Deepwater net cage culture method for decapterus maruadsi

Abstract

The invention provides a decapterus maruadsi deepwater net cage culture method, and belongs to the technical field of decapterus maruadsi culture. According to the method, the submersible net cage is adopted, the decapterus maruadsi is located in the optimal growth water layer at the temperature of 20-25 DEG C all the year round according to rising and falling of seasons (surface water temperature), a guide pipe is adopted for fixed-point feed feeding, and the feed coefficient is reduced to 1.25 or below. According to the method, a water temperature-feeding amount-allicin-probiotics coupling model is established, the enteritis incidence rate in the high-temperature period is controlled within 2%, and annual continuous growth of decapterus maruadsi in deep and far sea is achieved.

Description

Technical Field

[0001] This invention relates to the field of yellowtail aquaculture technology, and more particularly to a deep-water cage culture method for yellowtail aquaculture. Background Technology

[0002] The yellowtail trevally belongs to the order Perciformes, family Carangidae, and is also known as the island trevally, striped trevally, or large mackerel. Due to its large size, rich fat content, and firm, tender, delicate, and sweet flesh, it is considered the king of trevally. The yellowtail trevally is a high-value marine fish, but current aquaculture methods have limitations: traditional net cages are fixed to the surface and cannot adapt to seasonal water temperature changes, leading to stunted growth and lack of feeding in winter when temperatures are low, and susceptibility to disease in summer when temperatures are high. Feeding efficiency is low: deep-sea winds, waves, and currents cause feed to spread, resulting in significant waste and a high feed conversion ratio. Enteritis is a problem: when water temperatures rise, the fish's digestive system is vulnerable, and current technology lacks effective preventative measures. Summary of the Invention

[0003] In view of this, the present invention provides a method for deep-sea cage culture of *Pseudocarpus scutellarioides*, comprising the following steps:

[0004] (1) Set up submersible net cages in sea areas with a water depth of more than 30m and stock the net cages with yellow-banded trevally;

[0005] (2) Adjust the depth of the submersible cage according to the water temperature;

[0006] (3) Feed the yellow-banded trevally with feed or feed mixture according to the water temperature; the feed mixture consists of yellow-banded trevally feed, allicin and lactic acid bacteria.

[0007] Preferably, the submersible cage in step (1) is a cylindrical cage or a cubic cage; the volume of the cage is 500-1000 m³. 3 .

[0008] Preferably, the mesh size of the submersible cage in step (1) is 1-5cm.

[0009] Preferably, the breeding density of the yellow-banded trevally in step (1) is 12-15 kg / m³.

[0010] Preferably, the depth of the submersible cage in step (2) is adjusted as follows:

[0011] When the surface water temperature drops from high temperature to ≤22℃, the net cage is lowered to a water depth of 30m at a rate of 1m per day.

[0012] When the surface water temperature rises from low temperature to ≥20℃, the net cage is raised to a water depth of 15m at a rate of 2m per day.

[0013] When the surface water temperature rises from low to ≥28℃, the net cage is lowered to a water depth of 30 m at a rate of 1 m per day.

[0014] Preferably, the feeding amount of the yellow-banded trevally feed or feed mixture in step (3) is dynamically adjusted according to the water temperature:

[0015] When the water temperature is 26-29℃, feed the fish with a feed mixture, the amount of which is 1-2% of the fish's body weight.

[0016] When the water temperature is 20-26℃, feed the yellow-banded trevally with feed at an amount of 2.5-3% of the fish's body weight.

[0017] When the water temperature is 16-20℃, feed the yellow-banded trevally with feed, and the amount of yellow-banded trevally feed should be 1-1.6% of the fish's body weight;

[0018] When the water temperature is 12-16℃, feed the yellow-banded trevally with feed, and the amount of yellow-banded trevally feed should be 0.2-0.5% of the fish's body weight.

[0019] Preferably, in step (3), the feeding is carried out by fixed-point feeding through a guide tube, and the slow sinking speed of the feed in the net cage is controlled to be 40-50 cm / s, and the time the feed stays in the net cage is 20-30 s.

