Measuring equipment and measuring method for fish survival suitability based on gill cover activity

Abstract

The invention discloses fish survival suitability measuring equipment and method based on gill cover activity, and aims to accurately monitor response of fishes to environmental factors such as water temperature and sand content. The equipment comprises a test environment simulation module, a gill cover activity monitoring module and a data processing module. The test environment simulation module comprises a temperature control unit, a stirring unit and a water quality regulation and control assembly; the gill cover movement monitoring module comprises a distance sensor and a passive reflector and is used for realizing high-precision gill cover distance L monitoring; the data processing module determines a survival state based on the L value. According to the determination method, quantitative evaluation is realized through fish pretreatment, environmental variable gradient adjustment, 12-hour gill cover activity monitoring and death rate grading. According to the method, a technical route of'active coding emission + passive reflection 'is adopted, the limitation of traditional image recognition in a turbid water body is overcome, multivariable interaction analysis and individual difference correction are combined, and a scientific basis is provided for reservoir ecological scheduling and river ecological protection.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aquatic organism ecology and environmental monitoring, and specifically relates to a survival suitability determination device and method based on fish physiological indicators, which is particularly suitable for monitoring the response of fish to environmental factors such as water temperature and sediment concentration in river ecosystems under the background of water conservancy scheduling, and can be applied to scenarios such as reservoir ecological scheduling optimization, river ecological protection, and water environment risk assessment. BACKGROUND

[0002] River ecosystems are a core component of global ecosystems and play an irreplaceable role in biodiversity protection, water purification, ecological balance maintenance, flood control and disaster reduction, and climate regulation. Fish, as key species in the food chain of river ecosystems, their survival suitability directly reflects the health status of the ecosystem. However, climate change and human activities such as dam construction have significantly changed the natural hydrological characteristics of rivers: during the pre-flood discharge and sediment discharge process of reservoirs, low-temperature water and high-sediment water are concentrated and discharged, causing a dramatic change in the survival environment of downstream fish, and even causing the "floating fish" phenomenon (such as the large number of fish floating and dying during the Yellow River water and sediment regulation), which seriously threatens the stability of the ecological system. Therefore, accurately determining the survival suitability of fish under different water temperatures and sediment concentrations and determining their optimal survival threshold are of great significance for optimizing reservoir scheduling and protecting river ecology.

[0003] Taking the Yellow River flood season water and sediment regulation as an example, the short-term large discharge of sediment will cause a significant increase in sediment concentration in the downstream river channel in a short period of time, accompanied by the discharge of low-temperature water, which will affect the downstream river ecosystem and cause the "floating fish" phenomenon, with a large number of carp floating on the water surface, causing adverse effects on the water environment and affecting the ecological environment. If the survival suitability of fish under different water temperatures and sediment concentrations can be accurately determined and their optimal survival threshold can be determined, it will naturally be better to guide the practice of Yellow River flood season water and sediment regulation.

[0004] I. Prior art and application limitations Currently, the determination of fish survival suitability mainly relies on experience estimation, lacking scientific and quantitative standards, especially the lack of research on the impact of sediment stress. In the application of new technologies, image recognition methods (such as improved YOLOv8 and Mask-Rcnn) are the mainstream means for fish state monitoring, but they have significant defects: Macro-behavior dependence leads to judgment bias: YOLOv8 and Mask-Rcnn identify the state based on the overall behavior of fish (such as floating, sinking) or morphological features (such as body length, outline), which cannot capture the small movements of the gills or metabolic changes, making it difficult to distinguish between "false death" (such as coma caused by low temperature / high sediment concentration) and real death, and prone to misjudgment.

[0005] Poor adaptability to high-sand environments: the increase in water turbidity reduces image contrast and obscures fish contours, leading to a decrease in the detection accuracy of the YOLOv8 lightweight model and a significant increase in the false detection rate of instance segmentation by Mask-Rcnn due to its reliance on clear contours.

[0006] Data costs and lack of physiological quantification: existing methods require the annotation of a large amount of fish morphology data at different sand concentrations, which is costly; and can only qualitatively determine life and death, and cannot quantify fish physiological load (such as breathing rate and metabolic intensity), making it difficult to support the hierarchical evaluation of survival suitability.

[0007] II. Cause analysis of technical defects Direct technical reasons: existing technologies focus on the correlation between "external morphology-behavior" and fish survival status. Accordingly, the present invention establishes a new technical route for monitoring fish survival suitability through gill cover activity.

