A method for simultaneous seedling supply without screening in large-scale aquaculture farms

Abstract

This invention discloses a method for simultaneous, screening-free fry supply in large-scale aquaculture farms. The invention utilizes net cages of different sizes to cultivate fry in stages, achieving screening-free and large-scale simultaneous fry supply through progressively expanding the cage capacity. This invention fully leverages multi-stage cage cultivation and employs fish school dynamic monitoring technology to regulate fry feeding, ensuring that most fry are of uniform size. This eliminates the need for screening, avoiding tedious manual operations and damage to fry during the screening process. Ultimately, it enables large-scale simultaneous fry supply, ensuring relatively uniform fish size during the rearing stage and improving aquaculture profitability.

Description

Technical fields:

[0001] This invention belongs to the field of aquaculture, specifically relating to a method for simultaneous seedling supply without screening in large-scale aquaculture farms. Background technology:

[0002] Moving away from the coast and towards deep-sea aquaculture has been a consistent development direction for my country's aquaculture industry and an inevitable choice for the structural adjustment of marine fisheries. Fish farms are increasingly being designed for ultra-large scales. This large-scale development necessitates addressing the issue of simultaneous supply of large quantities of fry. Due to the high requirements and large demand for simultaneous fry supply in large-scale fish farms, traditional intermediate fry rearing methods require repeated manual screening of fry in each box and frequent net changes. This is labor-intensive, time-consuming, and results in significant fry losses. During peak periods, timely screening is often impossible, leading to inconsistent fry sizes and making it difficult to meet the simultaneous fry supply needs of large-scale aquaculture farms. Summary of the Invention:

[0003] The purpose of this invention is to provide a method for simultaneous fry supply to large-scale aquaculture farms without screening. This method overcomes a series of problems associated with traditional fry cultivation, such as the need for extensive manual screening and net changing in each box, and fry losses. It achieves relatively uniform fry size in each box, ensures a high fry survival rate, and can supply fry in a single batch to meet the needs of large-scale aquaculture farms exceeding 50,000 cubic meters. 3 The simultaneous supply of fish fry in large bodies of water eliminates the need for fry screening, saving significant manpower and increasing efficiency. It can simultaneously supply fry to multiple large fish farms on a large scale, resulting in relatively uniform fish size during the rearing stage and improving aquaculture profits. Furthermore, this invention employs a graded intermediate rearing model, solving the adaptation problem of small-sized fry from nearshore shallow waters to the high sea state conditions of deep-sea aquaculture, thus significantly improving the survival rate of fry during intermediate rearing.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for simultaneous seedling supply without screening in large-scale aquaculture farms, comprising the following steps:

[0005] A. Primary cultivation in small water bodies: The cultivation time for seedlings should be chosen to avoid the cold wave and typhoon seasons, and multiple seedlings of 1500-3000m should be selected. 3 The same batch of fry were used for primary rearing in net cages within the water body. The cultured species was oval pomfret. The primary rearing net cages were set at a water depth of 18-20m. To adapt to the later high sea state conditions of large-scale deep-sea aquaculture, the net cages were set in open sea areas with good water exchange conditions. The seawater flow velocity in the primary rearing sea area was controlled below 0.80m / s, with sufficient dissolved oxygen, and far away from estuaries. Fry with an average body length of 3-3.5cm were selected for rearing in the net cages. Primary rearing of fry was carried out uniformly in this type of net cage, with a fry rearing density of 250 fry / m³. 3Fish fry are fed using a boat-mounted feeder. The entire process is monitored by an underwater fish monitoring system to precisely control the amount of feed. By monitoring the size of the fish fry, the amount of feed in each primary net cage is controlled precisely to avoid the average size difference of fish fry in different net cages exceeding 2.0cm. If the average size of fish fry in a particular cage exceeds the average size of fish fry in all net cages by more than 2.0cm, the amount of feed is restricted to appropriately slow down the growth of fish fry in that cage, so as to ensure that the size of fish fry in the same batch is uniform. After the average size of fish fry in each net cage is cultivated to 8cm, primary cultivated fish fry are obtained.

