Method and system for cultivating juvenile grass carp in a rice field ring ditch

Abstract

The present application relates to the technical field of aquaculture, and particularly discloses a method and system for culturing Opsariichthys pachycephalus fry in a ring ditch of a rice field, which comprises the following steps: selecting a rice field and digging a ring ditch around the rice field; digging a fish ditch in the rice field and digging to the fish ditch being connected with the ring ditch; selecting a first-stage culture area in the ring ditch as a culture area for Opsariichthys pachycephalus fry and arranging double-layer blocking nets at two inner walls of the ring ditch; draining and disinfecting the ring ditch; injecting water into the ring ditch; applying amino acids and special organic fertilizer for water quality culture; selecting Opsariichthys pachycephalus fry in a horizontal swimming stage and putting the fry into the water body; feeding the first-stage culture area with the first feed; starting to feed the second feed; injecting water into the first-stage culture area again; adding microbial agents; removing the inner blocking net; pulling the net to count the number of fry and removing the outer blocking net. The present application has the characteristics of reducing stress damage of Opsariichthys pachycephalus, lowering mortality, having less loss and lower breeding cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aquaculture, in particular to a method and system for culturing Opsariichthys bidens fry in a rice field ring ditch. BACKGROUND

[0002] Opsariichthys bidens is a small carnivorous fish, known as "the best of fish", which is rich in polyunsaturated fatty acid brain gold (i.e. DHA) essential for human body, more than 2 times of common marine and freshwater fish such as large yellow croaker, yellow catfish, mandarin fish and topmouth gudgeon, far lower than pig, cow and sheep in atherosclerosis index and thrombosis index, and often eating can effectively reduce cholesterol, enhance immunity, prevent and treat atherosclerosis and coronary heart disease, and often eating by pregnant women and children is helpful for children's brain development, and is one of the best aquatic products. Opsariichthys bidens was widely distributed in small streams or tributaries of rivers all over the country, and due to its delicious taste, rich nutrition, softness after intermuscular puncture, and being one of the most favorite wild fish for anglers, the wild resource of Opsariichthys bidens has been sharply reduced due to overfishing and habitat destruction. The fry culture of Opsariichthys bidens is a key technology for artificial breeding.

[0003] The patent document with publication number "CN113040071A" discloses a method for culturing fry of Opsariichthys bidens, which sets a long and narrow pond with a length-width ratio of 3-5:1, sprays and disinfects the whole pond after slaking quicklime, then adds water and organic manure fermented by adding feed in the pond to uniformly stir to form fertilizer water, and then carries out fry stocking and culture management, and adds 1% EM bacteria and 0.2% astragalus polysaccharide in the feed; finally, 3-4 cm Opsariichthys bidens fry is obtained; the method can improve the survival rate of the fry of Opsariichthys bidens. At present, the rice-fish integrated breeding mode for Opsariichthys bidens has been successfully verified, however, due to the high stress and high mortality during transportation, the source of the fry has been affecting the overall benefit, and the Opsariichthys bidens fry cultured according to the method of the existing patent document still has high mortality during transportation and low survival rate after being placed in the rice field.

[0004] Therefore, the existing rice-fish integrated breeding mode for Opsariichthys bidens has problems of high stress damage and mortality, high loss and high breeding cost. SUMMARY

[0005] In order to solve the above technical problems of the existing rice-fish integrated breeding mode for Opsariichthys bidens, the present application provides a method and system for culturing Opsariichthys bidens fry in a rice field ring ditch, which has the characteristics of reducing stress damage, reducing mortality during transportation, small loss and low breeding cost.

[0006] The first technical solution of the present application is a method for culturing Opsariichthys bidens fry in a rice field ring ditch, comprising the following steps,

[0007] (A01) Select a paddy field and dig a ring ditch around it;

[0008] (A02) Dig a fish ditch in the paddy field in step (A01) and dig until the fish ditch is connected to the ring ditch;

[0009] (A03) Select the first-level cultivation area in the ring ditch in step (A01) as the breeding area for chub fry, and set up double-layer netting on the two inner walls of the ring ditch;

[0010] (A04) Disinfect the ring ditch in step (A01) before releasing the fry of the chub;

[0011] (A05) After the disinfection in step (A04) is completed, fill the ring trench with water;

[0012] (A06) After the water injection in step (A05) is completed, amino acids and aquatic-specific organic fertilizer are applied to the water body of the ring ditch for water quality cultivation;

[0013] (A07) Select juvenile chub that have entered the basal swimming stage and release them into the water body of step (A06);

[0014] (A08) After the seedlings in step (A07) have been cultivated for a period of time, the first feed is fed into the first-level cultivation area;

[0015] (A09) After the seedlings in step (A08) have been cultivated for a period of time, the second feed shall be fed.

[0016] (A10) After the second feed is started in step (A09), water is injected into the first-level culture area again;

[0017] (A11) After the water injection in step (A10) is completed, add the microbial preparation to the first-level culture zone;

[0018] (A12) Once the seedlings in step (A11) have reached a certain size, remove the inner layer of netting;

[0019] (A13) Continue cultivating the seedlings in step (A12) until they reach a certain size, then count the number of seedlings by pulling the net and remove the outer layer of netting;

[0020] (A14) After the rice tillering is complete, water is injected into the ring ditch in step (A13) until the water level in the ring ditch is higher than the water level in the paddy field. This invention directly digs a ring ditch around the selected paddy field and then digs a fish ditch connected to the ring ditch within the paddy field. The ring ditch is used directly for the cultivation of chub fry. After cultivation, the water level rises, allowing the cultivated chub fry to swim naturally into the paddy field through the fish ditch. This minimizes stress and mortality during the transfer of chub to the integrated rice-fish farming model, reducing losses and lowering farming costs. The first-level cultivation area can be the entire ring ditch area or a portion of it, selected as the chub fry cultivation area for specialized cultivation of chub fry. This invention uses double-layered netting on the inner walls of the ring ditch to prevent the fry from jumping out of the ring ditch or into the fish ditch and paddy field, thus ensuring the chub fry survive. The fry of the Chinese chub are cultivated only within a designated area. Before releasing the fry, the surrounding ditch is drained and disinfected to prevent pests and diseases within the ditch from affecting the health of the fry in the subsequent water body, ensuring the health and survival rate of the fry. Before releasing the fry into the water body, amino acids and aquatic-specific organic fertilizer are applied to cultivate the water quality, making the water rich in various amino acids and organic matter necessary for the fry's growth, thus providing a comfortable growing environment after release. This invention selects fry that have entered the lateral swimming stage and places them in the water body within the first-level cultivation area. Fry in the lateral swimming stage will have better environmental adaptability and... Healthier growth: After a period of cultivation, the fry are fed a first and second feed in stages. Feeding the appropriate feed according to the different growth stages of the fry allows them to better adapt to the nutritional needs of the fry at each stage, thus promoting better growth. After feeding the second feed for a period, water is continuously injected into the first-stage cultivation area. At this point, the fry have grown to a certain stage, possessing stronger adaptability and resistance, and are ready to be introduced into rice paddies. By adding microbial agents to the first-stage cultivation area after water injection, the concentrations of nitrite, ammonia nitrogen, and hydrogen sulfide in the aquaculture water can be effectively reduced, inhibiting the reproduction of harmful microorganisms in the water. This invention promotes the growth and purification of water, allowing chub fry to thrive. When the chub fry reach a certain size, the inner layer of the netting is removed to initially reduce restrictions. As they continue to grow, the netting is pulled back to count the number of fry about to enter the paddy field, facilitating statistics when they are fully grown and generating profits. The outer layer of the netting is then removed, completely removing restrictions and giving the chub fry more space to move. After the rice tillering stage, water is injected into the ring ditch, gradually reaching the fish ditch. The chub fry flow into the fish ditch, and as the water level rises further, submerging the paddy field, the chub fry can swim freely, creating a healthy integrated rice-fish farming model.

[0021] Preferably, an overflow outlet is provided at the corner of the annular groove in step (A01). The overflow outlet can prevent excessive water injection into the annular groove, causing the water level to overflow irregularly over the cultivated land. When too much water is injected, the excess water will flow out of the overflow outlet into the external ditch.

[0022] Preferably, the width of the annular groove in step (A01) is 0.5 m to 5 m. More preferably, the width of the annular groove in step (A01) is 0.8 m to 4 m. More preferably, the width of the annular groove in step (A01) is 1 m to 3.5 m. More preferably, the width of the annular groove in step (A01) is 1.5 m to 3 m. More preferably, the width of the annular groove in step (A01) is 2 m to 2.5 m. The specific limitation of the width of the annular groove can, on the one hand, cultivate a considerable number of Opsariichthys bidens fry, and on the other hand, provide a certain activity space for the Opsariichthys bidens fry, ensuring the comfort of their activities.

[0023] The specific limitation of the depth of the annular groove can, on the one hand, cultivate a considerable number of Opsariichthys bidens fry, and on the other hand, provide a certain activity space for the Opsariichthys bidens fry, ensuring the comfort of their activities. Preferably, the depth of the annular groove in step (A01) is 80 cm to 150 cm. More preferably, the depth of the annular groove in step (A01) is 90 cm to 140 cm. More preferably, the depth of the annular groove in step (A01) is 100 cm to 130 cm. More preferably, the depth of the annular groove in step (A01) is 110 cm to 120 cm. More preferably, the depth of the annular groove in step (A01) is 115 cm.

[0024] Preferably, the shape of the annular groove in step (A01) is a "return" shape. The "return" - shaped annular groove is convenient to dig and form, surrounds the paddy field, looks good, and is also convenient for the later net - pulling statistics of Opsariichthys bidens fry. The shape of the annular groove can be any polygon surrounding the paddy field, preferably a regular polygon.

[0025] Preferably, the diameter of the overflow outlet is 100 mm to 200 mm. More preferably, the diameter of the overflow outlet is 110 mm to 190 mm. More preferably, the diameter of the overflow outlet is 120 mm to 180 mm. More preferably, the diameter of the overflow outlet is 130 mm to 170 mm. More preferably, the diameter of the overflow outlet is 140 mm to 160 mm. More preferably, the diameter of the overflow outlet is 150 mm. The specific limitation of the diameter of the overflow outlet can effectively prevent the irregular overflow over the cultivated land caused by excessive water injection in the annular groove.

[0026] Preferably, a number of aeration pipes are provided in the annular groove of step (A01). The number of aeration pipes can effectively ensure the oxygen demand during the cultivation of Opsariichthys bidens fry in the annular groove.

[0027] Preferably, the spacing between adjacent oxygenation tubes is 50cm to 150cm. More preferably, the spacing between adjacent oxygenation tubes is 70cm to 130cm. More preferably, the spacing between adjacent oxygenation tubes is 80cm to 120cm. More preferably, the spacing between adjacent oxygenation tubes is 90cm to 110cm. More preferably, the spacing between adjacent oxygenation tubes is 100cm.

[0028] Preferably, the diameter of the oxygenation tube is 30cm to 70cm. More preferably, the diameter of the oxygenation tube is 35cm to 65cm. More preferably, the diameter of the oxygenation tube is 40cm to 60cm. More preferably, the diameter of the oxygenation tube is 45cm to 55cm. More preferably, the diameter of the oxygenation tube is 50cm. An oxygenation tube with a limited diameter will have sufficient oxygenation capacity.

[0029] Preferably, the system includes a blower, the blower's outlet of which is connected to the oxygenation pipe. The blower can efficiently deliver outside air into the oxygenation pipe.

[0030] Preferably, the blower is a Roots blower. Roots blowers operate stably and provide good blowing effect.

[0031] Preferably, the power of the blower is 1.4 kW to 3 kW. More preferably, the power of the blower is 1.6 kW to 2.8 kW. Even more preferably, the power of the blower is 1.8 kW to 2.5 kW. Even more preferably, the power of the blower is 2 kW to 2.2 kW. The blower with the limited power has a highly efficient and stable operating state.

[0032] Preferably, the width of the fish ditch in step (A02) is 50cm to 100cm. More preferably, the width of the fish ditch in step (A02) is 60cm to 90cm. Even more preferably, the width of the fish ditch in step (A02) is 70cm to 80cm. A fish ditch with a limited width allows juvenile chub to swim smoothly from the ring ditch into the paddy field, providing them with adequate swimming space.

[0033] Preferably, the depth of the fish ditch in step (A02) is 20cm to 50cm. More preferably, the depth of the fish ditch in step (A02) is 25cm to 45cm. More preferably, the depth of the fish ditch in step (A02) is 30cm to 40cm. More preferably, the depth of the fish ditch in step (A02) is 35cm. A fish ditch of a limited depth allows juvenile chub to swim smoothly from the ring ditch into the paddy field, providing them with adequate swimming space.