[0008] Historical development reasons: technological development has the characteristic of path dependence, such as the wheel spacing of the train using the wheel spacing of the previous standard horse carriage when it appeared; when introducing new technologies to monitor fish survival suitability, the technical route in this field is to use new technologies (deep learning, neural networks, image recognition) to implement old methods, to monitor fish "external morphology-behavior" through new technologies, and then to obtain fish survival status by using the correlation between "external morphology-behavior" and fish survival status.

[0009] III. Necessity of improvement Existing technologies cannot meet the demand for high-precision and high-adaptability fish survival status monitoring, leading to a lack of scientific basis for reservoir regulation and a prominent contradiction between ecological protection and engineering operation. Therefore, it is urgent to develop a measuring device and method that can directly quantify fish physiological status, is not disturbed by water turbidity, and can accurately evaluate survival suitability, in order to fill the gap in existing technologies and provide key technical support for river ecological protection and reservoir optimization. SUMMARY

[0010] The purpose of the present invention is to provide a measuring device for fish survival suitability based on gill cover activity, which realizes high-precision monitoring of gill cover micro-movement and implements the technical idea of monitoring fish survival suitability through gill cover activity.

[0011] To achieve the above-mentioned purpose, the measuring device for fish survival suitability based on gill cover activity of the present invention comprises a test environment simulation module, a gill cover activity monitoring module and a data processing module; The test environment simulation module comprises a test barrel for containing water, and a temperature control unit for adjusting water temperature and a stirring unit for adjusting sand content are arranged in the test barrel; The gill cover activity monitoring module comprises a distance sensor and a passive reflector, the distance sensor and the passive reflector are symmetrically installed on the outer surface of the gill cover of the fish, and the distance sensor is in communication connection with the data processing module to transmit the gill cover distance data. The distance sensor is configured to emit a detection signal with a unique feature code, and the passive reflector is configured to reflect the detection signal back to the distance sensor. The data processing module calculates the gill cover distance L according to the coding verification result of the reflected signal and the round trip time, and determines the survival state of the fish based on the L value.

[0012] The feature code of the distance sensor includes at least one of frequency coding, pulse sequence coding and amplitude modulation; the frequency coding is narrowband ultrasonic wave of 40 kHz±0.5 kHz, the pulse sequence coding is pulse group with preset time interval, and the amplitude modulation is signal amplitude changing according to sine law.

[0013] The distance sensor is built-in with a band-pass filter and a coding verification unit; the band-pass filter only allows signals in the frequency band of 40 kHz±0.5 kHz to pass, and the coding verification unit is used to compare the consistency of the received pulse sequence with the preset sequence.

[0014] The data processing module pre-stores a signal round trip time threshold Tmax, Tmax is calculated according to the maximum designed distance Lmax between the distance sensor and the passive reflector, when the actual round trip time>Tmax, the reflected signal is determined as invalid and discarded.

[0015] The passive reflector is a metal plating layer or a high-reflectivity film, and the ultrasonic reflectivity is >90%, and the surface is coated with a biocompatible waterproof material.

[0016] The temperature control unit comprises a semiconductor refrigeration sheet, a water temperature sensor and a temperature controller; the semiconductor refrigeration sheet is installed in the test barrel and extends into the water, the water temperature sensor is electrically connected with the temperature controller, the temperature controller controls the semiconductor refrigeration sheet to switch between heating and cooling modes according to the detection value of the water temperature sensor, the temperature control range is 1-60℃, and the sensitivity is 0.1℃.

[0017] The stirring unit comprises a variable frequency stirrer and an isolation net; the isolation net is horizontally arranged at a position 30 cm above the bottom of the test barrel, and the stirring blade of the variable frequency stirrer is located below the isolation net, the rotation speed range is 0-100 rad / min, and the length of the stirring blade is 0.2 m.

[0018] The standard for determining the survival state based on the gill cover distance L is: when L < 0.6 Lmax, it is determined as "poor state", and when L = Lmin, it is determined as "death state", wherein Lmax is the maximum distance of gill cover activity, and Lmin is the minimum distance of gill cover rest.

[0019] It also comprises an oxygen increasing instrument (6), a water quality instrument and a dissolved oxygen sensor, the dissolved oxygen sensor is electrically connected with the water quality instrument, the water quality instrument is electrically connected with the oxygen increasing instrument (6), when the dissolved oxygen concentration of the water body is lower than the initial value or the set value, the oxygen increasing instrument (6) is automatically started.

