Land-sea relay breeding method for Pseudosciaena crocea of sal families

Abstract

The invention relates to the technical field of aquaculture, in particular to a land-sea relay breeding method for Pseudosciaena crocea of the sal family. Through the land-sea relay breeding mode of land-based factory fry breeding, land-sea transition domestication and deepwater net cage breeding, the defects of a single environment breeding mode can be effectively overcome, and the growth efficiency, the health level and the product quality of the Pseudosciaena crocea in all stages are improved; and the overall economic benefit and market competitiveness of the industry can be greatly improved, and the method has remarkable popularization and application value and wide development prospects.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, and in particular to a land-sea relay farming method for large yellow croaker from the Naozhou group. Background Technology

[0002] Naozhou large yellow croaker ( Larimichthys crocea Large yellow croaker (Croton tigrinosa) is an important fishery resource in western Guangdong, possessing excellent biological characteristics such as high temperature resistance, rapid growth, and adaptability to deep-sea and high-sea-state aquaculture. In recent years, with the increasing demand for optimization of marine fishery structure and development of deep-sea ecological fisheries, the development and utilization prospects of large yellow croaker in deep-sea aquaculture are broad. However, the current aquaculture technology for large yellow croaker generally adopts traditional single models, namely land-based factory farming or offshore cage farming, each with significant shortcomings that restrict the further development of the industry. On the one hand, although the land-based factory farming model has certain advantages in environmental control, such as relatively stable water quality and disease prevention, the limited space, high infrastructure investment, and restricted farming density make it difficult to significantly improve yield per unit area and economic benefits. In addition, with the expansion of the farming scale, the difficulty of water quality control in the land-based farming model increases significantly, and the cost of water circulation and filtration purification rises sharply, further weakening its economic advantages and significantly restricting the long-term farming benefits. On the other hand, relying solely on offshore cage culture presents a series of problems in the early seedling stage and the intermediate stages. The most prominent issue is that the direct cultivation of seedlings at sea leads to low survival rates, slow growth, and poor size uniformity in the early stages. Due to the variable water quality and complex climate conditions in the marine environment, the individual large yellow croaker fry have relatively weak stress resistance. Directly releasing them into offshore cages makes them susceptible to pathogenic microorganisms, parasite infestations, and sudden environmental changes, resulting in large-scale mortality or poor growth. Furthermore, the significant size differences increase the difficulty of subsequent seedling management, directly impacting the overall economic benefits of aquaculture and the market competitiveness of the products. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a land-sea integrated aquaculture method for large yellow croaker from the Naozhou group. By optimizing the key technologies and refined management measures at each aquaculture stage, this invention fully leverages the advantages of both land-based and marine aquaculture, significantly improving the survival rate, growth rate, disease resistance, and final market quality of Naozhou large yellow croaker fry, thereby enhancing overall aquaculture efficiency and market competitiveness.

[0004] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a land-sea relay farming method for large yellow croaker from the Naozhou group, comprising the following steps: 1) Land-based factory-style seedling cultivation stage: Early seedling cultivation of *Large Yellow Croaker* (a type of grouper) is carried out using land-based factory-style aquaculture facilities. The cultivation methods include: water temperature control at 22-25℃; water salinity at 25-28 ppt; feeding with nutritionally fortified pelleted feed; ultraviolet treatment at 1.0 W / L twice a week for 45 minutes each time; when the fry reach a length of 8-10 cm, they are transferred to the land-sea transition acclimatization stage. The nutritionally fortified pelleted feed includes: fish meal 28-38 wt.%, soybean protein concentrate 8-16 wt.%, wheat flour 10-14 wt.%, fish and krill oil mixture 5-7 wt.%, lecithin 1-3 wt.%, β-glucan 0.10-0.20 wt.%, compound vitamin premix 0.6-0.9 wt.%, compound mineral premix 0.4-0.6 wt.%, probiotic powder 0.4-0.8 wt.%, and Antarctic krill meal 4.0 wt. The formula contains 3.0 wt.% chicken powder, 5.0 wt.% corn gluten powder, 8.0 wt.% maltodextrin, 1.2 wt.% calcium carbonate, 0.2 wt.% choline chloride, 0.25 wt.% lysine, 0.15 wt.% methionine, 0.2 wt.% taurine, 0.05 wt.% antioxidant, and 7.9 wt.% brewer's yeast powder; the probiotic powder includes one or more of Bacillus subtilis, Bacillus licheniformis, Lactobacillus plantarum, and Lactobacillus rhamnosus. 2) Land-Sea Transition Acclimation Stage: The salinity of the aquaculture water is gradually increased from 25-28 ppt to 28-32 ppt, with an adjustment increment of 0.5-1 ppt / day; a slow-release immunomodulator feed is provided, with a feeding cycle of 3 consecutive days every 7 days. After acclimation for 15-20 days, the fish is transferred to the deep-sea cage culture stage. The slow-release immunomodulator feed includes: 28-38 wt.% fish meal, 6.0 wt.% Antarctic krill meal, 4.0 wt.% chicken meal, 8-16 wt.% soybean protein concentrate, 6.0 wt.% corn gluten meal, 10-14 wt.% wheat flour, and 6.0 wt.% fish and krill oil mixture. Lecithin 2.0 wt.%, maltodextrin 5.0 wt.%, calcium carbonate 1.2 wt.%, choline chloride 0.2 wt.%, lysine 0.25 wt.%, methionine 0.15 wt.%, taurine 0.20 wt.%, β-glucan 0.15 wt.%, compound vitamin premix 0.70 wt.%, compound mineral premix 0.45 wt.%, probiotic powder 0.55 wt.%, antioxidant 0.05 wt.%, brewer's yeast powder 5.0 wt.%, seaweed polysaccharide 0.15 wt.%, yeast nucleotides 0.1 wt.%, and carrier material 4.85 wt.%; 3) Deep-sea cage culture stage: Cages are set up in deep-sea areas with a water flow velocity of 0.1-0.3 m / s, and the culture density is 15-20 kg / m³. 3Feed the animal with high-performance floating pellet feed 2-3 times daily. The high-performance floating pellet feed comprises: 30.0 wt.% fish meal, 6.0 wt.% Antarctic krill meal, 4.0 wt.% chicken meal, 12.0 wt.% soybean protein concentrate, 6.0 wt.% corn gluten meal, 14.0 wt.% wheat flour, 10.0 wt.% fish and krill oil mixture, 1.5 wt.% lecithin, 5.0 wt.% maltodextrin, 1.2 wt.% calcium carbonate, 0.2 wt.% choline chloride, 0.30 wt.% lysine, 0.25 wt.% methionine, 0.20 wt.% taurine, 0.10-0.15 wt.% β-glucan, 0.10-0.20 wt.% seaweed polysaccharide, 0.60-0.80 wt.% compound vitamin premix, 0.40-0.50 wt.% compound mineral premix, 0.05 wt.% antioxidant, and 5.0 wt.% brewer's yeast powder. wt.%, 1.00 wt.% of palatability enhancer and 1.65 wt.% of pregelatinized starch.

