A method for improving the quality of rockfish seedlings

Abstract

The application discloses a breeding method for improving the quality of Sebastes schlegelii fry, and comprises the following steps: collecting parent fish in a Sebastes schlegelii original seed field, artificially cultivating the parent fish in a net cage at sea, and performing nutrition rejuvenation on the parent fish; obtaining offspring fry by using an artificial fry squeezing method; controlling reasonable culture density according to different fry specifications; screening and using natural plant active ingredients and common micro-ecological preparations which are easy to absorb; avoiding disinfection and drug use; and controlling water flow rate in different growth stages. The method integrates nutrition rejuvenation, artificial fry production, pollution-free water quality regulation and fry behavior state regulation, solves problems such as poor parent germplasm, dead fry or insufficient activity of fry, slow growth and poor stress resistance in the process of fry breeding, has strong controllability in the operation period, has high survival rate of fry, has remarkable growth promotion and immunity effect, has good prevention and treatment effect on bacterial diseases, realizes pollution-free fry breeding, can reduce disease occurrence and mortality, reduces the feed conversion ratio, and effectively improves the economic benefit of breeding.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, and more specifically to a method for improving the quality of Scorpionfish fry. Background Technology

[0002] The Scorpionfish (Sebastesschlegelii), also known locally as the Black Rockfish, Blackfish, Spiny Fish, or Black Village Scorpionfish, belongs to the order Scorpaeniformes, family Scorpionidae, and genus Sebastes. It is mainly distributed in the coastal waters of the western Pacific Ocean, with an optimal growth temperature of 1-27℃, an optimal growth temperature of 4-25℃, and a suitable salinity of 28‰-33.4‰. It can overwinter naturally and is a eurythermal fish. This fish is highly nutritious, has few bones, and a delicious flavor. It is available around the Spring Festival and dominates the seafood market, commanding a high price. In recent years, to alleviate the declining natural resources of the Scorpionfish, stock enhancement and release programs have been gradually implemented, constructing "marine ranches" and creating "underwater forests." These programs involve bottom seeding and stock enhancement to develop recreational and ecological fisheries, benefiting future generations and promoting the sustainable development of the fisheries economy, yielding significant economic, social, and ecological benefits.

[0003] The rockfish (Scorpionichthys schlegelii) is highly popular among producers and consumers worldwide due to its delicious taste and rich nutritional value. Currently, many countries around the world have widely developed rockfish farming and seedling production. my country's aquaculture industry is developing rapidly, with fish factory farming continuously reaching new heights. However, the farming of marine fish is mainly concentrated on turbot, flounder, large yellow croaker, and sea bass. The rockfish, a cold-water reef fish, has tender flesh, a delicious flavor, and a high market price, offering a broad market potential. Its development and promotion are of significant and far-reaching importance for restoring marine ecological resources and developing regional specialty economies. Summary of the Invention

[0004] In view of this, the present invention provides a breeding method for improving the quality of Scorpionfish seedlings in artificial breeding, reducing disease occurrence and mortality, lowering the feed conversion ratio, and effectively improving the economic benefits of breeding.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for improving the quality of Scorpionfish fry includes the following steps:

[0007] Step 1: Select a breeding farm and adjust the quality of the water used for breeding;

[0008] Step 2: Select broodstock of *Scorpionfish schlegelii*;

[0009] Select lively, healthy, mature 2-year-old parent fish that were artificially cultured and raised in net cages at sea ahead of the original breeding farm of Xu's Scorpionfish;

[0010] Step 3: Breeding of broodstock of Scorpionfish Xu;

[0011] After the parent fish have undergone the second breeding treatment, they are placed in a culture pond at a ratio of female to male of 1:1. After the parent fish mate, the fertilized female broodstock is removed and placed in a breeding pond to give birth. After the fry are born, the newly hatched fry are placed in a fry rearing pond for cultivation.

[0012] Step 4: Seedling Propagation

[0013] (4.1) Control the stocking density, that is:

[0014] When the fry are larvae ≤1cm in length, the stocking density is 2000-2500 fish / m². 3 ;

[0015] When the fry are larvae with a length >1cm and ≤3cm, the stocking density is 1500-2000 fish / m². 3 ;

[0016] When the fry are larvae with a length >3cm and ≤5cm, the stocking density is 1000-1500 fish / m². 3 ;

[0017] When the fry are larvae with a length >5cm and ≤8cm, the stocking density is 700-800 fish / m². 3 ;

[0018] When the seedlings are longer than 8cm, the stocking density is 500-600 fish / m². 3 .

[0019] (4.2) Feeding of seedlings, i.e.:

[0020] Feed the seedlings with rotifers from day 1 to day 15 after they hatch, and sprinkle fresh Chlorella until the water has a slight algal color.

[0021] Feed the seedlings with rotifers and artichoke nauplii from day 15 to 30 after hatching, and sprinkle fresh Chlorella until the water has a slight algal color.

