Quantifiable fish swimming ability testing method and system

Abstract

The invention provides a test method and system for quantifying swimming capacity of fishes, which are used for evaluating performance, energy consumption and fatigue characteristics of the fishes under different water flow conditions. The method comprises the following steps: firstly, fixing the water flow velocity, and measuring the duration and fatigue proportion of fishes under the condition; when the fishes have fatigue signs, the flow speed is reduced to relieve fatigue, and then the flow speed is gradually increased until the fishes are completely tired. Carrying out integral calculation by combining a fatigue probability function, estimating the energy consumption of the fish at a specific flow velocity, and drawing a fatigue proportion curve. Determining the maximum energy consumption of the fish at different flow rates, and further calculating the relationship among the flow rates, the total energy consumption and the energy utilization rate; the test system comprises two water tanks with open top surfaces, and the two water tanks are connected through an S-shaped water flow channel to form a plurality of linear test areas. The system ensures the accuracy of the experiment, provides an accurate tool for biological and ecological research, and is beneficial to deeply understanding the fish swimming mechanism and the response to the environmental change.

Description

Technical Field

[0001] The present invention relates to the technical field of fish behavior research, and specifically, to a method and system for quantitatively testing the swimming ability of fish. Background Art

[0002] As aquatic organisms, fish often face various flow conditions in their natural environment, such as rivers, tides, etc. Their swimming ability and adaptability to different water flow conditions are crucial for survival. Understanding the swimming performance, energy utilization efficiency, and fatigue characteristics of fish under specific water flow conditions not only helps scientific research but also provides important information for fishery management and protection.

[0003] Traditionally, the research on fish swimming ability mostly relied on qualitative observations or simple quantitative experiments, such as measuring the maximum swimming speed of fish in static water bodies. However, these methods cannot accurately reflect the actual performance of fish under dynamic water flow conditions. With the development of technology, people have started to adopt more precise methods and techniques to study fish swimming behavior, such as using water tanks to simulate natural water flow conditions, combining video analysis technology to track fish movement trajectories, and applying biomechanical principles to calculate the energy consumption of fish.

[0004] Nevertheless, there is still a lack of a standardized and comprehensive method for quantitatively testing fish swimming ability, especially a method that can accurately measure the energy consumption and fatigue characteristics of fish under different flow velocity conditions. In addition, existing testing systems are usually simple in structure and difficult to simulate complex natural water flow environments, which limits the application scope of experimental results. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and system for quantitatively testing fish swimming ability, which can achieve a comprehensive quantitative evaluation of fish swimming ability, more deeply understand the swimming mechanism of fish, and provide strong support for the research and development in related fields.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is: a method for quantitatively testing fish swimming ability, comprising the following steps: 1) Control the water flow velocity to a fixed value and test the relationship between the duration and fatigue ratio of fish at the fixed flow velocity; 2) When the fish shows signs of fatigue at the fixed flow velocity value, control the water flow velocity to decrease to a fixed value; 3) After the water flow velocity decreases to the fixed value, increase the flow velocity to make the fish reach a completely fatigued state; 4) By observing the fatigue ratio of the fish and combining with the fatigue probability function for integral calculation, estimate the expected energy consumption at a specific flow velocity and draw the fatigue ratio curve of the fish; 5) Measure the maximum energy consumption of fish at different flow velocities and define this flow velocity as the "uniform flow maximum energy consumption velocity". 6) Calculate and plot the relationship curves of "flow velocity - total energy consumption" and "flow velocity - energy utilization rate", calculate the energy consumption per unit time, and obtain the relationship of "energy utilization rate - unit energy consumption".

[0007] 2. A method for quantifying the swimming ability of fish according to claim 1, wherein in the step 4), the expected energy consumption N at a specific flow velocity is calculated as follows: ; Wherein: is the fatigue probability function, which describes the probability density of fish fatigue at a certain flow velocity. is the initial flow velocity. is the final flow velocity.