[0006] B. Secondary Rearing in Mid-Water Bodies: The secondary rearing cages are set at a water depth of 25-26m. To better adapt to the high sea state conditions of large-scale fish farms in deep sea, the cages are selected and set in open sea areas with good water exchange conditions and relatively fast sea currents, generally controlled within 1.00m / s. Feeding is stopped for 1 day before the fry are transferred. Then, the primary rearing cages are moved to the vicinity of the secondary rearing cages. The fry are transferred on a sunny morning. If the distance from the primary cage to the secondary cage exceeds 5km, the primary cages are first fixed to the vicinity of the secondary cages, and the fry need to be placed for more than 12 hours before the transfer. The netting of the primary cage is gathered to the side close to the secondary cage, and the fry are directly transferred to the secondary cage using a large landing net operated by a ship-mounted crane. After the fry are transferred to the secondary cage, feeding is stopped for 1 day before feeding begins to enter the secondary rearing stage. The primary rearing fry are then transferred to a depth of 7500m. 3 Secondary rearing is carried out in aquatic cages, with the stocking density controlled at 100 fish / m². 3 Fish fry are fed using a boat-mounted feeder. The feeding amount is precisely controlled by an underwater fish monitoring system. By monitoring the size of the fish fry, the amount of feed in each secondary net cage is controlled precisely to avoid the average size difference of fish fry in different net cages exceeding 2.0cm. After the fish fry are raised to an average size of 13cm, they are transferred to a large fish farm for further rearing. Multiple secondary rearing net cages supply fish fry to one large fish farm.

[0007] C. Transfer of secondary-stage rearing fry to ultra-large water bodies for further rearing: The secondary-stage rearing net cages are designed to be mobile. Once the fry reach an average body length of 13cm, they can be transferred to ultra-large fish farms for further rearing. These large fish farms are set at a water depth of 36-38m and a water volume of 60,000m³. 3 Choose a sunny day and drag the secondary net cages to the vicinity of the large fish farm for simple fixation, or directly fix the movable secondary net cages on the large fish farm. After the fish fry have been placed for more than 12 hours, choose a sunny morning to transfer the fish fry. The fish fry transfer operation can be carried out by using a ship-mounted crane to operate a large landing net for transfer or by using a fish suction pump. After the fish fry are transferred to the large fish farm, stop feeding for 1 day and then start the fish farm rearing.

[0008] Preferably, to delay the replacement and washing cycle of nets, a comprehensive chemical and ecological netting antifouling method is also included. One method is to treat the nets with a harmless antifouling treatment, such as spraying them with an environmentally friendly antifouling coating and letting them dry before use, to reduce the attachment of marine fouling organisms. Another method is to raise bluefish of the same body length at a ratio of 0.5% of the number of farmed fish to feed on the algae caught in the nets. By using a comprehensive chemical and ecological netting antifouling method, the nets do not need to be replaced or washed during the seedling cultivation period.

[0009] Fish Screening-Free Operation: Based on a sonar system and an underwater high-definition camera, an underwater fish monitoring system is established to monitor the overall quantity of fish fry and analyze and statistically analyze fish size. ① Sonar System: Utilizing acoustic monitoring methods widely used in fisheries resource monitoring and assessment, the high-frequency detection signal for fish acoustic detection employs a 200 kHz frequency and a short-time pulse modulation signal with a pulse width of 0.2 ms, achieving optimal detection distance and target resolution. The sonar scanning distance is a 45m radius sphere. The echo intensity map of the sonar system visually reflects the activity status of the fish school. The system divides the echo amplitude values ​​of the fish school into 256 levels, corresponding to 256 color levels between blue and red. Blue represents an intensity level of 0, and red represents an intensity level of 255. Each detected data point is displayed on the screen from left to right in real-time, forming an echo intensity map. The spatial distribution and size of the fish school are monitored through the density distribution and color changes of the image, and displayed through a graphical 3D interface. ② Equipped with a binocular underwater high-definition camera, the image resolution is 200W, the imaging clarity is 1080P, the underwater measurement distance is 0-3m, and the highest accuracy is ±0.8cm. First, the binocular camera is calibrated to obtain the intrinsic and extrinsic parameters and homography matrix of the two cameras. Based on the calibration results, the original images are corrected. The two corrected images are located on the same plane and are parallel to each other. Pixel matching is performed on the two corrected images, and the depth of each pixel is calculated based on the matching results to obtain a depth map. This allows for underwater fish size imaging, and size analysis and statistics are performed based on the imaging results. When monitoring this species for the first time, the monitoring system parameters can be calibrated and corrected by manually measuring the size of the fry at different growth stages. This allows for accurate calculation of the number of fry and the average body length of the fry. Using the difference in the average body length of fry in different breeding cages as the main reference parameter, the feeding amount for each cage is accurately calculated, and the feeding rate of each cage is dynamically adjusted. ③ Based on fish school dynamic monitoring technology, the feeding of fish fry is controlled by limiting the amount of feed. When the average size of the fish fry exceeds the limit by 10% but does not exceed 20%, the daily feed amount is reduced by 50% until the size of the fish fry is controlled within an error of no more than 10%, and then normal feeding is resumed. When the size of the fish fry exceeds the limit by more than 20%, they are starved for 1-2 days, and then fed at 50% of the normal feed amount until the size of the fish fry is controlled within an error of no more than 10%, and then normal feeding is resumed. Through dynamic monitoring and limited feeding, the average size of fish fry in different net cages is maintained in a consistent manner, eliminating the need for fry screening, avoiding tedious manual fish screening operations, and reducing fish fry damage.

