Research equipment and analysis method for fish passing facility inlet shape

Abstract

The invention provides research equipment and an analysis method for the inlet shape of a fish passing facility. The research equipment comprises a fish passing experiment groove body of a long-strip-shaped structure, the middle position is separated through a fish inlet, a water outlet groove is formed in one end of the fish passing experiment groove body, the water outlet end of the water outlet groove is communicated with the fish inlet, and a downstream water groove is formed in the other end of the fish passing experiment groove body; a plurality of flow velocity sensors are arranged at the downstream water tank and the fish inlet; and a camera is also arranged in the fish inlet. Through specially designed experimental equipment and an analysis method, the influence of different inlet geometrical shapes on the behaviors of fishes entering the fishway can be accurately researched, and the influence comprises a plurality of aspects such as the fish entering quantity, the staying time, the entering time and the re-entering frequency, so that the advantages and disadvantages of various inlet shapes in the aspect of attracting the fishes are deeply known. Based on an experimental result, a scientific basis can be provided for fishway design, and which inlet geometrical shape or which inlet geometrical shape and suction flow configuration combination can attract fishes into the fishway to the greatest extent is determined.

Description

Technical Field

[0001] The invention relates to the field of research shape of an inlet of a fish passage facility, and in particular to a research device and an analysis method for the shape of an inlet of a fish passage facility. Background Art

[0002] In the field of hydraulic engineering, the presence of obstacles such as dams and weirs poses a significant barrier to fish migration. Although fish passes are constructed to provide fish with safe passages to resume their natural migration patterns, the effectiveness of fish passes relies heavily on whether they can reliably attract fish.

[0003] Although previous studies have focused on the importance of fishways for fish migration, there are still many gaps in the impact of fishway entrance design on fish attraction. Different fish species vary significantly in swimming ability, preferred water speed, and adaptability to entrance geometry.

[0004] Previous studies on fishway entrances have mostly focused on traditional pool fishways, while there is limited research on fish entering innovative closed pipe fishways such as the Whooshh system and the UNSW Tube Fishway. In practice, many fishways fail to function effectively due to unreasonable entrance design and mismatched attraction flow velocities, making it difficult for fish to migrate through obstacles. This situation highlights the need for in-depth research on the effects of fishway entrance geometry on fish attraction in order to fill the knowledge gap and provide a scientific basis for designing more efficient fishways, thereby better protecting fish resources and their ecological migration behaviors. Summary of the invention

[0005] The main purpose of the present invention is to provide a research device and analysis method for the shape of the entrance of a fish passage facility, so as to solve the problem that there are still many research gaps in the impact of the fishway entrance design on the fish attraction effect.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a research device for the inlet shape of a fish passing facility, comprising a fish passing experimental tank body with a long strip structure, the middle position of which is separated by a fish inlet, a water outlet tank is provided at one end of the fish passing experimental tank body, the water outlet end of the water outlet tank is connected to the fish inlet, and the other end of the fish passing experimental tank body forms a downstream water tank; Multiple flow rate sensors are installed at the downstream water tank and fish inlet; There is also a camera inside the fish inlet.

[0007] In the preferred embodiment, an observation port is provided above the water outlet trough, and a camera is arranged on one side of the observation port.

[0008] In the preferred embodiment, the fish passage experiment tank body is further provided with a water outlet gate at the tail of the downstream water tank.

[0009] In a preferred embodiment, the shape of the fish inlet is an elliptical opening, or a vertical elliptical slot, or a triangular slot, or a fan-shaped opening.

[0010] In a preferred embodiment, the flow velocity sensor is a miniature acoustic Doppler flow meter, and the flow velocity sensor is arranged at different depths.

[0011] In a preferred embodiment, the method comprises: S1, camera recording of the swimming behavior of fish under different inlet geometries and suction flow conditions, recorded from top and side views; The instantaneous velocity at the first and second flow sensor installation locations was measured using a micro acoustic Doppler current meter at four different water depths. , and data, and the calculated average flow rate ( , , ), standard deviation ( , and ) and turbulent kinetic energy data; Different attraction flow configurations are set for different fish inlet sizes, and the attraction flow configurations include flow velocity, different inlet flow velocities corresponding to constant momentum flux, and no-flow conditions; S2, extracting image data frame by frame from the experimental recording video, and identifying the position and number of fish for each frame of the image; Through image recognition algorithms, deep learning-based object detection algorithms, including YOLO or FasterR-CNN, pre-trained to identify specific fish species; Record the time when the fish enters the fish inlet: By tracking the movement trajectory of the fish, record the time when the center position of the fish crosses the boundary of the fish inlet; The extracted data were categorized and organized according to different fish inlets and attraction flow configurations; For each specific combination of entrance geometry and attractor flow configuration, a data list is created, where each element contains the number of fish at that moment and the entry time information; S3, reading a flow velocity measurement data file, and associating the flow velocity data of the measurement point with the corresponding inlet geometry and suction flow configuration, wherein the flow velocity data includes an average flow velocity, a standard deviation, and a turbulent kinetic energy; The flow velocity data were spatially matched with the fish behavior data based on the location of the measurement points in the downstream area of ​​the inlet and within the fish inlet; Calculate the average velocity, velocity range and turbulent kinetic energy distribution at different locations in the fish inlet under different inlet geometries and suction flow configurations; Analyze the relationship between flow velocity data and fish behavior, observe the distribution of fish in high and low flow velocity areas, and the changes in fish swimming trajectories under different TKE levels; S4. Calculation of fish behavior indicators: For the time series data of the number of fish under each experimental condition, traverse the list to find the maximum number of fish, which is ; According to the formula Calculate, where is the number of fish in the fish inlet at each moment, and S is the total number of fish put in each experiment; For each experimental condition, calculate the total time the fish spent in the fish inlet. ,in is the number of fish in the fish mouth at each moment, is the time the fish stays in the fish inlet at that moment, calculated by the time interval between adjacent frames; Calculate the total duration of the experiment : According to the formula Calculate proportional residence time; In the fish entry time data for each experimental condition, find the time point when the first fish enters the fish inlet ; According to the formula Calculate the time when the first fish enters; The number of times the fish re-entered the fish inlet during the one-hour experimental period was counted for each experimental condition; Cumulative reentry frequency was calculated as the average number of times per hour that fish reentered the fish inlet; S5. Create a data table with rows representing different combinations of inlet geometry and attraction flow configurations and columns including , , , and flow rate related data; Fill in the calculated fish behavior indicators and flow velocity data into the table; Analyze the effects of different inlet geometries and suction flow configurations on fish behavior indicators: including comparing size, judge which shape is more attractive to fish; observe Relationship with flow velocity and inlet shape to understand the willingness of fish to stay under different conditions; and to assess the impact of entrance design on fish entry efficiency and repeated entry behavior; Draw charts, such as bar graphs, to show the impact of different inlet geometries The line chart shows The trend of flow rate changes, etc., can present the results more intuitively.