[0005] Preferably, the dissolved oxygen content in the land-based factory seedling cultivation stage and the land-sea transition acclimatization stage are 6-8 mg / L or higher, the pH value is 7.8-8.3, and the ammonia nitrogen concentration is ≤0.1 mg / L.

[0006] Preferably, the land-based factory-style seedling cultivation stage lasts for 40-60 days.

[0007] Preferably, the daily feeding amount of the fortified pelleted feed is 3%-5% of the fish's body weight, and it is fed 4-5 times a day.

[0008] Preferably, the daily feeding amount of the slow-release immunomodulator feed is gradually reduced from the land-based factory seedling cultivation stage to 2%-3% of the fish body weight, fed 4-5 times a day, and reduced by 0.1-0.3% every 3-5 days.

[0009] Preferably, the initial size of the early seedlings of the Naozhou large yellow croaker is 2-3 cm.

[0010] Preferably, the water exchange rate during the land-sea transition acclimatization stage is 1-2 times / h.

[0011] Preferably, the water temperature during the land-sea transition acclimatization stage is gradually increased to 26-30 ℃, with daily temperature variations not exceeding ±0.5 ℃.

[0012] Preferably, the perimeter of the cage is not less than 40 meters and the depth is not less than 6 meters.

[0013] Preferably, the daily feeding amount of the high-performance floating pellet feed is 3%-5% of the fish's body weight.

[0014] Beneficial effects: The aquaculture method provided by this invention comprehensively utilizes the stability and controllability of land-based factory farming with the advantages of the vast space and rapid growth rate of marine cage farming, constructing a new land-sea relay aquaculture model. Specifically, the land-sea relay aquaculture technology will give full play to the technical advantages of land and marine aquaculture, and effectively link the early seedling cultivation stage, the land-sea environment transition and acclimatization stage, and the later growth and fattening stage of the large yellow croaker by precisely dividing the farming stages, thereby achieving precise matching of the farming environment at different stages.

[0015] This invention utilizes a land-sea relay aquaculture model consisting of "land-based factory seedling cultivation - land-sea transitional domestication - deep-sea cage culture." This model not only effectively overcomes the shortcomings of single-environment aquaculture models and improves the growth efficiency, health level, and product quality of large yellow croaker at various stages, but also significantly enhances the overall economic benefits and market competitiveness of the industry. It has significant promotion and application value and broad development prospects. Detailed Implementation

[0016] This invention provides a land-sea relay farming method for large yellow croaker from the Naozhou group, comprising the following steps: 1) Land-based factory-style seedling cultivation stage: Early seedling cultivation of *Large Yellow Croaker* (a type of grouper) is carried out using land-based factory-style aquaculture facilities. The cultivation methods include: water temperature control at 22-25℃; water salinity at 25-28 ppt; feeding with nutritionally fortified pelleted feed; ultraviolet treatment at 1.0 W / L twice a week for 45 minutes each time; when the fry reach a length of 8-10 cm, they are transferred to the land-sea transition acclimatization stage. The nutritionally fortified pelleted feed includes: fish meal 28-38 wt.%, soybean protein concentrate 8-16 wt.%, wheat flour 10-14 wt.%, fish and krill oil mixture 5-7 wt.%, lecithin 1-3 wt.%, β-glucan 0.10-0.20 wt.%, compound vitamin premix 0.6-0.9 wt.%, compound mineral premix 0.4-0.6 wt.%, probiotic powder 0.4-0.8 wt.%, and Antarctic krill meal 4.0 wt. The formula contains 3.0 wt.% chicken powder, 5.0 wt.% corn gluten powder, 8.0 wt.% maltodextrin, 1.2 wt.% calcium carbonate, 0.2 wt.% choline chloride, 0.25 wt.% lysine, 0.15 wt.% methionine, 0.2 wt.% taurine, 0.05 wt.% antioxidant, and 7.9 wt.% brewer's yeast powder; the probiotic powder includes one or more of Bacillus subtilis, Bacillus licheniformis, Lactobacillus plantarum, and Lactobacillus rhamnosus. 2) Land-Sea Transition Acclimation Stage: The salinity of the aquaculture water is gradually increased from 25-28 ppt to 28-32 ppt, with an adjustment increment of 0.5-1 ppt / day; a slow-release immunomodulator feed is provided, with a feeding cycle of 3 consecutive days every 7 days. After acclimation for 15-20 days, the fish is transferred to the deep-sea cage culture stage. The slow-release immunomodulator feed includes: 28-38 wt.% fish meal, 6.0 wt.% Antarctic krill meal, 4.0 wt.% chicken meal, 8-16 wt.% soybean protein concentrate, 6.0 wt.% corn gluten meal, 10-14 wt.% wheat flour, and 6.0 wt.% fish and krill oil mixture. Lecithin 2.0 wt.%, maltodextrin 5.0 wt.%, calcium carbonate 1.2 wt.%, choline chloride 0.2 wt.%, lysine 0.25 wt.%, methionine 0.15 wt.%, taurine 0.20 wt.%, β-glucan 0.15 wt.%, compound vitamin premix 0.70 wt.%, compound mineral premix 0.45 wt.%, probiotic powder 0.55 wt.%, antioxidant 0.05 wt.%, brewer's yeast powder 5.0 wt.%, seaweed polysaccharide 0.15 wt.%, yeast nucleotides 0.1 wt.%, and carrier material 4.85 wt.%; 3) Deep-sea cage culture stage: Cages are set up in deep-sea areas with a water flow velocity of 0.1-0.3 m / s, and the culture density is 15-20 kg / m³. 3 Feed the animal with high-performance floating pellet feed 2-3 times daily. The high-performance floating pellet feed comprises: 30.0 wt.% fish meal, 6.0 wt.% Antarctic krill meal, 4.0 wt.% chicken meal, 12.0 wt.% soybean protein concentrate, 6.0 wt.% corn gluten meal, 14.0 wt.% wheat flour, 10.0 wt.% fish and krill oil mixture, 1.5 wt.% lecithin, 5.0 wt.% maltodextrin, 1.2 wt.% calcium carbonate, 0.2 wt.% choline chloride, 0.30 wt.% lysine, 0.25 wt.% methionine, 0.20 wt.% taurine, 0.10-0.15 wt.% β-glucan, 0.10-0.20 wt.% seaweed polysaccharide, 0.60-0.80 wt.% compound vitamin premix, 0.40-0.50 wt.% compound mineral premix, 0.05 wt.% antioxidant, and 5.0 wt.% brewer's yeast powder. wt.%, 1.00 wt.% of palatability enhancer and 1.65 wt.% of pregelatinized starch.