[0020] The application also discloses a determination method using the determination equipment for fish survival fitness degree based on gill cover activity. (1) Fish pretreatment: the test fish is rested for 24 hours in a natural state to eliminate the interference of stress reaction on physiological state; (2) Environmental variable gradient adjustment: adjusting the test environmental variable A, including water temperature and sand content, gradually changing the variable A according to the gradient a, the water temperature gradient is 1-2 DEG C / gradient, and the sand content gradient is 5-10 kg / m³ / gradient; after adjusting one gradient, 6 hours are maintained to ensure that the fish is fully adapted to the environmental change; (3) Gill cover activity monitoring and data acquisition: after the variable A reaches the target value, the gill cover activity is continuously monitored through the distance sensor and the passive reflector for 12 hours, and the gill cover distance L value change and the fish mortality rate are recorded in real time; (4) Survival fitness degree grading: according to the 12-hour mortality rate, the survival fitness degree is divided into five levels: 0% mortality rate is "suitable", 0%-33% is "generally suitable", 30%-66% is "relatively suitable", 66%-100% is "unsuitable", and 100% is "very unsuitable".

[0021] The application has the following advantages: In the fish survival monitoring, the application discloses the following technical principle: the gill cover movement is a direct embodiment of the fish breathing function, and the frequency and amplitude change can reflect the survival state in real time.

[0022] The present application realizes high-precision monitoring of gill cover micro-movement through the closed-loop design of "active coding transmission + passive reflection", combining coding verification and time threshold filtering, solves the false detection problem of traditional image recognition in turbid water, and specifically includes feature coding transmission, high reflection characteristics of passive reflector, and multiple filtering mechanism of receiving end, which cooperates to improve the monitoring stability in poor water quality environment, obtains accurate L value, and accurately judges the survival state of fish.

[0023] Multi-dimensional feature coding ensures signal uniqueness, 40kHz narrowband frequency avoids fish body natural vibration noise, pulse sequence and amplitude modulation form "signal fingerprint", effectively distinguishing target reflection from environmental interference (such as water flow and fish body friction).

[0024] Double mechanism of hardware filtering (band pass filter) and algorithm verification (coding matching) excludes non-target frequency noise and irregular diffuse reflection signal from physical layer and signal layer, reduces the reflection interference signal strength of non-gill cover area of fish body to less than 1 / 5 of the target signal, and guarantees the effectiveness and accuracy of distance monitoring.

[0025] Through time threshold limitation (such as Tmax≈66μs when Lmax=5cm), filter long-distance reflection (such as fish body trunk and container wall), only keep the effective signal of gill cover area, further improve the anti-interference and distance measurement accuracy.

[0026] High reflectivity (90%) ensures the effective return of weak detection signal, passive design simplifies the structure and does not need power supply, waterproof material guarantees long-term stable work underwater, meets the miniaturization and low interference demand of fish physiological monitoring, and matches the situation of ultrasonic sensor used in distance sensor.

[0027] The closed-loop temperature control system realizes high-precision water temperature regulation, and 0.1℃ sensitivity ensures the accuracy of environmental variable control, providing a stable temperature background for gill cover activity monitoring.

[0028] The isolation net can prevent fish from contacting the stirring blade, and the variable frequency stirrer realizes uniform distribution of sediment content through 0-100 rad / min speed regulation, simulates the natural water body sediment environment, and ensures the controllability of test variables.

[0029] Below Lmax, the larger L indicates the better fish state; objective judgment of survival state is realized through quantitative threshold, avoiding artificial observation error, providing standardized data support for subsequent survival suitability classification.

[0030] Dissolved oxygen closed-loop control excludes dissolved oxygen interference, polyethylene test tank avoids water pollution, 1.5m×1.3m size provides sufficient test space, and ensures the natural activity state of fish.

[0031] The determination method has the following advantages: Quantitative grading standard: the objective grading of survival fitness is realized in the mortality interval, the subjectivity of traditional experience estimation is avoided, the quantitative evaluation of fish survival fitness is realized, scientific basis is provided for water conservancy work such as reservoir regulation, and the ecological influence of water conservancy work is reduced.

[0032] Gradient adaptation design: the 6-hour gradient maintenance period simulates the gradual change of the natural environment, reduces the interference of acute stress reaction of fish on the results, and improves the data authenticity; Long-term monitoring window: 12-hour continuous monitoring covers the dynamic change cycle of fish physiological state, captures the cumulative effect of short-term adaptation and long-term damage, and improves the evaluation accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 It is a structural schematic diagram of the present application. In order to avoid messy drawings, devices such as repeaters are not shown.