[0012] In the preferred scheme, GLMs generalized linear models, LMs linear models and ANOVA analysis of variance were used to test the attraction performance and determine the importance of predictive factors such as inlet geometry, flow rate and fish species and their effects on fish attraction indices; A1. Organize and collect relevant data obtained in the experiment, including fish behavior data under three suction flow configurations: elliptical opening, vertical elliptical slot, triangular slot, or fan-shaped opening; Including the maximum number of fish in the fish inlet 4 , the proportion of time that fish stay in the fish inlet , the time when the first fish enters the fish inlet and the cumulative re-entry frequency of fish per 1-hour experimental period , and corresponding information such as inlet geometry, flow velocity, and fish species; A2. For , due to the existence of overdispersion, quasi-binomial GLM is selected; It obeys binomial distribution, and its probability distribution function is: ,in is the number of trials, is the number of fish that actually enter the fish inlet ( ), is the probability of success; In the quasi-binomial GLM, the linear predictor is linked to the mean by building a linked logit function Connect, that is ,in is the connection function, is the linear predictor, is the regression coefficient to be estimated, For predictor variables, they included inlet geometry, flow velocity, and fish species; A3. The time when the first fish enters the fish inlet and and residence time ratio , linear model regression and ANOVA were used; The linear model is expressed as: ,in is the response variable, or , is the regression coefficient, is the predictor variable, is the error term, where Normal distribution with mean 0 and variance ; for and , before applying the linear model, the data is log-transformed, where , to meet the normality assumption, and then fit and analyze the linear model based on the transformed data; A4. ANOVA is used to test whether there are significant differences in the means between different groups. Here it is mainly used to analyze the effects of inlet geometry, flow rate, and fish species on the and The impact of The basic idea of ​​ANOVA is to decompose the total variation into variations from different sources, and then judge whether the influence of the factors is significant by comparing the size of these variations; calculate the total sum of squares , between-group sum of squares and within-group sum of squares , and according to the formula calculate Statistics, where , , is the between-group degrees of freedom, is the within-group degrees of freedom; calculated by comparing Value and critical value (, to judge whether the influence of factors is significant; A5. Inlet geometry, flow velocity and fish species were included as predictors in the model for a three-way interaction analysis to comprehensively evaluate the complex interactions between these factors on fish attraction indicators. , , , The impact of In the model, all possible interaction terms are considered, such as the interaction terms between inlet geometry and flow velocity, the interaction terms between inlet geometry and fish species, the interaction terms between flow velocity and fish species, and the interaction terms among the three; the corresponding statistics are calculated, including regression coefficients, Statistics and evaluate their significance value; A6. Check the results of the three-way interaction analysis. If all or most of the interaction terms are The values ​​are greater than the set significance level , it indicates that the three-way interaction is not significant; in this case, consider simplifying the model and conducting a two-way interaction analysis; A7. Perform pairwise interaction analysis between inlet geometry and flow rate, inlet geometry and fish species, and flow rate and fish species; In each two-way interaction analysis, the model was rebuilt to include only the corresponding two predictors and their interaction terms; the regression coefficients, Statistical indicators such as statistics and evaluate their significance; Among them, the interaction between inlet geometry and flow velocity is analyzed. When the influence of ,in represents the inlet geometry, Indicates flow rate, is the interaction term between the two; A8. For the significant interactions found in the two-way interaction analysis, the EstimatedMarginalMeans package was used for comparative analysis. This method calculates the marginal means under different level combinations and compares them pairwise to determine which level combinations have significant differences. In cases where the interaction between inlet geometry and flow rate is significant, the marginal means for different inlet geometries at different flow rate levels are calculated. , and compare; if The difference is significant, according to the corresponding standard error and The value is judged, which means that at this flow rate level, the inlet geometry and Have significantly different effects on fish attraction performance; A9. Based on the results of the statistical analysis, explain how factors such as inlet geometry, flow velocity, and fish species affect fish attraction indicators; The entire analysis process was completed using R software to ensure the accuracy of the calculation and the reliability of the results.

[0013] The present invention provides a research device and analysis method for the inlet shape of a fish passage facility. Through specially designed experimental equipment and analysis methods, the effects of different inlet geometric shapes (such as circular, slotted, semicircular, and fan-shaped) on the behavior of fish entering a fishway can be accurately studied, including the number of fish entering, residence time, entry time, and re-entry frequency, so as to gain an in-depth understanding of the advantages and disadvantages of various inlet shapes in attracting fish.

[0014] Based on the experimental results, a scientific basis can be provided for the design of fishways to determine which entrance geometry and attraction flow configuration combination can attract fish into the fishway to the greatest extent, and enable fish to have a more appropriate residence time and entry efficiency in the entrance pipe, thereby improving the overall effectiveness of the fishway and helping fish migrate through obstacles more smoothly.

[0015] It helps to improve the design and operation of fishways, reduce obstructions to fish migration caused by problems at the fishway entrances, and better restore the natural migration patterns of fish. It has positive significance for protecting fish resources and maintaining the integrity and biodiversity of aquatic ecosystems.

[0016] In view of the limited research on innovative closed-pipe fishway entrances, this research equipment and analysis method provides an effective research approach, provides data support and technical reference for further exploration of the optimal design of such fishways, and promotes the development and improvement of fishway technology.

[0017] Through experimental research on different fish species, we can take into account the differences in swimming ability, behavioral preferences, etc. of various fish species, so as to design more universal and adaptable fishway entrances to meet the migration needs of different fish species.

[0018] During the research process, hydrodynamic parameters such as water flow velocity and turbulence characteristics were measured and analyzed, and combined with fish behavior data, this helped to gain a deeper understanding of the relationship between hydrodynamics and fish behavior, provide theoretical guidance for the hydraulic design in fishway projects, and make the water flow conditions in the fishway more in line with the physiological and behavioral characteristics of fish. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 1 is a schematic top view of a fish passing experiment tank of the present invention; Figure 2 This is a schematic diagram of the elliptical opening of the fish inlet of the present invention; Figure 3 It is a schematic diagram of the vertical elliptical groove of the fish inlet of the present invention; Figure 4 This is a schematic diagram of the triangular slot of the fish inlet of the present invention; Figure 5 It is a schematic diagram of the fan-shaped opening of the fish inlet of the present invention.

[0020] In the figure: fish passage test tank 1; water outlet tank 2; observation port 3; fish inlet 4; elliptical opening 401; vertical elliptical slot 402; triangular slot 403; fan-shaped opening 404; downstream water tank 5; water outlet gate 6; camera 7; first flow velocity sensor installation position 8; second flow velocity sensor installation position 9. DETAILED DESCRIPTION

[0021] Example 1 like Figures 1 to 5 As shown, a research device for the inlet shape of a fish passing facility comprises a fish passing experimental tank body 1 of a long strip structure, the middle part of which is separated by a fish inlet 4, a water outlet tank 2 is provided at one end of the fish passing experimental tank body 1, the water outlet end of the water outlet tank 2 is connected to the fish inlet 4, and a downstream water tank 5 is formed at the other end of the fish passing experimental tank body 1; Multiple flow rate sensors are provided at the downstream water tank 5 and the fish inlet 4; A camera 7 is also provided inside the fish inlet 4 .