[0017] The present invention uses specific ultraviolet light treatment to reduce the total number of bacteria in the water from 3.10 log CFU / mL to 2.70 log CFU / mL, with an inhibition rate of over 70%.

[0018] The core objective of this land-sea transition acclimatization phase is to guide juvenile large yellow croaker from a controlled land-based water environment to an open marine environment, systematically improve the juveniles' adaptability to seawater salinity, temperature fluctuations, and changes in the external environment, enhance their stress resistance, and lay the foundation for subsequent marine cage culture.

[0019] In one implementation, the initial size of the early seedlings of the Naozhou grouper is 2-3 cm.

[0020] As one implementation method, the dissolved oxygen content in the land-based factory seedling cultivation stage and the land-sea transition acclimatization stage are 6-8 mg / L or higher, the pH value is 7.8-8.3, and the ammonia nitrogen concentration is ≤0.1 mg / L.

[0021] In one implementation method, the land-based factory-style seedling cultivation stage lasts for 40-60 days.

[0022] In one implementation method, the daily feeding amount of the fortified pelleted feed is 3%-5% of the fish's body weight, divided into 4-5 feedings per day. This invention provides fortified pelleted feed that meets the nutritional needs of rapidly growing fry, employing a "small, frequent meals" approach to improve feed utilization and reduce uneaten feed contamination. Feeding times are: 08:00, 11:00, 14:00, and 17:00. Reason: Fry have a rapid metabolism and are best fed rhythmically at fixed intervals of 2.5-3 hours to maintain continuous intestinal absorption and stable growth.

[0023] In one implementation method, the daily feeding amount of the slow-release immunomodulator feed is gradually reduced from the land-based factory-style seedling cultivation stage to 2%-3% of the fish's body weight, decreasing by 0.1-0.3% every 3-5 days, and fed 4-5 times daily, preferably at 07:30-08:00, 10:00, 12:30, 15:00, and 17:30, to maintain a stable feeding rhythm in juvenile fish, promote intestinal absorption, and reduce stress responses caused by changes in environmental parameters. This invention, through appropriate feeding methods, can avoid feeding stress, excessively rapid gastric emptying, and disordered feeding behavior in juvenile fish, reducing the digestive burden on juvenile fish and improving feed utilization.

[0024] During the acclimatization period, slow-release immunomodulators are added to the feed. These feeds primarily utilize microencapsulation technology to encapsulate immune-active components such as β-glucan (0.1%-0.3%), seaweed polysaccharides (0.05%-0.2%), and nucleic acid substances (0.05%-0.15%) within carrier materials (such as gelatin or sodium alginate), achieving sustained release of these components in the digestive tract, prolonging the immune stimulation time, and enhancing the fish's immunity. The feed protein content is generally controlled at 45%-50%, and the fat content at 8%-12%. Probiotics (Bacillus subtilis, lactic acid bacteria, etc., at a concentration of approximately 1×10⁻⁶) are also added.8 Up to 1×10 9 The feed contains CFU / g of feed, vitamin C (300-500 mg / kg), vitamin E (150-300 mg / kg), and trace minerals such as zinc and selenium to improve gut microbiota, provide antioxidant benefits, and support immune function. Crude fiber content is controlled at 3%-5% to promote gut health. The total amount of immunomodulators added is 0.3%-0.6% of the feed weight (with good palatability). Feeding is done in 7-day cycles, with 3 consecutive days of feeding within each cycle, and regular feed for the remaining time, significantly reducing stress responses. A gentle water circulation system simulates marine water flow, enhancing the swimming ability and muscle development of juvenile fish and improving their overall health. Juvenile fish behavior is monitored, including feeding activity, swimming frequency, and any abnormal behavior; environmental parameters are adjusted immediately upon detection of discomfort. Daily visual and microscopic health checks are performed to monitor the risk of pathogen infection, and any abnormal individuals are treated promptly.