[0010] No-Net-Change Operation: The rearing time for each stage of fish fry is strictly controlled within 15-30 days, and the rearing of each stage is completed within the net-changing cycle, avoiding damage to fish fry and the consumption of a large amount of labor during net changing and washing. A comprehensive chemical and ecological netting antifouling method is used. First, the netting undergoes a harmless antifouling treatment. The netting is sprayed with an environmentally friendly antifouling coating and dried before use, which can greatly reduce the attachment of marine fouling organisms. Second, to prevent large algae such as green algae and brown algae from clogging the net holes, a small number of herbivorous fish such as bluefish of the same size can be stocked in the net cage at a ratio of 0.5% to graze on the algae clinging to the net, acting as scavengers and cleaning the netting. This achieves the goal of eliminating the need for netting replacement and washing during the fry rearing cycle.

[0011] Mobile floating cage culture: Primary and secondary breeding cages are flexibly fixed around large fish farms and adopt a floating culture method. When the fry are raised to the final size of the fish species, the secondary cages are moved to the vicinity of the super-large fish farm and the fish species are transferred to the large fish farm for further growth, reducing the damage to the fish species during transportation.

[0012] This invention utilizes fish fry to be cultivated in different sizes of net cages, and by gradually expanding the capacity of the net cages, it achieves the effect of eliminating the need for screening and supplying a large number of fry simultaneously.

[0013] The beneficial effects of this invention are:

[0014] 1. This invention is the first to adopt a two-stage intermediate cultivation method, which solves the problem of fish fry adaptability from nearshore to deep-sea environments, and can meet the needs of large-scale aquaculture farms exceeding 50,000m in a single stage. 3 The above-mentioned supply of fry for large water bodies overcomes the problems of traditional fry cultivation, which requires a lot of manpower for repeated manual screening and box-changing operations, as well as fry loss. It achieves fry screening-free operation, saves manpower, and increases aquaculture profits.

[0015] 2. This invention uses fish swarm dynamic monitoring technology and feeding restriction technology to regulate the feeding of fish fry, ensuring that most fish fry are of the same size, realizing the synchronous supply of fish fry of the same size on a large scale, and ensuring that the fish size is relatively uniform during the rearing stage of large fish farms.

[0016] 3. This invention adopts a chemical and ecological integrated netting antifouling method to achieve intermediate cultivation without changing nets, reducing the damage to fish fry caused by net changing operations. Detailed implementation method:

[0017] The invention will be further described in detail below with reference to implementation examples.

[0018] Example 1

[0019] 1. Primary rearing: The rearing time for seedlings should be chosen to avoid the cold wave and typhoon seasons. The species to be raised is the oval pomfret, and four 3000m seedlings should be selected. 3The primary rearing stage is conducted in net cages at a water depth of 18m. To adapt to the later high-sea-state aquaculture conditions in large-scale deep-sea fishing grounds, the net cages are located in open sea areas with good water exchange conditions. The seawater flow velocity in the primary rearing area is controlled below 0.80m / s, with sufficient dissolved oxygen, and far from estuaries. Fish fry of about 3.5cm are selected for rearing at a density of approximately 250 fish / m³. 3 Fish fry are fed using a boat-mounted feeder, with a precise underwater monitoring system controlling the feeding amount throughout the process. The amount of feed per primary cage is controlled by monitoring the fry's body length, preventing the average body length difference between cages from exceeding 2.0cm. If the average body length of fry in a particular cage exceeds the average of all cages by more than 2.0cm, the feeding amount is restricted, such as reducing the daily feed by 50% or starving the fry for 1-2 days, followed by feeding at 50% of the normal amount. This appropriately slows the growth of the fry in that cage until the average body length does not exceed the average of all cages by more than 2.0cm. Normal feeding is then resumed. This ensures that the fry in the same batch are of uniform size. The fry are then uniformly cultured in these cages until they reach approximately 8cm in length (primary culture fry), after which they are transferred to medium-sized cages for secondary culture.