[0008] In a preferred embodiment, in the step 6), the calculation of "flow velocity - total energy consumption" includes: First, calculate the expected energy consumption E at a specific flow velocity, obtain the relationship between the flow velocity and the total energy consumption, and the calculation formula is as follows: ; In the formula, t is the time; P(t) is the power; ; In the formula, f is the swimming resistance of the fish; v is the swimming speed of the fish; ; In the formula, is the drag coefficient, , , is the Reynolds number of the fish body, ; , is the wetted surface area of the fish body, is the body length of the fish, and are both empirical coefficients; is the water flow velocity; is the swimming speed of the experimental fish.

[0009] In a preferred embodiment, in the step 6), the calculation of "flow velocity - energy utilization rate" includes: The calculation formula of the energy utilization rate is as follows: ; In the formula, Taking the total energy as a fixed value, the relationship curve of "flow velocity - energy utilization rate" and the relationship curve of "flow velocity - total energy consumption" have the same change trend and reach the highest point at the same abscissa; Analyze the relationship between energy utilization rate and unit energy consumption: ; In the formula, is the unit energy consumption, is the time; ; In the formula, is the unit energy consumption, is the energy utilization rate.

[0010] and are constants. Therefore, the relationship curve of "unit energy consumption - energy utilization rate" and the relationship curve of "flow velocity - total energy consumption" also have the same change trend and reach the highest point at the same abscissa.

[0011] In a preferred embodiment, the curve of the flow velocity and the total energy consumption includes the energy consumption change under unlimited time and the energy consumption change under unlimited energy; The intersection point of the energy consumption change curve under unlimited time and the energy consumption change curve under unlimited energy is the ideal state of the fish at a fixed flow velocity. In this state, the total energy consumption of the fish reaches the peak.

[0012] In a preferred embodiment, in step 2), when the fish hits the rear wall or stops at rest for two consecutive long times, it is determined that the fish shows signs of fatigue.

[0013] A system based on the above - mentioned quantifiable fish swimming ability test method includes two water tanks, which are connected by a water flow channel, and are also connected by a water circulation pipeline to form a water circulation system.

[0014] In a preferred embodiment, the water flow channel is in an "S" shape, and multiple linear test areas are formed in the water flow channel.

[0015] In a preferred embodiment, partitions are provided in the multiple linear test areas in the water flow channel, and a wave - suppressing plate is provided on the top surface of the water flow channel upstream of the partition.

[0016] In a preferred embodiment, both the water tank and the water flow channel are of an open - top structure form.

[0017] The device for measuring free silica in dust provided by the present invention has the following beneficial effects by adopting the above structure: (1)The measurement is carried out by the increasing fixed flow rate method. When the fish reaches the fatigue point at a fixed flow rate, the test ends, avoiding the stress response of the fish during the process of increasing the flow rate. This helps to improve the accuracy and reliability of the experiment, and the flow rate is adjustable. By gradually increasing the flow rate, the critical swimming speed of the fish can be measured more accurately; (2)The relationship curves of "flow rate - total energy consumption", "flow rate - energy utilization rate", and "energy utilization rate - unit energy consumption" are constructed. Given the known flow rate, data such as energy consumption can be directly calculated, and the results of indoor experiments are linked to field engineering design through energy consumption indicators, providing a reliable design data basis for field engineering design; (3)By integrating the fatigue probability function, the cumulative energy consumption in different fatigue states (from the start of movement to complete fatigue) is reflected. This method is carried out in an open flume, where the oxygen content is relatively constant, and harmful metabolites will not accumulate due to long-term enclosure, affecting the health of organisms and thus the measurement results of oxygen consumption. Description of the Drawings

[0018] The present invention will be further described below in conjunction with the drawings and embodiments: Figure 1 It is the fatigue probability curve graph of the present invention.

[0019] Figure 2 It is the relationship curve graph of "flow rate - total energy consumption" of the present invention.

[0020] Figure 3 It is the energy consumption change curve graph of the present invention under the conditions of unlimited time and unlimited energy.

[0021] Figure 4 It is the energy consumption change curve graph of the present invention under the condition of unlimited time in combination with three kinds of fish.

[0022] Figure 5 It is the energy consumption change curve graph of the present invention under the condition of unlimited energy in combination with three kinds of fish.

[0023] Figure 6 It is the structure diagram of the test system of the present invention.

