Large-water-surface freshwater fish breeding method capable of effectively preventing algal bloom

Abstract

The invention discloses a large-water-surface freshwater fish breeding method capable of effectively preventing algal blooms. The large-water-surface freshwater fish breeding method sequentially comprises the following steps that filter-feeding mixed fish is bred in a large-water-surface water area; and the control equipment is started mechanically to prevent water bloom. During large-water-surface freshwater fish culture, ecological chain regulation and control are introduced in an ecological restoration regulation and control mode, filter-feeding fishes including chub and bighead are put for mixed culture with freshwater fish, algal blooms are effectively avoided, algal blooms are prevented by combining a mechanical mode, and algal breeding is inhibited, so that the effect of preventing algal blooms can be achieved by combining the two modes; troublesome investigation work such as design, evaluation or adjustment to local conditions required by a biological control method can be overcome; the controller controls the automatic desilting equipment to remove part of bottom mud at the water bottom of the large-water-surface water area, excessive desilting is avoided, the trouble that sampling analysis is needed for accurate positioning desilting after sampling analysis is avoided, then water is supplemented from a clean water source, water bloom can be effectively avoided, and complex prevention and treatment scheme design and the like are not needed.

Description

Technical Field

[0001] The invention relates to the breeding of fish fry and fish fingerlings, and in particular to a large-surface freshwater fish breeding method that effectively prevents algal blooms. Background Art

[0002] Eutrophication of water bodies promotes the abnormal growth of algae, especially cyanobacteria, which can easily lead to cyanobacterial blooms. These blooms pose a significant threat to the structure and function of aquatic ecosystems, as well as the sustainable development and utilization of ecological resources. These blooms primarily manifest in the following ways: 1. They cause water bodies to turn black or red, deteriorating water quality; 2. They threaten the growth of other algae and release toxins, threatening the health and lives of humans and livestock; 3. They increase the difficulty of treating tap water and increase urban water supply costs; and 4. They impact urban landscapes. Given the harmful effects of cyanobacterial blooms on the environment and humans, their control and elimination are crucial. Cyanobacteria are characterized by their wide distribution, strong adaptability, high reproductive capacity, and difficulty in treatment. They often erupt during the hot summer months. During these periods, they consume significant amounts of oxygen, reduce water clarity, and alter the structure of aquatic communities. Cyanobacterial metabolism also releases toxins, which can weaken the immunity of farmed animals and lead to frequent diseases, resulting in significant economic losses for aquaculture. Therefore, preventing and controlling blue-green algae blooms on aquaculture water surfaces and improving the ecological environment of large water bodies have become key issues for the sustainable and healthy development of the aquaculture industry.

[0003] In his paper, "A Study on Measures to Suppress Algal Blooms by Farming Silver and Bighead Carp in Small Urban Lakes," published in the April 2017 issue of Scientific Fish Farming, Li Geng noted that the determination of aquaculture capacity cannot be a constant, but rather a variable that constantly changes with numerous factors and conditions, requiring timely adjustments tailored to local conditions. Therefore, while existing technologies exist to suppress algal blooms using filter-feeding fish such as silver and bighead carp, this approach requires investigation and evaluation, which is a complex process. Patent publication number CN115299391A: A method for fully ecological sea cucumber farming, comprising the following steps: S1: Sprinkling microorganisms in seawater to inhibit the growth of Enteromorpha, with a 2-3 month interval between sprinklings; S2: After the sprinkling of microorganisms is complete, placing sea cucumber seedlings in a breeding cage, which is then hoisted in the seawater; S3: Hoisting a Chinese herbal medicine box in the seawater at a height consistent with the height of the breeding cage, using Chinese herbal medicine to inhibit the growth of harmful bacteria around the breeding cage. By inhibiting Enteromorpha in seawater through microorganisms, the method can effectively prevent the rapid proliferation of Enteromorpha from affecting the oxygen content of seawater, effectively ensuring the oxygen content of seawater and the growth requirements of sea cucumbers. Patent publication number CN108668971A: Provides a method for preventing and controlling the outbreak of blue-green algae in ponds, which are usually river crab breeding ponds. The method includes: 1) releasing water in early February and planting Elodea in the pond; 2) stocking bighead carp in mid-February; 3) releasing snails in late February; 4) releasing crab seeds in early March; 5) harvesting and managing the Elodea from April to October; 6) harvesting river crabs and bighead carp from October to November. The method achieves the purpose of preventing and controlling the outbreak of blue-green algae in river crab breeding ponds by introducing Elodea into the river crab breeding ponds and harvesting and managing the Elodea in reasonable ways and methods. As can be seen, existing technologies use biological methods such as the introduction of bacteria or algae to suppress algal blooms, but both require design or research on the methods of introduction. For example, the introduction of bacteria requires screening for control strains. For example, Wang Qiufu's paper "Research Progress on the Hazards of Cyanobacteria Blooms in Aquaculture Ponds and Biological Control Measures" published in Anhui Agricultural Sciences, Vol. 53, No. 2, 2025, mentions that when screening control strains, researchers should consider key factors such as strain tolerance, bactericidal activity against cyanobacteria, and ecological impact. Regarding the biological method of introducing algae, such as patent publication number CN108668971A, how to rationally manage the introduction and harvesting of Elodea requires research, design, or evaluation. Summary of the Invention