[0034] Fig. 2 It is a schematic diagram of the distance sensor 2 and the passive reflector 3 installed on the gill cover of the fish.

[0035] Fig. 3 It is a waveform diagram of the distance between the distance sensor 2 and the passive reflector 3 changing with time during the determination process, and different amplitudes correspond to different health states of the fish.

[0036] List the corresponding technical features and effects of each reference sign: Test barrel (reference sign 1): the main container for containing water, the material is polyethylene, the inner diameter is 1.5±0.1 m, and the height is 1.3±0.1 m.

[0037] Distance sensor (reference sign 2): installed on the outer surface of the gill cover of the fish, emits a detection signal (such as 40kHz±0.5kHz narrowband ultrasonic wave) with a unique feature code, and the model is preferably HC-SR04.

[0038] Passive reflector (reference sign 3): symmetrically installed with the distance sensor, uses aluminum plated PET film (reflectivity>90%), and the surface is coated with a biocompatible waterproof material.

[0039] Semiconductor refrigeration sheet (reference sign 4): the core component of the temperature control unit, installed in the test barrel and immersed in water, used for adjusting the water temperature.

[0040] Water temperature sensor (reference sign 5): electrically connected with the temperature controller, and detects the water temperature in real time.

[0041] Temperature controller (reference numeral 6): controls the semiconductor refrigeration chip to switch between heating and cooling modes according to the detection value of the water temperature sensor. The temperature control range is 1-60℃ and the sensitivity is 0.1℃.

[0042] Temperature recorder (reference numeral 7): Installed on the wall of the test tank, used to record water temperature changes and can be connected to the data processing module. Reference numeral 71 is the temperature measurement point of the temperature recorder.

[0043] Variable frequency agitator (reference numeral 8): a power component of the agitation unit, with a speed range of 0-100 rad / min, used to adjust the sediment content of the water body to make the sediment content of the water body uniform, and preferably equipped with a reducer.

[0044] Isolation net (reference numeral 9): Set horizontally 30 cm above the bottom of the test tank to prevent fish from contacting the stirring blades.

[0045] Mixing blade (reference numeral 10): located below the isolation net, 0.2m long, rotates with the variable frequency stirrer to evenly mix the mud and sand.

[0046] Oxygenator (reference numeral 11): electrically connected to the water quality meter, automatically starts when the dissolved oxygen concentration is lower than the set value to maintain the dissolved oxygen balance in the water body.

[0047] Water quality meter (reference numeral 12): connected to the dissolved oxygen sensor and pH sensor, monitors water quality parameters and provides feedback control for the addition of oxygenators or pH regulators.

[0048] Dissolved oxygen sensor (reference numeral 13): electrically connected to the water quality meter to detect the dissolved oxygen concentration in the water in real time, with a target threshold range of 8±0.5mg / L. DETAILED DESCRIPTION

[0049] like Figs. 1 to 3 As shown, the device for measuring the survival fitness of fish based on gill cover activity of the present invention includes a test environment simulation module, a gill cover activity monitoring module and a data processing module; The test environment simulation module includes a test barrel 1 for containing water, wherein the test barrel 1 is provided with a temperature control unit for adjusting the water temperature and a stirring unit for adjusting the sand content; The gill cover activity monitoring module includes a distance sensor 2 and a passive reflector 3. The distance sensor 2 and the passive reflector 3 are symmetrically mounted on the outer surface of the fish's gill cover via fixings. The distance sensor 2 is integrated with a wireless communication module, preferably a Bluetooth module. The distance sensor 2 is connected to the data processing module via the wireless communication module to transmit gill cover distance data. A plurality of (Bluetooth) repeaters are evenly arranged in the circumferential direction of the barrel wall of the test barrel 1 to extend the wireless communication distance. No matter what angle the fish swims to, the nearest repeater will relay the communication.

[0050] The distance sensor 2 is configured to emit a probe signal (such as an ultrasonic signal or an infrared signal) with a unique feature code, and the passive reflector 3 is configured to reflect the probe signal back to the distance sensor 2. The data processing module calculates the gill cover distance L according to the coding verification result of the reflected signal and the round-trip time, and determines the fish survival state based on the L value, and is arranged outside the test barrel 1.