[0020] Preferably, the yellow-banded trevally feed comprises the following raw materials by weight percentage:

[0021] Red fish meal 40-50%, krill meal 5-8%, soy protein concentrate 7-10%, high-gluten flour 10-16%, brewer's yeast 2-3%, fish oil 5-8%, phospholipids 1-2%, calcium dihydrogen phosphate 1-1.5%, vitamin premix 1-1.5%, mineral premix 1-1.5%, choline chloride 0.5-1%.

[0022] Preferably, the method for preparing the yellow-banded trevally feed includes the following steps:

[0023] (1) Raw material pretreatment: Red fish meal, krill meal, concentrated soybean protein, high gluten flour and mineral premix are micro-pulverized by an ultra-micro pulverizer so that more than 98% of the raw materials pass through an 80-mesh sieve.

[0024] (2) Ingredients and mixing

[0025] Weigh out the red fish meal, krill meal, concentrated soy protein, high-gluten flour, and mineral premix in precise proportions, dry mix them, and then add brewer's yeast and calcium dihydrogen phosphate for further mixing.

[0026] (3) Conditioning and extrusion granulation

[0027] The uniformly mixed powder is fed into a conditioner and conditioned for 45-60 seconds with dry saturated steam at 90±2℃ and a pressure of 0.35-0.45 MPa. This process matures and softens the material, increases the moisture content to 21-25%, promotes starch gelatinization, and achieves a gelatinization degree >90%.

[0028] After conditioning, the material enters the screw extruder, where the temperature is set at 80-90℃ in Zone I (feeding zone), 128±2℃ in Zone II (melting zone), and 140-150℃ in Zone III (pressure equalization zone). Under the action of high shear force of 25-35 atm and 400-500 rpm, the material is transformed into a molten state and extruded through the die to atmospheric pressure, forming porous, loosely structured extruded granules with an expansion degree of 1.6-1.8.

[0029] (4) Post-ripening and drying

[0030] The puffed granules enter the post-curing unit and are kept at 80-85℃ for 8-10 minutes to further promote starch gelatinization and improve the stability of the granule structure. Then, a multi-layer conveyor dryer is used with hot air temperature of 90-100℃ for 20-25 minutes to reduce the moisture content from ~25% to 9±0.5%.

[0031] (5) Liquid spraying

[0032] Vitamin premix, fish oil, soybean lecithin, and choline chloride were stirred in a spray can until emulsified and mixed, and then sprayed under vacuum conditions of -0.03 to -0.05 MPa to obtain 5.0 mm particle size yellow-banded trevally extruded feed.

[0033] Preferably, the feed mixture contains 0.05-0.1% allicin and 0.2-0.3% probiotics and lactic acid bacteria.

[0034] Low surface water temperatures in winter negatively impact the growth of the Yellow-banded Trevally. This invention employs a submersible net cage design. When the seawater temperature drops to 22°C in autumn, the net cage can be lowered by 1 meter per day to a depth of 30 meters. At a depth of 30 meters, the surface and bottom water temperatures differ significantly, greatly influenced by seasonal changes and climate conditions. In winter, the bottom water temperature is relatively stable, while the surface water temperature is significantly affected by atmospheric temperature and fluctuates drastically. Surface water temperature fluctuates greatly in winter, while the temperature variation at a depth of 30 meters is smaller than at the surface. Similarly, when the surface water temperature rises to 20°C in spring, the net cage is raised by 2 meters per day to a depth of 15 meters. When the water temperature rises to 28°C in summer, the net cage height is lowered by 1 meter per day to a depth of 30 meters. This invention uses a submersible net cage, adjusting its height according to the season (surface water temperature), ensuring that the Yellow-banded Trevally is in its optimal growth water layer of 20-25°C year-round.