[0004] The object of the present invention is to overcome the defects existing in the prior art and provide a large-scale freshwater fish farming method that effectively prevents algal blooms. When farming freshwater fish on large water surfaces, ecological chain regulation is introduced through ecological restoration and regulation: filter-feeding fish such as silver carp and bighead carp are released and mixed with freshwater fish to effectively avoid algal blooms. Combined with mechanical methods, the occurrence of algal blooms is prevented and the reproduction of algae is inhibited. The combination of these two methods can achieve the effect of preventing algal blooms and also overcome the design and evaluation (or the cumbersome investigation work such as adapting to local conditions) required for biological control methods.

[0005] To achieve the above objectives, the technical solution of the present invention is to design a large-surface freshwater fish farming method that effectively prevents algal blooms, which comprises the following steps in sequence: releasing filter-feeding polyculture fish into large water areas; and controlling equipment to activate mechanical prevention of algal blooms.

[0006] A further technical solution is to control the equipment to start mechanical prevention of algal bloom based on the sensor signals collected on the large water surface or the information obtained from the sampling and analysis of the bottom mud of the large water surface.

[0007] A further technical solution is that the equipment is an automated dredging equipment; the controller controls the automated dredging equipment to remove part of the bottom mud on the large water surface area, and then replenishes water from a clean water source; based on the signals collected from the fluorescent sensors installed in the large water surface area, the controller controls the automated dredging equipment to travel to the target area to remove the bottom mud.

[0008] A controller controls automated dredging equipment to partially remove sediment from large water bodies (this avoids both excessive dredging and the need for accurate sampling and analysis required for accurate dredging). Water is then replenished from clean water sources (a combination of these two factors effectively prevents algal blooms without requiring complex control plan design, evaluation, or investigation). Subsequently, based on the bloom activity detected by the fluorescent sensor, mechanical desilting is performed to precisely identify the areas where sediment has been removed, significantly delaying and reducing the extent of the bloom. Preliminary control measures are also less stringent and simple to operate, eliminating the tedious work of designing and researching control plans. Even if a bloom does occur later, the introduction of filter-feeding fish and the removal of some sediment, which may have removed some areas rich in organic matter and cysts, combined with water diversion and regulation to dilute pollutant concentrations (or, more accurately, dilute organic matter and cysts), significantly reduces the extent of the bloom and effectively prevents it. This extensive initial treatment allows for targeted and immediate treatment of any blooms that occur, effectively preventing them while also reducing the need for designing and researching control plans, significantly reducing the overall cost of the program.

[0009] A further technical solution is that the filter-feeding polycultured fish are polycultured fish of silver carp and bighead carp; and the stocking density of the polycultured fish is 37g / m3.

[0010] By co-culturing silver carp or bighead carp in large-scale freshwater fish farming, the growth of Microcystis aeruginosa can be effectively controlled and the growth of beneficial algae can be promoted. By using silver carp and bighead carp as filter-feeding fish, the internal and external loads can be reduced to a certain extent, which can play a preliminary (or smaller) role in limiting the occurrence of cyanobacterial blooms. This process can save design and evaluation, and only a certain degree of inhibition is required, which can be combined with mechanical and physical algae removal methods. Some studies believe that the stocking density of silver carp and bighead carp to curb algal blooms is 46-50g / m 3 Some studies believe that it is 40~50g / m 3 There is no specific unified standard. The determination of aquaculture capacity cannot be a constant, but can only be a variable that changes with many factors or conditions. It needs to be adjusted according to local conditions and in a timely manner (see the existing technology: Li Geng’s paper "Discussion on Measures to Suppress Water Blooms by Farming Silver Carp and Bighead Carp in Small Lakes in Urban Areas" published in "Scientific Fish Farming" in April 2017). Select the minimum stocking density and then carry out a certain amount of stocking, and select 37g / m 3 , there is no need to consider many other factors; by reducing the biomass of phytoplankton through biological control, the purpose of avoiding algal blooms is achieved, so as to effectively maintain the water quality of the composite aquaculture pond, and combined with mechanical methods, the occurrence of algal blooms is prevented and the reproduction of algae is inhibited. The combination of these two methods can achieve the effect of preventing algal blooms and overcome the design and evaluation (or the troublesome investigation work such as adapting to local conditions) required for biological control methods.