[0025] In one implementation, the water exchange rate during the land-sea transition acclimatization stage is 1-2 times / h.

[0026] In one implementation method, the water temperature during the land-sea transition acclimatization phase is gradually increased to 26-30 ℃, with daily temperature variations not exceeding ±0.5 ℃.

[0027] After acclimatization, specialized live fish transport equipment is used to ensure stable water temperature, dissolved oxygen, salinity, and density during transportation, reducing transport stress. Feeding is stopped for 12 hours during transportation to prevent residual feed in the digestive tract from affecting water quality.

[0028] Through the above scientific and reasonable land-sea transition acclimatization process, juvenile fish can successfully adapt to the marine environment, significantly improve their resistance and survival rate, effectively reduce mortality in the early stages of marine aquaculture, and lay a solid foundation for efficient production in deep-sea cage culture.

[0029] In one implementation, the perimeter of the cage is not less than 40 meters and the depth is ≥6 meters.

[0030] In one implementation, the daily feeding amount of the high-performance floating pellet feed is 3%-5% of the fish's body weight.

[0031] This invention strictly controls the water temperature within a narrow range of 22-25 ℃ during the land-based factory-scale seedling cultivation stage, which can promote the early growth of large yellow croaker fry and inhibit stress response.

[0032] This invention effectively overcomes the problems of low fry survival rate, slow growth, and weak disease resistance in traditional single-species aquaculture by constructing a land-sea relay aquaculture system. It significantly improves the overall economic benefits and market competitiveness of large yellow croaker from Naozhou grouper, and has important technological innovation and broad application value.

[0033] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, of a land-sea relay aquaculture method for large yellow croaker provided by the present invention, should not be construed as limiting the scope of protection of the present invention.

[0034] Preparation Example The feed formulation used in this embodiment of the invention is as follows: Nutritionally fortified pelleted feed: fish meal 34.0 wt.%, soybean protein concentrate 14.0 wt.%, wheat flour / starch 12.0 wt.%, fish and krill oil mixture 6.0 wt.%, lecithin 2.0 wt.%, β-glucan 0.15 wt.%, compound vitamin premix 0.8 wt.%, compound mineral premix 0.5 wt.%, probiotic powder 0.6 wt.%, Antarctic krill meal 4.0 wt.%, chicken meal 3.0 wt.%, corn gluten meal 5.0 wt.%, maltodextrin 8.0 wt.%, calcium carbonate 1.2 wt.%, choline chloride 0.2 wt.%, lysine 0.25 wt.%, methionine 0.15 wt.%, taurine 0.2 wt.%, antioxidant (vitamin E) 0.05 wt.%, and brewer's yeast powder 7.9 wt.%.

[0035] Slow-release immunomodulator feed: Fish meal 32.0 wt.%, Antarctic krill meal 6.0 wt.%, Chicken meal 4.0 wt.%, Soy protein concentrate 12.0 wt.%, Corn gluten meal 6.0 wt.%, Wheat flour 13.0 wt.%, Fish and krill oil mixture 6.0 wt.%, Lecithin 2.0 wt.%, Maltodextrin 5.0 wt.%, Calcium carbonate 1.2 wt.%, Choline chloride 0.2 wt.%, Lysine 0.25 wt.%, Methionine 0.15 wt.%, Taurine 0.2 wt.%, β-glucan 0.15 wt.%, Compound vitamin premix 0.7 wt.%, Compound mineral premix 0.45 wt.%, Probiotic powder 0.55 wt.%, Antioxidant (Vitamin E) 0.05 wt.%, Brewer's yeast powder 5.0 wt.%, Seaweed polysaccharide 0.15 wt.%, Nucleic acid substances 0.1 wt.% and carrier material (sodium alginate) 4.85 wt.%.

[0036] High-performance floating pellet feed: Fish meal 30.0 wt.%, Antarctic krill meal 6.0 wt.%, Chicken meal 4.0 wt.%, Soy protein concentrate 12.0 wt.%, Corn gluten meal 6.0 wt.%, Wheat flour 14.0 wt.%, Fish and krill oil mixture 10.0 wt.%, Lecithin 1.5 wt.%, Maltodextrin 5.0 wt.%, Calcium carbonate 1.2 wt.%, Choline chloride 0.2 wt.%, Lysine 0.3 wt.%, Methionine 0.25 wt.%, Taurine 0.2 wt.%, β-glucan 0.15 wt.%, Algae polysaccharide 0.2 wt.%, Compound vitamin premix 0.8 wt.%, Compound mineral premix 0.5 wt.%, Antioxidant (Vitamin E) 0.05 wt.%, Brewer's yeast powder 5.0 wt.%, Appetizer 1.00 wt.%, and Pregelatinized starch 1.65 wt.%.

[0037] The fish and krill oil mixture was obtained by mixing fish oil and krill oil at a volume ratio of 7:3; the probiotic powder was purchased from Hunan Huarui Animal Pharmaceutical Co., Ltd.; the compound vitamin premix was purchased from Sichuan Hechen Agricultural Technology Co., Ltd.; the compound mineral premix was purchased from Chia Tai Premix (Tianjin) Co., Ltd.; the yeast nucleotides were purchased from Zhuhai Wenqi Biotechnology Co., Ltd.; and the attractant was purchased from Jiangsu Puxin Biotechnology Co., Ltd.

[0038] Example 1 A land-sea relay aquaculture method for large yellow croaker from the Naozhou group consists of the following steps: 1. Land-based industrialized seedling cultivation stage 1.1 Facilities and Environment A multi-pond recirculating aquaculture system is employed, with each pond having a volume of 50 cubic meters. Equipped with mechanical filtration, biological filters, and ultraviolet sterilization devices, it ensures clean and stable water quality. Online water quality monitoring instruments continuously monitor water temperature, salinity, dissolved oxygen, pH, and ammonia nitrogen concentration, automatically feeding data back to the management system for automatic parameter adjustment. Water temperature is controlled at 22-25℃, salinity at 25-28 ppt, dissolved oxygen (DO) consistently above 6 mg / L, pH maintained at 7.8-8.3, and ammonia nitrogen concentration kept below 0.1 mg / L. Real-time water quality monitoring ensures environmental stability.

