, the start and end of the test were recorded. After the test, the body length (cm), fork length (cm), total length (cm), body width (cm), body height (cm), and weight (g) of the test fish were measured. In order to avoid external interference in the test process, plastic sheeting was placed around the test device.

[0099] Taking fish in different water layers as examples, calculation examples of three test fish, namely, black carp, grass carp and silver carp, are provided to specifically illustrate the calculation method and process involved in the present invention. Black carp is a middle and upper layer fish, grass carp is a lower layer fish, and silver carp is an upper layer fish. The specific determination process is as follows:

[0100] 1) Obtain the swimming behavior of three test fish under different test conditions through field measurements, including water temperature, body length and flow rate, and determine the maximum swimming speed (U max ), the swimming speeds of the three test fishes in the open water tank device are shown in Tables 1 to 3, and the water flow velocities of working conditions 1 to 5 are 0.42m / s, 0.65m / s, 0.85m / s, 1.02m / s, and 1.24m / s, respectively.

[0101] Table 1 Maximum swimming ability of grass carp in open tank apparatus

[0102]

[0103] Table 2 The plunging swimming ability of silver carp in the open tank apparatus

[0104]

[0105] Table 3 The swimming ability of silver carp in the open tank

[0106]

[0107] Combination Figure 12 The figure shows a schematic diagram of a swimming ability test tank in a closed environment in the prior art, in which A represents a motor, B represents a speed converter, C represents a propeller, D represents a flow stabilizer, E represents a test area, and F represents a blocking net. The closed tank is easy to carry, and the speed of the propeller C is indirectly controlled by the speed converter B to control the water flow speed in the test area F to meet the flow rate requirements under the closed tank test, thereby testing the fish's swimming speed (i.e., the maximum swimming speed) under the closed tank. Generally, the length of the test area of ​​a closed tank is mostly 40cm to 50cm, providing a small swimming space for fish.

[0108] In the present invention, the length L of the test area 7 is 试验区≥6.0 m, and presents different gradient flow velocities in space, which is more suitable for observing the swimming behaviors of fish in different inhabiting water layers and testing the maximum swimming ability of fish. Considering that the structures of the two different test water tanks are different, but in order to compare the maximum swimming speed test results of fish under the two water tanks, the present invention compares the maximum swimming speeds of grass carp, silver carp and Opsariichthys bidens under the open water tank device based on the same test condition factors as those under the closed water tank. The test condition factors include fish body length, test water temperature, water body acidity and alkalinity, etc. As shown in Tables 1 to 3, through experimental research, it is found that the swimming speeds of the three test fish under the open water tank device are all greater than those under the closed water tank test. Among them, the maximum swimming speed of grass carp under the open water tank device is 60% greater than that under the closed water tank, the maximum swimming speed of silver carp under the open water tank device is 64% greater than that under the closed water tank, and the maximum swimming speed of Opsariichthys bidens under the open water tank device is about 74% greater than that under the closed water tank.

[0109] 2) Through on-site experiments, the monitoring device 14 analyzes the fish behaviors in the test area 7 and records the behavior frequencies corresponding to different behaviors, such as Figures 9 to 11 shown. By statistically analyzing the behavior frequencies of different behaviors and combining the upstream standard statistical rates in different ranges corresponding to the evaluation indicators in Table 4, the operation effect of the fishway is obtained, and an evaluation of the fishway problems is made.

[0110] Table 4 Score table of evaluation indicators for various behaviors and fishway discrimination and diagnosis positions

[0111]

[0112]

[0113] 3) Through multi-factor variance analysis, analyze the significant differences in the maximum swimming speeds of the three test fish under different flow rates, different body lengths and different water temperatures, and eliminate the factors that are not relevant to the maximum swimming speed of fish.

[0114] 4) Construct a swimming ability prediction model with the maximum swimming speed of fish under the open water tank device as the dependent variable and flow rate, body length and water temperature as the independent variables.