[0024] In the figure: water tank 1, water flow channel 2, wave suppression plate 3, partition plate 4, water circulation pipeline 5, circulation water pump 6. Specific Embodiments

[0025] Example 1: A test method for quantifying the swimming ability of fish includes the following steps: 1) Control the water flow rate to a fixed value and test the relationship between the duration and fatigue ratio of fish at the fixed flow rate; 2) At a fixed flow velocity value, when signs of fish fatigue appear, control the water flow velocity to decrease to a fixed value; 3) After the water flow velocity decreases to a fixed value, increase the velocity to make the fish reach a state of complete fatigue; 4) By observing the proportion of fish fatigue and integrating with the fatigue probability function, estimate the expected energy consumption at a specific flow velocity and draw a curve of the proportion of fish fatigue; 5) Measure the maximum energy consumption of fish at different flow velocities and define this flow velocity as the "uniform flow maximum energy consumption velocity"; 6) Calculate and draw the relationship curves of "flow velocity - total energy consumption" and "flow velocity - energy utilization rate", calculate the energy consumption per unit time, and obtain the relationship of "energy utilization rate - unit energy consumption".

[0026] Example 2: Based on Example 1, steps 1) - 3) in Example 1 are specifically as follows: Without causing fish stress, quickly adjust the flow velocity to a fixed value. Test the relationship between the duration of fish at a specific flow velocity and the proportion of fatigue. Since fish rarely swim continuously at the same flow velocity under natural conditions, the maximum experimental time is set to 1 hour. At the beginning of the experiment, the flow velocity increases at a speed of 0.1 m / s under the previously adjusted flow velocity. When the fish start to show signs of fatigue within 1 hour, the flow velocity increase rate slows down to 0.01 m / s, and continue to increase the flow velocity until the fish are completely fatigued within 30 seconds. In the above, the determination of signs of fatigue is that the fish hit the back wall or rest against the side for a long time twice in a row.

[0027] In step 4), by observing the proportion of fish fatigue and integrating with the fatigue probability function, estimate the expected energy consumption at a specific flow velocity. Measure the maximum energy consumption of fish at different flow velocities and define this flow velocity as the "uniform flow maximum energy consumption velocity".

[0028] Fatigue probability function: Suppose there is a fatigue probability density function, which describes the probability density of fish fatigue at a certain flow velocity. Let the flow velocity change from v 1 to v 2 and calculate the following definite integral:

[0029] According to the above definite integral, draw the curve graph as shown in the appendix Figure 1 It can be seen from the figure that: As the flow velocity increases, the proportion of fish fatigue basically shows an increasing trend. It means that at a lower flow velocity, fish can easily cope with the water flow and are not easily fatigued; while as the flow velocity increases, fish need to exert more effort to maintain their position or move forward, so the proportion of fatigue also increases.

[0030] When the flow velocity reaches a certain level, fish will almost certainly show obvious signs of fatigue.

[0031] Example 3: Based on Example 1, step 6) in Example 1 is specifically as follows: In step 6), according to the experimental data, draw the relationship curves of "flow velocity - total energy consumption" and "flow velocity - energy utilization rate". Calculate the energy consumption per unit time, so as to obtain the relationship of "energy utilization rate - unit energy consumption".

[0032] In this regard, first, it is necessary to calculate the expected energy consumption at a specific flow velocity, obtain the relationship between the flow velocity and the total energy consumption, and the calculation method is as follows:

[0033] In the formula, t is the time. Since the experimental time is one hour, the upper limit of integration is 3600, and the unit of t is seconds; P(t) is the power.

[0034]

[0035] In the formula, is the swimming resistance of the fish, is the swimming speed of the fish.

[0036] The swimming resistance of the fish is calculated as follows:

[0037] In the formula, , is the resistance coefficient, , is the Reynolds number of the fish body, , and , is the wetted surface area of the fish body, is the body length of the fish, and are both empirical coefficients, is the water flow velocity, is the swimming speed of the experimental fish.