[0039] 1.2 Seedling selection and breeding Healthy, vigorous larvae without external injuries or parasites were selected from the artificially bred population. Initial size was controlled at 2-3 cm to ensure uniformity and regular body shape, laying the foundation for rapid growth. The initial stocking density was controlled at 500 larvae per cubic meter to ensure ample swimming space and prevent high-density stress.

[0040] 1.3 Feed and Nutrition Management Use formulated fortified pelleted feed with a pellet size of 1.0-1.2 mm. Feed four times a day (08:00, 11:00, 14:00, 17:00), with a daily feed amount of 4% of the fish's body weight. Feed in a dispersed manner to avoid feed accumulation.

[0041] 1.4 Water disinfection and disease control Ultraviolet (UV) disinfection is performed twice a week at an intensity of 1 W / L of aquaculture water for 45 minutes each time, combined with mechanical filtration to reduce pathogenic microorganisms in the water and lower the risk of disease outbreaks in the early stages of seedling development. To maintain the microecological balance of the aquaculture water, probiotic preparations are administered regularly every 5-7 days, with a single administration aimed at achieving a final probiotic concentration of 1×10⁻⁶ in the aquaculture water. 6 -1×10 7 CFU / mL. Observe the health status of the fish fry daily during the rearing period, and isolate and treat any abnormal individuals promptly.

[0042] 1.5 Cultivation cycle and results The rearing period is 40-60 days, during which the size of the fry increases from 2-3 cm to 8-10 cm, with a survival rate of over 92%. The fry have smooth bodies, intact mucus layers, stable intestinal flora, and excellent overall health.

[0043] 2. Land-Sea Transition and Domestication Stage 2.1 Facility Conditions The acclimatization tank has a volume of 50-100 cubic meters and adopts a closed-loop circulating water system to ensure a water exchange rate of 1-2 times per hour, maintaining stable water quality. It is equipped with aerators and temperature control equipment to ensure precise control of environmental parameters. The acclimatization tank is designed to simulate the natural flow of seawater, with a flow velocity maintained at 0.05-0.1 m / s, to promote the fish's adaptation to the dynamic seawater environment.

[0044] 2.2 Environmental Parameter Adjustment Water temperature should be slowly increased by 0.2-0.3℃ daily, reaching 26-30℃, to avoid sudden stress. Salinity should be gradually increased from 25 ppt to 30-32 ppt, adjusted in stages, increasing by 0.5-1 ppt daily. Dissolved oxygen should be maintained at ≥6.5 mg / L, pH at 7.8-8.3, and ammonia nitrogen at ≤0.1 mg / L.

[0045] 2.3 Feed Conversion The feed was transitioned from fortified pelleted feed to a slow-release immunomodulator feed suitable for the marine environment, with a crude protein content of 45%-48% and a pellet diameter adjusted to 1.2-1.5 mm. The slow-release immunomodulator feed was fed periodically, for 3 consecutive days every 7 days. The daily feed amount was controlled at 2%-3% of the fish's body weight, divided into 5 feedings (07:30-08:00, 10:00, 12:30, 15:00, and 17:30), ensuring feed freshness. The feed amount was gradually reduced from 4% (wt%) during the land-based stage to 2wt.%-3wt.% during the transitional acclimatization stage. The reduction was made by decreasing by 0.1-0.3 percentage points (as a percentage of the fish's body weight) every 3-5 days, equivalent to a single reduction of 5%-10% of the current feed amount. This slow and gradual reduction prevented feeding stress, excessively rapid gastric emptying, and disordered feeding behavior in juvenile fish.

[0046] 2.4 Stress Management and Health Monitoring Regularly monitor the feeding status and swimming activity of the juvenile fish, and adjust the environment promptly if stress reactions occur. Conduct daily health checks, using microscopic examination and PCR technology to monitor major pathogenic microorganisms. Use water flow simulation equipment to enhance the physical fitness of the juvenile fish and promote muscle development.

[0047] 2.5 Domestication Results The acclimatization period is controlled within 15-20 days, until the fish reach a size of 12-15 cm and a weight of 20-25 g. The survival rate is maintained at over 90%, and the juvenile fish are in good health and fully prepared to adapt to the open sea environment.

[0048] 3. Deep-water cage aquaculture stage 3.1 Cage Facilities The net cages are made of high-density polyethylene (HDPE) and equipped with high-quality mesh that is corrosion-resistant and fouling-resistant. The mesh size is adjusted according to the size of the fish to ensure sufficient space for their movement while preventing escape and invasion by external predators. The nets have a circumference of ≥40 m and a depth of 6-8 m, meeting the space requirements for schooling and natural behavior of the large yellow croaker, helping to reduce density stress and improve aquaculture efficiency. The net cages are set up in waters 8-10 m deep, avoiding polluted areas and areas affected by strong winds and waves. The water flow velocity is maintained at 0.1-0.3 m / s to effectively promote water exchange, prevent waste accumulation, and maintain water quality stability. The stocking density is 15-20 kg / m³. 3 .

[0049] 3.2 Precision feeding High-performance floating pellet feed is used, with a crude protein content ≥46% and a crude fat content ≥12%, supplemented with β-glucan, seaweed polysaccharides, and vitamins C and E. Feed 2-3 times daily, evenly distributed across breakfast, lunch, and dinner, with the daily feed amount controlled at 3%-5% of the fish's body weight. Combined with intelligent feeding equipment and underwater camera monitoring, the feed amount is dynamically adjusted based on feeding behavior.

