A slimming fish farming intelligent regulation and control system based on multi-parameter monitoring

Abstract

The application discloses a kind of intelligent regulation and control method and system based on multi-parameter monitoring of slimming fish culture, it is related to aquaculture intelligent control technical field, method includes: for the problem that slimming degree is difficult to online evaluation, fixed flow rate does not match slimming process, this method periodically switches to standard test flow rate with circulating water pump, collects the top flow swimming maintenance ratio of fish school under the flow rate, according to its inversion fish school is located in the slimming process stage, then according to process stage selects target flow rate band with process first rise and then fall, and adjusts the working flow rate of circulating water pump under the water quality safety constraint, and when top flow swimming maintenance ratio reaches end threshold in continuous several test cycles, output slimming cycle end signal.The application uses the motion ability index of initiative test as the online ruler of slimming process, eliminates dissection and sampling inspection, so that water flow is self-adapting progressive with slimming process and automatically determines slimming end point.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology for aquaculture, and in particular to an intelligent regulation method, system, computer-readable storage medium, and electronic device for the cultivation of lean fish based on multi-parameter monitoring. Background Technology

[0002] Slimming fish is a farming method that involves transferring fish raised in ordinary ponds to a clean, flowing water environment, allowing them to burn off excess body fat through continuous swimming. This removes the muddy taste and makes the fish meat firmer. Slimmed fish often sell for several times the price of ordinary fish, and this method has been rapidly adopted in recent years for species such as grass carp, tilapia, and bass.

[0003] The key to successful weight loss lies in two aspects: First, ensuring the fish are actively moving, achieved through the circulating water in the tank. To avoid being swept away, the fish swim against the current, burning fat in the process. Second, controlling the weight loss process is crucial. Insufficient weight loss results in an unremoved muddy taste and loose flesh. Excessive weight loss leads to excessive fat loss, reduced meat yield, and poor appearance. Currently, in weight loss aquaculture, the water flow speed is mostly set by humans based on experience, and the entire weight loss cycle remains unchanged. The degree of weight loss is determined by harvesting a few fish every few days for dissection or testing to measure fat and meat content, thus deciding whether to continue.

[0004] The problem with existing technology is that during evaluation, dissecting the fish is both harmful and labor-intensive, and only a few fish can be examined at a time, which is not representative of the entire tank. By the time the test results are available, the fish's condition is often several days old, and the progress is entirely subjective. Furthermore, maintaining a constant flow rate is difficult to match with the fish's fattening process. At the beginning of the fattening process, the fish are still fat and heavy, and cannot swim easily. A slightly stronger current will push them to the edge, causing them to lose appetite due to stress, thus halting the fattening process. In the middle stage, the fish have slimmed down and gained strength, but the original flow rate is too slow, and insufficient fat burning occurs. In the final stage, if the fish are still forced to swim vigorously, they are prone to becoming overly thin.

[0005] Therefore, there is a need for a fish farming control scheme that does not rely on dissection and manual sampling, can assess the fish's slimming process online, and can adaptively adjust the water flow speed according to the process and automatically determine whether the slimming is in place. Summary of the Invention

[0006] To address the problems of difficulty in online assessment of fish aging progress and mismatch between fixed flow rates and aging processes in the aforementioned background technologies, this invention provides an intelligent control method, system, computer-readable storage medium, and electronic device for fish aging based on multi-parameter monitoring. The basic idea is to periodically switch the circulating water pump to a fixed standard test flow rate, measure the proportion of fish swimming against the current at this standard flow rate, and use this as an online measure of the aging process. The water flow velocity is then progressively increased segment by segment according to the stages measured by this measure, and the aging endpoint is automatically determined based on this.

[0007] According to one aspect of the present invention, a smart control method for slender fish farming based on multi-parameter monitoring is provided, comprising: Obtain the standard test flow rate of the slimming aquaculture circulating water tank, the target flow rate band corresponding to each stage of the slimming process, and the conditions for the end of the slimming cycle. Collect water quality parameters of the circulating water tank, and periodically switch the circulating water pump of the circulating water tank to the standard test flow rate. Under the standard test flow rate, collect the proportion of fish swimming against the current. The proportion of fish swimming against the current is the proportion of fish swimming against the current in the fish school or the duration of fish swimming against the current. Based on the aforementioned swimming ratio at the top of the current, the current stage of the fish population's slimming process can be determined. Based on the inverted slimming process stage, a corresponding target flow velocity band is selected, and under the condition that the water quality parameters meet the preset safety constraints, the working flow rate of the circulating water pump is adjusted to the selected target flow velocity band. The target flow velocity band first rises and then falls as the slimming process stage progresses. When the top-flow swimming maintenance ratio reaches the end condition of the slimming cycle, a slimming cycle end signal is output.