[0011] A further technical solution is that after the control device starts the mechanical step of preventing algal bloom, the following step is also provided: based on the signals collected from the fluorescent sensors set in the large water surface area, the aforementioned filter-feeding polyculture fish are added again, and the stocking density of this stocking is greater than 37g / m3.

[0012] The fluorescent sensor is fixedly connected to the buoy and is arranged under the water surface.

[0013] The occurrence of algal bloom can be detected by setting up a fluorescent sensor (although a small amount of stocking in the early stage is combined with mechanical blowing to move the water or mechanical sediment removal, local or small amounts of algal bloom may still occur. At this time, additional stocking and stocking density are higher than before, which can better solve the algal bloom problem and still does not require the design and evaluation of the prevention and control plan. The whole process is based on the sensor or analysis to drive the equipment action). The additional stocking density can take the middle value of existing technical research, such as 45g / m 3 , increase the stocking density. Since the fluorescent sensor can detect that algal bloom has occurred, the stocking density can be increased. In order to reduce the trouble of designing the prevention and control plan, the minimum stocking density can be selected, such as 40g / m 3, and then add mechanical algae removal methods, combine the two methods, if a small amount of algal bloom still appears in the later stage, you can add more stocking and increase the stocking density appropriately, so that the stocking density can be gradually changed according to the area of the algal bloom, and the design and evaluation (or the troublesome investigation work such as adapting to local conditions) required for the algal bloom prevention method can still be overcome; because the fluorescent sensor here is used to detect algal blooms after the early prevention and control measures for algal blooms (a small amount of stocking combined with mechanical blowing of water flow or oxygenation or mechanical sediment removal), the fluorescent sensor here can use an anchoring system or not, because it only needs to increase the amount of nutrients when algal blooms are detected.

[0014] A further technical solution is that the stocking ratio of silver carp and bighead carp in the mixed fish culture is 3: (1-2).

[0015] A further technical solution is that the equipment is an aerator or a flow-generating device; a plurality of sensors are provided and are dispersed at intervals in a large water surface area, and a plurality of equipment are also provided, and the number of equipment is consistent with the number of sensors; the sensor is a flow meter or a wind speed sensor; a float is fixedly provided on the sensor, an anchor rope is fixedly connected under the float, and the other end of the anchor rope is fixedly connected to an anchor.

[0016] The aerator and sensor share a common anchor, reducing the number of anchors and anchor ropes. The aerator is equipped with a forward and reverse servo motor, and a reducer is fixedly connected to the output shaft of the forward and reverse servo motor. The output shaft of the reducer is fixedly connected to the output shaft of the reducer. After receiving the sensor signal through the controller, the controller not only controls the aerator to start aeration, but also controls the forward and reverse servo motor to start, causing the propeller to rotate and blow air. The rotation of the propeller pushes the air backward. Due to the reaction force, the aerator is thrust forward, causing the aerator to move and glide on the water surface. A fixed anchor rope is installed under the aerator and is rotatably connected to the anchor. Therefore, the aerator reciprocates with the anchor as the center during the forward and reverse rotation of the forward and reverse servo motor, covering a larger aeration range. (Since the sensor detects no flow rate or a low flow rate, it means that this is the case in a certain range near the sensor. Therefore, the aerator's aeration range can be appropriately increased, which is more in line with the working conditions.) (Another solution is to directly install electric propellers on the aerator to directly push water to achieve the movement and glide of the aerator.) The length of the anchor rope under the aerator is greater than that under the sensor.

[0017] A further technical solution is that the steps for sampling the bottom sediment on a large water surface are: sampling with an automatic gravity sampler, then taking it out of the water for organic matter detection and cyst detection, and based on the information on organic matter and naked algae cysts in the bottom sediment obtained by the detection and analysis, the controller controls the automated dredging equipment to remove the bottom sediment rich in organic matter and naked algae cysts.