[0050] 3.3 Intelligent Water Quality Monitoring An automatic water quality monitoring system was established to monitor water temperature, salinity, and dissolved oxygen in real time. The data was fed back to the intelligent aquaculture management platform in real time, enabling precise regulation and risk warning.

[0051] 3.4 Health Management Regularly examine the fish to monitor their coloration and behavior, and deal with any abnormalities promptly.

[0052] Apply preventative immunization to promote the periodic addition of feed to reduce the incidence of disease.

[0053] 3.5 Breeding cycle and results The breeding cycle is 7-8 months, with fish reaching a body weight of 400-500 g and a survival rate of no less than 85%. The feed conversion ratio (FCR) is 1.25-1.35. Compared with the traditional marine cage culture method, the incidence of disease is reduced by about 55%. The fish are of uniform size and have good meat quality, which can meet market demand and significantly improve the economic benefits of aquaculture.

[0054] Comparative Example 1: Traditional Land-based Full-Process Aquaculture Model The entire process of culture for large yellow croaker (Cyprinus naan) was carried out using a traditional land-based factory farming system. The stocking density was controlled at 500 fish per cubic meter, the water temperature was maintained at a constant 24 ℃, and the salinity was kept at around 27 ppt. This system generally adopts a single-pond or a few-pond interconnected recirculating water design, and the mechanical and biological filtration equipment is relatively basic, resulting in relatively low water quality stability.

[0055] Feed and nutrition management: The fish were fed commercially available high-protein pelleted feed (purchased from Guangdong Hengxing Feed Industry Co., Ltd.), with a crude protein content of approximately 45% and a crude fat content of 8%-10%. No immunomodulators or probiotic functional additives were added. The pellet diameter was generally 1.0-1.2 mm, suitable for juvenile fish. Feeding was done three times daily, with the total daily feed amount controlled at 4% of the fish's body weight. The feeding method was relatively traditional, without the use of intelligent feeding equipment, resulting in feed waste.

[0056] Water quality management: The circulating water treatment mainly relies on mechanical filtration, with low utilization rates of ultraviolet or ozone sterilization equipment. This results in higher levels of pathogenic microorganisms in the water and significant fluctuations in ammonia nitrogen and nitrite levels. The water quality index ranges are as follows: Dissolved oxygen: 5.5-6.5 mg / L, pH: 7.5-8.2, ammonia nitrogen concentration: 0.15-0.25 mg / L, nitrite concentration: 0.03-0.05 mg / L.

[0057] Breeding cycle and growth performance: Traditional land-based aquaculture typically has a long cycle, approximately 7 months, during which the fish reach an average size of 300g. However, the growth rate and survival rate are lower than in Example 1. The survival rate remains around 80%, and due to the high stocking density and fluctuating water quality, fish fry frequently experience stress.

[0058] Disease occurrence and control measures: Due to the lack of effective immune-boosting measures, diseases occur frequently, with common bacterial diseases and parasitic infections leading to losses in aquaculture. Frequent use of antibiotics and chemical control agents during the aquaculture process increases costs and also brings potential risks of drug resistance and environmental pollution.

[0059] Economic benefit analysis: Feed utilization rate is low (FCR is 1.6-1.8), and some feed is wasted, resulting in resource loss. Frequent disease control increases management difficulty and cost, and the overall aquaculture efficiency is relatively limited, making it difficult to meet the demands of modern intensive aquaculture for high-efficiency, high-quality fish production.

[0060] Comparative Example 2: Traditional Offshore Cage Aquaculture Model In this model, artificially bred seedlings (approximately 3 cm in size) are directly released into marine net cages, with a cultivation cycle of 7 months. The net cages are 35 meters in circumference and 6 meters in depth, and are placed in suitable sea areas with a water depth of approximately 10 meters and a stable water flow velocity of around 0.2 m / s.

[0061] Net cage facilities and environmental conditions: The net cage structure is made of conventional polyethylene, which has moderate corrosion resistance and antifouling ability. The mesh size is approximately 30-40 mm; in some stages, the mesh is too large, resulting in a high escape rate for juvenile fish. The water flow velocity is maintained at 0.15-0.25 m / s, and the water quality fluctuates significantly, especially during the rainy season and stormy weather when the water quality deteriorates noticeably.

[0062] The environment has a wide range of water temperatures, with summer temperatures reaching 28-30 ℃ and winter temperatures dropping below 15 ℃, leading to frequent stress among fish.

[0063] Feed management: Commercially available standard compound feed (purchased from Guangdong Hengxing Feed Industry Co., Ltd.) was used, with a crude protein content of approximately 42%-44% and a crude fat content of 8%-10%, and it did not contain immunomodulatory components. The feed pellet size was not suitable for the fish fry's body size, resulting in low feed utilization.

[0064] The feeding frequency was 3 times a day, and the total amount of feed was 5% of the fish's body weight. Due to overfeeding and insufficient monitoring, there was a significant waste of feed (FCR was 1.5-1.7).

[0065] Growth performance and survival rate: After 7 months of rearing, the average size of the fish reached 350 g. The fish were uneven in size and the size distribution was wide, which made grading difficult in the later stages and affected the commercial value. The survival rate was about 75%, mainly due to the poor adaptability of the fry stage and the high mortality rate caused by frequent diseases.

[0066] Disease and Aquaculture Risks: When fry are directly released into net cages, they face the stresses of a complex and ever-changing marine environment, making them susceptible to bacterial and parasitic diseases. The lack of effective immune-boosting and early disease prevention measures leads to frequent disease outbreaks, increasing aquaculture risks. Disease control primarily relies on drug treatment, which carries the risk of drug resistance and drug residues.

[0067] Economic benefit evaluation: Due to high incidence of diseases, low survival rate, and inconsistent size, the overall economic benefits are below ideal. Wasted feed and excessive drug use increase breeding costs and weaken market competitiveness.