[0008] Preferably, the standard test flow rate is a preset multiple of the critical swimming speed of the fish, and the preset multiple is not less than 0.5 and not greater than 0.8; Fish images are obtained through underwater image recognition. The fish images are divided into grids, and the proportion of fish swimming in the opposite direction to the water flow and located in the top flow zone on the inlet side of the circulating water tank is counted. The top flow swimming maintenance ratio is determined based on the proportion of fish swimming in the top flow zone.

[0009] Preferably, the weight loss process includes: an induction period, a strengthening period, and a shape-maintaining period, which proceed sequentially. The target velocity band corresponding to the induction period is the lowest, the target velocity band corresponding to the strengthening period is the highest, and the target velocity band corresponding to the shape-maintaining period is between the induction period and the strengthening period.

[0010] Preferably, the process of determining the current slimming stage of the fish population based on the top-current swimming maintenance ratio includes: Set a first process boundary value and a second process boundary value that increase with the proportion of top current swimming. When the proportion of top current swimming is lower than the first process boundary value, it is inverted into the induction period. When the proportion of top current swimming is between the first process boundary value and the second process boundary value, it is inverted into the reinforcement period. When the proportion of top current swimming is not lower than the second process boundary value, it is inverted into the shape preservation period.

[0011] Preferably, the water quality parameters include at least two of dissolved oxygen, water temperature, and ammonia nitrogen concentration; the preset safety constraints include: when the dissolved oxygen is lower than the preset lower limit, or when fish are observed to gather near the edge or float to the surface as signs of stress, the operating flow rate of the circulating water pump is adjusted downward step by step according to the preset flow rate increments until the dissolved oxygen is not lower than the preset lower limit and the signs of stress are eliminated, and the downward adjustment takes precedence over the flow rate adjustment based on the stage of the slimming process.

[0012] Preferably, the conditions for ending the weight loss cycle are: The proportion of swimming in the top current is maintained at or above the preset end proportion threshold for no less than three consecutive test cycles.

[0013] Preferably, it also includes collecting the residual feed rate after feeding, and when the residual feed rate is higher than a preset residual feed threshold, lowering the upper limit of the target flow rate band corresponding to the current slimming process stage.

[0014] According to another aspect of the present invention, a smart control system for lean fish farming based on multi-parameter monitoring is provided for performing the above-described method, the system comprising: The acquisition module is used to acquire the standard test flow rate of the slimming aquaculture circulating water tank, the target flow rate band corresponding to each slimming process stage, and the end conditions of the slimming cycle. The monitoring module is used to collect water quality parameters of the circulating water tank and periodically switch the circulating water pump of the circulating water tank to the standard test flow rate. Under the standard test flow rate, the proportion of fish swimming against the current is collected. The proportion of fish swimming against the current is the proportion of fish swimming against the current in the fish school or the duration of fish swimming against the current. The evaluation module is used to invert the current slimming process stage of the fish school based on the swimming maintenance ratio at the top of the current. The control module is used to select the corresponding target flow velocity band according to the inverted slimming process stage, and adjust the working flow rate of the circulating water pump to the selected target flow velocity band under the condition that the water quality parameters meet the preset safety constraints. The target flow velocity band first rises and then falls as the slimming process stage progresses. The determination module is used to output a slimming cycle end signal when the top-current swimming maintenance ratio reaches the slimming cycle end condition.

[0015] A third aspect of the present invention provides a computer-readable storage medium on which a computer program stored is executed by a processor to implement the steps of the above-described method.

[0016] A fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the steps of the above-described method.

[0017] The beneficial effects of this invention are as follows: This invention uses an actively applied standard test flow rate to measure the fish's movement ability, using the proportion of fish swimming against the current as an online measure of the weight loss process, eliminating the need for dissection and sampling for testing, thus neither harming the fish nor causing delays. This invention allows the target flow rate to gradually increase with the weight loss process, and then actively decreases in the later stages to maintain its shape, ensuring that the water flow always matches the rhythm that the fish can currently withstand and is sufficient for fat loss, avoiding early shock stress and excessive weight loss later. This invention sets low dissolved oxygen and stress signs as higher priority safety constraints, ensuring that flow rate adjustments do not come at the expense of fish survival. This invention automatically determines the weight loss endpoint based on movement ability indicators, eliminating reliance on subjective experience when releasing fish. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments are briefly introduced below.