[0022] In the preferred embodiment, an observation port 3 is further provided above the water outlet trough 2 , and a camera 7 is arranged on one side of the observation port 3 .

[0023] In the preferred embodiment, the fish passage experiment tank body 1 is further provided with a water outlet gate plate 6 at the tail of the downstream water tank 5 .

[0024] In a preferred embodiment, the shape of the fish inlet 4 is an elliptical opening 401 , or a vertical elliptical slot 402 , or a triangular slot 403 , or a fan-shaped opening 404 .

[0025] In a preferred embodiment, the flow velocity sensor is a miniature acoustic Doppler flow meter, and the flow velocity sensor is arranged at different depths.

[0026] The present embodiment aims to use specially designed equipment to study the shape of fish passage facility inlets to conduct a detailed study on the effects of different inlet shapes (such as elliptical openings, vertical elliptical slots, triangular slots, and fan-shaped openings) in attracting fish into the fishway. By measuring water flow velocity and observing fish behavior, the influence of the inlet shape on the behavior of fish entering the fishway is deeply analyzed, providing a scientific basis for optimizing the design of fish passage facility inlets.

[0027] The fish passage experiment tank 1 is a strip-shaped structure, with a length of [X] meters (the appropriate length is determined according to the actual experimental requirements, such as 6 meters), a width of [Y] meters (such as 0.6 meters), and a height of [Z] meters (such as 0.6 meters). The middle part of the tank is separated by a fish inlet 4, and the shape of the fish inlet 4 can be adjusted according to the experimental requirements, and is respectively set to an elliptical opening 401, a vertical elliptical slot 402, a triangular slot 403, and a fan-shaped opening 404, and is replaced at different experimental stages to ensure that there is only one fish inlet shape in each experiment.

[0028] A water outlet 2 is provided at one end of the fish passing experiment tank 1, and the water outlet end of the water outlet 2 is connected to the fish inlet 4 through a pipeline to form a water circulation path. An observation port 3 is provided above the water outlet 2, and the observation port 3 is made of transparent material, so that the experimenter can observe the behavior of the fish.

[0029] The other end of the fish passage experiment tank body 1 forms a downstream water tank 5 , and a water outlet gate 6 is arranged at the tail of the downstream water tank 5 to control the water level and water outflow speed of the downstream water tank 5 .

[0030] A plurality of miniature acoustic Doppler flowmeters are installed as flow sensors at the downstream water tank 5 and the fish inlet 4. In the downstream water tank 5, flow sensors are installed at different positions along the water flow direction, such as 0.5m, 1.0m, 1.5m from the fish inlet, and 0.1m, 0.3m, 0.5m below the water surface, to comprehensively measure the distribution of water flow velocity in the downstream water tank 5. Inside the fish inlet 4, flow sensors are also installed at the bottom, middle, and near the top depth to accurately measure the change of water flow velocity at the fish inlet 4.

[0031] A camera 7 is installed on one side of the observation port 3. The camera 7 adopts a high-definition waterproof camera, which can clearly capture the behavior of the fish in the fish inlet 4. The shooting angle of the camera 7 is adjustable to ensure that the entire area of ​​the fish inlet 4 can be covered, so as to accurately record the process of the fish entering the fish inlet 4, the swimming trajectory, the residence time and other behavioral information.

[0032] 1. Check the experimental equipment Ensure that there is no water leakage in the fish experiment tank body 1, the outlet tank 2, the downstream tank 5 and other tank structures, and that all connecting pipes are well sealed.

[0033] Check whether the flow rate sensor is working properly, obtain stable flow rate measurement data through pre-test, and calibrate the sensor's zero point, range and other parameters.

[0034] Test the shooting function of the camera 7, adjust the shooting angle and focal length, ensure that the fish behavior in the fish inlet 4 can be clearly captured, and the image can be stably transmitted and stored.

[0035] Check the opening and closing flexibility and sealing of the water outlet gate plate 6 to ensure that the water level and water outflow speed of the downstream water tank 5 can be accurately controlled.

[0036] 2. Preparation of Experimental Fish Select experimental fish species, such as bighead carp and carp. Keep the fish in a suitable environment to adapt them to the experimental environment. Before the experiment, conduct a health check on the fish to ensure that the fish are disease-free, have good vitality, and meet the experimental requirements. The body length of bighead carp ranges from 30-50mm, and the body length of carp ranges from 20-30mm.

[0037] The prepared fish are transferred to the downstream tank 5 and allowed to adapt to the downstream tank 5 for 30 minutes to reduce the stress response caused by the transfer.

[0038] 3. Set the shape of the fish inlet: First, set the fish inlet 4 to a fully open 401 shape, ensuring that it is firmly installed, well sealed, and there is no abnormal diversion or leakage of water flow.

[0039] 4. Adjust water flow parameters: Turn on the circulating water system, and adjust the water flow velocity at the downstream water tank 5 and the fish inlet 4 by controlling the opening of the water outlet gate 6 and the flow rate of the circulating water system. According to the experimental design, set different water flow velocity conditions, such as simulating a constant flow velocity of 0.2m / s at the inlet, a constant momentum flux of 0.15N, and a no-flow condition of 0m / s. At the same time, measure and record the actual water flow velocity under different conditions, and obtain data through the flow velocity sensor.

[0040] 5. Experimental data collection: During the experiment, the flow velocity sensor measures and records the water flow velocity data at different positions and depths of the downstream water tank 5 and the fish inlet 4 in real time. The data collection frequency is set to 50 Hz, and the data of the entire experimental process is continuously collected.

[0041] The camera 7 continuously shoots the behavior of the fish in the fish inlet 4, and records the time, quantity, swimming trajectory, residence time and other information of the fish entering the fish inlet 4. The video data is stored in a special storage device for subsequent analysis.

[0042] 6. Repeat the experiment: After completing the experiment of the fish inlet with the elliptical opening 401, change the shape of the fish inlet 4 to the vertical elliptical slot 402, and repeat the above experimental steps such as adjusting the water flow parameters and collecting data. Experiments are conducted on the fish inlets with the triangular slot 403 and the fan-shaped opening 404 in turn to ensure that the fish inlets of different shapes are fully tested under the same experimental conditions (except for the shape of the fish inlet).

[0043] After the experiment is over, the circulating water system, the camera 7 and other equipment are turned off in sequence, and the water outlet gate 6 is closed to stop the water flow.

[0044] Carefully transfer the fish in the downstream tank 5 back to the original breeding environment, observe the status of the fish, and ensure that the fish are not harmed during the experiment.

[0045] The water flow velocity data collected by the flow sensor is sorted and stored according to different fish inlet shapes and water flow velocity configurations according to experimental conditions to ensure the accuracy and completeness of the data.