[0115] Through multi-factor variance analysis, analyze the significant differences (P < 0.05) in the maximum swimming speeds of the three experimental fish under different flow rates, different body lengths and different water temperatures. Since the body lengths and experimental environments of Opsariichthys bidens are relatively similar, with little difference, and the correlation with each influencing factor is relatively low (P > 0.05), which cannot form the basic conditions for linear regression, the irrelevant factors are excluded, and only the relationships between grass carp and silver carp and temperature T, body length FL and working condition flow rate Q are analyzed.

[0116] The functional relationship between the maximum swimming speed of grass carp and the flow rate condition, body length and water temperature is:

[0117] U max = 0.004Q - 0.02T - 2.255FL + 2.147(R 2 = 0.98)

[0118] The functional relationship between the maximum swimming speed of silver carp and the flow condition, body length, and water temperature is:

[0119] U max = 0.001Q + 18.965T - 0.049FL - 0.597(R 2 = 0.66)

[0120] The maximum upstream distance D of the experimental fish under their respective flow conditions was obtained by referring to the Logistic non - linear regression max The prediction model and the prediction model of upstream distance - success rate are shown in Table 5. The maximum upstream distance D obtained in this step max represents behavioral fatigue, rather than obvious physiological fatigue, such as Figures 6 to 8 shown. This prediction model is more specific and has a higher credibility than the results of previous studies. It can be used to predict the successful upstream proportion under similar hydraulic barriers and further provide a reference for the repair design of fish - passing facilities.

[0121] Table 5 Upstream distance (D max ) - Weight coefficients of the prediction model of success rate (y)

[0122]

[0123]

[0124] In the above table, A 1 : represents the starting value, close to 1; A 2 : represents the final value, which is the coefficient value when the function fitting approaches a steady state; x 0 : represents the central value of the function fitting; p: exponent, that is, the degree of the function; y: upstream success rate; D max : the upstream distance of the experimental fish relative to the ground, m.

[0125] Reduced Chi - Sqr: To clarify how much effect is produced by the explanatory variable and the random error respectively, statistically, the difference between the data point and its corresponding position on the regression line is called the residual. The result of adding up the squares of each residual represents the effect of the random error. The closer it is to 0, the better the fitting effect.

[0126] R 2 , also called the "coefficient of determination", is a "measurement method" used to evaluate the fitting effect of a linear regression model. R 2When the coefficient is 1, it means that all data points of the model fall exactly on the regression curve. R 2 The closer the coefficient is to 1, the better the fitting effect, indicating a higher fitting degree of the model.

[0127] 5) Use the above open flume device to test the maximum swimming speed U max and the maximum upstream distance D of fish max — The success rate y prediction model provides a reference for the values of the fishway layout route, length, and slope. For example, as Figure 6 shown, when the water temperature is in the range of 11.1 - 12.5 °C, the flow rates are 22 L / s (V = 0.42 m / s) and 35 L / s (V = 0.65 m / s), the upstream distances of grass carp are relatively close (P > 0.05), the maximum predicted upstream distances are nearly parallel, and the success rates are all above 80%. Therefore, when the flow velocity at the vertical slot of the fishway is close to these two working conditions, it will not cause an upstream obstacle to them. At a flow rate of 83 L / s (V = 1.24 m / s), when the upstream distance is 3.8 m, the upstream success rate is 50%. Therefore, to ensure that 50% of the fish can enter the fishway, successfully pass through the vertical slot, and reach the fishway outlet, the flow velocities at the inlet and the vertical slot should be less than 1.24 m / s, and the length of the fishway chamber is recommended to be less than 3.8 m. When the temperature is 11.1 - 12.5 °C and the flow rate is 83 L / s, it causes an upstream obstacle to 50% of the grass carp.

[0128] The present invention takes into account that fish cannot fully exhibit a near-natural state in a closed and narrow space. In particular, the maximum swimming ability behaviors of fish when passing through the intersection of different turbulent kinetic energy water flows, the low weirs for upstream / swimming, and passing through high-flow velocity areas cannot be observed. Such behaviors can be better manifested under near-natural conditions and near-natural flow conditions. Accordingly, the present invention provides a method and device for testing the maximum swimming ability of fish in a near-natural open flow state, and compares it with the maximum swimming speed under closed flume test conditions.