[0019] Figure 1 A flowchart illustrating the intelligent control method for slim fish farming provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the intelligent control system for slim fish farming provided in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the principle of actively testing the proportion of swimming in top current at a standard test flow rate and reversing the weight loss process stage, as provided in an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating how the target flow velocity band first increases and then decreases during the slimming process, as provided in an embodiment of the present invention. Figure 5 This is a schematic diagram illustrating the inversion of weight loss process stages and the determination of weight loss endpoints provided in an embodiment of the present invention. Figure 6 This is a schematic diagram of the process for adjusting and controlling a certain grass carp weight loss batch during a test cycle, as described in a specific embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. The specific flow rates, critical swimming speeds, process boundary values, thresholds, and cycle days used in the following embodiments are all illustrative examples and do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can adjust the corresponding parameters according to the species, size, and tank conditions of the fish; the adjusted implementation methods still fall within the scope of protection of this invention. The following content first combines... Figure 1The overall process of the method of the present invention is summarized, and in conjunction with... Figures 3 to 5 The paper elaborates on the three stages of active testing and evaluation, velocity band progression, and endpoint determination, and then combines them with... Figure 2 The system's modular structure is introduced, followed by an explanation of the electronic equipment and computer-readable storage media, and finally, a combination of... Figure 6 A specific end-to-end implementation is given.

[0021] The term "slimming fish" refers to fish that have been transferred from ordinary farmed fish to a clean, flowing water environment, where they continuously swim against the current to burn body fat and improve meat quality and flavor. Swimming against the current refers to the fish swimming against the current to resist its scouring effect; this is the primary way flowing water slimming helps fish burn fat. The term "standard test flow rate" refers to a fixed flow rate specifically designed to assess the fish's swimming ability. It does not change during the slimming process. At each testing cycle, the circulating water pump is switched to this flow rate to measure the fish's performance, essentially giving the fish a standardized "physical fitness test." It is usually set slightly lower than the fish's critical swimming speed, allowing fish at different stages to give differentiated responses. The term "critical swimming speed" refers to the maximum flow rate at which a fish can continuously swim against the current without being swept away; it is a commonly used indicator of fish swimming ability.

[0022] The aforementioned head-up swimming sustaining ratio is an indicator of a fish school's ability to move under a standard test flow rate. It can be measured in two ways: one is by quantity, which is the proportion of fish in the school that maintain upstream swimming and remain in the head-up flow zone on the inlet side of the tank under the standard test flow rate; the other is by duration, which is the duration for which the fish school can maintain head-up swimming as a whole from the moment they enter the standard test flow rate until they noticeably fall behind. This invention uses it as an online measure of the weight loss process because the thinner the fish, the lower their body fat, and the higher their muscle mass, the lower their specific gravity and the stronger their movement ability. Therefore, at the same standard test flow rate, more fish can maintain head-up swimming for a longer period. In other words, the head-up swimming sustaining ratio steadily increases as weight loss progresses. After repeated testing and observation of multiple batches of slimmed grass carp, the inventors found that this upward trend is quite stable and sufficient to distinguish the current stage of weight loss in the fish school.

[0023] The slimming process is divided into several stages based on the fish's movement ability. This invention divides it into three progressively advancing stages: the induction stage, the strengthening stage, and the shape-maintaining stage. The induction stage refers to the period when the fish have high body fat, weak movement ability, and the focus is on adapting to the current and starting to move. The strengthening stage refers to the period when the fish's movement ability has increased, and the focus is on increasing the flow rate to concentrate on burning fat. The shape-maintaining stage refers to the period when the fish are close to the slimming target, and the focus is on reducing the flow rate to a moderate level to maintain their body shape and prevent further weight loss. The target flow rate band is a range of permissible working flow rates corresponding to each slimming stage, within which the working flow rate is fine-tuned according to water quality. The target flow rate bands for the three stages are arranged in the order of "low in the induction stage, high in the strengthening stage, and reduced to the middle in the shape-maintaining stage," presenting an overall outline of first increasing and then decreasing. The end condition of the slimming cycle is the basis for determining that slimming has been completed and the fish can be harvested. The end condition for the slimming cycle of this invention can be that the proportion of fish swimming in the current does not fall below a preset end ratio threshold within a number of consecutive test cycles. The uneaten feed rate, which is the proportion of feed that has not been eaten by the fish after feeding to the total amount of feed, can be used as an auxiliary criterion.