[0046] Arrange the video data captured by the camera 7, and perform preliminary processing on the video, such as marking the key time points when the fish enters the fish inlet 4, so as to analyze the fish behavior data in detail later. Store the sorted data in a safe and reliable storage medium, and back up the data to prevent data loss.

[0047] Result analysis of the embodiment: The data collected by the flow velocity sensors at the downstream water tank 5 and the fish inlet 4 under different fish inlet shapes and water flow velocity configurations are analyzed. The average flow velocity, flow velocity variation range (such as standard deviation) and flow velocity distribution at different positions and depths are calculated. By comparing the flow velocity data under different fish inlet shapes, the influence of the fish inlet shape on the water flow velocity is analyzed, for example, to observe which shape of the fish inlet can produce a more stable and more conducive water flow velocity condition for fish entry.

[0048] Fish behavior data analysis: Use video analysis software to analyze the video data captured by camera 7 in detail. According to the video records, count the number of fish entering the fish inlet 4 under different fish inlet shapes and water flow speed configurations (maximum number ), proportional residence time ( ), the first fish enters the time ( ) and the cumulative reentry frequency ( ) and other behavioral indicators.

[0049] Analyze the movement trajectories of fish in the fish inlet 4, observe the preferred swimming areas of fish under different fish inlet shapes, and how fish respond to different water flow speeds and fish inlet shape conditions. Combined with flow data, explore how water flow speed and fish inlet shape jointly affect fish behavior, such as whether fish tend to enter in low-flow areas or certain locations of a specific fish inlet shape.

[0050] According to the results of flow rate analysis and fish behavior analysis, the advantages and disadvantages of different fish inlet shapes in attracting fish into the fishway are comprehensively evaluated. Determine which fish inlet shape can better attract fish to enter under different water flow conditions, so that fish have a more appropriate residence time and entry efficiency, while considering factors such as fish behavior preferences and energy consumption. Through the research results of this embodiment, a scientific basis is provided for the design of the inlet shape of actual fish passing facilities, and optimization suggestions are put forward to improve the effectiveness of fish passing facilities and promote the smooth migration of fish through obstacles.

[0051] Example 2 Further illustrate with reference to Example 1, Figure 1-5 The structure shown in FIG. 1 includes: S1, camera 7 records the swimming behavior of fish under different inlet geometries and suction flow conditions, recorded through top and side views; The first flow sensor installation location 8 and the second flow sensor installation location 9 use a micro acoustic Doppler current meter to measure the instantaneous velocity at four horizontal layers at different water depths. , and data, and the calculated average flow rate ( , , ), standard deviation ( , and ) and turbulent kinetic energy data; Different attraction flow configurations are set for different sizes of fish inlets 4, and the attraction flow configurations include flow velocity, different inlet flow velocities corresponding to constant momentum flux, and no-flow conditions; S2, extracting image data frame by frame from the experimental recording video, and identifying the position and number of fish for each frame of the image; Through image recognition algorithms, deep learning-based object detection algorithms, including YOLO or FasterR-CNN, pre-trained to identify specific fish species; Record the time point when the fish enters the fish inlet 4: by tracking the movement trajectory of the fish, record the time when the center position of the fish crosses the boundary of the fish inlet 4; The extracted data were classified and sorted according to different fish inlets 4 and suction flow configurations; For each specific combination of entrance geometry and attractor flow configuration, a data list is created, where each element contains the number of fish at that moment and the entry time information; S3, reading a flow velocity measurement data file, and associating the flow velocity data of the measurement point with the corresponding inlet geometry and suction flow configuration, wherein the flow velocity data includes an average flow velocity, a standard deviation, and a turbulent kinetic energy; The flow velocity data are spatially matched with the fish behavior data according to the location of the measurement points in the downstream area of ​​the inlet and the fish inlet 4; The average flow velocity, flow velocity variation range and turbulent kinetic energy distribution at different positions in the fish inlet 4 were calculated under different inlet geometries and suction flow configurations; Analyze the relationship between flow velocity data and fish behavior, observe the distribution of fish in high and low flow velocity areas, and the changes in fish swimming trajectories under different TKE levels; S4. Calculation of fish behavior indicators: For the time series data of the number of fish under each experimental condition, traverse the list to find the maximum number of fish, which is ; According to the formula Calculate, where is the number of fish in the fish inlet 4 at each moment, and S is the total number of fish put in each experiment; For each experimental condition, calculate the total time the fish spent in the fish inlet 4. ,in is the number of fish in the fish inlet 4 at each moment, The time that the fish stays in the fish inlet 4 at that moment is calculated by the time interval between adjacent frames; Calculate the total duration of the experiment : According to the formula Calculate proportional residence time; In the fish entry time data for each experimental condition, find the time point when the first fish enters fish inlet 4 ; According to the formula Calculate the time when the first fish enters; The number of times the fish re-entered the fish inlet 4 during the one-hour experimental period was counted under each experimental condition; Calculate the cumulative re-entry frequency, which is the average number of times per hour that fish re-enter the fish inlet4; S5. Create a data table with rows representing different combinations of inlet geometry and attraction flow configurations and columns including , , , and flow rate related data; Fill in the calculated fish behavior indicators and flow velocity data into the table; Analyze the effects of different inlet geometries and suction flow configurations on fish behavior indicators: including comparing size, judge which shape is more attractive to fish; observe Relationship with flow velocity and inlet shape to understand the willingness of fish to stay under different conditions; and to assess the impact of entrance design on fish entry efficiency and repeated entry behavior; Draw charts, such as bar graphs, to show the impact of different inlet geometries The line chart shows The trend of flow rate changes, etc., can present the results more intuitively.

[0052] Example of experimental analysis of the effect of fishway entrance design on fish attraction In water conservancy projects, fishways are important facilities to ensure fish migration, but the design of fishway entrances has a significant impact on the fish attraction effect. In order to further study how different entrance geometries and attraction flow configurations affect the behavior of fish entering fishways, this experimental example was carried out. Based on a specific experimental device and experimental process, this example studies bighead carp and carp, aiming to provide a scientific basis for the design of fishway entrances.

[0053] Example equipment and environment: An open fish passage experimental tank 1 with a length of 5 meters and a width and height of 0.5 meters was used as the experimental body. A 1.0-meter-long observation channel (OC) was set in the tank, and both sides of the observation channel were made of glass to facilitate the observation of fish behavior.

[0054] An inlet pipe (ET) with a diameter of 0.2 m and a length of 0.5 m is connected upstream of the observation channel. There is a circular opening on the top of the inlet pipe to ensure that the internal light conditions are similar to those of the observation channel. At the upstream end of the inlet pipe, there is a water inlet pipe with a diameter of 0.05 m, which gradually expands to the 0.2 m inlet pipe to deliver a uniform water flow from the circulation system.

[0055] The SonTek 16MHz miniature acoustic Doppler velocimeter (ADV) was used to measure the water velocity. The ADV can accurately measure the water velocity in four horizontal layers ( , 0.3d, 0.5d and 0.7d, where d = 0.15 m is the water depth) , and .