[0035] Due to the large space and the influence of ocean currents, tides, and waves, feeding can be affected. Using a feeding tube for targeted feeding can improve feeding efficiency and reduce waste. When feeding, a slow-sinking feed should be used, with a sinking speed of 40-50 cm / s. With a net cage height of 10-15 meters, the formulated feed will remain in the net cage for 20-30 seconds, giving the fry sufficient time to swim over and feed, thus improving feeding efficiency.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] This invention provides a deep-sea cage culture method for *Pteranodon fulvidraco*. The method utilizes submersible cages, adjusting the temperature according to seasonal changes (surface water temperature) to maintain the *Pteranodon fulvidraco* at its optimal growth level of 20-25℃ year-round. Targeted feeding via a guide tube reduces the feed conversion ratio to below 1.25. This invention establishes a coupled model of "water temperature-feeding amount-allicin-probiotics," controlling the incidence of enteritis during high-temperature periods to below 2%, achieving continuous year-round growth of *Pteranodon fulvidraco* in deep-sea environments. The cage culture survival rate is ≥95%, with a marketable fish size of 1.5 kg / fish, and the culture cycle is shortened by 15%. Attached Figure Description

[0038] Figure 1 Morphological images of healthy gut tissue in group A;

[0039] Figure 2 Morphological images of the gut health of group B. Detailed Implementation

[0040] This invention provides a method for deep-sea cage culture of *Pseudocarpus scutellarioides*, the steps of which are as follows:

[0041] (1) Set up submersible net cages in sea areas with a water depth of more than 30m, and stock the net cages with yellow-banded trevally (stocking density of 12-15kg / m³).

[0042] (2) Adjust the depth of the submersible cage according to the water temperature:

[0043] When the surface water temperature drops from high temperature to ≤22℃, the net cage is lowered to a water depth of 30m at a rate of 1m per day.

[0044] When the surface water temperature rises from low temperature to ≥20℃, the net cage is raised to a water depth of 15m at a rate of 2m per day.

[0045] When the surface water temperature rises from low temperature to ≥28℃, the net cage is lowered to a water depth of 30 m at a rate of 1 m per day.

[0046] (3) Use a guide pipe for fixed-point feeding, control the slow sinking speed of the feed in the net cage to be 40-50cm / s, and the residence time of the feed in the net cage to be 20-30s; adjust the amount of feed according to the water temperature;

[0047] The amount of the feed mixture is dynamically adjusted according to the water temperature.

[0048] When the water temperature is 26-29℃, feed a mixture of feed, with the amount being 1-2% of the fish's body weight. During this stage, the yellowtail trevally has a vigorous metabolism, but excessive feeding will significantly increase the burden on the intestines. Therefore, the feeding amount should be controlled at 1-2% of the yellowtail trevally's body weight. At the same time, add allicin and lactic acid bacteria to prevent enteritis.

[0049] When the water temperature is 20-26℃, feed the yellow-banded trevally with feed at a rate of 2.5-3% of the fish's body weight. This is near the optimal growth temperature. Increasing the feed rate to 2.5-3% of the fish's body weight will achieve the best growth rate.

[0050] When the water temperature is 16-20℃, feed the yellow-banded trevally with feed at a rate of 1-1.6% of the fish's body weight. As the water temperature decreases, the fish's appetite and digestive capacity weaken, so reduce the feed amount to 1-1.6% of the fish's body weight to reduce feed waste.

[0051] When the water temperature is 12-16℃, feed the yellow-banded trevally with feed at a rate of 0.2-0.5% of the fish's body weight. At this time, the fish are very inactive and eat very little, so the amount of feed is greatly reduced to 0.2-0.5% of the fish's body weight in order to maintain basic metabolism and avoid feed waste and water pollution.

[0052] Preferably, the submersible cage in step (1) is a cylindrical cage or a cubic cage, wherein the diameter of the cylindrical cage is 11m and the height is 11m; and the side length of the cubic cage is 9.5m.

[0053] Preferably, the mesh size of the submersible net cage in step (1) is 1-5cm; in a specific embodiment of the present invention, the mesh size of the submersible net cage is adjusted according to the size of the farmed fish, and the specific mesh size selection is shown in Table 1.