[0018] When the automatic gravity sampler is deployed on a large water surface, it is fixedly connected to the unmanned boat through a cable (or steel cable); the automatic gravity sampler drives the sampling tube vertically into the bottom mud through gravity or counterweight, and the trigger mechanism automatically closes the sampling tube; after the sampler touches the bottom and completes sampling, the cable is lifted vertically at a uniform speed (about 0.5 m / s). When the sampler leaves the water surface, it pauses briefly to allow excess water to flow out, reducing the risk of sample loss; several automatic gravity samplers are set up and distributed to determine the location of bottom mud rich in organic matter or cysts, so that dredging work is more targeted, the working range of the automated dredging equipment is reduced, and energy consumption is reduced; the automated dredging equipment can use a cutter suction dredging vessel, a drag suction dredging vessel, a solar dredging platform, or an underwater robot.

[0019] This method removes organic matter and Euglena cysts from the sediment to the surface of the water, improving the bottom environment, removing the root causes of Euglena, and reducing the occurrence of algal blooms. Compared to methods that use aerators, flow generators, flow meters, and wind speed sensors to blow air to the water surface, this method consumes less energy and directly controls the equipment based on the information obtained. The only difficulty is testing the sampled sediment, but compared to existing technologies, it still eliminates the need for design and evaluation (or the cumbersome investigation and design work required to adapt to local conditions). The method of creating flow to change the stagnant water environment to inhibit algae growth consumes slightly more energy, but does not require any testing and also has the advantage of not requiring the design and evaluation of a control plan (or the cumbersome investigation and design work required to adapt to local conditions).

[0020] A further technical solution is that the equipment is a scraping equipment and an aeration equipment; the sensor is a fluorescent sensor arranged under the water surface in a large water area, the fluorescent sensor is fixedly connected to a water tank submerged under the water surface, the water tank is fixedly connected to the bottom anchor through a connecting rope, a bottom valve is provided at the bottom of the water tank, a vent valve is provided at the top of the water tank, and the side surface of the water tank is also fixedly connected to a high-pressure gas cylinder connected to the water tank.

[0021] The length of the connecting rope determines the maximum height (or minimum water depth) of the fluorescent sensor. Initially, there is almost no water in the water tank, so the buoyancy of the whole (that is, the water tank, high-pressure gas cylinder, and fluorescent sensor) is greater than the gravity. Due to the action of the anchor, the water tank is located below the water surface, and the anchor rope is stretched straight because the buoyancy of the water tank (more specifically, the whole composed of the water tank, fluorescent sensor, and high-pressure gas cylinder) is greater than the gravity. When algal bloom is detected, the controller controls the aeration equipment to aerate and at the same time controls the vent valve to open. The surface water naturally flows into the water tank under the action of gravity and then closes the vent valve. When the amount of water in the water tank is so large that the overall gravity is greater than the buoyancy, the whole tank sinks. This facilitates the subsequent scraping operation of the scraping equipment and prevents the fluorescent sensor in the shallow water from being hit by the scraping equipment.

[0022] A further technical solution is that the aeration equipment is a dissolved air flotation boat; according to the signal sent by the fluorescent sensor at the detected water bloom area, the controller controls the dissolved air flotation boat to move to the detected water bloom area to generate micro bubbles.

[0023] Using silver carp and bighead carp as filter feeders to reduce the internal and external source loads to a certain extent, it can play a preliminary (or smaller) role in limiting the occurrence of cyanobacteria blooms. The minimum stocking density is selected and a certain amount of stocking is carried out. 37g / m 3 , there is no need to consider many other factors; after the blue-green algae bloom occurs, on the one hand, mechanical and physical methods are used to remove the algae, and on the other hand, a small amount of silver carp and bighead carp are added at the same time to increase the stocking density to prevent the subsequent expansion of the bloom. By drawing on the advantages of both methods, it can also overcome the design and evaluation (or the troublesome investigation work such as adapting to local conditions) required by biological control methods.