[0034] Preferably, the fish ditch in step (A02) is in the shape of a "well". The "well" shaped fish ditch has multiple connection points with the ring ditch, so that the fry of the mandarin fish that have been cultivated to a certain size can swim smoothly from the ring ditch into the paddy field, and the fry of the mandarin fish can also move freely in the "well" shaped fish ditch.

[0035] Preferably, the fish ditches and ring ditches occupy 5% to 15% of the total paddy field area. More preferably, the fish ditches and ring ditches occupy 7% to 12% of the total paddy field area. Even more preferably, the fish ditches and ring ditches occupy 9% to 11% of the total paddy field area. This limited ratio of fish ditches and ring ditches to the total paddy field area ensures a healthy integrated rice-fish farming system, guaranteeing the simultaneous healthy growth of both rice and chub fry.

[0036] Preferably, the first-stage culture area in step (A03) is located at the inlet of the ring ditch. This location facilitates the unobstructed entry of the juvenile chub fry into the first-stage culture area.

[0037] Preferably, the first-level cultivation area in step (A03) occupies 40% to 100% of the total area of ​​the annular ditch. More preferably, the first-level cultivation area in step (A03) occupies 50% to 90% of the total area of ​​the annular ditch. Even more preferably, the first-level cultivation area in step (A03) occupies 60% to 80% of the total area of ​​the annular ditch. Even more preferably, the first-level cultivation area in step (A03) occupies 65% to 75% of the total area of ​​the annular ditch. The area occupied by the first-level cultivation area in the annular ditch can be flexibly set and adjusted according to the number of juvenile chub fry to be cultivated over time.

[0038] Preferably, the number of chub fry cultivated in the first-level cultivation area in step (A03) is 1500-2500 fry / mu. More preferably, the number of chub fry cultivated in the first-level cultivation area in step (A03) is 1600-2400 fry / mu. More preferably, the number of chub fry cultivated in the first-level cultivation area in step (A03) is 1700-2300 fry / mu. More preferably, the number of chub fry cultivated in the first-level cultivation area in step (A03) is 1800-2200 fry / mu. More preferably, the number of chub fry cultivated in the first-level cultivation area in step (A03) is 1900-2100 fry / mu. More preferably, the number of chub fry cultivated in the first-level cultivation area in step (A03) is 1950-2000 fry / mu. The number of chub fry cultivated in the first-level cultivation area is determined according to the size of the paddy field area. The purpose is to form a good integrated rice-fish farming system, where rice and chub fry grow healthily together. The determined cultivation amount can ensure that rice and chub fry grow healthily together.

[0039] Preferably, in step (A03), the inner layer of the double-layer mesh is a 60-100 mesh mesh, and the outer layer is a 10-30 mesh mesh. More preferably, in step (A03), the inner layer of the double-layer mesh is a 65-95 mesh mesh, and the outer layer is a 12-28 mesh mesh. More preferably, in step (A03), the inner layer of the double-layer mesh is a 70-90 mesh mesh, and the outer layer is a 15-25 mesh mesh. More preferably, in step (A03), the inner layer of the double-layer mesh is a 75-85 mesh mesh, and the outer layer is an 18-22 mesh mesh. More preferably, in step (A03), the inner layer of the double-layer mesh is an 80 mesh mesh, and the outer layer is a 20 mesh mesh. The inner layer of the double-layered net with a limited mesh size can prevent the fry of the mandarin fish in the initial swimming stage from escaping through the mesh; the outer layer of the double-layered net with a limited mesh size can prevent the fry of the mandarin fish that have been cultivated to a certain size from escaping through the mesh after the inner layer of the net is removed.

[0040] Preferably, in step (A03), the height of the double-layered barrier net is higher than the depth of the annular ditch. Setting the height of the double-layered barrier net to be higher than the depth of the annular ditch ensures that the fry of the mandarin fish inside the double-layered barrier net cannot jump out of the annular ditch to the outside.

[0041] Preferably, in step (A03), the height of the double-layered barrier net is 5cm to 15cm higher than the depth of the annular ditch. More preferably, in step (A03), the height of the double-layered barrier net is 7cm to 12cm higher than the depth of the annular ditch. Even more preferably, in step (A03), the height of the double-layered barrier net is 9cm to 11cm higher than the depth of the annular ditch. This limitation on the height of the double-layered barrier net ensures that the fry of the mandarin fish inside the double-layered barrier net cannot jump out of the annular ditch to the outside.

[0042] Preferably, the disinfectant used in step (A04) is bleaching powder. Bleaching powder can effectively remove pests and diseases in the ring ditch, better ensuring the health and survival rate of the chub fry subsequently placed in the ring ditch for cultivation.

[0043] Preferably, in step (A04), the bleaching powder is slurried and then poured onto the entire ring trench. This ensures thorough sterilization and disinfection of the ring trench.

[0044] Preferably, the amount of disinfectant used in step (A04) is 30 kg / mu to 70 kg / mu. More preferably, the amount of disinfectant used in step (A04) is 35 kg / mu to 65 kg / mu. More preferably, the amount of disinfectant used in step (A04) is 40 kg / mu to 60 kg / mu. More preferably, the amount of disinfectant used in step (A04) is 45 kg / mu to 55 kg / mu. More preferably, the amount of disinfectant used in step (A04) is 50 kg / mu. This limitation on the amount of disinfectant used ensures thorough sterilization and disinfection of the ring ditch without excessive dosage.

[0045] Preferably, in step (A04), the time interval between draining and disinfecting the ring ditch and releasing the fry of the mandarin fish is 5 to 8 days. More preferably, in step (A04), the time interval between draining and disinfecting the ring ditch and releasing the fry of the mandarin fish is 6 to 7 days. This ensures thorough sterilization and disinfection of the ring ditch.

[0046] Preferably, the water injection time in step (A05) is 1 to 3 days after disinfection. More preferably, the water injection time in step (A05) is 2 days after disinfection. This ensures thorough sterilization and disinfection of the ring ditch.

[0047] Preferably, the water volume in step (A05) is 50% to 80% of the depth of the annular ditch. More preferably, the water volume in step (A05) is 55% to 75% of the depth of the annular ditch. Even more preferably, the water volume in step (A05) is 60% to 70% of the depth of the annular ditch. Even more preferably, the water volume in step (A05) is 65% of the depth of the annular ditch. This provides the water volume required for the rearing of chub fry without causing the water level to become too high and enter the fish ditch.

[0048] Preferably, in step (A06), the amino acids and aquaculture-specific organic fertilizer are applied 3 to 5 days before the release of the chub fry. More preferably, in step (A06), the amino acids and aquaculture-specific organic fertilizer are applied 4 days before the release of the chub fry. This ensures that the water is uniformly rich in various amino acids and organic matter necessary for the growth and development of the chub fry.

[0049] Preferably, the application rate of amino acids and aquaculture-specific organic fertilizer in step (A06) is 80 kg / mu to 120 kg / mu. More preferably, the application rate is 85 kg / mu to 115 kg / mu. More preferably, the application rate is 90 kg / mu to 110 kg / mu. More preferably, the application rate is 95 kg / mu to 105 kg / mu. More preferably, the application rate is 100 kg / mu. This ensures that the water body is rich in the various amino acids and organic matter required for the cultivation and growth of chub fry, without excessive amounts.

[0050] Preferably, the aquatic-specific organic fertilizer is a fermented organic fertilizer. More preferably, the fermented organic fertilizer is fermented chicken manure organic fertilizer.

[0051] Preferably, in step (A06), the water is cultured until the water transparency reaches 25cm to 35cm. More preferably, in step (A06), the water transparency reaches 28cm to 32cm. Even more preferably, in step (A06), the water transparency reaches 30cm. This requirement for transparency indicates good water cleanliness, which is very beneficial for the cultivation of chub fry and allows for timely observation of the chub fry's activity.

[0052] Preferably, the water culture time in step (A06) is 2 to 5 days. More preferably, the water culture time in step (A06) is 3 to 4 days. This approach ensures good horizontal culture conditions and meets the requirements for raising chub fry while also considering timeliness.

[0053] Preferably, in step (A06), the number of cladocerans in the water sample is more than 3 per mL. This requirement for a high number of cladocerans helps maintain the environmental balance in the water, providing ample initial food for the fry and also purifying the water during the fry rearing process.

[0054] Preferably, the stocking density of chub fry in the water body during step (A06) is 2000 to 2500 fry / m². More preferably, the stocking density is 2100 to 2400 fry / m². Even more preferably, the stocking density is 2200 to 2300 fry / m². Limiting the stocking density ensures a balance between the number of chub fry and the size of the cultivation environment, allowing for the healthy cultivation of a suitable number of chub fry within a known cultivation area.

[0055] Preferably, in step (A08), when the number of cladocerans in the water body decreases to 1 to 2 cladocerans per mL of water sample, the first feed is introduced into the water body. This specific timing for introducing the first feed indicates that the chub fry have been cultivated in the primary culture area for a period of time, have adapted to the culture environment, and have partially consumed the cladocerans in the water. Introducing the first feed at this point ensures a good food supply in the water body and guarantees the nutritional supply for the chub fry at the corresponding stage.

[0056] Preferably, the first feed in step (A08) is a powder with a crude protein content of ≥48%. This specific specification of the first feed provides sufficient protein for the fry at the corresponding stage and facilitates good feeding for the fry. The powder contains dried earthworm powder, dried fly larvae powder, and / or dried insect powder.

[0057] Preferably, the particle size of the first feed in step (A08) is 0.2 mm to 0.3 mm. A first feed with a limited particle size facilitates good consumption and digestion for chub fry.

[0058] Preferably, the first feed in step (A08) is delivered by dry sprinkling along the ring ditch. This method is simple and convenient for fish farmers, and allows for timely observation of the growth of the chub fry during the feeding process.

[0059] Preferably, the feeding of the first feed in step (A08) is 6-9 days after the release of the chub fry. More preferably, the feeding of the first feed in step (A08) is 7-8 days after the release of the chub fry. The specific time limit for feeding the first feed is based on a summary of extensive breeding experience. Feeding the first feed within this time period is appropriate because the chub fry have been cultivated in the primary culture area for a period of time, have adapted to the culture environment, and have partially consumed cladocerans in the water. To ensure a good supply of food in the water, feeding the first feed within this time period is more suitable.

[0060] Preferably, the feeding frequency of the first feed in step (A08) is 2 to 5 times per day. More preferably, the feeding frequency of the first feed in step (A08) is 3 to 4 times per day. Limiting the feeding frequency of the first feed can ensure a good food supply for the fry in the water, and ensure the regular diet and metabolic balance of the fry.

[0061] Preferably, the feeding amount of the first feed in step (A08) is 5g / 10,000 fish to 15g / 10,000 fish. More preferably, the feeding amount of the first feed in step (A08) is 7g / 10,000 fish to 12g / 10,000 fish. Even more preferably, the feeding amount of the first feed in step (A08) is 9g / 10,000 fish to 11g / 10,000 fish. Limiting the feeding amount of the first feed ensures that the fry have a sufficient food supply to eat their fill without overfeeding them.

[0062] Preferably, the second feed in step (A08) is a crushed feed and pelleted feed with a crude protein content of ≥46%. The second feed is intended for feeding chub fry that have grown to a certain size. At this stage, the chub fry have reached a certain size and possess good feeding and digestive abilities. The size-specific second feed provides sufficient protein for the chub fry at this stage, and the crushed feed and pelleted feed are readily consumed by the chub fry at this size. Both the crushed feed and pelleted feed contain dried earthworm powder, dried fly larvae powder, and / or dried insect powder.

[0063] Preferably, the crushed feed and pelleted feed are fed sequentially. Feeding the crushed feed and pelleted feed sequentially provides different food forms, which can improve the appetite of the chub fry.

[0064] Preferably, the feeding frequency of the second feed in step (A08) is 2 to 5 times per day. More preferably, the feeding frequency of the second feed in step (A08) is 3 to 4 times per day. Limiting the feeding frequency of the second feed can ensure a good food supply for the fry in the water, and ensure the regular diet and metabolic balance of the fry.

[0065] Preferably, the amount of the second feed in step (A08) is 6% to 12% of the fish's body weight. More preferably, the amount of the second feed in step (A08) is 7% to 11% of the fish's body weight. Even more preferably, the amount of the second feed in step (A08) is 8% to 10% of the fish's body weight. Even more preferably, the amount of the second feed in step (A08) is 9% of the fish's body weight. Limiting the amount of the second feed ensures that the chub fry have a sufficient food supply to eat their fill without overfeeding them.