[0024] Exemplary methods See Figure 1 The intelligent control method 100 for slimming fish farming provided in this embodiment of the invention includes steps 101 to 105, which can be executed cyclically by a program deployed on a recirculating aquaculture controller according to a test cycle (e.g., once every two or three days).

[0025] Step 101: Obtain the standard test flow rate, the target flow rate bands corresponding to each stage of the slimming process, and the end conditions of the slimming cycle. These serve as the benchmarks for subsequent adjustments and are set once during system deployment according to the fish species and size: the standard test flow rate is selected based on the critical swimming speed of the species; the target flow rate bands are given in three segments: induction, enhancement, and shape preservation; and the end conditions are given as the end threshold for maintaining the proportion of fish swimming in the current current. This step only reads the set values ​​and does not involve current data collection.

[0026] Preferably, the standard test flow rate is a preset multiple of the critical swimming speed of the fish school, wherein the preset multiple is not less than 0.5 and not greater than 0.8. Fish school images are obtained through underwater image recognition. The fish school images are divided into grids, and the proportion of fish swimming in the opposite direction to the water flow and located in the top flow zone on the inlet side of the circulating water tank is counted. Based on this proportion, the top flow swimming maintenance ratio is determined.

[0027] Step 102: Collect water quality parameters and measure the head-up swimming sustaining ratio at the standard test flow rate. At least two of the following water quality parameters should be collected: dissolved oxygen, water temperature, and ammonia nitrogen concentration. These parameters should be routinely collected by the corresponding water quality sensors for subsequent safety constraints.

[0028] Preferably, the slimming process includes three sequentially progressive stages: an induction period, a strengthening period, and a shape-maintaining period. The target flow velocity band corresponding to the induction period is the lowest, the target flow velocity band corresponding to the strengthening period is the highest, and the target flow velocity band corresponding to the shape-maintaining period is between the induction and strengthening periods. The key point of this step is in the latter half, which is where this invention differs from general variable-flow aquaculture: at each test cycle, the controller actively switches the circulating water pump from the current working flow rate to a fixed standard test flow rate, maintains it for a short period of time, and uses an underwater camera to capture images of the fish school, measuring the proportion of fish swimming against the current.

[0029] See Figure 3 When taking measurements, the water tank is divided into grids from a top-down or side view. The swimming direction of the fish in each grid is determined, and the fish that swim against the current and remain in the top flow area on the inlet side are counted. The proportion of these fish in the total fish population is calculated. If a time-lapse meter is used, the time elapsed from the start of the standard test flow rate to the point where the fish noticeably fall behind is recorded. The reason for specifically switching to a unified standard test flow rate for measurement, rather than directly observing the fish's performance at the current working flow rate, is that measurements taken in each test cycle under the same flow rate condition are necessary for the obtained top-flow swimming maintenance ratio to be comparable and reflect the progress of the weight reduction process.

[0030] If the working flow rate is different in each cycle, the measured activity level will be mixed with the flow rate difference and will not reflect the changes in the fish's own movement ability. After the test, the controller first switches the circulating water pump back to the working flow rate before the test. After steps 103 and 104 reconstruct the slimming process stage based on the measured top current swimming maintenance ratio and determine the working flow rate for this cycle, the circulating water pump is then adjusted to that working flow rate. A single test usually only occupies a very short segment of a test cycle.

[0031] Step 103: Based on the aforementioned top-current swimming maintenance ratio, determine the current stage of the fish swarm's slimming process. (See also...) Figure 5 Since the proportion of fish maintaining their swimming position against the current increases monotonically as the slimming process progresses, it is only necessary to set several process thresholds and place the maintenance proportion against the corresponding thresholds: If the proportion is below the first process threshold (i.e., less than the first process threshold), it indicates the fish is not yet able to withstand the current and its movement ability is weak, thus indicating the induction phase; if it is between the first and second process thresholds (i.e., greater than or equal to the first process threshold and less than the second process threshold), it indicates the fish is already able to swim well against the current, thus indicating the strengthening phase; if it is not below the second process threshold (i.e., greater than or equal to the second process threshold), it indicates the fish's movement ability is strong and it is close to the slimming target, thus indicating the shape-preservation phase. The process thresholds are determined during system calibration by the maintenance proportion curves of historical slimming batches, taking values ​​near the inflection points from induction to strengthening and from strengthening to shape preservation on the curve. This step transforms a continuous movement ability indicator into discrete stages that facilitate the selection of velocity bands.