[0056] Equipped with a Yamatake Honeywell flow meter to monitor water flow, with an accuracy of up to ±0.5% of the flow rate.

[0057] The fish species used in the experiment are bighead carp and carp, with the body length of bighead carp ranging from 30-50 mm and that of carp ranging from 20-30 mm.

[0058] Prior to the experiment, the fish were maintained in twelve polyethylene tanks of 1.2 × 10 cm (2.3 × 10 cm) in the temperature-controlled fish culture facility at the UNSW Water Research Laboratory. or Fish were fed pelleted feed supplied by Aquaculture once a day in the morning and were kept on a 12-h light-dark cycle (from 6 a.m. to 6 p.m.). During the experiment, water quality within the experimental facility, including conductivity, ammonia, nitrates, pH, dissolved oxygen, and temperature, was assessed daily to ensure that the water quality was within the range suitable for fish survival. 10% of the water was transferred from the fish farming facility to the experimental facility daily to maintain similar water quality conditions. The experimental water temperature was controlled at 19°C-21°C by three glass aquarium heaters (AquaOneTM) Example process: Experimental preparation: Build the experimental device according to the above equipment and environmental requirements, and ensure that the water tank, inlet pipe, observation channel, water inlet pipe, flow meter, flow meter and other equipment are installed accurately and operate normally.

[0059] The experimental fish were adaptively raised to adapt them to the experimental environment and breeding conditions.

[0060] Experimental operation: Inlet geometry setting: Four different inlet geometries were set for the experiment, namely, elliptical opening (FO) inlet, vertical elliptical slot (S) inlet (width 0.03 m), semicircular (SC) inlet, and quarter-circular (QC) inlet. When changing the inlet geometry, ensure that the inlet pipe is tightly connected to the observation channel without water leakage or abnormal water flow.

[0061] Attraction flow configuration adjustment: For each inlet geometry, three attraction flow configurations are set: First, set the constant flow rate at the inlet to By adjusting the flow rate of the circulation system, the constant flow rate is achieved under different inlet geometries. At this flow rate, the flow rate of the FO inlet is 4.70 L / s, the S inlet is 0.81 L / s, the SC inlet is 2.39 L / s, and the QC inlet is 1.49 L / s.

[0062] Then set the constant momentum flux to , the inlet suction flow rates corresponding to different inlet geometries are: FO is (flow rate 1.96L / s), S is (flow rate 0.81L / s), SC is (flow rate 1.39L / s), QC is (flow rate 1.09L / s).

[0063] Finally, set the no-flow condition, that is, turn off the water flow, so that the inlet flow rate is .

[0064] Fish experimental manipulations: For each flow condition and inlet geometry combination (a total of 12 experimental treatments, each treatment including four inlet geometries and three flow rate configurations), three groups of five bighead carp and three groups of five common carp were randomly selected for testing.

[0065] Before the experiment, the fish were carefully transferred from the rearing tank to the starting area of ​​the experimental tank and allowed to acclimate for 30 min. The inlet was then opened to establish the suction flow and start the 60-min experimental observation period.

[0066] During the experiment, two GoPro HERO8 cameras (1080p, 60fps) were used to film the fish behavior from the top and side. The cameras were controlled by a PC located outside the observation area to ensure clear and stable images and to fully record the activities of the fish in the observation channel and the entrance tube area.

[0067] Data collection: Under each inlet geometry and suction flow configuration, SonTek 16 MHz miniature acoustic Doppler velocimeter (ADV) was used to measure the flow velocity at four horizontal layers ( , 0.3d, 0.5d and $0.7d) to measure instantaneous velocity , and At each measurement point, two minutes of data were collected at a frequency of 200 Hz, focusing on 80 measurement points in the downstream area of ​​the inlet and 23 measurement points inside the inlet pipe. In total, 3000 points of flow velocity were measured under all inlet geometries and flow rate conditions (depending on the combination of experimental conditions, such as the distribution of measurement points under different inlet geometries and flow rate configurations).

[0068] To improve the quality of ADV raw data, clay powder was added to the water to provide additional suspended sediment. The raw data were then post-processed using WinADV software to calculate the average flow velocity at each measurement point ( , , ), standard deviation ( , and ) and turbulent kinetic energy (TKE).

[0069] Fish behavior data collection: The fish behavior data were recorded by video captured by the camera, including the time when the fish entered the fish inlet 4, the residence time in the inlet tube, the swimming trajectory of the fish, etc. After the experiment, the video was manually analyzed using VLC media player.

[0070] For the time when the fish entered the entrance tube, the time was recorded to the nearest second when the fish's center position crossed the entrance tube boundary by reviewing the video frame by frame. For the time the fish stayed in the entrance tube, the time interval from the fish entering the entrance tube to leaving the entrance tube was calculated based on the video timeline.

[0071] When analyzing the swimming trajectory of fish, for the first fish entry under each experimental condition, the open source video analysis software Tracker (Brownetal., 2020) was used to manually analyze the swimming trajectory of the fish frame by frame (60fps), focusing on the swimming behavior of the fish in the observation channel and recording the speed and direction changes of the fish at different positions.

[0072] Example result analysis: 1. Flow velocity distribution under different inlet geometries At constant inlet velocity When the velocity distribution of the FO and S inlet geometries is similar, the attraction flow forms a straight jet downstream of the inlet, and two recirculation zones are generated in the channel corners. However, the SC and QC inlets produce asymmetric attraction flow, with similar flow patterns but different intensities due to different opening sizes (SC has a large opening, high momentum flux, and greater attraction flow intensity). In the inlet pipe, the FO and SC inlets are close to the riverbed ( ) The flow velocity is high, the flow velocity in the upper layer is reduced, and the flow velocity in the tube is complex, and there is a roller-like motion ( negative velocity).

[0073] For a constant momentum flux ( ) case, the flow pattern is similar to the constant velocity case, but the size of the attraction flow is different. The inlet velocities of FO, SC and QC are reduced, with an average reduction of 23%75%. The velocity and TKE values ​​are larger in the inlet pipe, the largest near the bottom, and decrease with height.

[0074] 2. TKE Distribution Under all inlet geometries, TKE is highest downstream of the inlet and decays with distance, with a shape similar to the flow velocity. The TKE value in the inlet pipe is significantly higher than that in the observation channel, reflecting the chaotic nature of the water flow in the inlet pipe. The strongest TKE value is near the riverbed ( ),upper layer( ) was significantly reduced, with a reduction of 60%.

[0075] Fish behavior data analysis: 1. Analysis of fish swimming trajectories: The swimming trajectories of bighead carp and carp are significantly different under different entrance geometries. At the SC entrance, most bighead carp prefer to use the jet side walls; at the QC entrance, bighead carp prefer to swim along the middle of the channel and the non-jet side walls, which indicates that the flow submergence at the QC entrance may affect the response of bighead carp. The trajectories of carp appear on both side walls at the SC entrance. In general, most fish tend to swim in low-velocity areas, some fish will adjust their positions before entering, and use sprint swimming to approach the entrance. When entering, some fish swim along the main suction jet, and some look for favorable conditions to enter. Fish will avoid the backflow area near the entrance caused by the jet angle.