[0038] Combined with the attached Figure 2 , the attached drawing is a typical "flow velocity - total energy consumption" relationship curve, which shows how the total energy consumption of fish changes with the increase of the flow velocity. In this example, when the flow velocity is small, the total energy consumption of fish is relatively low; as the flow velocity increases, the total energy consumption gradually increases; then it reaches the maximum value at a certain flow velocity, that is, the "highest energy consumption point" marked in the figure, and then as the flow velocity continues to increase, the total energy consumption begins to decrease again.

[0039] This phenomenon conforms to biological laws. Because within a certain flow velocity range, fish can reduce their own energy consumption by utilizing vortices and other structures in the water flow, so that the total energy consumption does not increase linearly with the increase in flow velocity. However, when the flow velocity exceeds a certain level, fish have to exert more effort to resist the water flow, resulting in a significant increase in total energy consumption. When the flow velocity continues to increase, fish may not be able to maintain a high swimming speed due to overexertion (specific reference attached Figure 1 ), so the total energy consumption will decrease again.

[0040] However, regarding the curve of flow velocity and total energy consumption (attached Figure 2 ), the following two cases need to be considered: (1) Energy consumption change under the condition of unlimited time When the time is unlimited, the energy of the fish itself is limited. Therefore, when the speed continues to increase, the energy consumption will always return to zero; (2) Energy consumption change under the condition of unlimited energy. This situation is exactly the opposite of the case of unlimited time. Since the energy is unlimited, it can maintain the energy consumption within one hour at any speed. Therefore, when the speed continues to increase, the energy consumption also continues to increase.

[0041] Combining the curves of the above two cases (as shown in the attached Figure 3 ), exploring the total energy consumption curve, when the energy it consumes is less than its own total energy, its energy consumption curve is the curve of unlimited energy consumption. But when the energy it consumes is greater than the energy it owns, the energy curve will not continue along the curve of unlimited energy consumption. The intersection point of these two curves may correspond to the ideal state of fish at a specific flow velocity, that is, in this state, the total energy consumption of fish reaches the peak. The green curve shown in the figure is the total energy consumption curve.

[0042] Secondly, regarding the relationship between flow velocity and energy utilization rate, it is necessary to know the calculation method of the energy utilization rate :

[0043] In the formula, is the total energy. Since the total energy is a fixed value, the relationship curve between flow velocity and energy utilization rate has the same change trend as the relationship curve between flow velocity and total energy consumption, and reaches the highest point at the same abscissa. Therefore, the attached Figure 3 can also be used as the "flow velocity - energy utilization rate" relationship curve, where the horizontal axis represents the flow velocity and the vertical axis represents the energy utilization rate, indicating the energy utilization efficiency of fish at different flow velocities. This highest point also means that at this flow velocity, fish can utilize energy in the most effective way, neither consuming too much energy nor sacrificing good swimming performance.

[0044] Finally, analyze the relationship between energy utilization rate and unit energy consumption:

[0045] In the formula, is the unit energy consumption, is the time;

[0046] In the formula, is the unit energy consumption, is the energy utilization rate.

[0047] Since is a constant, is also a constant. Therefore, the relationship curve of "unit energy consumption - energy utilization rate" and the relationship curve of "flow velocity - total energy consumption" have the same changing trend and reach the highest point under the same abscissa.

[0048] Therefore, it can be seen from Figure 3 that the energy utilization rate first rises and then falls with the increase of the unit energy consumption, also forming a single-peak curve. At a certain unit energy consumption, that is, Figure 3 at the highest point, the fish reaches the highest point of the energy utilization rate. This highest point means that at this unit energy consumption, the fish can utilize energy in the most effective way, neither consuming too much energy nor sacrificing good swimming performance.

[0049] Example 4: Combined with Example 3, since is a cubic function of , the energy-unlimited curve increases cubically. And because the total energy of each fish is different, three curves (as shown in Appendix Figure 4 ) are drawn to represent the different energies of three fish for analysis. Since the energies are different, with the increase of the flow velocity, the differences among the three should increase. And the final result obtained should be a general result. Therefore, instead of choosing any one of the three curves as part of the energy consumption curve, a curve is drawn starting from the intersection point of the energy-unlimited curve and the time-unlimited curve with the minimum self-energy consumption and ending at the end point of the time-unlimited curve with the maximum self-total energy consumption.