[0032] Step 104: Select the target flow velocity zone according to the inverted slimming process stage, and adjust the working flow rate under water quality safety constraints. Preferably, the preset safety constraints include: when dissolved oxygen is lower than the preset dissolved oxygen lower limit, or when fish are observed to gather near the edge or float to the surface as signs of stress, the working flow rate of the circulating water pump is adjusted downward step by step according to the preset flow rate increments until the dissolved oxygen is not lower than the preset dissolved oxygen lower limit and the stress signs are eliminated, and the downward adjustment takes precedence over the flow rate adjustment based on the slimming process stage.

[0033] See Figure 4 First, select the target velocity band corresponding to the current stage: the lowest segment during the induction phase, the highest segment during the strengthening phase, and the segment between the two during the shape-maintaining phase. Connecting these three segments forms a velocity profile that first rises and then falls. Next, consider the water quality: provided that water quality parameters such as dissolved oxygen meet the preset safety constraints, adjust the operating velocity of the circulating water pump to within the selected target velocity band. The specific point within the band can be fine-tuned based on feeding and activity levels.

[0034] Safety constraints take precedence over phased flow rate adjustments: If dissolved oxygen falls below the preset lower limit, or if the camera detects stress signs such as fish gathering near the edge or surfacing, the operating flow rate is immediately reduced step-by-step according to the preset flow rate increments until dissolved oxygen rises back to at least the preset lower limit and stress signs disappear, even if this means temporarily deviating from the target flow rate zone for the current phase. This is because fish survival always takes precedence over the slimming process. In this way, the water flow rate both progresses in stages with the slimming process, actively decreasing in the later stages to maintain its shape, and always remains within a safe range that the fish can tolerate. In one implementation, the uneaten feed rate after feeding can also be collected as an auxiliary indicator: a high uneaten feed rate often means that the fish are discouraged from feeding due to the fast flow. In this case, the upper limit of the target flow rate zone for the current phase is lowered, giving the fish room to feed.

[0035] The downward adjustment is carried out in stages according to a preset flow rate step size: after each step down, an observation period is maintained, dissolved oxygen is re-collected, and the fish's condition is assessed. If the dissolved oxygen is still below the preset lower limit or stress symptoms persist, the flow rate is lowered by one step until the dissolved oxygen rises back to above the preset lower limit and the stress symptoms disappear. The step-by-step adjustment, rather than a sudden drop to the bottom, is to minimize interruptions to the fish reduction process while eliminating the danger. The preset flow rate step size can be 0.03 to 0.08 meters per second, and the observation period can be 10 to 30 minutes. A larger step size results in faster elimination of the danger but a greater drop in flow rate, while a smaller step size has the opposite effect. The lower limit of the downward adjustment is the minimum guaranteed flow rate required to maintain water circulation and basic fish activity. If the flow rate falls below this level, other measures such as oxygenation and feed reduction should be implemented instead of further speed reduction. Once the dissolved oxygen rises and the fish's condition recovers, the flow rate will return to the target flow rate zone corresponding to the current stage of the fish reduction process.

[0036] Step 105: Determine the weight loss endpoint. When the proportion of fish swimming in the top current reaches the end condition of the weight loss cycle, that is, when it is not lower than the preset end proportion threshold for no less than three consecutive test cycles, it is determined that the fish's movement ability has stabilized and the weight loss has reached its goal. A weight loss cycle end signal is output, indicating that the fish can be released. The requirement of "several consecutive cycles" rather than "end upon reaching the target once" is to avoid accidental fluctuations in a single test and prevent premature release of fish due to a single high measurement.

[0037] Exemplary device See Figure 2 This invention also provides an intelligent control system 200 for slender fish farming based on multi-parameter monitoring, which can be used to execute the above-described method. System 200 includes: an acquisition module 201, a monitoring module 202, an evaluation module 203, a control module 204, and a judgment module 205. It should be noted that the module division here is illustrative and only represents a logical functional division; other division methods may be used in actual implementation.

[0038] The acquisition module 201 is used to acquire the standard test flow rate of the slimming aquaculture circulating water tank, the target flow rate band corresponding to each slimming process stage, and the slimming cycle termination conditions.