[0051] The direction of the test barrel 1 towards the user is defined as the front direction, the up-down direction is defined as the height direction of the test barrel 1, and the left-right direction is defined as the diameter direction of the test barrel 1. The fixing member is made of a biocompatible material. The data processing module can use a single-chip microcomputer, such as an enhanced 32-bit single-chip microcomputer (ARM Cortex-M series), and can also use an industrial computer. The data processing module is preferably connected with a display screen.

[0052] The present application realizes high-precision monitoring of the gill cover micro-movement through the closed-loop design of "active coding emission + passive reflection", combined with coding verification and time threshold filtering, solves the false detection problem of traditional image recognition in turbid water, and specifically includes feature coding emission, high reflection characteristics of the passive reflector 3 and a multiple filtering mechanism at the receiving end, which cooperates to improve the monitoring stability in poor water quality environment, obtains accurate L value, and accurately judges the fish survival state.

[0053] The feature code of the distance sensor 2 includes at least one of frequency coding, pulse sequence coding and amplitude modulation; the frequency coding is a narrow-band ultrasonic wave of 40 kHz±0.5 kHz, the pulse sequence coding is a pulse group with a preset time interval, and the amplitude modulation is a signal amplitude that changes according to a sine law.

[0054] Multi-dimensional feature coding ensures signal uniqueness, 40 kHz narrow-band frequency avoids fish body natural vibration noise, pulse sequence and amplitude modulation form "signal fingerprint", and effectively distinguish target reflection from environmental interference (such as water flow and fish body friction).

[0055] The distance sensor 2 is built-in with a band-pass filter and a coding verification unit; the band-pass filter only allows signals in the frequency band of 40 kHz±0.5 kHz to pass, and the coding verification unit is used to compare the consistency of the pulse sequence of the received signal with the preset sequence.

[0056] The double mechanism of hardware filtering (band-pass filter) and algorithm verification (coding matching) excludes non-target frequency band noise and irregular diffuse reflection signals from the physical layer and signal layer, reduces the reflection interference signal strength of the fish body non-gill cover area to less than 1 / 5 of the target signal, and guarantees the effectiveness and accuracy of distance monitoring.

[0057] The data processing module pre-stores a signal round-trip time threshold Tmax, which is calculated according to the maximum design distance Lmax of the distance sensor 2 and the passive reflector 3 (the gill cover distance of the fish is a constraint condition when Lmax is specified, so fish of the same size are preferred for testing; when the fish sizes are inconsistent, Lmax needs to be determined for each size of fish in advance, and the Lmax value corresponding to each distance sensor 2 is pre-stored in the data processing module), and when the actual round-trip time > Tmax, the reflection signal is determined to be invalid and discarded.

[0058] By limiting the time threshold (e.g. Tmax≈66μs when Lmax=5cm), filtering long-distance reflections (e.g. fish body, container wall), and only keeping the valid signals in the gill cover area, the anti-interference performance and distance measurement accuracy are further improved.

[0059] The passive reflector 3 is a metal plating layer or a high-reflectivity film, with an ultrasonic reflectivity >90%, and the surface is coated with a biocompatible waterproof material.

[0060] The high reflectivity (90%) ensures the effective return of weak detection signals, the passive design simplifies the structure and eliminates the need for power supply, and the waterproof material ensures long-term stable operation underwater, meeting the miniaturization and low interference requirements of fish physiological monitoring, and matching the use of ultrasonic sensors in distance sensors 2.

[0061] The temperature control unit includes a semiconductor refrigeration sheet 4, a water temperature sensor 5, and a temperature controller 6; the semiconductor refrigeration sheet 4 is installed in the test barrel 1 and extends into the water, the water temperature sensor 5 is electrically connected with the temperature controller 6, and the temperature controller 6 controls the semiconductor refrigeration sheet 4 to switch between heating and cooling modes according to the detection value of the water temperature sensor 5, with a temperature control range of 1-60℃ and a sensitivity of 0.1℃. A temperature recorder 7 is preferably provided on the barrel wall of the test barrel 1 to record the changes in water temperature. The temperature recorder can be connected with the data processing module, so that the temperature conditions can be displayed on the display screen.

[0062] The closed-loop temperature control system achieves high-precision water temperature regulation, with a sensitivity of 0.1℃ to ensure the accuracy of environmental variable control and provide a stable temperature background for gill cover activity monitoring.

[0063] The stirring unit includes a variable-frequency stirrer 8 and an isolation net 9; the isolation net 9 is horizontally arranged 30cm above the bottom of the test barrel 1, and the stirring blade 10 of the variable-frequency stirrer 8 is located below the isolation net 9, with a rotation speed range of 0-100 rad / min (radians per minute) and a length of 0.2m (meters).