[0066] Preferably, the water injection interval in step (A09) is 2 to 3 days. This limited water injection interval, implemented gradually, further prepares the paddy field for the introduction of chub fry.

[0067] Preferably, the water injection depth in step (A09) is 2cm to 3cm each time. The limited water injection volume each time was determined after extensive experimental verification. This gradual approach allows the chub fry to adapt to the changing aquatic environment, further preparing them for introduction into the paddy fields.

[0068] Preferably, the pH of the water in the first-stage culture zone of step (A10) is 7.5–9. More preferably, the pH of the water in the first-stage culture zone of step (A10) is 7.8–8.8. Even more preferably, the pH of the water in the first-stage culture zone of step (A10) is 8–8.5. Even more preferably, the pH of the water in the first-stage culture zone of step (A10) is 8.2–8.4. A water environment with a specific alkaline condition is better suited for the cultivation and growth of chub fry.

[0069] Preferably, the dissolved oxygen level in the water of the first-stage culture zone in step (A10) is ≥6 mg / L. This requirement for dissolved oxygen content promotes the growth and reproduction of nitrifying bacteria, thus better converting ammonia nitrogen; it inhibits the growth of anaerobic bacteria, preventing water deterioration; and it facilitates better respiration and digestion in the fry, promoting their growth.

[0070] Preferably, the microbial preparation includes at least one of photosynthetic bacteria, Bacillus, nitrifying bacteria, denitrifying bacteria, or EM bacteria.

[0071] Preferably, in step (A12), the inner netting is removed when the fry reach a length of 1.5cm to 2.5cm. More preferably, in step (A12), the inner netting is removed when the fry reach a length of 1.7cm to 2.2cm. Even more preferably, in step (A12), the inner netting is removed when the fry reach a length of 1.9cm to 2.1cm. Removing the inner netting when the fry reach a certain length can initially reduce the restriction on the fry and prevent them from escaping through the outer netting.

[0072] Preferably, in step (A13), when the fry are cultivated to 3cm-4cm, the number of fry is counted by pulling the net. Counting the number of fry when they reach 3cm-4cm allows us to know the exact number that will soon enter the paddy field, facilitating the counting when they are fully grown and generating profits. The outer net is then removed, completely removing any restrictions on the fry and giving them more space to move around.

[0073] Preferably, in step (A14), after the rice tillering is completed, water is injected into the ring ditch daily. At this time, the rice has grown to a certain height, and the chub fry have been cultivated to a certain size, thus completing the preliminary preparations for good integrated rice-fish farming.

[0074] Preferably, the daily water injection volume in step (A14) is 8cm to 12cm. More preferably, the daily water injection volume in step (A14) is 9cm to 11cm. Even more preferably, the daily water injection volume in step (A14) is 10cm. This limitation on the daily water injection volume is implemented gradually, allowing the chub fry to adapt to the changing aquatic environment. As the water level gradually reaches the fish ditch, the chub fry flow into the ditch. As the water level continues to rise and submerges the paddy field, the chub fry can swim freely within the paddy field, forming a good integrated rice-fish farming model.

[0075] Preferably, the water injection duration in step (A14) is 3 to 5 days. More preferably, the water injection duration in step (A14) is 4 days. This limitation on the water injection duration ensures that the water level continues to rise and submerges the paddy field without injecting too much water.

[0076] Preferably, in step (A14), water is injected until the water level in the ring ditch is 35cm to 45cm higher than the water level in the paddy field. More preferably, in step (A14), water is injected until the water level in the ring ditch is 38cm to 42cm higher than the water level in the paddy field. Even more preferably, in step (A14), water is injected until the water level in the ring ditch is 40cm higher than the water level in the paddy field. This specific water level limit is determined through experimental analysis and is considered optimal for integrated rice-fish farming. It does not negatively impact the healthy growth of the rice, while allowing the fry to swim and move freely in the paddy field. After the rice tillers, the water level can completely submerge the rice roots; since the fry are small fish, only about 5cm in height, the limited water level ensures their free movement.

[0077] As a preferred method, inspect the blowers and bird nets, and record the fish's activity and feeding behavior. Ensure the blowers operate continuously to provide a stable supply of dissolved oxygen in the water; use bird nets to effectively prevent birds from catching and feeding on rice and chub fry; monitor the fish's growth and feeding behavior in real time to gain an overall understanding of the rice-fish integrated farming situation.

[0078] As a preferred option, multiple feeding platforms are set up in the primary rearing area. Multiple feeding platforms make it easier to feed the fry of the mandarin fish.

[0079] The second technical solution of the present invention is a system for cultivating chub fry in a paddy field ring ditch, comprising a paddy field area, a ring ditch surrounding the paddy field area, and several fish ditches within the paddy field area, the fish ditches being connected to the ring ditch, the depth of the fish ditches being less than the depth of the ring ditch; several oxygenation pipes within the ring ditch; a blower, the blower's outlet being connected to the interior of the oxygenation pipes; and a first-stage cultivation zone located near the water inlet of the ring ditch, the inner wall of the first-stage cultivation zone having an inner layer of netting and an outer layer of netting arranged from the inside out. In this invention, the paddy field area is used for rice planting and the digging of fish ditches; the ring ditch is used for the cultivation of chub fry; the fish ditch is used to allow the chub fry cultivated in the ring ditch to enter the paddy field area, ultimately achieving a good integrated rice-fish farming system; the depth of the fish ditch is less than the depth of the ring ditch, which can prevent chub fry from entering the fish ditch during the cultivation process in the ring ditch; oxygenation pipes are distributed in the ring ditch, and in conjunction with blowers, can stably and continuously deliver external air into the water body to ensure the dissolved oxygen content required in the water body; the first-level cultivation area is used for the primary cultivation of chub fry before they enter the paddy field area; the inner and outer barrier nets are... The double-layered net effectively prevents fish fry from jumping out of the paddy field and into the fish ditch and rice paddy, ensuring that the fry are cultivated only within a limited area. The entire system of this invention has a simple structure and ingenious design. A ring ditch is dug around the selected rice paddy, and a fish ditch connected to the ring ditch is dug inside the rice paddy. The fry are cultivated directly using the rice paddy ring ditch. After cultivation, the water level rises, allowing the cultivated fry to swim naturally into the rice paddy through the fish ditch. This minimizes stress damage and mortality of the fry during the transfer to the rice-fish integrated farming model, reducing losses and lowering farming costs, making it suitable for widespread application.

[0080] Preferably, the oxygenation pipe is connected to several oxygenation nozzles. The oxygenation nozzles can evenly and gently deliver air from the oxygenation pipe into the water body, while preventing water from flowing back into the oxygenation pipe.

[0081] Preferably, the oxygenation pipe is equipped with at least one first waterproof motor, and the drive end of the first waterproof motor is provided with a disturbance part. The first waterproof motor drives the disturbance part to rotate, so that the air coming out of the oxygenation nozzle is distributed throughout the water body as quickly as possible.

[0082] Preferably, the disturbance part is a disturbance cylinder with a small disturbance flap. The disturbance cylinder with the disturbance flap can better disturb the water body, so that the air from the aeration nozzle can be distributed throughout the water body as quickly as possible.

[0083] Preferably, an overflow outlet is provided at the corner of the ring ditch. The overflow outlet can prevent excessive water from being injected into the ring ditch, causing irregular overflow of water level above the field. When too much water is injected, the excess water will flow out from the overflow outlet into the external ditch.

[0084] Preferably, the first-level rearing area is equipped with multiple feeding platforms. Multiple feeding platforms make it easier to feed the fry of the chub.

[0085] Preferably, the system includes a fry rearing area, which is connected to the first-level rearing area via a water passageway. A barrier gate is installed at the water passageway. The fry rearing area is used for the initial rearing of chub fry before they enter the first-level rearing area. Fertilized chub eggs from a proper hatchery or self-bred chub are incubated in hatching tanks. Once the yolk sac disappears after hatching, all fry are transferred to the fry rearing area for further rearing. After reaching the swimming stage, the fry are transferred to the first-level rearing area for further cultivation. The water passageway is used to transfer fry that have reached the swimming stage in the fry rearing area to the first-level rearing area. The barrier gate is used to control the flow of water between the fry rearing area and the first-level rearing area.

[0086] Preferably, at least one fish ditch is equipped with a netting mechanism. The netting mechanism is used to catch and catch the chub after the rice-fish integrated farming has matured.

[0087] Preferably, the fishing net mechanism includes a fishing net motor and a mounting block, which are located at both ends of the corresponding fish ditch. The fishing net motor is provided with a guide tube, and the end of the guide tube away from the fishing net motor is connected to the mounting block. The guide tube is provided with a guide groove, and a guide slider is slidably disposed in the guide groove. A fishing net is disposed on the guide slider, and the fishing net is movably disposed in the corresponding fish ditch. The driving end of the fishing net motor is provided with a screw, which is located in the guide tube. The end of the screw away from the fishing net motor is rotatably connected to the mounting block, and the screw is threadedly connected to the guide slider. The electric motor powers the back-and-forth movement of the fishing net; the mounting block supports one end of the guide tube and screw; the guide tube and guide groove provide stable guidance for the directional back-and-forth movement of the fishing net; the guide slider drives the fishing net back and forth to catch the shaped chub in the fish ditch; the fishing net drives the shaped chub in the fish ditch to the outer perimeter of the paddy field for manual capture and placement into the frame; the rotation of the screw drives the guide slider to move back and forth in the guide groove; the entire fishing net structure facilitates manual capture of the shaped chub that have entered the fish ditch, reducing the workload of manually entering the paddy field and fish ditch to capture them one by one.

[0088] Preferably, the fish fry rearing area is equipped with a water treatment tank, which is connected to the fish ditch and / or ring ditch via a drainage pipe, and a drainage pump is installed on the drainage pipe; a waste collection trough is provided at the bottom of the water treatment tank, and the bottom surface of the water treatment tank is inclined along the direction of the waste collection trough; a waste collection box is provided outside the paddy field area, and a waste conveying pipe is provided inside the waste collection box. The waste conveying pipe passes through the paddy field area and the water treatment tank and is located in the waste collection trough. A spiral conveying rod is provided inside the waste conveying pipe, and a conveying motor is provided inside the waste collection box. The drive end of the conveying motor is connected to one end of the spiral conveying rod, and the bottom part of the waste conveying pipe located in the waste collection trough has a notch. The water treatment pond can properly treat the water from the ring ditches, fish ditches, and paddy fields after the fish have been raised, so that the water can be reused. Drainage pipes are used to deliver the water from the ring ditches, fish ditches, and paddy fields into the water treatment pond. Drainage pumps provide the power to deliver the water from the ring ditches, fish ditches, and paddy fields into the water treatment pond. A waste collection trough is used to collect the flocculated and settled waste from the wastewater in the water treatment pond. The bottom of the water treatment pond is inclined along the direction of the waste collection trough to facilitate the flocculation and sedimentation of wastewater in the water treatment pond. The system facilitates the collection of waste into the waste collection trough; the waste collection box is used to collect and process the waste from the waste collection trough for further external processing; the waste conveying pipe is used to transport the waste from the waste collection trough into the waste collection box; the screw conveyor is used to efficiently and stably transport the waste from the waste collection trough into the waste collection box; the conveyor motor provides power for the screw conveyor; and the notch allows the screw conveyor to better contact the waste in the waste collection trough, thereby better transporting the waste from the waste collection trough into the waste collection box.

[0089] Preferably, the end of the screw conveyor rod away from the conveying motor extends to the outside of the dirt conveying pipe. This allows the screw conveyor rod to better contact the dirt in the dirt collection trough, thereby achieving more efficient conveying.

[0090] Preferably, the inner wall of the water treatment tank is provided with a chute, and a floating net containing a water treatment agent slides within the chute. The floating net slides up and down within the chute, dynamically changing with the water level in the water treatment tank. The water treatment agent within the floating net continuously disperses and dissolves in the wastewater within the water treatment tank, causing the impurities in the water treatment tank to flocculate and then settle.

[0091] Preferably, the water treatment agent is a mixture of polyacrylamide and activated carbon. Polyacrylamide enables small particles in wastewater to quickly coagulate into large particles and settle rapidly; activated carbon effectively adsorbs pollutants such as color, odor, chlorine, organic matter, bacteria, and viruses from the wastewater.