[0039] The monitoring module 202 is used to collect water quality parameters of the circulating water tank, including at least two of dissolved oxygen, water temperature and ammonia nitrogen concentration, and periodically switch the circulating water pump of the circulating water tank to the standard test flow rate. At the standard test flow rate, the proportion of fish swimming against the current is collected. The proportion of fish swimming against the current is the proportion of fish swimming against the current in the fish school or the duration of fish swimming against the current.

[0040] The evaluation module 203 is used to invert the current slimming process stage of the fish school based on the top current swimming maintenance ratio.

[0041] The control module 204 is used to select the corresponding target flow velocity band according to the inverted slimming process stage, and adjust the working flow rate of the circulating water pump to the selected target flow velocity band under the condition that the water quality parameters meet the preset safety constraints. The target flow velocity band first rises and then falls as the slimming process stage progresses.

[0042] The determination module 205 is used to output a slimming cycle end signal when the top-current swimming maintenance ratio reaches the slimming cycle end condition.

[0043] Exemplary electronic devices and computer-readable storage media The method provided in this invention can be implemented by an electronic device. This electronic device includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor. When the processor executes the computer program, it implements the steps of the aforementioned intelligent control method for slimming fish farming. This electronic device can be a programmable controller in a recirculating aquaculture system or a centralized monitoring server for the aquaculture farm. This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the aforementioned method. The computer-readable storage medium includes, but is not limited to, a disk, an optical disk, a read-only memory, and a random access memory. This invention can also be implemented as a computer program product, which includes computer program instructions that, when executed by a processor, implement the steps of the aforementioned method. Specific Implementation The following example uses a batch of grass carp that has undergone weight loss. Figure 6 This paper presents an end-to-end process for regulating the fish tank within a test cycle according to the present invention. All numerical values ​​used in this embodiment are illustrative examples.

[0045] A recirculating aquarium was used to raise grass carp for weight loss. The average weight of the fish was about 1.2 kg, and the measured critical swimming speed for adult fish of this species was about 0.9 m / s. In step 101, the system was set as follows: the standard test flow rate was 0.65 times the critical swimming speed and rounded according to the pump speed adjustment resolution, which was 0.58 m / s; the target flow rate range during the induction period was 0.20 to 0.30 m / s, the range during the enhancement period was 0.45 to 0.60 m / s, and the range during the shape preservation period was reduced to 0.32 to 0.42 m / s; the first process boundary value was 0.45, the second process boundary value was 0.72, the weight loss cycle completion threshold was 0.85, and the preset dissolved oxygen lower limit was 5.0 mg / L.

[0046] The above-mentioned settings are determined as follows. The standard test flow rate is obtained by multiplying the critical swimming speed of the fish species and size by a preset multiple, which is between 0.5 and 0.8. If the multiple is too low, the fish at each stage can easily withstand the current, and the proportion tends to saturate, resulting in a loss of differentiation; if the multiple is too high, the fish population in the early stages generally cannot withstand the current, and the proportion tends to approach zero, also resulting in a lack of differentiation. In this example, a multiple of 0.65 is used. The target flow rate zones for the three stages are also given in multiple ranges based on the critical swimming speed: 0.2 to 0.35 times for the induction period, 0.5 to 0.7 times for the strengthening period, and 0.35 to 0.5 times for the shape preservation period. The critical swimming speed in this example is 0.9 m / s. Based on this, the induction period is calculated to be 0.18 to 0.315 m / s, the strengthening period to be 0.45 to 0.63 m / s, and the shape retention period to be 0.315 to 0.45 m / s. Then, within the calculated range, values ​​that are convenient for pump speed adjustment are selected, resulting in the above three ranges of 0.20 to 0.30, 0.45 to 0.60, and 0.32 to 0.42 m / s.

[0047] The first and second process boundary values ​​are determined by historical slimming batches of the same species and specifications: the proportion of fish swimming in the top current during each test cycle of the historical batches is recorded, and a curve showing its increase with the number of slimming days is obtained. The proportion at the two inflection points where the curve changes from a steep rise to a flattening is taken as the boundary value; in this example, the average of the inflection points of the curves of the three historical batches is taken, resulting in 0.45 and 0.72. A higher boundary value indicates a conservative approach to the stage, a delayed increase in flow rate, and a longer slimming cycle; a lower boundary value indicates an aggressive approach, with increased flow rate before the fish have adapted, which can easily lead to stress. The threshold for the proportion at the end of the slimming cycle is determined by historical batches whose fat content and meat content have been confirmed to have reached the slimming target: the proportion of fish swimming in the top current at the target point is statistically analyzed, and the lower quantile is taken as the threshold; in this example, 0.85 is used; a higher threshold indicates that the fish are harvested too late and there is a risk of over-slimming, while a lower threshold may indicate that the fish are harvested before they have reached the target. The preset dissolved oxygen lower limit is set according to the safe dissolved oxygen requirements of the species being raised. In this example, it is set to 5.0 mg / L for grass carp.