[0129] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made using the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for testing the maximum swimming ability of fish, characterized in that, it includes the following steps: Step.1: Conduct a fish release experiment using an open flume device; Step.2: Obtain the swimming behaviors of fish and the corresponding time under different factor conditions; Step.3: Determine the swimming speeds of fish under different factor conditions in the open flume device; Step.4: Establish a maximum swimming speed model of fish and a prediction model for the success rate of the maximum upstream distance of fish under different factor conditions in the open flume device; The factors include the working flow rate, water temperature, and fish body length in the open flume device; The open flume device includes a test flume (5), a water pump (1), a monitoring device (14), and a water delivery pipe (13); an inlet (4) is provided at the upstream end of the test flume (5), a flume tail gate (6) is provided at the downstream end, and a reservoir (8) is provided at the flume tail gate (6); one end of the water delivery pipe (13) is arranged in the reservoir (8), and the other end is connected to the inlet (4); the water pump (1) is installed on the water delivery pipe (13); a test area (7) is arranged in the test flume (5); the monitoring device (14) is arranged at a position close to the test area (7) for monitoring the behaviors of fish inside the test area (7); In Step.3, the swimming speed of fish is calculated by the following formula: D max = (U max - U s ) * E, Among them, D max : The upstream distance of the test fish relative to the ground, m; U max : The maximum upstream swimming speed of the test fish under the open flume device, m / s; U s : Average water flow velocity in the test area (7), m / s; E: The upstream time of the test fish in the test area (7), s; In Step.4, the maximum swimming speed model of fish is: U max = β 1 Q + β 2 T + β 3 FL + ε, Among them, Q: the working flow rate of the test area (7), L / s; T: the water temperature of the test area (7), °C; FL: the body length of the test fish, cm; β i : the weight coefficient, i = 1, 2, 3; ε: the error coefficient; U max : the maximum upstream swimming speed of the test fish under the open flume device, m / s; The prediction model for the success rate of the maximum upstream distance of fish is: y = (A 1 - A 2 ) / [1 + (D max / x 0 ) ^ p)] + A 2 , Among them, A 1 : represents the starting value, close to 1; A 2 : represents the final value, which is the coefficient value when the function fitting approaches stability; x 0 : represents the central value of the function fitting; p: exponent, that is, the degree of the function; y: upstream success rate; D max : the upstream distance of the test fish relative to the ground, m.

2. A method for testing the maximum swimming ability of fish as described in claim 1, characterized in that: A flow controller (2) is arranged on the water delivery pipe (13).

3. A method for testing the maximum swimming ability of fish as described in claim 1, characterized in that: A slope adjusting device (3) is arranged at the bottom of the test flume (5).

4. A method for testing the maximum swimming ability of fish as described in claim 1, characterized in that: On the inner surface of one side wall of the test area (7) in the test water tank (5), a control board (10) is provided, and the control board (10) is used to adjust the lateral width W of the test area (7). 试验区 A diversion inclined plane is provided at the upstream end of the control board (10).

5. A method for testing the maximum swimming ability of fish as described in claim 4, characterized in that: The lateral width W of the test area (7) 试验区 is 1.5 to 3.0 times the tail-swing amplitude of the test fish; the water depth of the test area (7) ≥ 30 cm, and the length L of the test area (7) 试验区 ≥ 6.0 m.

6. A method for testing the maximum swimming ability of fish as described in claim 1, characterized in that: The tail gate (6) of the water tank is a folding door; a downstream net (11) and an adaptation net (12) are arranged near the tail gate (6) of the water tank. The downstream net (11) and the adaptation net (12) are arranged at intervals to form a fish adaptation area (16). During the fish release experiment, the test fish are first adapted in the fish adaptation area (16), and the adaptation time T 适应 = 30 - 60 min.

7. A method for testing the maximum swimming ability of fish as described in claim 1, characterized in that: A rectifying grid (9) is arranged at the upstream end of the test flume (5).

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