[0054] Table 1

[0055] Yellow-banded trevally specifications Mesh size ≤30g 1cm 30-100g 1.5cm 100-300g 2.5cm 300-500g 3.0cm 500g-1000g 4.0cm ≥1000g 5.0cm

[0056] In a specific embodiment of the present invention, the yellow-banded trevally feed is composed of the following raw materials by weight percentage:

[0057] Red fish meal 40-50%, krill meal 5-8%, soybean protein concentrate 7-10% (Fengyuan brand, Yihai Grain & Oil Industry Co., Ltd., product standard number: Q / 321203YYL008), high gluten flour 10-16% (high gluten flour, Shandong Luwang Group Co., Ltd., production license number: SC10137082700061), brewer's yeast 2-3%, fish oil 5-8%, soybean lecithin 1-2%, calcium dihydrogen phosphate 1-1.5%, vitamin premix 1-1.5% (Hualuo No. 1 PV998, specification 1kg, China Animal Husbandry Agricultural Chain Development Co., Ltd., Beijing Hualuo Feed Additives Factory, batch number: 10012302564), mineral premix (trace element premix, specification 500g, Guangdong Yishengbao Animal Pharmaceutical Co., Ltd., production license number: Yue Si Yu (2021) 01080) 1-1.5%, choline chloride 0.5-1%. Control the crude protein content of the feed to 46-48% and the crude fat content to 12-14%.

[0058] The preparation method of the yellow-banded mackerel feed includes the following steps:

[0059] 1. Raw material pretreatment

[0060] Red fish meal, krill meal, concentrated soy protein, high-gluten flour, and mineral premix were each micronized using an ultra-fine grinder, ensuring that over 98% of the raw materials passed through an 80-mesh sieve. Micronization helps increase the specific surface area of ​​the raw materials, resulting in more uniform subsequent mixing, improved conditioning and extrusion effects, and enhanced feed stability in water.

[0061] 2. Ingredients and Mixing

[0062] Accurately weigh red fish meal, krill meal, concentrated soy protein, high-gluten flour, and mineral premix according to the specified proportions, and put them into a twin-shaft paddle mixer for dry mixing. Then add brewer's yeast and calcium dihydrogen phosphate for preliminary mixing to ensure uniform overall nutrient distribution.

[0063] 3. Conditioning and Extrusion Granulation

[0064] The uniformly mixed powder is fed into a conditioner and saturated dry steam at 90±2℃ is introduced. The conditioner is then subjected to a pressure of 0.45MPa for 60 seconds to cook and soften the material, increase the moisture content to 22±1%, promote starch gelatinization, and achieve a gelatinization degree of >90%, which is beneficial for forming a stable porous structure.

[0065] After conditioning, the material enters the screw extruder, where Zone I (feeding zone) is set at 85℃, Zone II (melting zone) at 128±2℃, and Zone III (pressure equalization zone) at 145℃. Under the action of pressure of 30 atm and high shear force (500 rpm), the material is transformed into a molten state. When it is extruded through the die to atmospheric pressure, the moisture evaporates instantly, forming porous, loosely structured extruded granules with an expansion degree of 1.6-1.8.

[0066] 4. Post-ripening and drying

[0067] The puffed granules enter the post-curing unit and are kept at 85℃ for 10 minutes to further promote starch gelatinization and improve the stability of the granule structure. Then, a multi-layer conveyor dryer is used with hot air temperature of 95℃ for 25 minutes to reduce the moisture content from ~25% to 9±0.5% to fix its internal porous structure.

[0068] 5. Liquid spraying

[0069] Vitamin premix, fish oil, soybean lecithin, and choline chloride were stirred in a spray can until emulsified and mixed, then sprayed under a vacuum of -0.05 MPa to obtain 5.0 mm diameter yellow-banded trevally extruded feed. Heat-sensitive nutrients (vitamin premix), oils (fish oil, soybean lecithin), and choline chloride were added after the pellets were dried to ensure the stable retention and uniform distribution of the active ingredients.

[0070] 6. Cooling and Packaging

[0071] After being sprayed, the feed is cooled to room temperature, then sieved to remove debris, weighed, and sealed in packaging to complete the entire preparation process.

[0072] The preparation method is related to the slow settling mechanism of feed:

[0073] (1) Density matching: The ratio of feed body density (528 g / L) to seawater density (1022 g / L) is about 0.52. This ratio range is the key to forming slow sinking rather than rapid sinking.

[0074] (2) Structural support: The stable porous structure formed by high gelatinization degree (>90%) provides physical support, delaying water penetration and particle compaction and settling.

[0075] (3) Surface hydrophobicity: The uniform oil spray coating (oil content 10.5%) effectively slows down the initial water absorption rate and further controls the settling rhythm.