[0050] The drawing of the curve is determined by the ratio. If an experiment is conducted, the graph drawn from the experimental results should be a scatter plot, with corresponding energy consumption for each velocity. For the intersection point of the energy-unlimited curve and the time-unlimited curve with the minimum self-energy consumption, all the experimental results should fall exactly at this intersection point. After this intersection point, the experimental results no longer fall exactly on the energy-unlimited curve, and the ratio gradually decreases; at the average energy, 50% falls on the left and right of the energy-unlimited curve, and the remaining 50% falls below the energy-unlimited curve; when at the maximum self-total energy consumption, it will not fall on the energy-unlimited curve at all, so the end point returns to the x-axis.

[0051] Example 5: According to the design scheme disclosed in the above embodiments and in combination with the attached Figure 5 , when the curve 2 in the figure is used as the experimental scheme, the obtained curve is shown. However, since it is not necessary to take one hour as the standard in actual engineering, different situations are assumed. When the required experimental time in actual engineering is less than 1 hour, curve 1 will be obtained; when the required experimental time in actual engineering is greater than 1 hour, curve 3 will be obtained.

[0052] If the above curves are applied to actual engineering, the "flow velocity - total energy consumption" relationship curve illustrates the energy consumption of fish at different flow velocities, so that researchers can analyze the adaptability of fish under different environmental conditions based on the above curves, in order to optimize the breeding environment or improve the living conditions of fish.

[0053] The "flow velocity - energy utilization rate" curve helps to understand the survival strategies and ecological adaptability of fish at different flow velocities. In practical applications, it can help select the flow velocity conditions suitable for the growth and reproduction of fish to improve the breeding efficiency or protect wild fish resources. Therefore, the "unit energy consumption - energy utilization rate" curve helps to understand the survival strategies and ecological adaptability of fish under different unit energy consumptions.

[0054] Example 6: The system structure based on the above method for quantifying the swimming ability of fish specifically includes two water tanks 1, which are connected by a water flow channel 2, and a water circulation system is formed by connecting the two water tanks 1 through a water circulation pipeline 5.

[0055] Furthermore, the water flow channel 2 is in an "S" shape, and multiple linear test areas are formed in the water flow channel 2.

[0056] Furthermore, partition plates 4 are provided in the multiple linear test areas in the water flow channel 2, and a wave - suppressing plate 3 is provided on the top surface of the water flow channel 2 upstream of the partition plates 4.

[0057] Furthermore, both the water tank 1 and the water flow channel 2 are in an open - top structural form.

[0058] In this example, the open - top water tank has a good circulation system and a filtration system, which can maintain the oxygen and carbon dioxide contents within a relatively stable range, will not affect the physiological state of fish, and ensure good water quality.

[0059] In addition, multiple linear test areas are formed in the water flow channel 2, enabling multiple experiments to be carried out simultaneously in different areas of the same water tank, reducing the floor area of the laboratory, improving the experimental efficiency and resource utilization rate. Compared with operating multiple independent water tanks separately, the S - type bend design can share part of the circulation and control systems, thereby reducing energy consumption and maintenance costs to a certain extent.

[0060] Moreover, conducting multiple groups of experiments simultaneously means that a large amount of data can be obtained in a relatively short period of time. The influence of environmental variables on temperature can be controlled, improving the reliability and universality of research results. Also, since each bend is relatively independent and the interference between experimental rooms is small, even when multiple groups of experiments are conducted simultaneously, the independence and accuracy of the experimental data for each group can be ensured.

[0061] In addition, reducing the rectification area through the wave suppressor plate helps to eliminate the possible turbulence or irregular flow upstream of the test area, providing a more stable and smooth water flow environment. To avoid occupying a large experimental space, the wave suppressor plate rectification is selected here, and a long straight flow area is no longer required for rectification.

[0062] In summary, the above scheme disclosed in this application obtains the relationship curves of "flow velocity - total energy consumption", "flow velocity - energy utilization rate", and "energy utilization rate - unit energy consumption" through construction. Given the known flow velocity, data such as its energy consumption can be calculated. In this way, the results of indoor experiments are linked to field engineering designs through energy consumption indicators, providing strong support for the research and development in related fields.