[0092] Preferably, the amount of polyacrylamide added is 0.03 mg / L to 0.4 mg / L, and the amount of activated carbon added is 10 mg / L to 30 mg / L. More preferably, the amount of polyacrylamide added is 0.05 mg / L to 0.35 mg / L, and the amount of activated carbon added is 12 mg / L to 28 mg / L. More preferably, the amount of polyacrylamide added is 0.1 mg / L to 0.3 mg / L, and the amount of activated carbon added is 15 mg / L to 25 mg / L. More preferably, the amount of polyacrylamide added is 0.15 mg / L to 0.25 mg / L, and the amount of activated carbon added is 18 mg / L to 22 mg / L. More preferably, the amount of polyacrylamide added is 0.2 mg / L, and the amount of activated carbon added is 20 mg / L. The limited amount of polyacrylamide effectively promotes the rapid coagulation of small particles in wastewater into larger particles that settle quickly; the limited amount of activated carbon effectively adsorbs and treats the wastewater.

[0093] Preferably, the water treatment tank is connected to the interior of the fish fry rearing area via a water delivery channel, and the water delivery channel is equipped with a water delivery gate. The treated water is then returned to the fish fry rearing area for reuse via the water delivery channel; the water delivery gate controls whether the treated water in the water treatment tank is sent to the fish fry rearing area.

[0094] Preferably, the waste collection box is equipped with a waste discharge outlet. The waste in the waste collection box is discharged through the waste discharge outlet for centralized reprocessing.

[0095] Preferably, the paddy field area is equipped with a water supply and drainage system. This system can supply water to the fish fry rearing area, the surrounding ditch, and the paddy field area as needed, and can also discharge water from the surrounding ditch as appropriate.

[0096] Preferably, the water supply and drainage mechanism includes a water supply and drainage pipe, which is connected to a water supply pipe and a drainage pipe. A hose support is provided on the water supply and drainage pipe, and water supply and drainage hoses are wound around the hose support. A treatment box is connected to the water supply and drainage pipe, and a sliding frame is movably provided on the treatment box. A filter screen is provided on the sliding frame, and the filter screen is located inside the treatment box. The water supply and drainage pipe is used to replenish water into the ring ditch or to drain water from the ring ditch; the water supply pipe is used to replenish water into the ring ditch; the drainage pipe is used to drain water from the ring ditch; the hose support is used to hold the water supply and drainage hoses; the water supply and drainage hoses can be pulled out from the hose support as needed to realize water supply and drainage operations within the ring ditch or to the fish fry cultivation area; the treatment box is used to filter and collect larger volume substances in the water when draining water from the ring ditch; the sliding frame is used to install the filter screen, and the sliding frame is pushed out and pulled in relative to the interior of the treatment box to periodically clean the filter material on the filter screen, ensuring smooth water supply and drainage; the filter screen is used to filter larger volume substances in the drainage from inside and outside the ring ditch.

[0097] Preferably, the push-pull frame is equipped with a second waterproof motor. The drive end of the second waterproof motor has a rotating disk, and the eccentric surface of the rotating disk has a handle. A cleaning brush is located at the end of the handle away from the second waterproof motor, and the cleaning brush contacts the surface of the filter screen. The second waterproof motor provides power for the rotation of the cleaning brush; the rotating disk drives the handle to rotate eccentrically; the handle drives the cleaning brush to rotate, cleaning the adsorbed substances on the filter screen and preventing blockage of the water channels in the treatment tank; the cleaning brush effectively cleans the surface of the filter screen, preventing dirt from clogging the filter screen.

[0098] Preferably, the fish ditch is equipped with multiple water level monitoring devices. These devices can monitor the water level in the fish ditch in real time. Both the water level monitoring devices and the external water pumps are electrically connected to the control board. Through the cooperation of the water level monitoring devices and the external water pumps, the water level in the fish ditch can be adjusted according to the actual situation.

[0099] Preferably, the water level monitoring mechanism includes a filter screen barrel, an inner protective shell, a drive motor at the top of the protective shell, a screw at the drive end of the drive motor, a lifting plate threaded onto the screw, a slide rail on the inner wall of the protective shell, a slider at the edge of the lifting plate, and the slider slidably disposed within the slide rail; a plurality of water level monitoring holes are provided on the protective shell along the vertical direction, a sensor is provided in each water level monitoring hole, and a water level sensor is provided at the bottom of the lifting plate. The filter screen effectively prevents debris from the external water from affecting the stability of the sensors and water level sensor inside the casing. The casing provides a mounting position for the drive motor and other related components. The drive motor determines whether to rotate based on signals from the control board, thereby controlling the operation of the external water pump to ensure that the water level inside the casing and in the fishpond is at the same height. The screw drives the lifting plate to rise and fall stably according to the rotation of the drive motor. The raising and lowering of the lifting plate adjusts the bottom space inside the casing. When the water level sensor at the bottom of the lifting plate contacts the water surface, it transmits a signal to the external control board. The control board determines whether the drive motor and the external water pump operate. The lifting plate divides the interior of the casing into upper and lower sections. The system uses a water level sensor and a sensor inside a water level monitoring hole to monitor and control the water level in the fish ditch. The sliding track and slider work together to ensure the lifting plate can only slide up and down along a fixed track. Several water level monitoring holes monitor the water level in the fish ditch. When the water level reaches the corresponding monitoring hole, the sensor detects the water and the lifting plate's rise, prompting the control panel to decide whether to inject water into the ditch. The sensor can accurately detect whether water has reached the monitoring hole and whether the lifting plate has reached the corresponding monitoring hole. The water level sensor can accurately detect the water level in the bottom space inside the protective casing.

[0100] Preferably, the water level monitoring holes are arranged at equal intervals on the protective shell. The evenly spaced water level monitoring holes allow for more accurate monitoring of the water level in the fishpond.

[0101] Preferably, the bottom of the protective shell is provided with a water inlet bend, and the water inlet of the water inlet bend is located at the bottom of the fish ditch. When the water level reaches the fish ditch, it can enter the interior of the protective shell in a timely manner along the water inlet bend, thereby facilitating the water level sensor to promptly detect the water level height inside the protective shell.

[0102] Preferably, the system includes a control board, to which the blower, first waterproof motor, fishing net motor, drainage pump, conveyor motor, second waterproof motor, drive motor, sensor, and water level sensor are all electrically connected. The control board can comprehensively coordinate signals and effectively control the start and stop of each device.

[0103] The present invention has the following beneficial effects:

[0104] (1) Dig a ring ditch around the selected paddy field and dig a fish ditch in the paddy field that is connected to the ring ditch. Use the paddy field ring ditch to cultivate chub fry. After cultivation, the water rises and the cultivated chub fry swim naturally into the paddy field through the fish ditch. This minimizes stress damage and mortality of chub fry during transfer to the rice-fish integrated farming model, reduces losses, and lowers farming costs. The first-level cultivation area can be the entire ring ditch area or a part of the ring ditch. It is selected as the chub fry cultivation area for the special cultivation of chub fry.

[0105] (2) By setting up double-layer nets on the inner walls of the ring ditch, fish fry are prevented from jumping out of the ring ditch or into the fish ditch and paddy field, so that the fry of the chub can only be cultivated in a limited area.

[0106] (3) Before releasing the fry of the chub, the surrounding ditch should be drained and disinfected to prevent the pests and diseases in the surrounding ditch from affecting the health of the chub fry in the subsequent water body, and to ensure the health and survival rate of the chub fry cultivation; before releasing the chub fry into the water body, amino acids and aquatic-specific organic fertilizer should be applied to cultivate the water quality, so that the water body is rich in a variety of amino acids and organic matter required for the cultivation and growth of the chub fry, so that the chub fry can have a comfortable growth water environment after being released.

[0107] (4) Select fry of the pufferfish that have entered the quail stage and place them in the water of the first-level culture area for culture. The pufferfish fry in the quail stage will have better environmental adaptability and grow healthier. After the fry have been cultured for a period of time, feed them the first feed and the second feed in stages. Feed the pufferfish fry according to the size of the fry at different stages of cultivation. This will better meet the nutritional needs of the pufferfish fry at the corresponding stage and thus enable them to grow better.

[0108] (5) After feeding the second feed for a period of time, continue to inject water into the first-level cultivation area. At this time, the fry of the chub have grown to a certain stage and have stronger adaptability and self-resistance. They can be further prepared to enter the paddy field area. By adding microbial preparations to the first-level cultivation area after water injection, the concentration of nitrite, ammonia nitrogen and hydrogen sulfide in the aquaculture water can be effectively reduced, the reproduction and growth of harmful microorganisms in the water can be inhibited, the water quality can be purified, and the chub fry can grow better.

[0109] (6) When the fry of the Chinese sturgeon reach a certain size, the inner layer of netting is removed to initially reduce the restriction on the fry. When they reach a certain size, the netting is pulled to count the number of fry so that the exact number that will enter the paddy field can be known. This will facilitate the counting when they are fully grown and generate benefits. The outer layer of netting is then removed to completely remove the restriction on the fry and give them more room to move. After the rice tillering is completed, water is poured into the ring ditch. The water level gradually reaches the fish ditch, and the fry flow into the fish ditch. As the water level continues to rise and submerge the paddy field, the fry will be able to swim freely in the paddy field, forming a good integrated rice-fish farming model. Attached Figure Description

[0110] Figure 1 This is an overall structural diagram of the system of the present invention;

[0111] Figure 2 This is a schematic diagram of the structure in the paddy field area of ​​this invention;

[0112] Figure 3 This is a schematic diagram of the structure of the fish fry cultivation area of ​​the present invention;

[0113] Figure 4 This is a schematic diagram of the structure of the water treatment tank in this invention;

[0114] Figure 5 This is a schematic diagram of the structure of the oxygenation tube in this invention;

[0115] Figure 6 This is a first structural schematic diagram of the drainage mechanism of the present invention;

[0116] Figure 7 This is a schematic diagram of the second structure of the water supply and drainage mechanism of the present invention;

[0117] Figure 8 This is a schematic diagram of the structure of the filter screen in this invention;

[0118] Figure 9 This is a schematic diagram of the structure of the handle of the present invention;

[0119] Figure 10 This is a first structural schematic diagram of the fishing net mechanism of the present invention;

[0120] Figure 11This is a schematic diagram of the second structure of the fishing net mechanism of the present invention;

[0121] Figure 12 This is a schematic diagram of the structure of the water level monitoring mechanism of the present invention;

[0122] Figure 13 This is a schematic diagram of the internal structure of the water level monitoring mechanism of the present invention.

[0123] The labels in the attached diagram are as follows: 100-Paddy field area, 101-Circular ditch, 102-Fish ditch, 103-Aeration pipe, 104-Blower, 105-First-stage cultivation area, 106-Inner layer barrier net, 107-Outer layer barrier net, 108-Aeration nozzle, 109-First waterproof motor, 1010-Disturbing part, 1011-Feeding ear platform, 200-Fish fry cultivation area, 201-Flow passageway, 202-Barrier gate, 300-Fish netting mechanism, 301-Fish netting motor, 302-Mounting block, 303-Guide pipe, 304-Guide chute, 305-Guide slider, 306-Fishing net, 307-Screw, 400-Water treatment tank, 401-Drainage pipe, 402-Drainage pump, 403-Debris collection trough, 404-Debris collection box, 405- 406-Screw conveyor rod, 407-Conveyor motor, 408-Crater, 409-Floating net, 4010-Water trough, 4011-Water gate, 4012-Dirty outlet, 500-Drainage mechanism, 501-Drainage pipe, 502-Water pipe, 503-Drainage pipe, 504-Hose frame, 505-Processing box, 506-Push-pull frame, 507-Filter screen, 508-Second waterproof motor, 509-Rotating disc, 5010-Handle, 5011-Cleaning brush, 600-Water level monitoring mechanism, 601-Filter screen bucket, 602-Shell, 603-Drive motor, 604-Screw, 605-Lifting disc, 606-Crater, 607-Slider, 608-Water level monitoring hole, 609-Inlet bend. Detailed Implementation

[0124] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0125] The method for cultivating chub fry in paddy field ditches includes the following steps.