[0076] 2. Comparative analysis of entry performance: Number of entries ( ): Different entrance geometries had a certain effect on the number of fish entering the entrance tube, but overall bighead carp and carp had no obvious preference for different combinations (the two-way interaction was not significant, bighead carp , ;carp , However, there was a significant two-way interaction between fish species and suction current velocity ( , ), the number of carp entering the inlet pipe was the largest under no-flow conditions (FO, S and SC inlet ).

[0077] Dwell time ( ): Reduce the FO inlet velocity to (Constant Momentum) can increase the residence time of bighead carp (the ratio is 3.33, ); Carp stayed longer when there was no flow (the ratio was 0.26, ), the FO inlet stays for the longest time when there is no flow (55%), and when the FO inlet flow rate is reduced to (constant momentum), Increased by 46% (ratio of 5.82, ).

[0078] Enter time ( ): Entrance geometry had no significant effect on fish entry time (two-way interaction between entrance geometry and entry time for bighead carp and common carp , ), the velocity of the attraction flow and the type of fish also had no significant effect on the entry time (two-way interaction , ), but carp enter the inlet pipe faster under constant speed conditions (except for the SC inlet design, ).

[0079] Cumulative reentry frequency ( ): The entrance geometry had no significant effect on the cumulative re-entry frequency of bighead carp and common carp ( , ), but there was a significant two-way interaction between the velocity of the attraction flow and the species of fish ( ), FO inlet is at no flow Maximum (up to 185, a ratio of 6.50 compared to constant speed, ; Compared with the constant momentum, the ratio is 5.40, ).

[0080] Summary and discussion of results: 1. The results of this example show that the inlet geometry and the configuration of the attraction flow have a significant effect on the behavior of fish entering the fishway inlet pipe. Different inlet geometries change the velocity distribution and turbulence characteristics of the water flow, which in turn affects the swimming trajectory and entry performance of fish. For example, the asymmetric flow patterns of semicircular and quarter-circular inlets change the swimming trajectory of fish and show different attraction effects in some aspects compared to elliptical openings and vertical elliptical slotted inlets.

[0081] 2. The behavior patterns of fish in the experiment are closely related to the characteristics of the water flow. Fish tend to swim in low-velocity and low-turbulence areas to reduce energy consumption, which is similar to the use of low-velocity areas near the river bank ("flow refuge" behavior) by fish in natural rivers. At the same time, before entering the inlet pipe, the fish will use sprint swimming to approach the Example 3 Further illustrate with reference to Examples 1-2, Figure 1-5The structures shown were tested for attraction performance using GLMs generalized linear models, LMs linear models and ANOVA analysis of variance to determine the importance of predictors such as inlet geometry, flow rate and fish species and their effects on fish attraction indices; A1. Arrange and collect relevant data obtained in the experiment, including fish behavior data under three suction flow configurations: an elliptical opening 401, a vertical elliptical slot 402, a triangular slot 403, or a fan-shaped opening 404; Including the maximum number of fish in the fish inlet (4) , the proportion of time that fish stay in the fish inlet 4 , the time when the first fish enters the fish inlet 4 and the cumulative re-entry frequency of fish per 1-hour experimental period , and corresponding information such as inlet geometry, flow velocity, and fish species; A2. For , due to the existence of overdispersion, quasi-binomial GLM is selected; It obeys binomial distribution, and its probability distribution function is: ,in is the number of trials, is the number of fish that actually enter the fish inlet 4 ( ), is the probability of success; In the quasi-binomial GLM, the linear predictor is linked to the mean by building a linked logit function Connect, that is ,in is the connection function, is the linear predictor, is the regression coefficient to be estimated, For predictor variables, they included inlet geometry, flow velocity, and fish species; A3, the time when the first fish enters the fish inlet 4 and and residence time ratio , linear model regression and ANOVA were used; The linear model is expressed as: ,in is the response variable, or , is the regression coefficient, is the predictor variable, is the error term, where Normal distribution with mean 0 and variance ; for and , before applying the linear model, the data is log-transformed, where , to meet the normality assumption, and then fit and analyze the linear model based on the transformed data; A4. ANOVA is used to test whether there are significant differences in the means between different groups. Here it is mainly used to analyze the effects of inlet geometry, flow rate, and fish species on the and The impact of The basic idea of ​​ANOVA is to decompose the total variation into variations from different sources, and then judge whether the influence of the factors is significant by comparing the size of these variations; calculate the total sum of squares , between-group sum of squares and within-group sum of squares , and according to the formula calculate Statistics, where , , is the between-group degrees of freedom, is the within-group degrees of freedom; calculated by comparing Value and critical value, to judge whether the influence of factors is significant; A5. Inlet geometry, flow velocity and fish species were included as predictors in the model for a three-way interaction analysis to comprehensively evaluate the complex interactions between these factors on fish attraction indicators. , , , The impact of In the model, all possible interaction terms are considered, such as the interaction terms between inlet geometry and flow velocity, the interaction terms between inlet geometry and fish species, the interaction terms between flow velocity and fish species, and the interaction terms among the three; the corresponding statistics are calculated, including regression coefficients, Statistics and evaluate their significance value; A6. Check the results of the three-way interaction analysis. If all or most of the interaction terms are The values ​​are greater than the set significance level , it indicates that the three-way interaction is not significant; in this case, consider simplifying the model and conducting a two-way interaction analysis; A7. Perform pairwise interaction analysis between inlet geometry and flow rate, inlet geometry and fish species, and flow rate and fish species; In each two-way interaction analysis, the model was rebuilt to include only the corresponding two predictors and their interaction terms; the regression coefficients, Statistical indicators such as statistics and evaluate their significance; Among them, the interaction between inlet geometry and flow velocity is analyzed. When the influence of ,in represents the inlet geometry, Indicates flow rate, is the interaction term between the two; A8. For the significant interactions found in the two-way interaction analysis, the EstimatedMarginalMeans package was used for comparative analysis. This method calculates the marginal means under different level combinations and compares them pairwise to determine which level combinations have significant differences. In cases where the interaction between inlet geometry and flow rate is significant, the marginal means for different inlet geometries at different flow rate levels are calculated. , and compare; if The difference is significant, according to the corresponding standard error and The value is judged, which means that at this flow rate level, the inlet geometry and Have significantly different effects on fish attraction performance; A9. Based on the results of the statistical analysis, explain how factors such as inlet geometry, flow velocity, and fish species affect fish attraction indicators; The entire analysis process was completed using R software to ensure the accuracy of the calculation and the reliability of the results.