[0024] The advantages and beneficial effects of the present invention are as follows: a controller controls the automated silt removal equipment to remove a portion of the bottom silt from a large water surface area (this avoids both excessive silt removal and the troublesome sampling and analysis required for accurate silt location after sampling and analysis), and then replenishes water from a clean water source (the combination of these two methods effectively prevents algal blooms without requiring complex prevention and control program design, evaluation, and investigation). Subsequently, based on the algal bloom situation detected by the fluorescent sensor, the area of the water area where the silt has been removed is accurately determined, and mechanical silt removal is then performed, thereby significantly delaying and reducing the scope of the algal bloom. Furthermore, the early prevention and control work is not rigorous and is simple to operate, eliminating the tedious work of designing and researching prevention and control programs. Even if algal blooms occur later, the introduction of filter-feeding fish in the early stage of mixed farming and the removal of some bottom silt may remove a portion rich in organic matter and cysts. Combined with water diversion and water regulation to dilute the pollutant concentration (or dilute the organic matter and cysts), the scope of the late algal bloom is greatly reduced, effectively preventing algal blooms. Through the early stage of extensive treatment, any algal blooms that do occur can be immediately and targetedly treated later, effectively preventing algal blooms while reducing the design and research of prevention and control programs, thereby significantly reducing the cost of the entire prevention and control program.

[0025] By co-culturing silver carp or bighead carp in large-scale freshwater fish farming, the growth of Microcystis aeruginosa can be effectively controlled and the growth of beneficial algae can be promoted. By using silver carp and bighead carp as filter-feeding fish, the internal and external source loads can be reduced to a certain extent, which can play a preliminary (or smaller degree) role in limiting the occurrence of cyanobacterial blooms. This process can save design and evaluation, and only requires a certain degree of inhibition, which can be combined with mechanical and physical algae removal methods. Because the stocking density of silver carp and bighead carp to curb algal blooms is considered by some studies to be 46~50g / m3, and some studies to be 40~50g / m3, there is no specific unified standard. The determination of aquaculture capacity cannot be a constant, but can only be a variable that changes with many factors or conditions. It needs to be adjusted according to local conditions and in a timely manner. Select the minimum stocking density and then adjust the release amount to a certain extent, and choose 37g / m3, without considering many other factors; reduce the phytoplankton biomass through biological control to achieve the purpose of avoiding algal blooms, so as to effectively maintain the water quality of the composite aquaculture pond, and combine it with mechanical methods to prevent algal blooms and inhibit algal reproduction. The combination of these two methods can achieve the effect of preventing algal blooms and overcome the design and evaluation (or the troublesome investigation work such as adapting to local conditions) required for biological control methods.

[0026] This method removes organic matter and Euglena cysts from the sediment to the surface of the water, improving the bottom environment, removing the root causes of Euglena, and reducing the occurrence of algal blooms. Compared to methods that use aerators, flow generators, flow meters, and wind speed sensors to blow air to the water surface, this method consumes less energy and directly controls the equipment based on the information obtained. The only difficulty is testing the sampled sediment, but compared to existing technologies, it still eliminates the need for design and evaluation (or the cumbersome investigation and design work required to adapt to local conditions). The method of creating flow to change the stagnant water environment to inhibit algae growth consumes slightly more energy, but does not require any testing and also has the advantage of not requiring the design and evaluation of a control plan (or the cumbersome investigation and design work required to adapt to local conditions).

[0027] Silver carp and bighead carp filter-feeding fish are used to reduce internal and external source loads to a certain extent, which plays a preliminary (or smaller degree) role in limiting the occurrence of cyanobacterial blooms. The minimum stocking density is selected and a certain amount of stocking is carried out, and 37g / m3 is selected without considering many other factors. After the cyanobacterial bloom occurs, mechanical and physical methods are used to remove the algae. On the other hand, a small amount of silver carp and bighead carp are added at the same time to increase the stocking density to prevent the subsequent expansion of the bloom. By drawing on the advantages of both methods, the design and evaluation (or the troublesome investigation work such as adapting to local conditions) required for biological control methods can be overcome. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of water bloom detection in Example 1 of a large-surface freshwater fish farming method for effectively preventing water blooms according to the present invention; Figure 2 yes Figure 1 Schematic diagram of the exploded buoy and fluorescent sensor; Figure 3 yes Figure 1 Schematic diagram of the mid-level buoy; Figure 4 Schematic diagram of wind speed detection using a wind speed sensor according to the first embodiment; Figure 5 Schematic diagram of flow velocity detection using a propeller flow meter according to the first embodiment; Figure 6 is a schematic diagram of a second embodiment of the present invention; Figure 7 It is a schematic diagram of embodiment 3 of the present invention.