[0126] (A01) Select a paddy field and dig a ring ditch around the paddy field; set a water overflow outlet at the corner of the ring ditch in step (A01); the width of the ring ditch in step (A01) is 0.5 m to 5 m; the depth of the ring ditch in step (A01) is 80 cm to 150 cm; the shape of the ring ditch in step (A01) is a "return" shape; the caliber of the water overflow outlet is 100 mm to 200 mm; there are several oxygenation pipes in the ring ditch in step (A01); the spacing between adjacent oxygenation pipes is 50 cm to 150 cm; the diameter of the oxygenation pipe is 30 cm to 70 cm; it includes a blower, and the air outlet of the blower is connected to the oxygenation pipe; the blower is a Roots blower; the power of the blower is 1.4 kw to 3 kw;

[0127] (A02) Dig fish ditches in the paddy field in step (A01) and dig until the fish ditches are connected to the ring ditch; the width of the fish ditches in step (A02) is 50 cm to 100 cm; the depth of the fish ditches in step (A02) is 20 cm to 50 cm; the fish ditches in step (A02) are in a "well" shape; the fish ditches and the ring ditch account for 5% to 15% of the total area of the paddy field;

[0128] (A03) Select the first-level cultivation area in the ring ditch in step (A01) as the breeding area for Opsariichthys bidens fry, and set double-layer barriers at the inner walls of the two sides of the ring ditch; the first-level cultivation area in step (A03) is located at the water inlet of the ring ditch; the first-level cultivation area in step (A03) accounts for 40% to 100% of the total area of the ring ditch; the breeding quantity of Opsariichthys bidens fry in the first-level cultivation area in step (A03) is 1500 tails / mu to 2500 tails / mu; the inner layer of the double-layer barrier in step (A03) is a 60-mesh to 100-mesh barrier, and the outer layer of the double-layer barrier is a 10-mesh to 30-mesh barrier; the height of the double-layer barrier in step (A03) is higher than the depth of the ring ditch; the height of the double-layer barrier in step (A03) is 5 cm to 15 cm higher than the depth of the ring ditch;

[0129] (A04) Drain and disinfect the ring ditch in step (A01) before releasing Opsariichthys bidens fry; the disinfectant used in step (A04) is bleaching powder; in step (A04), make the bleaching powder into a slurry and sprinkle it over the entire ring ditch; the dosage of the disinfectant in step (A04) is 30 kg / mu to 70 kg / mu; in step (A04), the time interval between draining and disinfecting the ring ditch and releasing Opsariichthys bidens fry is 5 days to 8 days;

[0130] (A05) After the disinfection in step (A04) is completed, inject water into the ring ditch; the water injection time in step (A05) is 1 day to 3 days after disinfection; the water injection volume in step (A05) is 50% to 80% of the depth of the ring ditch;

[0131] (A06) After water injection in step (A05), amino acids and aquatic-specific organic fertilizer are applied to the water body of the ring ditch for water quality cultivation; the application time of amino acids and aquatic-specific organic fertilizer in step (A06) is 3 to 5 days before the release of chub fry; the application rate of amino acids and aquatic-specific organic fertilizer in step (A06) is 80 kg / mu to 120 kg / mu; the water quality is cultivated in step (A06) until the water transparency reaches 25 cm to 35 cm; the water quality cultivation time in step (A06) is 2 to 5 days; the number of cladocerans in the water body in step (A06) is more than 3 per mL of water sample; the stocking density of chub fry in the water body in step (A06) is 2000 fish / m² to 2500 fish / m²;

[0132] (A07) Select juvenile chub that have entered the basal swimming stage and release them into the water body of step (A06);

[0133] (A08) After the seedlings in step (A07) have been cultured for a period of time, the first feed is fed into the first-level culture area; in step (A08), when the number of cladocerans in the water body decreases to 1 to 2 per mL of water sample, the first feed is fed into the water body; the first feed in step (A08) is a powder with crude protein ≥48%; the particle size of the first feed in step (A08) is 0.2 mm to 0.3 mm; the first feed in step (A08) is fed by dry sprinkling along the ring ditch; the first feed in step (A08) is fed... The feeding time is 6-9 days after the release of the chub fry; the feeding frequency of the first feed in step (A08) is 2 to 5 times per day; the feeding amount of the first feed in step (A08) is 5g / 10,000 fish to 15g / 10,000 fish; the second feed in step (A08) is crushed feed and pelleted feed with crude protein ≥46%; the crushed feed and pelleted feed are fed sequentially; the feeding frequency of the second feed in step (A08) is 2 to 5 times per day; the feeding amount of the second feed in step (A08) is 6% to 12% of the fish's body weight;

[0134] (A09) After the seedlings in step (A08) have been cultivated for a period of time, the second feed shall be fed; the water injection interval in step (A09) shall be 2 to 3 days; the water injection depth in step (A09) shall be 2 to 3 cm each time.

[0135] (A10) After the second feed is fed in step (A09), water is injected into the first-stage culture zone again; the pH of the water in the first-stage culture zone in step (A10) is 7.5-9; the dissolved oxygen in the water in the first-stage culture zone in step (A10) is ≥6 mg / L;

[0136] (A11) After the water injection in step (A10) is completed, add the microbial preparation to the first-level culture zone;

[0137] (A12) When the seedlings in step (A11) have grown to a certain size, remove the inner layer of netting; when the seedlings in step (A12) have grown to 1.5cm to 2.5cm, remove the inner layer of netting.

[0138] (A13) Continue cultivating the seedlings in step (A12) to a certain size, pull the net to count the number of seedlings and remove the outer net; continue cultivating the seedlings in step (A13) to 3cm-4cm, pull the net to count the number of seedlings;

[0139] (A14) After the rice tillering is completed, water is injected into the ring ditch in step (A13) until the water level in the ring ditch is higher than the water level in the paddy field; in step (A14), water is injected into the ring ditch daily after the rice tillering is completed; the daily water injection volume in step (A14) is 8cm to 12cm; the water injection duration in step (A14) is 3 to 5 days; in step (A14), water is injected until the water level in the ring ditch is 35cm to 45cm higher than the water level in the paddy field;

[0140] Inspect the blowers and bird nets, and record the fish's activity and feeding behavior; set up multiple feeding stations in the first-level culture area.

[0141] like Figure 1 The system shown is for cultivating chub fry in a paddy field with a surrounding ditch. It includes a paddy field area 100, a surrounding ditch 101 around the paddy field area, and several [unclear text - possibly related to fish farming systems]. Figure 2 The fish ditch 102 shown is connected to the ring ditch, and the depth of the fish ditch is less than the depth of the ring ditch; the ring ditch contains several... Figure 5 The oxygenation pipe 103 shown includes a blower 104, the air outlet of which is connected to the interior of the oxygenation pipe; a first-stage culture zone 105 is provided near the water inlet of the ring ditch, and an inner layer of netting 106 and an outer layer of netting 107 are provided on the inner wall of the first-stage culture zone from the inside to the outside.

[0142] A number of aeration nozzles 108 are connected to the aeration pipe. At least one first waterproof motor 109 is installed on the aeration pipe, and the drive end of the first waterproof motor has a disturbance part 1010. The disturbance part is a disturbance cylinder with a small disturbance flap. An overflow outlet is provided at the corner of the annular groove. Multiple feed trays 1011 are provided in the first-stage cultivation area.

[0143] Including, for example Figure 3 The fish fry cultivation area 200 shown is connected to the first-level cultivation area through a water passage 201, and a barrier gate 202 is provided at the water passage.

[0144] At least one fish ditch is equipped with such Figure 10The fishing net mechanism 300 is shown. The fishing net mechanism includes a fishing net motor 301 and a mounting block 302. The fishing net motor and the mounting block are located at opposite ends of the corresponding fishpond. The fishing net motor is equipped with a guide tube 303, the end of which is connected to the mounting block. The guide tube is equipped with a guide groove 304, and a guide slider 305 slides within the guide groove. A fishing net 306 is mounted on the guide slider, and the fishing net is movably positioned within the corresponding fishpond. The drive end of the fishing net motor is equipped with... Figure 11 The screw 307 shown is located inside the guide tube. The end of the screw away from the fishing motor is rotatably connected to the mounting block, and the screw is threadedly connected to the guide slider.

[0145] The fish fry rearing area is equipped with, for example Figure 4 The water treatment tank 400 shown is connected to a fish ditch and / or a ring ditch via a drain pipe 401, on which a drain pump 402 is installed. A waste collection trough 403 is located at the bottom of the water treatment tank, and the bottom surface of the water treatment tank slopes along the direction of the waste collection trough. A waste collection box 404 is located outside the paddy field area, containing a waste conveying pipe 405. The waste conveying pipe passes through the paddy field area and the water treatment tank and is located within the waste collection trough. A spiral conveying rod 406 is installed inside the waste conveying pipe, and a conveying motor 407 is installed inside the waste collection box. The drive end of the conveying motor is connected to one end of the spiral conveying rod. The bottom portion of the waste conveying pipe located within the waste collection trough has a notch. The end of the spiral conveying rod away from the conveying motor extends to the outside of the waste conveying pipe. A chute 408 is provided on the inner wall of the water treatment tank, within which a floating net 409 slides, containing a water treatment agent. The water treatment agent is a mixture of polyacrylamide and activated carbon. The dosage of polyacrylamide is 0.03 mg / L to 0.4 mg / L, and the dosage of activated carbon is 10 mg / L to 30 mg / L. The water treatment tank is connected to the interior of the fish fry rearing area via a water delivery channel 4010, which is equipped with a water delivery gate 4011. The waste collection box is equipped with a waste outlet 4012.

[0146] A drainage system of 500 meters is installed outside the paddy field area. The drainage system includes, for example: Figure 6 The water supply and drainage pipe 501 shown is connected to a water supply pipe 502 and a drainage pipe 503. A hose support 504 is provided on the water supply and drainage pipe, and water supply and drainage hoses are wound around the hose support. A treatment box 505 is connected to the water supply and drainage pipe, and the treatment box is movably equipped with... Figure 7 The push-pull bracket 506 shown has the following features: Figure 8 The filter screen 507 shown is located inside the processing box. A second waterproof motor 508 is mounted on the push-pull frame, and a rotating disk 509 is mounted on the drive end of the second waterproof motor. The eccentric surface of the rotating disk has features such as... Figure 9The shown horizontal bar 5010 has a cleaning brush 5011 at one end away from the second waterproof motor, and the cleaning brush contacts the surface of the filter screen.

[0147] There are multiple water level monitoring mechanisms 600 in the fish ditch. The water level monitoring mechanism includes, as Figure 12 shown, a filter screen barrel 601. Inside the filter screen barrel, there is a protective shell 602. At the top of the protective shell, there is a driving motor 603. The driving end of the driving motor is provided with a screw rod 604. Threaded on the screw rod is a lifting plate 605 as Figure 13 shown. On the inner wall surface of the protective shell, there is a slideway 606. At the edge of the lifting plate, there is a slider 607, and the slider is slidably arranged in the slideway; along the vertical direction on the protective shell, there are several water level monitoring holes 608. Inside the water level monitoring holes, there are sensors. At the bottom of the lifting plate, there is a water level sensor, and the water level sensor corresponds to the sensors. The several water level monitoring holes are equally spaced on the protective shell. At the bottom of the protective shell, there is a water inlet elbow 609, and the water inlet of the water inlet elbow is located at the bottom of the fish ditch. It includes a control board, and the blower, the first waterproof motor, the fish-catching motor, the dredging pump, the conveying motor, the second waterproof motor, the driving motor, the sensors, and the water level sensor are all electrically connected to the control board. Among them, the control board is a prior art, and a multifunctional environmental control box with the brand Schneider / Schneider and the model LC1E can be selected.

[0148] Embodiment 1:

[0149] A method for cultivating Opsariichthys bidens fry in a paddy field ring ditch includes the following steps.

[0150] (A01) Select a paddy field and dig a ring ditch around the paddy field; set an overflow outlet at the corner of the ring ditch in step (A01); the width of the ring ditch in step (A01) is 0.5 m; the depth of the ring ditch in step (A01) is 80 cm; the shape of the ring ditch in step (A01) is a "return" shape; the diameter of the overflow outlet is 100 mm; there is an aeration pipe in the ring ditch of step (A01); the diameter of the aeration pipe is 30 cm; it includes a blower, and the air outlet of the blower is connected to the aeration pipe; the blower is a Roots blower; the power of the blower is 1.4 kW.

[0151] (A02) Dig a fish ditch in the paddy field of step (A01) and dig until the fish ditch is connected to the ring ditch; the width of the fish ditch in step (A02) is 50 cm; the depth of the fish ditch in step (A02) is 20 cm; the fish ditch in step (A02) is in a "well" shape; the fish ditch and the ring ditch account for 5% of the total area of the paddy field.