[0064] The isolation net 9 can prevent fish from contacting the stirring blade 10, and the variable frequency stirrer 8 realizes uniform distribution of the sediment content through 0-100 rad / min speed adjustment, simulates a natural water body sediment environment, and ensures controllability of test variables.

[0065] The standard for determining the survival state based on the gill cover interval L is: when L is less than 0.6 Lmax, it is determined as "poor state", and when L is Lmin, it is determined as "death state", wherein Lmax is the maximum interval of gill cover activity, and Lmin is the minimum interval of gill cover rest.

[0066] Below Lmax, the larger L is, the better the state of the fish is; the objective determination of the survival state is realized through a quantitative threshold value, artificial observation errors are avoided, and standardized data support is provided for subsequent survival suitability classification.

[0067] The oxygenation instrument 11, the water quality instrument 12 and the dissolved oxygen sensor 13 are further included, the dissolved oxygen sensor 13 is electrically connected with the water quality instrument 12, the water quality instrument 12 is electrically connected with the oxygenation instrument 11, and the oxygenation instrument 11 is automatically started when the dissolved oxygen concentration of the water body is lower than an initial value or a set value; the test barrel 1 has an inner diameter of 1.5±0.1 m, a height of 1.3±0.1 m and a polyethylene material.

[0068] The dissolved oxygen closed-loop control excludes dissolved oxygen interference, the test barrel 1 made of polyethylene avoids water pollution, and the size of 1.5 m*1.3 m provides sufficient test space, and ensures a natural activity state of the fish.

[0069] In the embodiment, the distance sensor 2 is preferably HC-SR04 (narrow beam <15°, sensing distance 2-400 cm); the passive reflector 3 is preferably an aluminum-coated PET film (thickness 0.1 mm, reflectivity 92%); and the fixing member is preferably made of a biocompatible material of a medical silicone rubber adhesive.

[0070] The application further discloses a fish survival suitability determination method using the fish survival suitability determination device based on gill cover activity. (1) Fish pretreatment: the test fish is rested for 24 hours in a natural state to eliminate the interference of stress reaction on the physiological state; (2) Environmental variable gradient adjustment: adjusting the test environmental variable A, including water temperature and sediment content, gradually changing the variable A according to the gradient a, the water temperature gradient is 1-2 ℃ / gradient, and the sediment content gradient is 5-10 kg / m³ / gradient; after adjusting one gradient, the fish is maintained for 6 hours to ensure sufficient adaptation to the environmental change; (3) Gill cover activity monitoring and data acquisition: after the variable A reaches the target value, the gill cover activity is continuously monitored through the distance sensor 2 and the passive reflector 3 for 12 hours, and the gill cover interval L value change and the fish mortality rate are recorded in real time. (4) Survival suitability grading: According to the 12-hour mortality, the survival suitability is divided into five levels: 0% mortality is "suitable", 0%-33% is "generally suitable", 30%-66% is "relatively suitable", 66%-100% is "unsuitable", and 100% is "very unsuitable".

[0071] The determination method of the application has the following advantages: Quantitative grading standard: The objective grading of survival suitability is realized through the mortality interval for the first time, avoiding the subjectivity of traditional empirical estimation, realizing the quantitative evaluation of fish survival suitability, providing scientific basis for water conservancy work such as reservoir regulation, and reducing the ecological impact of water conservancy work.

[0072] Gradient adaptation design: The 6-hour gradient maintenance period simulates the gradual change of the natural environment, reduces the interference of acute stress response of fish on the results, and improves the data authenticity; Long-term monitoring window: 12-hour continuous monitoring covers the dynamic change cycle of fish physiological state, captures the cumulative effect of short-term adaptation and long-term damage, and improves the evaluation accuracy.

[0073] The application also provides a sensor calibration method for monitoring gill cover activity, which adds a sensor calibration step before step (3): (1) Fix the distance sensor 2 and the passive reflector 3 on the standard spacing calibration device (accuracy ±0.01 cm), and calibrate at 0 cm, 2 cm and Lmax (such as 5 cm) respectively, and record the deviation of the round-trip time of the detection signal from the theoretical value; (2) Linear fitting is performed on the deviation by the built-in algorithm of the data processing module to generate the calibration coefficient k (k=measured distance / theoretical distance), and the calculation result of the subsequent gill cover spacing L is corrected in real time.