[0029] In the figure: 1. Buoy; 2. Fluorescent sensor; 3. Wind speed sensor; 4. Floating body; 5. Propeller current meter; 6. Anchor rope; 7. Anchor; 8. Aerator; 9. Automatic gravity sampler; 10. Cutter suction dredging vessel; 11. Unmanned boat; 12. Water tank; 13. Connecting rope; 14. Bottom valve; 15. Vent valve; 16. High-pressure gas cylinder; 17. Dissolved air flotation vessel. DETAILED DESCRIPTION

[0030] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0031] Example 1: The present invention is a large-scale freshwater fish farming method for effectively preventing algal blooms, comprising the following steps: stocking filter-feeding polycultured fish into a large water area; controlling a device to activate a mechanical method to prevent algal blooms based on sensor signals collected from the large water area; the filter-feeding polycultured fish are polycultured silver carp and bighead carp; the polycultured fish are stocked at a density of 37g / m 3 According to the signal collected by the fluorescent sensor 2 in the large water area, the aforementioned filter-feeding polyculture fish are added again, and the stocking density of this stocking is greater than 37g / m 3 ;like Figures 1 to 3 As shown, the fluorescent sensor 2 is fixedly connected to the buoy 1, and the fluorescent sensor 2 is set under the water surface; the stocking ratio of silver carp and bighead carp in the mixed fish culture is 3: (1-2); The device is an aerator 8 or a flow-making device; the sensors are provided in plurality and are spaced apart in a large water area, and the devices are also provided in plurality, the number of the devices being the same as the number of the sensors; the sensors are current meters or wind speed sensors; a floating body 4 is fixedly provided on the sensor, an anchor rope 6 is fixedly connected to the bottom of the floating body, and an anchor 7 is fixedly connected to the other end of the anchor rope; Figure 5 shown.

[0032] The genus Euglena likes to live in small, still, non-flowing water bodies. Mechanical oxygenation can change the still environment of the water body and inhibit its reproduction. Alternatively, by blowing air on the surface of large water bodies to interfere with the aggregation and surface dominance of cyanobacteria, the formation of Euglena blooms can be inhibited. Although the mechanical method of blowing air on the water surface is generally an auxiliary method, it can effectively prevent blooms when combined with the early stocking of filter-feeding silver carp and bighead carp. The wind speed sensor 3 is a cup-type anemometer, and a float 4 is fixedly arranged under its base; the current meter is a Doppler current meter or a propeller current meter 5, the detection part of the Doppler current meter is located under the water surface, and the display part is fixedly connected to the upper surface of the float, and a baffle can be fixedly arranged around the float to prevent water waves from hitting the display part of the main unit; the propeller current meter 5 is fixedly connected to the bottom of the float 4, and the anchor rope connection point can be set at the center of the lower surface of the float, and the propeller current meter 5 is fixedly connected to the bottom of the float. The lower surface of the body avoids the area at the center position to prevent the anchor rope 6 from affecting the propeller current meter; the aerator 8 is an impeller aerator or a turbine aerator; the flow-making device is a floating wind-powered flow-making device or a floating propeller flow-making device; the floating wind-powered flow-making device is an existing technology, generally composed of a floating platform and a high-power propeller, generally 5~20kw, which can cover a range of 200~500 meters and can generate a large wind force, which will not be described in detail; when the sensor detects that the water body in the water area has no flow velocity or the flow velocity is small (such as Figure 5 For the sake of illustration, the anchoring structure under the aerator is not shown), or there is no wind speed or the wind speed is small (such as Figure 4 As shown, for ease of illustration, the anchoring fixing structure under the aerator and the anchoring fixing structure under the wind speed sensor float are not shown). The controller connected to the sensor signal controls the aerator 8 for mechanical aeration or the flow-generating device to start flow, thereby changing the static environment of the water body and inhibiting the reproduction of algae. Since the sensor is fixedly connected to the float, and the float is connected to the anchor by an anchor rope, the sensor can be fixed at the desired detection position after the anchor is dropped. In this way, the detected signal can be located. When an area with no flow rate or a low flow rate is detected (or an area with no wind speed or a low wind speed is detected), the aerator in the corresponding area is controlled to start (the anchoring fixing structure below the float 4 on the aerator, i.e., the anchor rope and anchor, is used to fix the position of the aerator so that the aerator is located on one side of the corresponding sensor) or the flow-generating device. This can specifically start the equipment in the corresponding area and effectively inhibit the occurrence of algal bloom in the static area of the water body. When the fluorescent sensor 2 fixedly connected to the buoy 1 detects the occurrence of algal bloom, silver carp and bighead carp are added again.