[0048] The testing cycle for this batch of fish reduction, up to day 15, was conducted as follows: Step 102: Water quality was first collected: dissolved oxygen 6.8 mg / L, water temperature 24.3°C, and ammonia nitrogen 0.21 mg / L, all within safe ranges. Then, the controller switched the circulating water pump from the pre-test operating flow rate of 0.52 m / s to the standard test flow rate of 0.58 m / s, maintaining this for 3 minutes. The underwater camera captured images and counted them by grid: 189 fish were swimming against the current with their heads facing the inlet, located in the top current zone on the inlet side, out of a total of 300 fish in the tank, maintaining a top current swimming ratio of 0.63. After the test, the pump was switched back to the pre-test operating flow rate of 0.52 m / s.

[0049] Step 103: 0.63 falls between the first process boundary value of 0.45 and the second process boundary value of 0.72, indicating an inversion into the reinforcement phase. Step 104: The target flow rate for the reinforcement phase is set to 0.45 to 0.60 m / s; dissolved oxygen is 6.8 mg / L, above the lower limit of 5.0, and safety constraints are not triggered; considering the current residual feed rate of approximately 8% (below the preset residual feed threshold of 15%, no need to lower the upper limit), the working flow rate is set to 0.55 m / s, and the pump is then adjusted from 0.52 m / s to 0.55 m / s for this cycle. Step 105: The current maintenance ratio of 0.63 has not reached the end threshold of 0.85, so the slimming process continues.

[0050] As a continuation of subsequent testing cycles for the same batch, by day 28, the proportion of fish swimming in the current at the standard test flow rate was 0.87, which was no lower than the end threshold of 0.85. Looking back at day 24, the proportions were 0.86 and day 26, respectively. With three consecutive testing cycles not falling below 0.85, the conditions for ending the slimming cycle were met, and the system output a signal indicating the slimming cycle was over, suggesting that the fish could be harvested. It is evident that the slimming process for the entire batch was determined by the objective upward curve of the fish's movement ability, no longer relying on manual fish harvesting and dissection.

[0051] In addition, a safety restraint action was taken on day 18 of this batch: after feeding, dissolved oxygen dropped to 4.6 mg / L, below the lower limit of 5.0 mg / L, and the camera simultaneously detected some fish sticking to the edge of the water. The controller then gradually reduced the operating flow rate in increments of 0.05 m / s, observing for 15 minutes at each level, and after five levels, it was reduced from 0.55 m / s to 0.30 m / s. After oxygenation restored dissolved oxygen to 6.0 mg / L, which was no lower than the lower limit of 5.0 mg / L, and the fish sticking to the edge of the water disappeared, the flow rate was restored to the intensive period flow rate. This action demonstrates that safety restraint takes precedence over phased flow rate adjustments.

[0052] As a comparative example, we examined the scenario where no active testing or evaluation was used, and the entire weight loss process was conducted at a fixed flow rate. Using the aforementioned grass carp batch as an example, if the fixed working flow rate was 0.40 meters per second throughout, the fish, due to their high body fat, high density, and weak motility during the induction phase, exceeded their ability to sustain the current in the early stages. This caused the fish to be pushed against the edge of the flow, resulting in stress, decreased feeding, and stagnation in weight loss. During the strengthening phase, when the fish's motility could withstand higher flow rates, 0.40 meters per second was too low, leading to insufficient fat consumption. This significantly prolonged the overall weight loss period and reduced the uniformity of individual weight loss. It is evident that by actively testing the fish's motility and then gradually increasing the flow rate according to the stages of weight loss, the water flow speed can consistently match the rhythm that the fish can currently withstand and that is sufficient for fat burning—something a fixed flow rate cannot achieve.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A smart control method for slender fish farming based on multi-parameter monitoring, characterized in that, include: Obtain the standard test flow rate of the slimming aquaculture circulating water tank, the target flow rate band corresponding to each stage of the slimming process, and the conditions for the end of the slimming cycle. Collect water quality parameters of the circulating water tank, and periodically switch the circulating water pump of the circulating water tank to the standard test flow rate. Under the standard test flow rate, collect the proportion of fish swimming against the current. The proportion of fish swimming against the current is the proportion of fish swimming against the current in the fish school or the duration of fish swimming against the current. Based on the aforementioned swimming ratio at the top of the current, the current stage of the fish population's slimming process can be determined. Based on the inverted slimming process stage, a corresponding target flow velocity band is selected, and under the condition that the water quality parameters meet the preset safety constraints, the working flow rate of the circulating water pump is adjusted to the selected target flow velocity band. The target flow velocity band first rises and then falls as the slimming process stage progresses. When the top-current swimming maintenance ratio reaches the end condition of the slimming cycle, a slimming cycle end signal is output.