[0082] Generalized linear models (GLMs), linear models (LMs), and analysis of variance (ANOVA) play an important role in testing attraction performance: Generalized Linear Models (GLMs): Working principle: GLMs are an extension of linear models that allow the response variable to follow distributions other than normal distribution (such as binomial distribution, Poisson distribution, etc.), and link the linear predictor to the mean of the response variable through a link function. (The maximum number of fish in the inlet tube), due to its data characteristics (may be over-dispersion, does not meet the normal distribution assumption), the quasi-binomial GLM is used. It can handle this non-normal distribution data and reasonably model The relationship between the inlet geometry, flow rate and fish species and other predictors can be estimated. For example, by estimating the regression coefficients, it is possible to quantify the influence of different inlet geometries and flow rates on the maximum number of fish entering the inlet tube and to determine which factors have an impact on the maximum number of fish entering the inlet tube. The influence of is more significant, thus providing a basis for optimizing the design of fishway entrances, that is, determining which combination of entrance geometry and flow rate is more conducive to attracting more fish into the entrance pipe.

[0083] Linear models (LMs): How it works: Linear models assume that there is a linear relationship between the response variable and the predictor variable. Its general form is (in is the response variable, is the regression coefficient, is the predictor variable, is the error term and is assumed to be normally distributed). In this study, (the time when the first fish enters the entry tube) and The data were log-transformed to meet the normality assumption before applying the linear model. The linear model regression and ANOVA analysis were used to evaluate the effects of inlet geometry, flow rate, and fish species on the and The main effect of each factor is analyzed separately to see whether it has a significant effect on the response variable at different levels. At the same time, the variance analysis part can be used to test whether there is an interaction between these factors, such as whether the interaction between inlet geometry and flow rate has an effect on or This helps us to gain a deeper understanding of how different factors, alone or in combination, affect the time when fish enter the inlet pipe and the proportion of their residence time, and then adjust the fishway entrance design and water flow conditions based on the analysis results to optimize the fish attraction effect.

[0084] Analysis of variance (ANOVA): Working principle: ANOVA is mainly used to test whether multiple population means are equal and to decompose the total variation into between-group variation (caused by different factor levels) and within-group variation (random error). In this study, ANOVA was used to analyze the effects of inlet geometry, flow rate, fish species, etc. and By calculating Statistics ( , where MSB is the mean square between groups and MSW is the mean square within groups) and compared with the critical value to determine whether the factor has a significant effect. The value is significantly greater than the critical value. The value is less than the set significance level (such as ), it means that different inlet geometries have or The mean of the entrance geometry has a significant effect, that is, different entrance geometries have significant differences in the time it takes to attract fish into the entrance tube and the proportion of fish residence time. This helps to determine which factors are the key factors affecting fish attraction performance and whether there are interactions between these factors, providing a scientific basis for fishway design and the formulation of fish protection measures.

[0085] In summary, GLMs, LMs and ANOVA cooperated with each other in this study to analyze the effects of factors such as inlet geometry, flow rate and fish species on fish attraction performance (e.g. , , , It helps researchers to fully understand the relationship between fish behavior and fishway entrance design and water flow conditions, thereby providing scientific guidance for improving fishway efficiency and promoting fish migration.

[0086] In this study, , , , They represent the following meanings respectively: Maximum number of fish: The maximum number of fish in the inlet tube. ), which is the maximum number of fish in the inlet tube at any time. This indicator is used to measure the maximum number of fish that the inlet can accommodate under different experimental conditions, reflecting the inlet's ability to attract and accommodate fish. For example, if , indicating that during a certain experimental observation period, the maximum number of fish in the inlet tube reached 3.

[0087] (Proportional residence time): The proportion (percentage) of the time that the fish stays in the inlet pipe, which is calculated by the formula Calculate. is the number of fish in the inlet tube at any given time, yes The time that a fish spends in the inlet tube, is the maximum number of fish in the inlet tube, is the total experimental time. This indicator reflects the relative length of time that fish stay in the inlet pipe, which helps to understand the effects of different inlet geometries and flow conditions on fish stay behavior. For example, if , meaning that the time the fish stayed in the inlet tube accounted for 20% of the total experimental time.

[0088] (Time to first fish entry): The time (minutes) when the first fish enters the entry tube, calculated by the formula (when Calculate when is the cumulative experimental time (seconds). This indicator can reflect the initial reaction speed of fish to the entrance, that is, the time from the start of the experiment to the time when the first fish enters the entrance tube. The shorter the This may indicate that the entrance is more attractive to fish. For example, if Minutes means that 5 minutes have passed since the start of the experiment when the first fish entered the inlet tube.

[0089] (Cumulative fish re-entry frequency): The cumulative re-entry frequency of fish during each 1-hour experimental period, calculated by the formula Calculate, where is the number of fish entering per second during the experiment. This indicator measures how frequently fish enter the entrance tube during the experiment, reflecting the fish's exploratory behavior toward the entrance or the entrance's continued attraction to the fish. For example, if , indicating that the fish re-entered the entrance tube 10 times cumulatively during the 1-hour experimental period.

[0090] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A research device for the shape of the inlet of a fish passage facility, characterized by: The fish-passing experimental tank body (1) comprises a long strip structure, the middle part of which is separated by a fish inlet (4), one end of the fish-passing experimental tank body (1) is provided with a water outlet tank (2), the water outlet end of the water outlet tank (2) is connected to the fish inlet (4), and the other end of the fish-passing experimental tank body (1) forms a downstream water tank (5); A plurality of flow rate sensors are provided at the downstream water tank (5) and the fish inlet (4); A camera (7) is also provided inside the fish inlet (4).

2. The research equipment for the shape of the inlet of a fish passage facility according to claim 1, characterized in that: An observation port (3) is also provided above the water outlet trough (2), and a camera (7) is arranged on one side of the observation port (3).

3. The research equipment for the shape of the inlet of a fish passage facility according to claim 1, characterized in that: The fish passage experiment tank body (1) is also provided with a water outlet gate (6) at the tail of the downstream water tank (5).

4. The research equipment for the shape of the inlet of a fish passage facility according to claim 1, characterized in that: The shape of the fish inlet (4) is an elliptical opening (401), or a vertical elliptical slot (402), or a triangular slot (403), or a fan-shaped opening (404).

5. The research equipment for the shape of the inlet of a fish passage facility according to claim 1, characterized in that: The flow velocity sensor is a miniature acoustic Doppler flow meter, and the flow velocity sensor is arranged at different depth positions.