[0076] The feed of this invention ensures that seedlings have a sufficient 20-30 second effective feeding time window, during which they can maintain structural integrity (water stability > 30 minutes) and greatly reduce feed loss.

[0077] Feed slow settling test:

[0078] The extruded feed for *Triplophysa fulvidraco* was tested in artificial seawater (salinity 30, temperature 25±1℃) (three different batches of feed were tested). One hundred feed pellets were randomly selected and released one by one from the still water surface. A high-speed camera (1000 frames / second) was used to record the time it took for each pellet to sink to a 50 cm mark, and the average settling velocity (cm / s) was calculated. Simultaneously, the pellet density and suspension time were measured. The experimental results are shown in Table 2.

[0079] Table 2

[0080] detection indicators Batch A Batch B Batch C Mean ± Standard Deviation Test methods / remarks Settlement velocity (cm / s) 46.2 48.7 44.9 46.6 ± 1.9 Measured in artificial seawater at a depth of 50cm Bulk density (g / L) 528 535 521 528 ± 7.3 Standard volume method Suspension time (min) >30 >30 >30 >30 Time during which particles remain intact and do not disintegrate in still seawater Oil content (%) 10.5 11.2 9.8 10.5 ± 0.7 Soxhlet extraction

[0081] Experimental data show that the average settling velocity of the feed of this invention in seawater is 46.6 cm / s, which is stable within the target range of 40-50 cm / s.

[0082] In a specific embodiment of the present invention, the allicin content in the feed mixture is 0.05-0.1% by mass, and the probiotic lactic acid bacteria (effective bacteria content ≥10) are also present. 9 CFU / g, Fukang Biotechnology, 100g pack, ZXM-100) 0.2-0.3%.

[0083] The present invention will be further described below with reference to the embodiments.

[0084] Healthy, uniformly sized juvenile yellowtail trevally (150.67±13.56g) were selected for the experiment. After one week of acclimatization at the experimental water temperature (24-25℃), all experimental fish were randomly divided into two groups, A and B, with three replicates in each group. Group A was used as Comparative Example 1, serving as the control group; Group B was used as Example 1, serving as the experimental group.

[0085] Routine management: Feed the fish twice a day at fixed times (08:00 and 16:00). Observe the fish's feeding, activity, and fecal morphology daily.

[0086] Data recording: Weigh fish weekly and adjust feeding amounts based on weight. During the experiment, closely observe and record the number of fish exhibiting symptoms of enteritis (such as anal swelling, ascites, and white mucus in feces).

[0087] Sample collection and analysis: At the end of the experiment, a certain number of fish were randomly selected from each group for dissection, observation of intestinal morphology, and sampling for HE staining.

[0088] Example 1

[0089] A method for deep-sea cage culture of yellow-banded trevally, the steps of which are as follows:

[0090] (1) Set up submersible net cages in sea areas with a water depth of more than 30m and stock the net cages with yellow-banded trevally (stocking density of 13.7kg / cubic meter).

[0091] (2) Adjust the depth of the submersible cage according to the water temperature (the initial cage depth is 11 meters, and the upper edge is basically parallel to the water surface):

[0092] In November, when the surface water temperature dropped from a high temperature to 22°C, the net cages were lowered to a water depth of 30m at a rate of 1m per day.

[0093] In April, when the surface water temperature rose from low to 20°C, the net cages were raised to a water depth of 15m at a rate of 2m per day.

[0094] In July, when the surface water temperature rose from low to 28°C, the net cages were lowered to a water depth of 30m at a rate of 1m per day.

[0095] (3) Use a guide pipe for fixed-point feeding, control the slow sinking speed of the feed in the net cage to be 40-50 cm / s, and the residence time of the feed in the net cage to be 20-30 s; adjust the amount of feed mixture according to the water temperature;

[0096] The amount of the feed mixture is dynamically adjusted according to the water temperature.

[0097] When the water temperature is 26-29℃, the feeding amount of the feed mixture is 1.35% of the fish's body weight; the feed mixture contains 0.1% allicin and 0.3% probiotics and lactic acid bacteria.