[0152] (A03) Select the first-level cultivation area within the ring ditch in step (A01) as the fry cultivation area for chub fry, and set up double-layer nets on both inner walls of the ring ditch; the first-level cultivation area in step (A03) is located at the inlet of the ring ditch; the first-level cultivation area in step (A03) occupies 40% of the total area of ​​the ring ditch; the fry cultivation rate in the first-level cultivation area in step (A03) is 1500 fry / acre; the inner layer of the double-layer net in step (A03) is a 60-mesh net, and the outer layer of the double-layer net is a 10-mesh net; the height of the double-layer net in step (A03) is higher than the depth of the ring ditch; the height of the double-layer net in step (A03) is 5cm higher than the depth of the ring ditch;

[0153] (A04) Before releasing the fry of the mandarin fish, the ring ditch in step (A01) is drained and disinfected; the disinfectant used in step (A04) is bleaching powder; in step (A04), the bleaching powder is slurried and then sprinkled throughout the ring ditch; the amount of disinfectant used in step (A04) is 30 kg / mu; in step (A04), the time interval between draining and disinfecting the ring ditch and releasing the fry of the mandarin fish is 5 days;

[0154] (A05) After the disinfection in step (A04) is completed, water is injected into the ring trench; the water injection time in step (A05) is 1 day after disinfection; the water injection volume in step (A05) is 50% of the depth of the ring trench;

[0155] (A06) After water injection in step (A05), amino acids and aquatic-specific organic fertilizer are applied to the water body of the ring ditch for water quality cultivation; the application time of amino acids and aquatic-specific organic fertilizer in step (A06) is 3 days before the release of chub fry; the application rate of amino acids and aquatic-specific organic fertilizer in step (A06) is 80 kg / mu; the water quality is cultivated in step (A06) until the water transparency reaches 25 cm; the water quality cultivation time in step (A06) is 2 days; the number of cladocerans in the water body in step (A06) is more than 3 per mL of water sample; the stocking density of chub fry in the water body in step (A06) is 2000 fish / m²;

[0156] (A07) Select juvenile chub that have entered the basal swimming stage and release them into the water body of step (A06);

[0157] (A08) After the seedlings in step (A07) have been cultured for a period of time, the first feed is fed into the first-level culture area; in step (A08), when the number of cladocerans in the water body decreases to 1 per mL of water sample, the first feed is fed into the water body; the first feed in step (A08) is a powder with crude protein ≥48%; the particle size of the first feed in step (A08) is 0.2 mm; the feeding method of the first feed in step (A08) is dry sprinkling along the ring ditch; in step (A08) The first feed is given 6 days after the release of the chub fry; the feeding frequency of the first feed in step (A08) is twice a day; the feeding amount of the first feed in step (A08) is 5g per 10,000 fish; the second feed in step (A08) consists of crushed feed and pelleted feed with crude protein ≥46%; the crushed feed and pelleted feed are fed sequentially; the feeding frequency of the second feed in step (A08) is twice a day; the feeding amount of the second feed in step (A08) is 6% of the fish's body weight;

[0158] (A09) After the seedlings in step (A08) have been cultivated for a period of time, the second feed is started; the water injection interval in step (A09) is 2 days; the water injection depth in step (A09) is 2cm each time;

[0159] (A10) After the second feed is fed in step (A09), water is injected into the first-stage culture zone again; the pH of the water in the first-stage culture zone in step (A10) is 7.5; the dissolved oxygen in the water in the first-stage culture zone in step (A10) is ≥6 mg / L;

[0160] (A11) After the water injection in step (A10) is completed, add the microbial preparation to the first-level culture zone;

[0161] (A12) When the seedlings in step (A11) have grown to a certain size, remove the inner layer of netting; when the seedlings in step (A12) have grown to 1.5cm, remove the inner layer of netting.

[0162] (A13) Continue cultivating the seedlings in step (A12) to a certain size, count the number of seedlings with a net and remove the outer net; continue cultivating the seedlings in step (A13) to 3cm, count the number of seedlings with a net;

[0163] (A14) After the rice tillering is completed, water is injected into the ring ditch in step (A13) until the water level in the ring ditch is higher than the water level in the paddy field; in step (A14), water is injected into the ring ditch daily after the rice tillering is completed; the daily water injection volume in step (A14) is 8 cm; the water injection duration in step (A14) is 3 days; in step (A14), water injection is stopped when the water level in the ring ditch is 35 cm higher than the water level in the paddy field.

[0164] Check the blower and anti-bird net, and record the activities and feeding conditions of the fish; set up multiple bait tables in the first-stage cultivation area.

[0165] Example 2:

[0166] A method for cultivating Opsariichthys bidens fry in a paddy field ring ditch, including the following steps

[0167] (A01) Select a paddy field and dig a ring ditch around the paddy field; set an overflow outlet at the corner of the ring ditch in step (A01); the width of the ring ditch in step (A01) is 5m; the depth of the ring ditch in step (A01) is 150cm; the shape of the ring ditch in step (A01) is a "return" shape; the diameter of the overflow outlet is 200mm; there are several aeration pipes in the ring ditch of step (A01); the distance between adjacent aeration pipes is 150cm; the diameter of the aeration pipe is 70cm; including a blower, the air outlet of the blower is connected to the aeration pipe; the blower is a Roots blower; the power of the blower is 3kw;

[0168] (A02) Dig fish ditches in the paddy field of step (A01) and dig until the fish ditches are connected to the ring ditch; the width of the fish ditches in step (A02) is 100cm; the depth of the fish ditches in step (A02) is 50cm; the fish ditches in step (A02) are in a "well" shape; the fish ditches and the ring ditch account for 15% of the total area of the paddy field;

[0169] (A03) Select the first-stage cultivation area in the ring ditch of step (A01) as the cultivation area for Opsariichthys bidens fry, and set up a double-layer barrier net on the inner walls of both sides of the ring ditch; the first-stage cultivation area in step (A03) is located at the water inlet of the ring ditch; the first-stage cultivation area in step (A03) accounts for 100% of the total area of the ring ditch; the cultivation amount of Opsariichthys bidens fry in the first-stage cultivation area in step (A03) is 2500 tails per mu; the inner layer of the double-layer barrier net in step (A03) is a 100-mesh barrier net, and the outer layer of the double-layer barrier net is a 30-mesh barrier net; the height of the double-layer barrier net in step (A03) is higher than the depth of the ring ditch; the height of the double-layer barrier net in step (A03) is 15cm higher than the depth of the ring ditch;

[0170] (A04) Drain and disinfect the ring ditch in step (A01) before releasing Opsariichthys bidens fry; the disinfectant used in step (A04) is bleaching powder; in step (A04), dissolve the bleaching powder into a slurry and sprinkle it over the entire ring ditch; the dosage of the disinfectant in step (A04) is 70kg per mu; in step (A04), the time interval between draining and disinfecting the ring ditch and releasing Opsariichthys bidens fry is 8 days;

[0171] (A05) After the disinfection in step (A04) is completed, inject water into the ring ditch; the water injection time in step (A05) is 3 days after disinfection; the water injection volume in step (A05) is 80% of the depth of the ring ditch;

[0172] (A06) After water filling in step (A05), amino acids and aquatic-specific organic fertilizer are applied to the water body of the ring ditch for water quality cultivation; the application time of amino acids and aquatic-specific organic fertilizer in step (A06) is 5 days before the release of chub fry; the application rate of amino acids and aquatic-specific organic fertilizer in step (A06) is 120 kg / mu; the water quality is cultivated in step (A06) until the water transparency reaches 35 cm; the water quality cultivation time in step (A06) is 5 days; the number of cladocerans in the water body in step (A06) is more than 3 per mL of water sample; the stocking density of chub fry in the water body in step (A06) is 2500 fish / m²;

[0173] (A07) Select juvenile chub that have entered the basal swimming stage and release them into the water body of step (A06);

[0174] (A08) After the seedlings in step (A07) have been cultured for a period of time, the first feed is fed into the first-level culture area; in step (A08), when the number of cladocerans in the water body decreases to 2 per mL of water sample, the first feed is fed into the water body; the first feed in step (A08) is a powder with crude protein ≥48%; the particle size of the first feed in step (A08) is 0.3 mm; the feeding method of the first feed in step (A08) is dry sprinkling along the ring ditch; the feeding method of the first feed in step (A08) is dry sprinkling. The first feed is given 9 days after the release of the chub fry; the feeding frequency of the first feed in step (A08) is 5 times / day; the feeding amount of the first feed in step (A08) is 15g / 10,000 fish; the second feed in step (A08) consists of crushed feed and pelleted feed with crude protein ≥46%; the crushed feed and pelleted feed are fed sequentially; the feeding frequency of the second feed in step (A08) is 5 times / day; the feeding amount of the second feed in step (A08) is 12% of the fish's body weight;

[0175] (A09) After the seedlings in step (A08) have been cultivated for a period of time, the second feed is started; the water injection interval in step (A09) is 3 days; the water injection depth in step (A09) is 3cm each time;

[0176] (A10) After the second feed is fed in step (A09), water is injected into the first-level culture zone again; the pH of the water in the first-level culture zone in step (A10) is 9; the dissolved oxygen in the water in the first-level culture zone in step (A10) is ≥6 mg / L;

[0177] (A11) After the water injection in step (A10) is completed, add the microbial preparation to the first-level culture zone;

[0178] (A12) When the seedlings in step (A11) have grown to a certain size, remove the inner layer of netting; when the seedlings in step (A12) have grown to 2.5cm, remove the inner layer of netting.

[0179] (A13) When the fry in step (A12) are cultivated to a certain specification, pull the net to count the number of fry and remove the outer retaining net; when the fry in step (A13) are cultivated to 4 cm, pull the net to count the number of fry;

[0180] (A14) After the rice tillering ends, inject water into the ring ditch in step (A13) until the water level in the ring ditch is higher than the water level in the paddy field and then stop; after the rice tillering ends in step (A14), inject water into the ring ditch every day; the daily water injection volume in step (A14) is 12 cm; the water injection duration in step (A14) is 5 days; stop injecting water when the water level in the ring ditch is 45 cm higher than the water level in the paddy field;

[0181] Check the blower and the anti-bird net, and record the fish body activities and feeding conditions; set up multiple bait platforms at the first-stage cultivation area;

[0182] Example 3:

[0183] A method for cultivating Opsariichthys bidens fry in a paddy field ring ditch, comprising the following steps:

[0184] (A01) Select 20 mu of paddy fields and dig ring ditches around the paddy fields; set an overflow outlet at the corner of the ring ditch in step (A01); the width of the ring ditch in step (A01) is 3 m; the depth of the ring ditch in step (A01) is 130 cm; the shape of the ring ditch in step (A01) is a "return" shape; the diameter of the overflow outlet is 160 mm; several aeration pipes are provided in the ring ditch in step (A01); the distance between adjacent aeration pipes is 100 cm; the diameter of the aeration pipe is 50 cm; including a blower, the air outlet of the blower is connected to the aeration pipe; the blower is a Roots blower; the power of the blower is 2.2 kw;

[0185] (A02) Dig fish ditches in the paddy field in step (A01) until the fish ditches are connected to the ring ditch; the width of the fish ditch in step (A02) is 80 cm; the depth of the fish ditch in step (A02) is 30 cm; the fish ditch in step (A02) is in a "well" shape; the fish ditches and the ring ditch account for 9% of the total area of the paddy field;

[0186] (A03) Select the first-level cultivation area within the ring ditch in step (A01) as the fry cultivation area for chub fry, and set up double-layer nets on both inner walls of the ring ditch; the first-level cultivation area in step (A03) is located at the inlet of the ring ditch; the first-level cultivation area in step (A03) occupies 50% of the total area of ​​the ring ditch; the fry cultivation quantity in the first-level cultivation area in step (A03) is 1500-2500 fry / mu; the inner layer of the double-layer net in step (A03) is an 80-mesh net, and the outer layer of the double-layer net is a 20-mesh net; the height of the double-layer net in step (A03) is higher than the depth of the ring ditch; the height of the double-layer net in step (A03) is 10cm higher than the depth of the ring ditch.