2. The method according to claim 1, characterized in that, The standard test flow rate is a preset multiple of the critical swimming speed of the fish, and the preset multiple is not less than 0.5 and not greater than 0.

8. Fish images are obtained through underwater image recognition. The fish images are divided into grids, and the proportion of fish swimming in the opposite direction to the water flow and located in the top flow zone on the inlet side of the circulating water tank is counted. The top flow swimming maintenance ratio is determined based on the proportion of fish swimming in the top flow zone.

3. The method according to claim 1, characterized in that, in, The weight loss process includes the following stages: the induction period, the strengthening period, and the maintenance period, which proceed sequentially. The target velocity band corresponding to the induction period is the lowest, the target velocity band corresponding to the strengthening period is the highest, and the target velocity band corresponding to the shape-maintaining period is between the induction period and the strengthening period.

4. The method according to claim 3, characterized in that, in, Based on the aforementioned top-current swimming maintenance ratio, the current slimming process stage of the fish school can be determined, including: Set a first process boundary value and a second process boundary value that increase with the proportion of top current swimming. When the proportion of top current swimming is lower than the first process boundary value, it is inverted into the induction period. When the proportion of top current swimming is between the first process boundary value and the second process boundary value, it is inverted into the reinforcement period. When the proportion of top current swimming is not lower than the second process boundary value, it is inverted into the shape preservation period.

5. The method according to claim 1, characterized in that, in, The water quality parameters include at least two of dissolved oxygen, water temperature, and ammonia nitrogen concentration. The preset safety constraints include: when the dissolved oxygen is lower than the preset lower limit, or when fish are observed to gather near the edge or float to the surface, the operating flow rate of the circulating water pump is adjusted downward step by step according to the preset flow rate increments until the dissolved oxygen is not lower than the preset lower limit and the stress symptoms are eliminated. The downward adjustment takes precedence over the flow rate adjustment based on the slimming process stage.

6. The method according to claim 1, characterized in that, in, The conditions for ending the weight loss cycle are: The proportion of swimming in the top current is maintained at or above the preset end proportion threshold for no less than three consecutive test cycles.

7. The method according to claim 1, characterized in that, It also includes collecting the residual feed rate after feeding, and when the residual feed rate is higher than the preset residual feed threshold, lowering the upper limit of the target flow rate band corresponding to the current slimming process stage.

8. A smart control system for slender fish farming based on multi-parameter monitoring, characterized in that, The system is used to perform the method of any one of claims 1 to 7, the system comprising: The acquisition module is used to acquire the standard test flow rate of the slimming aquaculture circulating water tank, the target flow rate band corresponding to each slimming process stage, and the end conditions of the slimming cycle. The monitoring module is used to collect water quality parameters of the circulating water tank and periodically switch the circulating water pump of the circulating water tank to the standard test flow rate. Under the standard test flow rate, the proportion of fish swimming against the current is collected. The proportion of fish swimming against the current is the proportion of fish swimming against the current in the fish school or the duration of fish swimming against the current. The evaluation module is used to invert the current slimming process stage of the fish school based on the swimming maintenance ratio at the top of the current. The control module is used to select the corresponding target flow velocity band according to the inverted slimming process stage, and adjust the working flow rate of the circulating water pump to the selected target flow velocity band under the condition that the water quality parameters meet the preset safety constraints. The target flow velocity band first rises and then falls as the slimming process stage progresses. The determination module is used to output a slimming cycle end signal when the top-current swimming maintenance ratio reaches the slimming cycle end condition.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

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