[0098] When the water temperature is 20-26℃, the feeding amount of the yellow-banded trevally feed is 2.80% of the fish's body weight;

[0099] When the water temperature is 16-20℃, the feeding amount of the yellow-banded trevally feed is 1.55% of the fish's body weight;

[0100] When the water temperature is 12-16℃, the feeding amount of the yellow-banded trevally feed is 0.30% of the fish's body weight.

[0101] The submersible cage mentioned in step (1) is a cube-shaped cage with a side length of 9.5 meters.

[0102] The yellow-banded trevally feed comprises the following ingredients by weight percentage:

[0103] The feed contains 50% red fish meal, 7% krill meal, 10% concentrated soybean protein, 16% high-gluten flour, 3% brewer's yeast ("Saifute" brewer's yeast powder from Xuzhou Saifu Biotechnology Co., Ltd., protein ≥43%, moisture ≤10.0%, ash ≤9.0%), 8% fish oil, 2% soybean lecithin, 1.2% calcium dihydrogen phosphate, 1.2% vitamin premix, 1.1% mineral premix, and 0.5% choline chloride. The crude protein content is 48%; the crude fat content is 14%.

[0104] Comparative Example 1

[0105] A deep-water cage culture method for yellowtail trevally, with the steps referring to Example 1, the difference being that in Example 1, the amount of feed is 3.0% of the fish's body weight, not adjusted according to water temperature, and no allicin or lactic acid bacteria are added to the feed.

[0106] Example 1 was used as the experimental group, and Comparative Example 1 was used as the control group. Seedlings with an initial weight of about 10g were selected for one cycle of cultivation.

[0107] Experimental Results and Data Analysis:

[0108] Incidence of enteritis: The cumulative incidence of enteritis in group A (control group) was 8.5% (ranging from 6.1% to 9.3%). The cumulative incidence of enteritis in group B (experimental group) was 3.2% (ranging from 2.2% to 4.1%).

[0109] Group A (control group, enteritis histology) intestinal health morphology images (HE staining) as follows: Figure 1 Group B (experimental group, normal intestinal histology) intestinal morphology images (HE staining) are shown below. Figure 2 The statistical results of growth performance and feed utilization are shown in Table 3.

[0110] Table 3

[0111] Indicator Items Group A (control group) Group B (Experimental Group) Final average weight (g) 218.45±16.82 195.33±14.75 Total food intake (g / group) 385.63±19.53 226.10±15.67 is only about 58.63% of Group A. Feed conversion ratio 1.85±0.12 1.22±0.08

[0112] Growth performance: Despite the lower feeding amount, group B's feed conversion ratio (feed coefficient) was significantly better than group A. Group A, due to enteritis, did not effectively utilize some feed, resulting in a higher feed coefficient. Group B fish had thicker and more elastic intestinal walls with neatly arranged intestinal villi, while some diseased fish in group A showed symptoms such as intestinal congestion and thinning.

[0113] Final average weight gain: Although the absolute weight gain of group B was lower than that of group A, this was because the feed intake of group B was only 58.63% of that of group A. The key factor was the high feed utilization efficiency of group B.

[0114] Feed conversion ratio: The feed conversion ratio of group B (1.22) was significantly lower than that of group A (1.85) (P < 0.01). This means that group B consumes less feed to produce 1 kg of fish, and the feed efficiency is improved by more than 51%.

[0115] This indicates that the feed in Group B was converted into fish tissue more efficiently, with less waste.

[0116] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for deep-water cage culture of *Pseudocarpus scutellarioides*, characterized in that, Includes the following steps: (1) Set up submersible net cages in sea areas with a water depth of more than 30m and stock the net cages with yellow-banded trevally; (2) Adjust the depth of the submersible cage according to the water temperature; (3) Feed the yellow-banded trevally with feed or feed mixture according to the water temperature; the feed mixture consists of yellow-banded trevally feed, allicin and lactic acid bacteria.

2. The deep-sea cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, The submersible cage mentioned in step (1) is a cylindrical or cubic cage; the volume of the cage is 500-1000 m³. 3 .

3. The deep-water cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, The mesh size of the submersible cage described in step (1) is 1-5cm.

4. The deep-sea cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, The breeding density of the yellow-banded trevally in step (1) is 12-15 kg / m³.