[0074] The sensor calibration step compensates for the factory deviation of the sensor and the influence of the underwater environment (such as temperature and pressure) on signal propagation through the standard device, reducing the L value measurement error from ±0.1 cm to ±0.05 cm; Through the sensor calibration step, the calibration coefficient can be updated at any time to ensure that the performance drift of the sensor does not affect the validity of the data in long-term use.

[0075] The application also provides a multivariate synergistic regulation and interaction effect analysis method, which uses orthogonal test design when adjusting water temperature and sediment concentration simultaneously in step (2): (1) Set the water temperature gradient (1-60℃, interval 2℃) and the sediment concentration gradient (0-50kg / m³, interval 5kg / m³), forming 30x10=300 groups of combined working conditions; (2) Each group of working conditions is repeated 3 times, and the interaction coefficient P of water temperature and sediment concentration is calculated by variance analysis (ANOVA) (P<0.05 is a significant interaction), to determine the dominant influencing factor.

[0076] The multivariate synergistic regulation and interaction effect analysis method can reveal the composite stress mechanism: breaking the limitation of single variable regulation, quantifying the synergistic effect of water temperature and sediment concentration on fish survival (such as low temperature aggravating gill blockage in high-sediment environment); The multivariate synergistic regulation and interaction effect analysis method can optimize the test efficiency: orthogonal design reduces the number of test groups by 50%, reduces the cost while ensuring data coverage, and is suitable for ecological risk assessment of multi-factor coupling.

[0077] The present application also provides an individual difference correction and population adaptability evaluation method, which adds individual baseline determination in step (1): (1) Record the initial maximum gill cover distance Lmax0 and average movement frequency f0 of each fish during the rest period, calculate the population mean μ(Lmax0) and standard deviation σ(Lmax0); (2) In the test, the individual Lmax0 / μ(Lmax0) is used as a correction coefficient to correct the mortality rate (such as individuals with Lmax0<μ-σ are given 1.2 times weight), and finally the survival suitability at the population level is output.

[0078] Individual baseline determination is beneficial to eliminate individual bias: through baseline correction, the influence of fish size, age and health status difference on the results is balanced, and the "strong individual" is avoided to cover the vulnerability of the whole population; Individual baseline determination is helpful for population-level evaluation: the weighted corrected mortality rate is closer to the real response of the natural population, and provides more reliable threshold reference for ecological protection strategy making.

[0079] The present application also provides an environmental parameter drift compensation method, in step (3), the environmental parameters of the test barrel 1 are dynamically compensated: (1) The water quality instrument 12 is also connected with a pH sensor, and the water quality instrument 12 detects the pH value and dissolved oxygen concentration of the water body through the pH sensor and the dissolved oxygen sensor 13 every 2 hours, the target threshold range of the water body pH value is 6.5-8.5, and the target threshold range of the dissolved oxygen concentration is 8±0.5 mg / L, and when the threshold is deviated, the oxygenation instrument or the pH regulator is started; (2) The uniformity of sediment concentration (coefficient of variation <5%) is maintained by adjusting the stirring unit speed feedback (such as when the sediment concentration detection value deviates from the set value ±2 kg / m³, the speed is ±5 rad / min).

[0080] The environmental parameter drift compensation method can control the environmental stability, the multi-parameter closed loop compensation ensures the long-term stability of the test conditions, and reduces the test deviation caused by the deterioration of water quality or uneven sediment content; The environmental parameter drift compensation method can also simulate natural disturbance, and the dynamic adjustment mechanism is closer to the small fluctuations of the river environment, thereby improving the applicability of the test results to the field scene.

[0081] The above examples are only used to illustrate and not to limit the technical solutions of the present application. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the present application can still be modified or equivalently replaced without departing from the spirit and scope of the present application. Any modification or partial replacement should be covered in the scope of the claims of the present application.

Claims

1. Apparatus for determining the fitness of a fish based on operculum activity, characterized in that: The test environment simulation module, the gill cover activity monitoring module and the data processing module are included. The test environment simulation module includes a test barrel for containing a water body, a temperature control unit for adjusting water temperature and a stirring unit for adjusting sand content are arranged in the test barrel. The gill cover activity monitoring module includes distance sensors and passive reflectors, the distance sensors and the passive reflectors are symmetrically installed on the outer surface of the gill cover of the fish, and the distance sensors are in communication connection with the data processing module to transmit gill cover distance data. The distance sensors are configured to emit detection signals with unique feature codes, and the passive reflectors are configured to reflect the detection signals back to the distance sensors. The data processing module calculates the gill cover distance L according to the coding verification result of the reflected signals and the round trip time, and determines the survival state of the fish based on the L value.