Claims

1. A method for testing the quantifiable swimming ability of fish, characterized in that The following steps are involved: 1) Control the water flow rate to a fixed value and test the relationship between the duration and fatigue ratio of fish at a fixed flow rate; 2) At a fixed flow rate, when fish show signs of fatigue, control the water flow rate to drop to a fixed value; 3) After the water flow rate drops to a fixed value, increase the flow rate to make the fish reach a state of complete fatigue; 4) By observing the proportion of fish fatigue and integrating the fatigue probability function, the expected energy consumption at a specific flow rate can be estimated and the fatigue proportion curve of the fish can be drawn; 5) Measure the maximum energy consumption of fish at different flow rates and define this flow rate as the "uniform flow maximum energy consumption flow rate"; 6) Calculate and draw the relationship curves of "flow rate-total energy consumption" and "flow rate-energy utilization rate", calculate the energy consumption per unit time, and obtain the relationship of "energy utilization rate-unit energy consumption".

2. A method for testing the quantifiable swimming ability of fish according to claim 1, characterized in that: In step 4), the expected energy consumption N at a specific flow rate is calculated as follows: ； in: is the fatigue probability function, which describes the probability density of fish fatigue at a certain flow rate. is the initial flow rate, is the final flow rate.

3. A method for testing the quantifiable swimming ability of fish according to claim 1, characterized in that: In step 6), the calculation of "flow rate - total energy consumption" includes: First, calculate the expected energy consumption E at a specific flow rate, and obtain the relationship between flow rate and total energy consumption. The calculation formula is as follows: ； Where, t is time; P(t) is power; ； Where f is the swimming resistance of the fish; v is the swimming speed of the fish; ； In the formula, is the drag coefficient, , , is the Reynolds number of the fish body, ; , is the wetted surface area of ​​the fish, is the body length of the fish, and All are empirical coefficients; is the water flow velocity; is the swimming speed of the experimental fish.

4. A method for testing the quantifiable swimming ability of fish according to claim 3, characterized in that: In step 6), the calculation of "flow rate-energy utilization rate" includes: Energy utilization The calculation formula is as follows: ； In the formula, is the total energy and is a fixed value. The relationship curve of "flow rate-energy utilization rate" and the relationship curve of "flow rate-total energy consumption" have the same change trend and reach the highest point on the same horizontal axis; Analyze the relationship between energy utilization rate and unit energy consumption: ； In the formula, is the unit energy consumption, For time; ； In the formula, is the unit energy consumption, is the energy utilization rate. and is a constant, so the relationship curve of "unit energy consumption-energy utilization rate" and the relationship curve of "flow rate-total energy consumption" also have the same change trend, reaching the highest point on the same horizontal axis.

5. A method for testing the quantifiable swimming ability of fish according to claim 4, characterized in that: The curve of flow rate and total energy consumption includes energy consumption changes under unlimited time and energy consumption changes under unlimited energy conditions; The intersection of the energy consumption change curve under unlimited time and the energy consumption change curve under unlimited energy conditions is the ideal state of fish under a fixed flow rate, in which the total energy consumption of fish reaches a peak value.

6. A method for testing the quantifiable swimming ability of fish according to claim 1, characterized in that: In step 2), when the fish hits the rear wall or stops to rest for a long time twice in a row, it is considered that the fish shows signs of fatigue.

7. A system for quantifying the swimming ability of fish according to any one of claims 1 to 6, characterized in that: The invention comprises two water tanks (1), wherein the two water tanks (1) are connected via a water flow channel (2), and the two water tanks (1) are also connected via a water circulation pipeline (5) to form a water circulation system.

8. A quantifiable fish swimming ability test system according to claim 7, characterized in that: The water flow channel (2) is in an "S" shape, and a plurality of linear test areas are formed in the water flow channel (2).

9. A quantifiable fish swimming ability test system according to claim 8, characterized in that: A plurality of linear test areas in the water flow channel (2) are provided with partitions (4), and a wave pressure plate (3) is provided on the top surface of the water flow channel (2) upstream of the partitions (4).

10. A quantifiable fish swimming ability test system according to claim 7, characterized in that: The water tank (1) and the water flow channel (2) are both structures with open top surfaces.

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