5. The deep-sea cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, The method for adjusting the depth of the submersible cage in step (2) is as follows: When the surface water temperature drops from high temperature to ≤22℃, the net cage is lowered to a water depth of 30m at a rate of 1m per day. When the surface water temperature rises from low temperature to ≥20℃, the net cage is raised to a water depth of 15m at a rate of 2m per day. When the surface water temperature rises from low to ≥28℃, the net cage is lowered to a water depth of 30 m at a rate of 1 m per day.

6. The deep-sea cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, The amount of feed or feed mixture for the yellow-banded trevally in step (3) is dynamically adjusted according to the water temperature: When the water temperature is 26-29℃, feed the fish with a feed mixture, the amount of which is 1-2% of the fish's body weight. When the water temperature is 20-26℃, feed the yellow-banded trevally with feed at an amount of 2.5-3% of the fish's body weight. When the water temperature is 16-20℃, feed the yellow-banded trevally with feed, and the amount of yellow-banded trevally feed should be 1-1.6% of the fish's body weight; When the water temperature is 12-16℃, feed the yellow-banded trevally with feed, and the amount of yellow-banded trevally feed should be 0.2-0.5% of the fish's body weight.

7. The deep-water cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, In step (3), the feeding is carried out by fixed-point feeding through a guide tube, and the slow sinking speed of the feed in the net cage is controlled to be 40-50 cm / s, and the time the feed stays in the net cage is 20-30 s.

8. The deep-sea cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, The yellow-banded trevally feed comprises the following ingredients by weight percentage: Red fish meal 40-50%, krill meal 5-8%, soy protein concentrate 7-10%, high-gluten flour 10-16%, brewer's yeast 2-3%, fish oil 5-8%, phospholipids 1-2%, calcium dihydrogen phosphate 1-1.5%, vitamin premix 1-1.5%, mineral premix 1-1.5%, choline chloride 0.5-1%.

9. The deep-water cage culture method for *Pseudocarpus scutellarioides* according to claim 8, characterized in that, The preparation method of the yellow-banded mackerel feed includes the following steps: (1) Raw material pretreatment: Red fish meal, krill meal, concentrated soybean protein, high gluten flour and mineral premix are micro-pulverized by an ultra-micro pulverizer so that more than 98% of the raw materials pass through an 80-mesh sieve. (2) Ingredients and mixing Weigh out the red fish meal, krill meal, concentrated soy protein, high-gluten flour, and mineral premix in precise proportions, dry mix them, and then add brewer's yeast and calcium dihydrogen phosphate for further mixing. (3) Conditioning and extrusion granulation The uniformly mixed powder is fed into a conditioner and conditioned for 45-60 seconds with dry saturated steam at 90±2℃ and a pressure of 0.35-0.45 MPa. This process matures and softens the material, increases the moisture content to 21-25%, promotes starch gelatinization, and achieves a gelatinization degree >90%. After conditioning, the material enters the screw extruder, where the temperature is set at 80-90℃ in Zone I (feeding zone), 128±2℃ in Zone II (melting zone), and 140-150℃ in Zone III (pressure equalization zone). Under the action of high shear force of 25-35 atm and 400-500 rpm, the material is transformed into a molten state and extruded through the die to atmospheric pressure, forming porous, loosely structured extruded granules with an expansion degree of 1.6-1.

8. (4) Post-ripening and drying The puffed granules enter the post-curing unit and are kept at 80-85℃ for 8-10 minutes to further promote starch gelatinization and improve the stability of the granule structure. Then, a multi-layer conveyor dryer is used with hot air temperature of 90-100℃ for 20-25 minutes to reduce the moisture content from ~25% to 9±0.5%. (5) Liquid spraying Vitamin premix, fish oil, soybean lecithin, and choline chloride were stirred in a spray can until emulsified and mixed, and then sprayed under vacuum conditions of -0.03 to -0.05 MPa to obtain 5.0 mm particle size yellow-banded trevally extruded feed.

10. The deep-sea cage culture method for *Pseudocarpus scutellarioides* according to claim 1, characterized in that, The feed mixture contains 0.05-0.1% allicin and 0.2-0.3% probiotics and lactic acid bacteria.

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