2. The gill cover activity-based fish livability determining apparatus according to claim 1, characterized by: The feature codes of the distance sensors include at least one of frequency coding, pulse sequence coding and amplitude modulation; the frequency coding is narrowband ultrasonic wave of 40 kHz±0.5 kHz, the pulse sequence coding is a pulse group with a preset time interval, and the amplitude modulation is a signal amplitude changing in a sinusoidal manner.

3. The gill cover activity-based fish livability determining apparatus according to claim 1, characterized by: The distance sensors are built-in with a band-pass filter and a coding verification unit; the band-pass filter only allows signals in the frequency band of 40 kHz±0.5 kHz to pass, and the coding verification unit is used to compare the consistency of the received pulse sequence with the preset sequence.

4. The gill cover activity-based fish livability determining apparatus according to claim 1, characterized by: The data processing module pre-stores a signal round trip time threshold Tmax, which is calculated according to the maximum designed distance Lmax between the distance sensor and the passive reflector, when the actual round trip time is greater than Tmax, the reflected signal is determined to be invalid and discarded.

5. The gill cover activity based fish livability determining apparatus according to claim 1, characterized in that: The passive reflector is a metal plating layer or a high-reflectivity film, and the ultrasonic reflectivity is greater than 90%, and the surface is coated with a biocompatible waterproof material.

6. The gill cover activity-based fish livability determining apparatus according to claim 1, characterized by: The temperature control unit includes a semiconductor refrigerating sheet, a water temperature sensor and a temperature controller; the semiconductor refrigerating sheet is installed in the test barrel and extends into the water, the water temperature sensor is electrically connected with the temperature controller, and the temperature controller controls the semiconductor refrigerating sheet to switch between heating and cooling modes according to the detection value of the water temperature sensor, the temperature control range is 1-60℃, and the sensitivity is 0.1℃.

7. The gill cover activity based fish livability determining apparatus according to claim 1, characterized in that: The stirring unit includes a variable frequency stirrer and an isolation net; the isolation net is horizontally arranged 30 cm above the bottom of the test barrel, and the stirring blade of the variable frequency stirrer is located below the isolation net, the rotation speed range is 0-100 rad / min, and the length of the stirring blade is 0.2 m.

8. The gill cover activity based fish livability determining apparatus according to claim 1, characterized in that: The standard for determining the survival state of the data processing module based on the gill cover distance L is: when L<0.6 Lmax, it is determined as "poor state", and when L=Lmin, it is determined as "death state", wherein Lmax is the maximum distance of gill cover activity, and Lmin is the minimum distance of gill cover static.

9. The gill cover activity based fish livability determining apparatus according to claim 1, characterized in that: It also comprises an oxygen increasing instrument (6), a water quality instrument and a dissolved oxygen sensor, the dissolved oxygen sensor is electrically connected with the water quality instrument, the water quality instrument is electrically connected with the oxygen increasing instrument (6), when the dissolved oxygen concentration of the water body is lower than the initial value or the set value, the oxygen increasing instrument (6) is automatically started; the test barrel has an inner diameter of 1.5±0.1 m and a height of 1.3±0.1 m, and is made of polyethylene.

10. A method of measurement using the gill cover activity-based fish livability measurement apparatus according to any one of claims 1 to 9, characterized by The following steps are taken: (1) Fish pretreatment: the test fish is rested for 24 hours in a natural state to eliminate the interference of stress reaction on physiological state; (2) Adjustment of environmental variable gradient: the test environmental variable A, including water temperature and sand content, is gradually changed in gradient a, the water temperature gradient is 1-2 ℃ / gradient, and the sand content gradient is 5-10 kg / m³ / gradient; after each gradient is adjusted, it is maintained for 6 hours to ensure that the fish fully adapts to the environmental change; (3) Gill cover activity monitoring and data collection: after the variable A reaches the target value, the gill cover activity is continuously monitored by a distance sensor and a passive reflector for 12 hours, and the gill cover distance L value change and fish mortality rate are recorded in real time; (4) Survival suitability classification: according to the 12-hour mortality rate, the survival suitability is classified into five levels: 0% mortality rate is "suitable", 0%-33% is "generally suitable", 30%-66% is "relatively suitable", 66%-100% is "unsuitable", and 100% is "very unsuitable".

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