[0020] 2. Secondary Rearing: The secondary rearing cages are set up in open sea areas with good water exchange conditions, at a water depth of 26m. The current speed is controlled within 1.00m / s. Feeding is stopped for 1 day before the fry are transferred. The primary rearing cages are then moved to the vicinity of the secondary rearing cages. The fry transfer is carried out on a sunny morning. If the distance from the primary to the secondary cages exceeds 5km, the primary cages are first fixed to the vicinity of the secondary cages, and the fry are left for at least 12 hours before the transfer. The netting of the primary cages is gathered up to the side closest to the secondary cages, and a large landing net is used directly with a ship-mounted crane to transfer the fry into the secondary cages. Feeding is stopped for 1 day after the fry are transferred to the secondary cages before feeding begins to enter the secondary rearing stage. The primary rearing fry are then transferred to 4 cages at a depth of 7500m. 3 Secondary rearing is carried out in aquatic cages, with the stocking density controlled at 100 fish / m². 3Around the same time, the fish fry were fed using a boat-mounted feeder. An underwater fish monitoring system was used to precisely control the feeding amount throughout the process. By monitoring the fry's body length, a precise feed control method was employed to regulate the feeding amount in each secondary cage, preventing the average body length difference between cages from exceeding 2.0cm. If the average body length of the fry in a particular cage exceeded the average size of all cages by more than 2.0cm, the feeding amount was restricted, such as reducing the daily feeding amount by 50% or allowing the fry to go hungry for 1-2 days before resuming feeding at 50% of the normal amount. Normal feeding was resumed once the average body length of the fry in that cage did not exceed the average size of all cages by more than 2.0cm. After the fry reached an average body length of 13cm, they were transferred to the fish farm for further rearing, with four secondary rearing cages supplying fry to one large fish farm.

[0021] 3. Transfer to fish farms for rearing: The secondary rearing cages are designed to be mobile. These cages are moved to the vicinity of large fish farms for fry transfer. The large fish farms are set up with a water depth of 38m and a rearing water volume of 60,000m³. 3 Choose a sunny day and drag the secondary net cages to the vicinity of the large fish farm for simple fixation, or directly fix the movable secondary net cages on the large fish farm. Place the fish fry for more than 12 hours, and transfer the fish fry in the early morning of a sunny day. The fish fry transfer operation uses a ship-mounted crane to operate a large landing net for transfer. After the fish fry are transferred to the large fish farm, stop feeding for 1 day and start fish farm rearing. The overall survival rate of fish fry in the rearing stage is over 82%.

[0022] To delay the replacement of nets, the netting can be treated with a harmless antifouling treatment. The netting can be sprayed with an environmentally friendly antifouling coating, dried, and then used. A small number of spotted bluefish of the same size can be raised in the net cage at a ratio of 0.5% to achieve the effect of cleaning the netting.

[0023] Example 2

[0024] 1. Primary rearing: The rearing time for seedlings should be chosen to avoid the cold wave and typhoon seasons. The species to be raised is the oval pomfret, and 8 seedlings of 1500m should be selected. 3 The primary rearing stage is conducted in net cages at a water depth of 20m. To adapt to the later high-sea-state aquaculture conditions in large-scale deep-sea fishing grounds, the net cages are located in open sea areas with good water exchange conditions. The seawater flow velocity in the primary rearing area is controlled below 0.80m / s, with sufficient dissolved oxygen, and far from estuaries. Fish fry of about 3cm are selected for rearing at a density of approximately 250 fish / m³. 3Fish fry are fed using a boat-mounted feeder, with a precise underwater monitoring system controlling the feeding amount throughout the process. The amount of feed per primary cage is controlled by monitoring the fry's body length, preventing the average body length difference between cages from exceeding 2.0cm. If the average body length of fry in a particular cage exceeds the average of all cages by more than 2.0cm, the feeding amount is restricted, such as reducing the daily feed by 50% or starving the fry for 1-2 days, followed by feeding at 50% of the normal amount. This appropriately slows the growth of the fry in that cage until the average body length does not exceed the average of all cages by more than 2.0cm. Normal feeding is then resumed. This ensures that the fry in the same batch are of uniform size. The fry are then uniformly cultured in these cages until they reach approximately 8cm in length (primary culture fry), after which they are transferred to medium-sized cages for secondary culture.