[0068] Comparative Example 3 A method similar to Example 1, except that the condition parameters for the land-based factory-scale seedling cultivation stage are different: (1) Experiment on the effects of water temperatures of 22 ℃, 24 ℃ and 25 ℃ on seedling growth and survival rate After the cultivation period under the same feed and density conditions, the weight gain (WG), specific growth rate (SGR), and survival rate of seedlings in different water temperature groups were compared. The results are shown in Table 1.

[0069] The results showed that growth was slower at a water temperature of 22 ℃, with a survival rate of around 85%, while growth was significantly faster at a water temperature of 24-25 ℃. P With a concentration of <0.05, the survival rate increased to 92-94%.

[0070] Table 1. Effects of different water temperatures on growth and survival of land-based seedlings.

[0071] (2) Effect test of different addition amounts of immune additive (β-glucan) Four groups were set up with 0%, 0.1%, 0.15%, and 0.2% concentrations. After the culture period, the differences in lysozyme, IgM, and survival rate were measured. The results are shown in Table 2.

[0072] The results showed that the 0.15% group had the best performance in all indicators, significantly higher than the control group. P <0.05%; a slight decrease in food intake was observed in the 0.2% group, indicating that excessive addition reduced palatability. This invention ultimately uses an immune enhancer dosage in the range of 0.1-0.2%.

[0073] Table 2 Effects of β-glucan addition on immunity and survival

[0074] (3) Test on UV intensity and treatment frequency of circulating water The ultraviolet disinfection intensity was set to 0.5 W / L, 1.0 W / L, and 1.5 W / L. After the culture period, the total bacterial count, ammonia nitrogen content, and fry survival rate were measured. The results are shown in Table 3.

[0075] The results showed that the 1.0 W / L group had the best reduction in total bacterial count (72%), and the fish fry showed no stress response.

[0076] Table 3. Effects of UV intensity in circulating water on aquatic microorganisms and their survival.

[0077] Comparative Example 4 A method similar to Example 1, except that the condition parameters for the land-sea transition acclimatization stage are different: (1) Set different salinity gradients: 0.5, 1.0, 1.5 ppt / day. After the culture period, cortisol, feeding index and survival rate were measured. The results are shown in Table 4.

[0078] The results showed that when the salinity increase was ≥1.5 ppt / day, the respiratory rate of the juvenile fish increased, indicating significant stress. The group with a salinity increase of 0.5-1.0 ppt / day experienced the lowest stress and had a survival rate of ≥92%.

[0079] Table 4. Effects of increasing salinity gradient on stress and survival.

[0080] (2) Set different acclimatization periods: 10 days, 15 days, and 20 days. After the cultivation cycle is completed, the survival rate of the net cages and the average daily weight gain are measured after 30 days. The results are shown in Table 5.

[0081] The results showed that the 10-day group did not fully adapt to the seawater salinity and had a higher mortality rate in the later stages of the cages; the 15-20 day group had the most stable physiological indicators and a subsequent survival rate of ≥90%.

[0082] Table 5. The impact of acclimatization period length on the early performance of subsequent net cages.

[0083] (3) Set the feeding cycle of slow-release immunomodulatory feed: no slow-release immunomodulatory feed, 3 days / week and 5 days / week. After the culture cycle is completed, the lysozyme content, IgM concentration and liver-to-body ratio are measured. The results are shown in Table 6.

[0084] The results showed that although the 5-day group had higher immune indicators, it also showed a slight increase in liver index. The 3-day / week group achieved the optimal balance between immune enhancement and health burden. This invention adopts an immune enhancement model of "feeding for 3 days in a 7-day cycle".

[0085] Table 6. Effects of the feeding cycle of slow-release immune feed on immunity and health.

[0086] Comparative Example 5 A method similar to Example 1, except that the condition parameters for the deep-water cage culture stage are different: (1) Set different net cage water flow rates: 0.05-0.1 m / s, 0.1-0.3 m / s, >0.3 m / s. After the cultivation period, the weight gain percentage (WG) and feed conversion ratio (FCR) were measured. The results are shown in Table 7.

[0087] The results showed that a water flow rate of <0.1 m / s in the net cages resulted in insufficient water exchange and accumulation of ammonia nitrogen; a water flow rate of >0.3 m / s in the net cages resulted in high energy consumption and decreased weight gain; the 0.1-0.3 m / s group had the fastest growth and the best body color (P<0.05).

[0088] Table 7. Effects of water flow velocity in the net cage on growth and feed conversion ratio

[0089] (2) Set different stocking densities: 15, 20, 25 kg / m 3 After the culture period ended, the weight gain percentage (WG), feed conversion ratio (FCR) and survival rate were measured, and the results are shown in Table 8.

[0090] The results showed that 25 kg / m 3 Later growth of the group was inhibited, 20 kg / m 3 The optimal density for WG, FCR, and survival rate was determined to be 15-20 kg / m³. 3 .

[0091] Table 8 Effects of stocking density on growth, feed conversion ratio, and survival rate

[0092] (3) Set different feeding frequencies: 2 times / day and 3 times / day. After the culture period, the specific growth rate (SGR) and feed conversion ratio (FCR) were measured. The results are shown in Table 9.

[0093] The results showed that the FCR of the 3-times / day group was better and the growth rate was significantly improved; the present invention adopts a precise feeding scheme of 2-3 times / day.

[0094] Table 9. Effects of feeding frequency on growth and feed conversion ratio

[0095] In summary, by optimizing the key technologies and refined management measures at each stage of aquaculture, this invention fully leverages the advantages of both land-based and marine aquaculture, significantly improving the survival rate, growth rate, disease resistance, and final market quality of large yellow croaker fry, thereby enhancing overall aquaculture efficiency and market competitiveness.