6. The method for analyzing the shape of the inlet of a fish passage facility according to any one of claims 1 to 5, characterized in that: The method includes: S1, camera (7) records the swimming behavior of fish under different inlet geometries and suction flow conditions, recorded from top and side views; The first flow sensor installation location (8) and the second flow sensor installation location (9) use a micro acoustic Doppler current meter to measure the instantaneous velocity at four horizontal layers at different water depths. , and data, and the calculated average flow rate ( , , ), standard deviation ( , and ) and turbulent kinetic energy data; Setting different attraction flow configurations for different sizes of fish inlets (4), the attraction flow configurations including flow velocity, different inlet flow velocities corresponding to a constant momentum flux, and a no-flow condition; S2, extracting image data frame by frame from the experimental recording video, and identifying the position and number of fish for each frame of the image; Through image recognition algorithms, deep learning-based object detection algorithms, including YOLO or FasterR-CNN, pre-trained to identify specific fish species; Recording the time point when the fish enters the fish inlet (4): by tracking the movement trajectory of the fish, recording the time when the center position of the fish crosses the boundary of the fish inlet (4); The extracted data were categorized and organized according to different fish inlets (4) and suction flow configurations; For each specific combination of entrance geometry and attractor flow configuration, a data list is created, where each element contains the number of fish at that moment and the entry time information; S3, reading a flow velocity measurement data file, and associating the flow velocity data of the measurement point with the corresponding inlet geometry and suction flow configuration, wherein the flow velocity data includes an average flow velocity, a standard deviation, and a turbulent kinetic energy; The flow velocity data were spatially matched to the fish behavior data based on the location of the measurement points in the downstream area of ​​the inlet and the fish inlet (4); Calculate the average flow velocity, flow velocity variation range and turbulent kinetic energy distribution at different locations in the fish inlet (4) under different inlet geometries and suction flow configurations; Analyze the relationship between flow velocity data and fish behavior, observe the distribution of fish in high and low flow velocity areas, and the changes in fish swimming trajectories under different TKE levels; S4. Calculation of fish behavior indicators: For the time series data of the number of fish under each experimental condition, traverse the list to find the maximum number of fish, which is ; According to the formula Calculate, where is the number of fish in the fish inlet (4) at each moment, and S is the total number of fish put in each experiment; For each experimental condition, calculate the total time the fish spent in the fish inlet (4). ,in is the number of fish in the fish inlet (4) at each moment, is the time the fish stays in the fish inlet (4) at that moment, calculated by the time interval between adjacent frames; Calculate the total duration of the experiment : According to the formula Calculate proportional residence time; In the fish entry time data for each experimental condition, find the time point when the first fish enters the fish inlet (4) ; According to the formula Calculate the time when the first fish enters; The number of times the fish re-entered the fish inlet (4) during the one-hour experimental period was counted for each experimental condition; The cumulative reentry frequency was calculated as the average number of times per hour that fish reentered the fish inlet (4); S5. Create a data table with rows representing different combinations of inlet geometry and attraction flow configurations and columns including , , , and flow rate related data; Fill in the calculated fish behavior indicators and flow velocity data into the table; Analyze the effects of different inlet geometries and suction flow configurations on fish behavior indicators: including comparing size, judge which shape is more attractive to fish; observe Relationship with flow velocity and inlet shape to understand the willingness of fish to stay under different conditions; and to assess the impact of entrance design on fish entry efficiency and repeated entry behavior; Draw charts, such as bar graphs, to show the impact of different inlet geometries The line chart shows The trend of flow rate changes, etc., can present the results more intuitively.

7. The method for analyzing the shape of the inlet of a fish passage facility according to claim 6, characterized in that: GLMs, LMs, and ANOVA were used to test the attraction performance and determine the importance of predictors such as inlet geometry, flow rate, and fish species and their effects on fish attraction indices; A1. Arrange and collect relevant data obtained in the experiment, including fish behavior data under three suction flow configurations: an elliptical opening (401), a vertical elliptical slot (402), a triangular slot (403), or a fan-shaped opening (404); Including the maximum number of fish in the fish inlet (4) , the proportion of time that fish stay in the fish inlet (4) , the time when the first fish enters the fish inlet (4) and the cumulative re-entry frequency of fish per 1-hour experimental period , and corresponding information such as inlet geometry, flow velocity, and fish species; A2. For , due to the existence of overdispersion, quasi-binomial GLM is selected; It obeys binomial distribution, and its probability distribution function is: ,in is the number of trials, is the number of fish that actually enter the fish inlet (4) ), is the probability of success; In the quasi-binomial GLM, the linear predictor is linked to the mean by building a linked logit function Connect, that is ,in is the connection function, is the linear predictor, is the regression coefficient to be estimated, For predictor variables, they included inlet geometry, flow velocity, and fish species; A3. The time when the first fish enters the fish inlet (4) and and residence time ratio , linear model regression and ANOVA were used; The linear model is expressed as: ,in is the response variable, or , is the regression coefficient, is the predictor variable, is the error term, where Normal distribution with mean 0 and variance ; for and , before applying the linear model, the data is log-transformed, where , to meet the normality assumption, and then fit and analyze the linear model based on the transformed data; A4. ANOVA is used to test whether there are significant differences in the means between different groups. Here it is mainly used to analyze the effects of inlet geometry, flow rate, and fish species on the and The impact of The basic idea of ​​ANOVA is to decompose the total variation into variations from different sources, and then judge whether the influence of the factors is significant by comparing the size of these variations; calculate the total sum of squares , between-group sum of squares and within-group sum of squares , and according to the formula calculate Statistics, where , , is the between-group degrees of freedom, is the within-group degrees of freedom; calculated by comparing Value and critical value (, to judge whether the influence of factors is significant; A5. Inlet geometry, flow velocity and fish species were included as predictors in the model for a three-way interaction analysis to comprehensively evaluate the complex interactions between these factors on fish attraction indicators. , , , The impact of In the model, all possible interaction terms are considered, such as the interaction terms between inlet geometry and flow velocity, the interaction terms between inlet geometry and fish species, the interaction terms between flow velocity and fish species, and the interaction terms among the three; the corresponding statistics are calculated, including regression coefficients, Statistics and evaluate their significance value; A6. Check the results of the three-way interaction analysis. If all or most of the interaction terms are The values ​​are greater than the set significance level , it indicates that the three-way interaction is not significant; in this case, consider simplifying the model and conducting a two-way interaction analysis; A7. Perform pairwise interaction analysis between inlet geometry and flow rate, inlet geometry and fish species, and flow rate and fish species; In each two-way interaction analysis, the model was rebuilt to include only the corresponding two predictors and their interaction terms; the regression coefficients, Statistical indicators such as statistics and evaluate their significance; Among them, the interaction between inlet geometry and flow velocity is analyzed. When the influence of ,in represents the inlet geometry, Indicates flow rate, is the interaction term between the two; A8. For the significant interactions found in the two-way interaction analysis, the EstimatedMarginalMeans package was used for comparative analysis. This method calculates the marginal means under different level combinations and compares them pairwise to determine which level combinations have significant differences. In cases where the interaction between inlet geometry and flow rate is significant, the marginal means for different inlet geometries at different flow rate levels are calculated. , and compare; if The difference is significant, according to the corresponding standard error and The value is judged, which means that at this flow rate level, the inlet geometry and Have significantly different effects on fish attraction performance; A9. Based on the results of the statistical analysis, explain how inlet geometry, flow velocity, and fish species factors affect fish attraction indicators; The entire analysis process was completed using R software to ensure the accuracy of the calculation and the reliability of the results.

Images