[0033] Example 2: The difference from Example 1 is that Figure 6As shown, based on the information obtained from the sampling and analysis of the bottom mud on a large water surface, the control device starts a mechanical method to prevent the formation of algal blooms; the bottom mud sampling steps on a large water surface are: using an automatic gravity sampler 9 to sample, then taking it out of the water for organic matter detection and cyst detection, based on the information on organic matter and Euglena cysts in the bottom mud obtained by the detection and analysis, the controller controls the automated dredging equipment to travel to the target area to remove the bottom mud rich in organic matter and Euglena cysts; When the automatic gravity sampler 9 is deployed on a large water surface, it is fixedly connected to the unmanned boat 11 through a cable (or steel cable); the automatic gravity sampler drives the sampling tube vertically into the bottom mud through gravity or counterweight, and the trigger mechanism automatically closes the sampling tube; after the sampler touches the bottom and completes sampling, the cable is lifted vertically at a uniform speed (about 0.5 m / s). When the sampler leaves the water surface, it pauses briefly to allow excess water to flow out, reducing the risk of sample loss; several automatic gravity samplers are set up and distributed to determine the location of bottom mud rich in organic matter or cysts, so that the dredging work is more targeted, the working range of the automated dredging equipment is reduced, and energy consumption is reduced; the automated dredging equipment can use a cutter suction dredging vessel 10 or a trailing suction dredging vessel or a solar dredging platform or an underwater robot.

[0034] Example 3: The difference from Example 1 is that Figure 7 As shown, filter-feeding polyculture fish are stocked into large water areas; according to the sensor signals collected on the large water areas, the control device starts a mechanical method to prevent algal bloom; the filter-feeding polyculture fish are polycultured fish of silver carp and bighead carp; the polycultured fish stocking density is 37g / m 3 The equipment is a scraping device and an aeration device; the sensor is a fluorescent sensor 2 installed under the water surface in a large water area. The fluorescent sensor is fixedly connected to a water tank 12 submerged under the water surface. The water tank is fixedly connected to the bottom anchor via a connecting rope 13. A bottom valve 14 is provided at the bottom of the water tank, and a vent valve 15 is provided at the top of the water tank. A high-pressure gas cylinder 16 connected to the water tank 12 is also fixedly connected to the side surface of the water tank. The length of the connecting rope 13 determines the maximum height (or minimum water depth) of the fluorescent sensor 2. Initially, there is almost no water in the water tank, so the buoyancy of the entire system (i.e., the water tank, high-pressure gas cylinder, and fluorescent sensor) is greater than gravity. Due to the action of the anchor, the water tank is below the water surface, and the anchor rope is stretched straight because the buoyancy of the water tank (more specifically, the entire system consisting of the water tank, fluorescent sensor, and high-pressure gas cylinder) is greater than gravity. When an algal bloom is detected, the controller controls the aeration device to aerate the water and simultaneously controls the vent valve 15 to open. The surface water naturally flows into the water tank under the action of gravity, and then the vent valve is closed. When the water volume in the water tank exceeds the buoyancy, the entire system sinks. This facilitates the subsequent scraping operation of the scraping device and prevents the fluorescent sensor (or water tank) in the shallower water from being hit by the scraping device. The aeration equipment is a dissolved air flotation vessel 17 (in the solution using the dissolved air flotation vessel 17, the vessel is generally equipped with a rotary scraper or suction device to collect the foam layer into a sludge tank for transport to shore for treatment. In this case, the scraper is equivalent to being incorporated into the aeration equipment). Based on the signal emitted by the fluorescent sensor 2 at the detected algal bloom area, the controller controls the dissolved air flotation vessel to move to the detected algal bloom area to generate microbubbles. The fluorescent sensor cooperates with the mechanical algae removal to attach the blue algae with tiny bubbles as carriers, and by forming foam (microbubbles are efficiently generated by the dissolved air flotation vessel (mobile DAF system), with a bubble diameter of about 20-50 microns), the blue algae are brought to the surface of the water and removed by the scraping equipment. After the scraping equipment has finished removing the algae, the controller controls the dissolved air flotation vessel to return to the initial position, and then controls the high-pressure gas cylinder 16 to fill the water tank with high-pressure gas, and opens the bottom valve 14 to drain the water in the water tank 12. The fluorescent sensor returns to the initial design water depth (to facilitate the removal of the fluorescent sensor, the water can continue to be drained). The water in the tank is drained until there is no water in the tank, and then the tank automatically floats on the water surface or the buoyancy is insufficient to overcome the connection force between the bottom anchor and the bottom of the large water surface, then the connecting rope 13 can be pulled manually or mechanically); for ease of operation, the water tank 12 can be filled with a certain amount of water at the beginning, and the amount of water filled makes the overall gravity and buoyancy equal (or the buoyancy is appropriately less than the gravity), so that the bottom anchor falls more smoothly and with less resistance; after the bottom anchor falls on the bottom of the large water surface, some water is discharged so that the fluorescent sensor is always at the designed water depth due to buoyancy (that is, the connecting rope 13 is in a straight state).