[0187] (A04) Before releasing the fry of the mandarin fish, the ring ditch in step (A01) is drained and disinfected; the disinfectant used in step (A04) is bleaching powder; in step (A04), the bleaching powder is slurried and then sprinkled throughout the ring ditch; the amount of disinfectant used in step (A04) is 50 kg / mu; in step (A04), the time interval between draining and disinfecting the ring ditch and releasing the fry of the mandarin fish is 6 days;

[0188] (A05) After the disinfection in step (A04) is completed, water is injected into the ring trench; the water injection time in step (A05) is 2 days after disinfection; the water injection volume in step (A05) is 60% of the depth of the ring trench;

[0189] (A06) After water injection in step (A05), amino acids and aquatic-specific organic fertilizer are applied to the water body of the ring ditch for water quality cultivation; the application time of amino acids and aquatic-specific organic fertilizer in step (A06) is 4 days before the release of chub fry; the application rate of amino acids and aquatic-specific organic fertilizer in step (A06) is 100 kg / mu; the water quality is cultivated in step (A06) until the water transparency reaches 30 cm; the water quality cultivation time in step (A06) is 3 days; the number of cladocerans in the water body in step (A06) is more than 3 per mL of water sample; the stocking density of chub fry in the water body in step (A06) is 2200 fish / m²;

[0190] (A07) Select juvenile chub that have entered the basal swimming stage and release them into the water body of step (A06);

[0191] (A08) After the seedlings in step (A07) have been cultured for a period of time, the first feed is fed into the first-level culture area; in step (A08), when the number of cladocerans in the water body decreases to 1 to 2 per mL of water sample, the first feed is fed into the water body; the first feed in step (A08) is a powder with crude protein ≥ 48%; the particle size of the first feed in step (A08) is 0.2 mm to 0.3 mm; the first feed in step (A08) is fed by dry sprinkling along the ring ditch; step (A07) In step (A08), the first feed is given 7 days after the release of the chub fry; the feeding frequency of the first feed in step (A08) is 3 times / day; the feeding amount of the first feed in step (A08) is 10g / 10,000 fish; the second feed in step (A08) is crushed feed and pelleted feed with crude protein ≥46%; the crushed feed and pelleted feed are fed sequentially; the feeding frequency of the second feed in step (A08) is 4 times / day; the feeding amount of the second feed in step (A08) is 6% to 12% of the fish's body weight;

[0192] (A09) After the seedlings in step (A08) have been cultivated for a period of time, the second feed is started; the water injection interval in step (A09) is 3 days; the water injection depth in step (A09) is 2.5cm each time;

[0193] (A10) After the second feed is fed in step (A09), water is injected into the first-stage culture zone again; the pH of the water in the first-stage culture zone in step (A10) is 7.8; the dissolved oxygen in the water in the first-stage culture zone in step (A10) is ≥6 mg / L;

[0194] (A11) After the water injection in step (A10) is completed, add the microbial preparation to the first-level culture zone;

[0195] (A12) When the seedlings in step (A11) have grown to a certain size, remove the inner layer of netting; when the seedlings in step (A12) have grown to 1.5cm to 2.5cm, remove the inner layer of netting.

[0196] (A13) Continue cultivating the seedlings in step (A12) to a certain size, pull the net to count the number of seedlings and remove the outer net; continue cultivating the seedlings in step (A13) to 3cm-4cm, pull the net to count the number of seedlings;

[0197] (A14) After the rice tillering is completed, water is injected into the ring ditch in step (A13) until the water level in the ring ditch is higher than the water level in the paddy field; in step (A14), water is injected into the ring ditch daily after the rice tillering is completed; the daily water injection volume in step (A14) is 10cm; the water injection duration in step (A14) is 4 days; in step (A14), water injection is stopped when the water level in the ring ditch is 40cm higher than the water level in the paddy field.

[0198] Check the blower and anti-bird net, and record the activities and feeding conditions of the fish bodies; set up multiple bait tables in the first-stage cultivation area.

[0199] Example 4:

[0200] A method for cultivating Opsariichthys bidens fry in a paddy field ring ditch, including the steps: preparation of the paddy field ring ditch, preparation of the seedling cultivation site in the paddy field ring ditch, disinfection of the ring ditch and water quality cultivation, stocking of Opsariichthys bidens fry, daily management of seedling cultivation, and stocking of paddy field seedlings, where:

[0201] Paddy field preparation:

[0202] The area of the experimental paddy field is 20 mu (about 120m - 11m), and a "return" - shaped ring ditch with a width of 3m and a depth of 100 - 130cm is dug around the paddy field; one φ160mm overflow outlet is set at each of the 4 corners of the return ditch for drainage, and oxygen - increasing pipes with a diameter of 50cm are installed every 10m and linked by a 2.2kw Roots blower (which can serve about 左右50); a "well" - shaped fish ditch with a width of about 80cm and a depth of 30cm is dug inside the experimental field to run through the entire paddy field (the total excavation of the "return" - shaped ring ditch and the "well" - shaped fish ditch is 1200m

[0206] , ,

[0207] , ,

[0205] , , accounting for about 9% of the total paddy field area), and the "return" - shaped ring ditch and the "well" - shaped fish ditch are interconnected to facilitate the subsequent swimming of Opsariichthys bidens fry into the paddy field for subsequent integrated rice - fishery farming.

[0203] Preparation of the seedling cultivation site in the paddy field ring ditch:

[0204] Select the water inlet of the south - side (concentrated on one side) ring ditch with sufficient sunlight as the place for cultivating Opsariichthys bidens fry. Set up a double - layer barrier net with 80 - mesh and 20 - mesh (80 - mesh inside and 20 - mesh outside) in the form of inserting nets on both sides of the ring ditch. The height of the barrier net is 10cm higher than the paddy field ridge to ensure that the fry do not escape. The entire seedling cultivation area accounts for 50% of the total area of the south - side ring ditch, about 2 170m 2 (The seedling cultivation area is set according to the area of rice - fishery farming. In this case, the area of rice - fishery farming is 20 mu, and the number of stocked fry is 40000 tails (2000 tails / mu)).

[0205] Disinfection of the ring ditch and water quality cultivation:

[0206] Ring ditch disinfection: One week before stocking Opsariichthys bidens fry (in early May, water temperature is higher than 25℃), drain the water, use 50kg / mu of bleaching powder, dissolve it into a slurry and sprinkle it all over the ring ditch to kill frog eggs, fish fry, Pomacea canaliculata eggs and other harmful organisms in the ring ditch. After 2 days of disinfection, then inject about 50cm of water (about 60% - 70% of the depth of the ring ditch).

[0207] Water quality cultivation: 3-5 days before stocking, on a sunny afternoon, apply 100 kg / mu of amino acids and aquatic-specific organic fertilizer to the water in the ring ditch to fertilize the water and cultivate algae. Keep the water transparency at about 30 cm. After 3 days, abundant zooplankton (the fry of the Chinese sturgeon mainly feed on cladocerans) will be cultivated in the water as food organisms for the fry. It is advisable to observe the number of cladocerans in the water using a graduated cylinder or beaker, which should be more than 3 per mL.

[0208] Stocking of fry of the Chinese sturgeon:

[0209] Choose fertilized eggs from a reputable hatchery or your own bred chub and incubate them in hatching tanks. Once the yolk sac disappears after hatching and the fry have all entered the basal swimming stage, release them into the water. Depending on the area of ​​the netted fry rearing area, control the stocking density to 2000-2500 fry per square meter.

[0210] Daily management of seedling cultivation:

[0211] Feeding and management of juvenile chub: Within 3 days after the juvenile chub are introduced into the water (around mid-May), the main food should be zooplankton that have been cultivated in the water in the early stage. The density of cladocerans in the water should be observed every afternoon using a measuring cylinder or beaker. When the density of cladocerans in the water drops to 1-2 individuals / mL (about 7-8 days after introduction into the water), artificial compound feed should be introduced. Select powdered feed with a crude protein content ≥48% (particle size 0.20-0.30mm), and dry-sprinkle it along the ring ditch 3-4 times a day, feeding at a stocking density of 10g / 10,000 chub fry. The fry should finish eating within 0.5 hours after feeding, and the amount of feed should be increased or decreased according to their satiety. Later, as the fry grow, the amount of feed should be increased as appropriate, successively feeding crushed feed with a crude protein content ≥46% and small pellet feed, 3-4 times a day, preferably finished within 0.5 hours after feeding, with the feed amount being 8%-10% of the fish's body weight.

[0212] Water quality management: After the chub have successfully transitioned to fresh food, add fresh water every 2-3 days, adding 2-3 cm each time. Regularly apply microbial agents to regulate the water quality, maintaining the pH between 7.8 and 8.5, and ensuring the water exhibits characteristics of being "rich, lively, tender, and refreshing." During the seedling stage, continuous aeration is necessary to maintain dissolved oxygen levels above 6 mg / L.

[0213] Patrol: Patrol once each in the morning, noon and evening to check oxygenation facilities and bird nets, observe fish activity and feeding, and prevent attacks from birds and other predatory creatures.

[0214] Seedling thinning: When the seedlings reach about 2cm in length, remove the inner 80-mesh netting, leaving only the outer 20-mesh netting to ensure unobstructed water flow within the ring ditch. After the seedlings reach 3cm-4cm in length, use a net to count the seedlings. Once the seedling quantity is confirmed, remove the outer 20-mesh netting to allow the juvenile chub to swim away on their own. Set up 3-5 feeding stations in the original seedling rearing area for convenient, targeted feeding later.

[0215] Rice seedling release:

[0216] After the rice tillering stage ends (around early to mid-July), water is injected into the ring ditch at a rate of about 10 cm per day for 3 to 5 days. Water injection is stopped when the water level in the ring ditch is 40 cm higher than the water level in the paddy field. At this time, juvenile chub can swim into the paddy field using the excavated "well"-shaped fish ditch, allowing for direct rice-fish integrated farming.

[0217] According to production measurement data from Jiangdong Farm in Qiantang District, Hangzhou City, Zhejiang Province in 2022 and 2023, the survival rate of chub fry cultivated in the paddy field ditches under the integrated rice-fish farming model increased by 30% and the cost of fry cultivation decreased by 40%.

[0218] The working principle of the paddy field ring ditch system for cultivating chub fry in this invention is as follows:

[0219] The paddy field area 100 is used for rice planting and the excavation of fish ditch 102; the ring ditch 101 is used for the cultivation of chub fry; the fish ditch is used to allow the chub fry cultivated in the ring ditch to enter the paddy field area, ultimately achieving a good integrated rice-fish farming system; the depth of the fish ditch is less than the depth of the ring ditch, which can prevent chub fry from entering the fish ditch during the cultivation process in the ring ditch; the aeration pipes 103 are distributed in the ring ditch, and in conjunction with the blower 104, can stably and continuously deliver external air into the water body to ensure dissolved oxygen in the water body. Content requirements; the first-level cultivation area 105 is used for the initial cultivation of chub fry in the paddy field; the double-layered barrier net formed by the inner barrier net 106 and the outer barrier net 107 can effectively prevent the fry from jumping out of the paddy field and into the ditches or paddy fields, so that the chub fry are cultivated only in a limited area; the aeration nozzle 108 can evenly and gently deliver the air in the aeration pipe into the water body, and prevent water from flowing back into the aeration pipe; the first waterproof motor 109 drives the disturbance part 1010. The rotation allows the air from the aeration nozzles to be distributed throughout the water body as quickly as possible; the agitator with agitation valves can better agitate the water body, allowing the air from the aeration nozzles to be distributed throughout the water body as quickly as possible; the overflow outlet can prevent excessive water from being injected into the ring ditch, causing irregular overflow of the water level above the field tillage; when too much water is injected, the excess water will flow out from the overflow outlet into the external ditch; multiple feeding platforms 1011 make it easier to feed the chub fry; the fry rearing area 200 is used for chub fry rearing. In the initial stage of cultivation, fertilized eggs of the Chinese sturgeon from a regular hatchery or self-bred are incubated in hatching tanks. Once the yolk sac disappears after hatching, all fry are transferred to the fry cultivation area for further cultivation. After reaching the swimming stage, the fry are sent to the first-level cultivation area for further development. The water passage 201 is used to transfer fry that have reached the swimming stage in the fry cultivation area to the first-level cultivation area. The barrier gate 202 is used to open and close the water flow between the fry cultivation area and the first-level cultivation area.