[0025] 2. Secondary Rearing: The secondary rearing cages are set up in water at a depth of 25m. The cages are located in open sea areas with good water exchange conditions, and the seawater current speed is controlled within 1.00m / s. Feeding is stopped for 1 day before the fry are transferred. Then, the primary rearing cages are moved to the vicinity of the secondary rearing cages. The fry are transferred on a sunny morning. If the distance from the primary cage to the secondary cage exceeds 5km, the primary cages are first fixed to the vicinity of the secondary cages. The fry need to be placed for more than 12 hours before the transfer. The netting of the primary cage is gathered to the side close to the secondary cage. The fry are then transferred directly to the secondary cage using a large landing net operated by a ship-mounted crane. After the fry are transferred to the secondary cage, feeding is stopped for 1 day before feeding begins to enter the secondary rearing stage. The primary rearing fry are then transferred to 4 cages at 7500m depth. 3 Secondary rearing is carried out in aquatic cages, with the stocking density controlled at 100 fish / m². 3 Fish fry are fed using a boat-mounted feeder, with an underwater fish monitoring system precisely controlling the feeding amount throughout the process. The amount of feed per secondary cage is controlled by monitoring the fry's body length. If the average body length of the fry in a particular cage exceeds the average size of all cages by more than 2.0 cm, the feeding amount is restricted, such as reducing the daily feeding amount by 50% or allowing the fry to go hungry for 1-2 days before resuming feeding at 50% of the normal amount. Normal feeding is resumed once the average body length of the fry in that cage does not exceed the average size of all cages by more than 2.0 cm. This process avoids differences in average body length between different cages exceeding 2.0 cm. After the fry reach an average length of 13 cm, they are transferred to the fish farm for further rearing. Four secondary rearing cages supply fry to one large fish farm.

[0026] 3. Transfer to fish farms for rearing: The secondary rearing cages are designed to be mobile. These cages are moved to the vicinity of large fish farms for fry transfer. The large fish farms are set up with a water depth of 36m and a rearing water volume of 60,000m³. 3Choose a sunny day and drag the secondary net cages to the vicinity of the large fish farm for simple fixation, or directly fix the movable secondary net cages on the large fish farm. Place the fry for more than 12 hours, and transfer the fry on a sunny morning. The fry transfer operation uses a ship-mounted crane to operate a large landing net for transfer. After the fry are transferred to the large fish farm, stop feeding for 1 day before starting the fish farm rearing. Affected by the water temperature fluctuations during the primary rearing stage, the survival rate of the fry is slightly reduced. The overall survival rate of the fry during the rearing stage is about 78%.

[0027] To delay the replacement of nets, the netting can be treated with a harmless antifouling treatment. The netting can be sprayed with an environmentally friendly antifouling coating, dried, and then used. A small number of spotted bluefish of the same size can be raised in the net cage at a ratio of 0.5% to achieve the effect of cleaning the netting.

[0028] In summary, the experimental results of Examples 1 and 2 show that the method involved in this invention can successfully achieve synchronous supply of fish fry in large-scale aquaculture farms. By controlling the amount of feed through fish swarm dynamic monitoring technology, the screening-free effect is achieved. Multi-stage cultivation solves the problem of eliminating the need for net changing during the cultivation process, while also reducing intermediate transportation links, lowering labor intensity, and improving the survival rate of fish fry.

[0029] The invention has been further described in detail above through specific implementation examples. It should be understood that these embodiments are only used to illustrate the invention and not to limit the scope of protection of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art fall within the scope of the appended claims.