[0035] Example 4: The difference from Example 1 is that it comprises the following steps performed in sequence: stocking filter-feeding polyculture fish into a large water area; controlling the device to start a mechanical method to prevent algal bloom; The equipment is an automated dredging equipment; a controller controls the automated dredging equipment to remove part of the bottom mud of a large water surface area (here it is not limited to where the dredging is specifically done, that is, the dredging range is uncertain and will not be determined, only part of the dredging work is carried out first), and then replenish water from a clean water source; based on the signal collected by the fluorescent sensor installed in the large water surface area (the signal can generally be collected after a period of time, that is, when algal bloom begins to appear in the water body, the fluorescent sensor detects it), the controller controls the automated dredging equipment to travel to the target area to remove the bottom mud.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal blooms, characterized in that: The method comprises the following steps which are carried out in sequence: stocking filter-feeding polyculture fish into a large water area; and controlling equipment to start mechanically preventing algal bloom.

2. A large-surface freshwater fish breeding method for effectively preventing algal bloom according to claim 1, characterized in that: According to the sensor signals collected on the large water surface or the information obtained from the sampling and analysis of the bottom mud of the large water surface, the control equipment starts the mechanical prevention of algal bloom.

3. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 1, characterized in that: The equipment is an automated dredging device; a controller controls the automated dredging device to remove part of the bottom mud from a large water surface area, and then replenishes water from a clean water source; based on the signals collected from the fluorescent sensors set up in the large water surface area, the controller controls the automated dredging device to travel to the target area to remove the bottom mud.

4. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 2 or 3, characterized in that: The filter-feeding polyculture fish is a polyculture of silver carp and bighead carp; the stocking density of the polyculture fish is 37g / m 3 .

5. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 2, characterized in that: After the control device starts the mechanical bloom prevention step, the following step is further provided: based on the signals collected from the fluorescent sensor set up in the large water surface area, the aforementioned filter-feeding polyculture fish are again stocked, and the stocking density of this stocking is greater than 37g / m 3 .

6. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 4, characterized in that: The stocking ratio of silver carp to bighead carp in the mixed fish culture is 3:(1-2).

7. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 2, characterized in that: The equipment is an aerator or a flow-generating device; a plurality of sensors are provided and are dispersed at intervals in a large water area, and a plurality of devices are also provided, and the number of devices is consistent with the number of sensors; the sensor is a flow meter or a wind speed sensor; a float is fixedly provided on the sensor, an anchor rope is fixedly connected under the float, and the other end of the anchor rope is fixedly connected to an anchor.

8. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 2, characterized in that: The large water surface sediment sampling steps are: using an automatic gravity sampler to sample, then taking it out of the water for organic matter detection and cyst detection, and based on the organic matter and Euglena cyst information in the sediment obtained by the detection analysis, the controller controls the automated dredging equipment to remove the sediment rich in organic matter and Euglena cysts.

9. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 2, characterized in that: The equipment is a scraping device and an aeration device; the sensor is a fluorescent sensor installed under the water surface in a large water area, the fluorescent sensor is fixedly connected to a water tank submerged under the water surface, the water tank is fixedly connected to the bottom anchor through a connecting rope, a bottom valve is provided at the bottom of the water tank, a vent valve is provided at the top of the water tank, and a high-pressure gas cylinder connected to the water tank is also fixedly connected to the side surface of the water tank.

10. A method for cultivating freshwater fish on a large surface of water that effectively prevents algal bloom according to claim 9, characterized in that: The aeration equipment is a dissolved air flotation boat; according to the signal sent by the fluorescent sensor at the detected water bloom area, the controller controls the dissolved air flotation boat to move to the detected water bloom area to generate micro bubbles.

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