[0220] The netting mechanism 300 is used to catch and frame the mature chub in the rice-fish integrated farming system; the netting motor 301 provides power for the back-and-forth movement of the net; the mounting block 302 supports one end of the guide tube 303 and the screw 307; the guide tube 303 and the guide groove 304 provide stable guidance for the directional back-and-forth movement of the net; the guide slider 305 drives the net 306 to move back and forth to catch the mature chub in the fish ditch; the net drives the mature chub in the fish ditch to the outer perimeter of the rice field for manual capture and frame; the rotation of the screw drives the guide slider to move back and forth in the guide groove; the entire netting structure facilitates manual capture of mature chub in the fish ditch, reducing the workload of manually entering the rice field and fish ditch to capture them one by one. The water treatment tank 400 can appropriately treat the water from the ring ditch 101, fish ditch 102, and paddy field 100 after the fish have been raised, so that the water can be reused. The drainage pipe 401 is used to send the water from the ring ditch, fish ditch, and paddy field into the water treatment tank. The drainage pump 402 provides power for sending the water from the ring ditch, fish ditch, and paddy field into the water treatment tank. The waste collection tank 403 is used to collect the waste after flocculation and sedimentation in the water treatment tank. The bottom surface of the water treatment tank is inclined along the direction of the waste collection tank, which facilitates better entry of the waste after flocculation and sedimentation into the waste collection tank for collection. The waste collection box 404 is used to send the waste from the waste collection tank out for collection and further external treatment. The material conveying pipe 405 is used to send the dirt in the dirt collection tank into the dirt collection box; the screw conveyor 406 is used to efficiently and stably send the dirt in the dirt collection tank into the dirt collection box; the conveying motor 407 provides power for the screw conveyor; the notch is used to allow the screw conveyor to better contact the dirt in the dirt collection tank, thereby better sending the dirt in the dirt collection tank into the dirt collection box; this allows the screw conveyor to better contact the dirt in the dirt collection tank, thereby achieving more complete conveying; the floating net 409 slides up and down in the chute 408, and the floating net dynamically changes with the water level in the water treatment tank. The water treatment agent in the floating net is continuously dispersed and dissolved in the sewage in the water treatment tank, causing the dirt in the water treatment tank to be dispersed. After flocculation and sedimentation, polyacrylamide enables small particles in wastewater to quickly coagulate and settle into large particles; activated carbon effectively adsorbs pollutants such as color, odor, chlorine, organic matter, bacteria, and viruses from wastewater; a limited amount of polyacrylamide effectively coagulates small particles in wastewater and causes them to settle into large particles; a limited amount of activated carbon effectively adsorbs and treats wastewater; the treated water is then returned to the fish fry rearing area 200 for reuse via the water delivery tank 4010; the water delivery gate 4011 controls whether the treated water in the water treatment tank is sent to the fish fry rearing area; and the waste is sent out of the waste collection box via the waste discharge outlet 4012 for centralized reprocessing.

[0221] The water supply and drainage mechanism 500 can supply water to the fish fry rearing area 200, the ring ditch 101, and the paddy field area 100 as needed, and can also discharge water from the ring ditch as needed. The water supply and drainage pipe 501 is used to replenish or drain water from the ring ditch; the water supply pipe 502 is used to replenish water from the ring ditch; the drainage pipe 503 is used to drain water from the ring ditch; the hose rack 504 is used to hold the water supply and drainage hoses; the water supply and drainage hoses can be pulled out from the hose rack as needed to perform water supply and drainage operations within the ring ditch or to the fish fry rearing area; the treatment tank 505 is used to treat larger volumes of water in the ring ditch when draining water from the ring ditch. The material is collected after filtration; the push-pull bracket 506 is used to install the filter screen 507. The push-pull bracket is pushed out and pulled in relative to the inside of the treatment box to regularly clean the filtered material on the filter screen and ensure smooth water supply and drainage; the filter screen is used to filter larger volume materials in the drainage inside and outside the ring groove; the second waterproof motor 508 provides power for the rotation of the cleaning brush 5011; the rotating disk 509 drives the handle 5010 to rotate eccentrically; the handle drives the cleaning brush to rotate and clean the adsorbed material on the filter screen, preventing the water channel inside the treatment box from being blocked; the cleaning brush can effectively clean the surface of the filter screen and avoid dirt clogging the filter screen.

[0222] The water level monitoring mechanism 600 can monitor the water level in the fish ditch 102 in real time. Both the water level monitoring mechanism and the external water pump are electrically connected to the control board. Through the cooperation of the water level monitoring mechanism and the external water pump, the water level in the fish ditch is adjusted according to the actual situation. The filter screen 601 effectively prevents debris from the external water from entering the protective shell 602 and affecting the working stability of the sensor and water level sensor. The protective shell provides an installation position for the drive motor 603 and other related components. The drive motor determines whether to rotate based on the signal from the control board, thereby controlling the operation of the external water pump to ensure that the water level inside the protective shell and in the fish ditch is at the same height. The screw 604 drives the lifting plate 605 to rise and fall stably according to the rotation of the drive motor. The rising and falling of the lifting plate adjusts the bottom space inside the protective shell. When the water level sensor at the bottom of the lifting plate contacts the water surface, it transmits a signal to the external control board. The control board determines whether the drive motor and the external water pump operate. The lifting plate divides the interior of the protective shell into upper and lower spaces, which are controlled by the water level sensor. The sensor inside the water level monitoring hole 608 senses the water level and monitors and controls the water level in the fish ditch. The cooperation of the slide 606 and the slider 607 ensures that the lifting plate can only slide up and down along a fixed slide direction. Several water level monitoring holes monitor the water level in the fish ditch. When the water level reaches the corresponding water level monitoring hole, the sensor detects the water body and the rise of the lifting plate, so that the control board decides whether to inject water into the ring ditch. The sensor can effectively detect whether there is water at the water level monitoring hole and whether the lifting plate has reached the corresponding water level monitoring hole. The water level sensor can effectively detect the water level in the bottom space inside the protective shell. The water level monitoring holes set at equal intervals can more accurately monitor the water level in the fish ditch. When the water level reaches the fish ditch, it can enter the protective shell in time along the water inlet bend 609, so that the water level sensor can detect the water level in the protective shell in time. The control board can coordinate the signals and effectively control the start and stop of each device.

Claims

1. The method of cultivating chub fry in paddy fields with surrounding ditches is characterized by: A system for cultivating chub fry in a paddy field with a ring ditch includes a paddy field area (100), a ring ditch (101) around the perimeter of the paddy field area, and several fish ditches (102) within the paddy field area. The fish ditches are connected to the ring ditch, and the depth of the fish ditches is less than the depth of the ring ditch. Several oxygenation pipes (103) are provided within the ring ditch. A blower (104) is included, and the outlet of the blower is connected to the interior of the oxygenation pipes. A first-stage cultivation area (105) is provided near the inlet of the ring ditch, and an inner layer of netting (106) and an outer layer of netting (107) are provided on the inner wall of the first-stage cultivation area from the inside out. At least one fish ditch is equipped with a netting mechanism (300); the netting mechanism includes a netting motor (301) and a mounting block (302), the netting motor and the mounting block are located at both ends of the corresponding fish ditch, the netting motor is provided with a guide tube (303), the end of the guide tube away from the netting motor is connected to the mounting block, the guide tube is provided with a guide groove (304), a guide slider (305) is slidably provided in the guide groove, the guide slider is provided with a fishing net (306), the fishing net is movably set in the corresponding fish ditch; the drive end of the netting motor is provided with a screw (307), the screw is located in the guide tube, the end of the screw away from the netting motor is rotatably connected to the mounting block, and the screw is threadedly connected to the guide slider; The fish ditch is equipped with multiple water level monitoring mechanisms (600); each water level monitoring mechanism includes a filter screen bucket (601), the inside of which is equipped with a protective shell (602), the top of which is equipped with a drive motor (603), the drive end of which is equipped with a screw (604), a lifting plate (605) is threaded onto the screw, a slide rail (606) is provided on the inner wall of the protective shell, and a slider (607) is provided at the edge of the lifting plate, the slider being slidably disposed within the slide rail; the protective shell is provided with several water level monitoring holes (608) along the vertical direction, each water level monitoring hole is equipped with a sensor, and the bottom of the lifting plate is equipped with a water level sensor, the water level sensor corresponding to the sensor; Includes the following steps, (A01) Select a paddy field and dig a ring ditch around it; (A02) Dig a fish ditch in the paddy field in step (A01) and dig until the fish ditch is connected to the ring ditch; (A03) Select the first-level cultivation area in the ring ditch in step (A01) as the breeding area for chub fry, and set up double-layer netting on the two inner walls of the ring ditch; (A04) Disinfect the drainage ditch in step (A01) before releasing the fry of the chub; (A05) After the disinfection in step (A04) is completed, fill the ring trench with water; (A06) After the water injection in step (A05) is completed, amino acids and aquatic-specific organic fertilizer are applied to the water body of the ring ditch for water quality cultivation; (A07) Select fry of the chub that have entered the basal swimming stage and release them into the water body of step (A06); (A08) After the seedlings in step (A07) have been cultivated for a period of time, the first feed is fed into the first-level cultivation area; (A09) After the seedlings in step (A08) have been cultivated for a period of time, the second feed shall be fed. (A10) After the second feed is fed in step (A09), water is injected into the first-stage culture area again; (A11) After the water injection in step (A10) is completed, add the microbial preparation to the first-level culture zone; (A12) Once the seedlings in step (A11) have reached a certain size, remove the inner layer of netting; (A13) Continue cultivating the seedlings in step (A12) to a certain size, count the number of seedlings with a net and remove the outer net; (A14) After the rice tillering is completed, add water to the ring ditch in step (A13) until the water level in the ring ditch is higher than the water level in the paddy field. In step (A08), when the number of cladocerans in the water body decreases to 1 to 2 per mL of water sample, the first feed is introduced into the water body; the first feed in step (A08) is a powder with crude protein ≥48%; the particle size of the first feed in step (A08) is 0.2 mm to 0.3 mm; the time for introducing the first feed in step (A08) is 6 to 9 days after the release of the juvenile chub; the feeding of the first feed in step (A08) The feeding frequency is 2 to 5 times per day; the feeding amount of the first feed in step (A08) is 5g / 10,000 fish to 15g / 10,000 fish; the second feed in step (A08) is crushed feed and pelleted feed with crude protein ≥46%; the crushed feed and pelleted feed are fed sequentially; the feeding frequency of the second feed in step (A08) is 2 to 5 times per day; the feeding amount of the second feed in step (A08) is 6% to 12% of the fish's body weight; In step (A09), the water injection interval is 2 to 3 days; in step (A09), the water injection depth is 2 to 3 cm each time; in step (A10), the pH of the water in the first-level cultivation area is 7.5 to 9; in step (A10), the dissolved oxygen in the water in the first-level cultivation area is ≥6 mg / L; in step (A12), when the seedlings are cultivated to 1.5 cm to 2.5 cm, the inner layer of the net is removed; in step (A13), when the seedlings are cultivated to 3 cm to 4 cm, the net is pulled to count the number of seedlings; in step (A14), after the rice tillering is completed, water is injected into the ring ditch daily; in step (A14), the daily water injection volume is 8 cm to 12 cm; in step (A14), the water injection duration is 3 to 5 days; in step (A14), water injection stops when the water level in the ring ditch is 35 cm to 45 cm higher than the water level in the paddy field.

2. The method for cultivating chub fry in paddy field ring ditches according to claim 1, characterized in that: In step (A01), the width of the ring ditch is 0.5m to 5m; the depth of the ring ditch in step (A01) is 80cm to 150cm; several oxygenation pipes are installed in the ring ditch in step (A01); in step (A02), the width of the fish ditch is 50cm to 100cm; the depth of the fish ditch in step (A02) is 20cm to 50cm; the fish ditch and the ring ditch occupy 5% to 15% of the total area of ​​the paddy field.

3. The method for cultivating chub fry in paddy field ring ditches according to claim 1, characterized in that: The first-level cultivation area in step (A03) is located at the inlet of the ring ditch; the first-level cultivation area in step (A03) occupies 40% to 100% of the total area of ​​the ring ditch; the number of chub fry cultivated in the first-level cultivation area in step (A03) is 1500 to 2500 fry / mu; the inner layer of the double-layer barrier net in step (A03) is a 60-100 mesh barrier net, and the outer layer of the double-layer barrier net is a 10-30 mesh barrier net; the height of the double-layer barrier net in step (A03) is higher than the depth of the ring ditch; the height of the double-layer barrier net in step (A03) is 5cm to 15cm higher than the depth of the ring ditch.

4. The method for cultivating chub fry in paddy field ring ditches according to claim 1, characterized in that: The disinfectant used in step (A04) is bleaching powder; in step (A04), the bleaching powder is slurried and then sprinkled throughout the entire ring ditch; the dosage of the disinfectant in step (A04) is 30 kg / mu to 70 kg / mu; in step (A04), the time interval between draining and disinfecting the ring ditch and releasing the fry of the mandarin fish is 5 to 8 days; the water injection time in step (A05) is 1 to 3 days after disinfection; the water injection volume in step (A05) is 50% to 80% of the depth of the ring ditch.

5. The method for cultivating chub fry in paddy field ring ditches according to claim 1, characterized in that: In step (A06), the application time of amino acids and aquatic-specific organic fertilizer is 3 to 5 days before the release of chub fry; the application rate of amino acids and aquatic-specific organic fertilizer in step (A06) is 80 kg / mu to 120 kg / mu; in step (A06), the water quality is cultivated until the water transparency reaches 25 cm to 35 cm; the water quality cultivation time in step (A06) is 2 to 5 days; in step (A06), the number of cladocerans in the water body is more than 3 per mL of water sample; and the stocking density of chub fry in the water body in step (A06) is 2000 fish / m² to 2500 fish / m².

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