[0096] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for the land-sea relay aquaculture of large yellow croaker from Naozhou grouper, characterized in that, Includes the following steps: 1) Land-based factory-style seedling cultivation stage: Early seedling cultivation of *Large Yellow Croaker* (a type of grouper) is carried out using land-based factory-style aquaculture facilities. The cultivation methods include: water temperature control at 22-25℃; water salinity at 25-28 ppt; feeding with nutritionally fortified pelleted feed; ultraviolet treatment at 1.0 W / L twice a week for 45 minutes each time; when the fry reach a length of 8-10 cm, they are transferred to the land-sea transition acclimatization stage. The nutritionally fortified pelleted feed includes: fish meal 28-38 wt.%, soybean protein concentrate 8-16 wt.%, wheat flour 10-14 wt.%, fish and krill oil mixture 5-7 wt.%, lecithin 1-3 wt.%, β-glucan 0.10-0.20 wt.%, compound vitamin premix 0.6-0.9 wt.%, compound mineral premix 0.4-0.6 wt.%, probiotic powder 0.4-0.8 wt.%, and Antarctic krill meal 4.0 wt. The formula contains 3.0 wt.% chicken powder, 5.0 wt.% corn gluten powder, 8.0 wt.% maltodextrin, 1.2 wt.% calcium carbonate, 0.2 wt.% choline chloride, 0.25 wt.% lysine, 0.15 wt.% methionine, 0.2 wt.% taurine, 0.05 wt.% antioxidant, and 7.9 wt.% brewer's yeast powder; the probiotic powder includes one or more of Bacillus subtilis, Bacillus licheniformis, Lactobacillus plantarum, and Lactobacillus rhamnosus. 2) Land-Sea Transition Acclimation Stage: The salinity of the aquaculture water is gradually increased from 25-28 ppt to 28-32 ppt, with an adjustment increment of 0.5-1 ppt / day; a slow-release immunomodulator feed is provided, with a feeding cycle of 3 consecutive days every 7 days. After acclimation for 15-20 days, the fish is transferred to the deep-sea cage culture stage. The slow-release immunomodulator feed includes: 28-38 wt.% fish meal, 6.0 wt.% Antarctic krill meal, 4.0 wt.% chicken meal, 8-16 wt.% soybean protein concentrate, 6.0 wt.% corn gluten meal, 10-14 wt.% wheat flour, and 6.0 wt.% fish and krill oil mixture. Lecithin 2.0 wt.%, maltodextrin 5.0 wt.%, calcium carbonate 1.2 wt.%, choline chloride 0.2 wt.%, lysine 0.25 wt.%, methionine 0.15 wt.%, taurine 0.20 wt.%, β-glucan 0.15 wt.%, compound vitamin premix 0.70 wt.%, compound mineral premix 0.45 wt.%, probiotic powder 0.55 wt.%, antioxidant 0.05 wt.%, brewer's yeast powder 5.0 wt.%, seaweed polysaccharide 0.15 wt.%, yeast nucleotides 0.1 wt.%, and carrier material 4.85 wt.%; 3) Deep-sea cage culture stage: Cages are set up in deep-sea areas with a water flow velocity of 0.1-0.3 m / s, and the culture density is 15-20 kg / m³. 3 Feed the animal with high-performance floating pellet feed 2-3 times daily. The high-performance floating pellet feed comprises: 30.0 wt.% fish meal, 6.0 wt.% Antarctic krill meal, 4.0 wt.% chicken meal, 12.0 wt.% soybean protein concentrate, 6.0 wt.% corn gluten meal, 14.0 wt.% wheat flour, 10.0 wt.% fish and krill oil mixture, 1.5 wt.% lecithin, 5.0 wt.% maltodextrin, 1.2 wt.% calcium carbonate, 0.2 wt.% choline chloride, 0.30 wt.% lysine, 0.25 wt.% methionine, 0.20 wt.% taurine, 0.10-0.15 wt.% β-glucan, 0.10-0.20 wt.% seaweed polysaccharide, 0.60-0.80 wt.% compound vitamin premix, 0.40-0.50 wt.% compound mineral premix, 0.05 wt.% antioxidant, and 5.0 wt.% brewer's yeast powder. wt.%, 1.00 wt.% of palatability enhancer and 1.65 wt.% of pregelatinized starch.

2. The aquaculture method according to claim 1, characterized in that, During the land-based factory-style seedling cultivation stage and the land-sea transition acclimatization stage, the dissolved oxygen content was above 6-8 mg / L, the pH value was 7.8-8.3, and the ammonia nitrogen concentration was ≤0.1 mg / L.

3. The aquaculture method according to claim 1, characterized in that, The land-based factory-style seedling cultivation stage lasts for 40-60 days.

4. The aquaculture method according to claim 1, characterized in that, The amount of the fortified pelleted feed is 3%-5% of the fish's body weight per day, and it is fed 4-5 times a day.

5. The aquaculture method according to claim 1, characterized in that, The daily feeding amount of the slow-release immunomodulator feed was gradually reduced from the land-based factory seedling cultivation stage to 2%-3% of the fish body weight, and fed 4-5 times a day, with a reduction of 0.1-0.3% every 3-5 days.

6. The aquaculture method according to claim 1, characterized in that, The initial size of the early seedlings of the Naozhou large yellow croaker is 2-3 cm.

7. The aquaculture method according to claim 1, characterized in that, The water exchange rate during the land-sea transition and acclimatization phase is 1-2 times / h.

8. The aquaculture method according to claim 1, characterized in that, During the land-sea transition and acclimatization phase, the water temperature is gradually increased to 26-30 ℃, with daily temperature variations not exceeding ±0.5 ℃.

9. The aquaculture method according to claim 1, characterized in that, The perimeter of the cage shall not be less than 40 meters and the depth of the cage shall be ≥6 meters.

10. The aquaculture method according to claim 1, characterized in that, The daily feeding amount of the high-performance floating pellet feed is 3%-5% of the fish's body weight.

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