Claims

1. A method for simultaneous seedling supply without screening in large-scale aquaculture farms, characterized in that, Includes the following steps: A. Primary cultivation in small water bodies: The cultivation time for seedlings should be chosen to avoid the cold wave and typhoon seasons, and multiple seedlings of 1500-3000 m should be selected. 3 The same batch of fry were used for primary rearing in net cages within the water body. The cultured species was oval pomfret. The primary rearing net cages were set at a water depth of 18-20m. To adapt to the later high sea state conditions of large-scale deep-sea aquaculture, the net cages were set in open sea areas with good water exchange conditions. The seawater flow velocity in the primary rearing sea area was controlled below 0.80m / s, with sufficient dissolved oxygen, and far away from estuaries. Fry with an average body length of 3-3.5cm were selected for rearing in the net cages. The primary rearing of fry was carried out uniformly in these net cages at a stocking density of 250 fry / m³. 3 Fish fry are fed using a boat-mounted feeder. The entire process is monitored by an underwater fish monitoring system to precisely control the amount of feed. By monitoring the size of the fish fry, the amount of feed in each primary net cage is controlled precisely to avoid the average size difference of fish fry in different net cages exceeding 2.0cm. If the average size of fish fry in a particular cage exceeds the average size of fish fry in all net cages by more than 2.0cm, the amount of feed is restricted to appropriately slow down the growth of fish fry in that cage, so as to ensure that the size of fish fry in the same batch is uniform. After the average size of fish fry in each net cage is cultivated to 8cm, primary cultivated fish fry are obtained. B. Secondary Rearing in Mid-Water Bodies: The secondary rearing cages are set at a water depth of 25-26m. To better adapt to the high sea state conditions of large-scale fish farms in deep water, the cages are selected and set in open sea areas with good water exchange conditions and relatively fast sea currents, generally controlled within 1.00m / s. Feeding is stopped for 1 day before the fry are transferred. Then, the primary rearing cages are moved to the vicinity of the secondary rearing cages. The fry are transferred on a sunny morning. If the distance from the primary cage to the secondary cage exceeds 5km, the primary cages are first fixed to the vicinity of the secondary cages, and the fry need to be placed for more than 12 hours before the transfer. The netting of the primary cage is gathered to the side close to the secondary cage, and a large landing net is used directly with a ship-mounted crane to transfer the fry into the secondary cage. After the fry are transferred to the secondary cage, feeding is stopped for 1 day before feeding begins to enter the secondary rearing stage. The primary rearing fry are then transferred to a depth of 7500m. 3 Secondary rearing is carried out in aquatic cages, with the stocking density controlled at 100 fish / m². 3 Fish fry are fed using a boat-mounted feeder. The feeding amount is precisely controlled by an underwater fish monitoring system. By monitoring the size of the fish fry, the amount of feed in each secondary net cage is controlled precisely to avoid the average size difference of fish fry in different net cages exceeding 2.0cm. After the fish fry are raised to an average size of 13cm, they are transferred to a large fish farm for further rearing. Multiple secondary rearing net cages supply fish fry to one large fish farm. C. Transfer of secondary-stage rearing fry to ultra-large water bodies for further rearing: The secondary-stage rearing net cages are designed to be mobile. Once the fry reach an average body length of 13cm, they are transferred to ultra-large fish farms for further rearing. These large fish farms are set at a water depth of 36-38m and a rearing volume of 60,000m³. 3 Choose a sunny day and drag the secondary net cage to the vicinity of the large fish farm for simple fixation or directly fix the movable secondary net cage on the large fish farm. After the fish fry have been placed for more than 12 hours, choose a sunny morning to transfer the fish fry. The fish fry transfer operation is carried out by using a ship-mounted crane to operate a large landing net for transfer or by using a fish suction pump. After the fish fry are transferred to the large fish farm, stop feeding for 1 day and then start the fish farm growth. The entire process of fish fry rearing utilizes an underwater fish swarm monitoring system to precisely control the feeding amount. This is based on dynamic fish swarm monitoring technology. By limiting the amount of feed, the feeding of fish fry is adjusted. When the average size of the fish fry exceeds the limit by 10% but does not exceed 20%, the daily feeding amount is reduced by 50% until the size of the fish fry is controlled within an error of no more than 10%, at which point normal feeding is resumed. When the size of the fish fry exceeds the limit by more than 20%, they are starved for 1-2 days, and then fed at 50% of the normal feeding amount until the size of the fish fry is controlled within an error of no more than 10%, at which point normal feeding is resumed. Through dynamic monitoring and limited feeding, the average size of fish fry in different net cages is kept consistent, achieving fish fry screening-free operation, avoiding tedious manual fish screening operations, and reducing fish fry damage.

2. The method for simultaneous seedling supply without screening in large-scale aquaculture farms according to claim 1, characterized in that, It also includes a comprehensive chemical and ecological netting antifouling method. One method is to treat the netting with a harmless antifouling treatment, spraying it with an environmentally friendly antifouling coating and letting it dry before use to reduce the attachment of marine fouling organisms. The other method is to raise bluefish of the same body length at a ratio of 0.5% of the number of farmed fish to feed on the algae caught in the netting. By using a comprehensive chemical and ecological netting antifouling method, the netting does not need to be replaced or cleaned during the seedling cultivation period.