[0022] From the 30th to the 45th day after hatching, feed the fry with Artemia nauplii and formulated feed for juvenile sea bream (particle size 0.25-0.36mm), and sprinkle or mix in microecological preparations, feed additives and disease prevention drugs.

[0023] For fry that are ≥45 days old, feed them with formulated feed for juvenile sea bream with appropriate particle size, and sprinkle or mix in microecological preparations, feed additives and disease prevention drugs.

[0024] (4.3) Control the light intensity of the aquaculture environment, namely:

[0025] The intensity of the light is below 1000 Lx, and the light cycle is light:dark = 12h:12h;

[0026] (4.4) Control the breeding environment, namely:

[0027] The aquaculture water temperature is 17℃~25℃, with the water temperature ≥17℃ in spring and ≤25℃ in summer.

[0028] The salinity of the water used in the aquaculture farm is 25‰–32‰, the pH is 7.8–8.3, and the dissolved oxygen content is ≥5mg / L. The ponds are emptied monthly. Before emptying the ponds, astaxanthin is administered for 5 consecutive days at a dosage of 10mL / kg mixed with feed. Astaxanthin administration is stopped before and after emptying the ponds, and a vitamin C stress reliever is applied at a dosage of 0.5g / m³. 3 .

[0029] Preferably, the aquaculture farm mentioned in step one is located in a sea area with smooth and unpolluted waters and convenient transportation; the water quality for aquaculture meets the requirements of the pollution-free food seawater aquaculture water quality standard NY5052~2001.

[0030] Preferably, the parent fish in step two are ≥2kg, the temperature in the parent fish farming area is 13℃, and they are fed fresh frozen small fish and shrimp during the farming period.

[0031] Preferably, in step three, the density of fertilized female broodstock in the breeding pond is 1 fish / m². 3 The production process is as follows:

[0032] Select a female fish that is about to give birth. Wrap the fish's body with a cloth soaked in seawater and cover the female fish's eyes. Gently squeeze the fish's abdomen towards the genital opening. The mature fry will slowly flow into the prepared tank. Stop squeezing the fry when the outflow of the fry slows down. Put the parent fish back into the marked net cage in the pond. Squeeze the fry again 2-4 hours later until the birth is over.

[0033] The culture tank contains naturally filtered seawater at a temperature of 13°C. The temperature is increased by 0.5°C daily during the culture period, and the seawater is kept at a constant temperature when it reaches 17°C.

[0034] Preferably, in step (4.2), the feeding amount of rotifers is 6-8 per mL and the feeding amount of Artemia nauplii is 3-5 per mL, based on the volume of the culture water.

[0035] The microecological preparations, feed additives, and disease control drugs, along with their application methods, are as follows:

[0036] Sugar-free EM probiotics, once a week, 3-5g / m² each time. 3 ; 0.2% multivitamins, once a week, diluted 2g / kg of feed each time; bile acids, 4-6g / kg of feed each time, preventive once a week, treatment for 5 consecutive days; poplar flower extract, 10mL / kg each time, mixed with 5g / kg of enteritis remedy, feed, preventive once a week, treatment for 3-5 consecutive days;

[0037] When the seedlings are ≤2cm in length, feed them 4-5 times a day; when the seedlings are >2cm in length, feed them 2-3 times a day.

[0038] Preferably, during the first 1-15 days after the seedlings hatch, 50% of the water is replaced daily with fresh seawater; during the 15-45 days after the seedlings hatch, 50%-100% of the water is replaced daily with fresh seawater; and after the 46th day after the seedlings hatch, they are cultured using fresh seawater with a constant flow.

[0039] Furthermore, in fresh seawater aquaculture, the flow rate is controlled at 1BL / s.

[0040] Preferably, the rotifers and artichoke nauplii described in step (4.2) need to be nutritionally fortified before being fed.

[0041] Furthermore, the rotifer culture method includes the following steps:

[0042] The culture density was 500 cells / mL, the water temperature was 28℃, the salinity was 28-30, the pH was 8.0-8.4, the light intensity was 1000 Lx, and sufficient aeration was provided to maintain the dissolved oxygen content in the water above 5 mg / L.

[0043] The rotifer nutrient enhancement treatment was performed using Schizochytrium powder at a dosage of 0.25 g / L based on water volume, and the nutrient enhancement time was 12 h.

[0044] The method for culturing Artemia nauplii includes the following steps:

[0045] The culture density was 150 cells / mL, the water temperature was 28℃, the salinity was 28-30, the pH was 8.0-8.4, the light intensity was 1000 Lx, and sufficient aeration was provided.

[0046] The fortifying agent for the Artemia nauplius nutrient fortification treatment includes Schizochytrium powder, and the amount of fortifying agent is 0.4 g / L based on the water volume, and the nutrient fortification time is 12 h.

[0047] Preferably, in step (4.2), when feeding rotifers and artichoke nauplii to the seedlings 15-30 days after birth, the feeding method for rotifers and artichoke nauplii is as follows: feed rotifers normally, reduce the amount of rotifers in the afternoon, supplement with a small amount of artichoke nauplii, and gradually advance the feeding time and increase the amount of artichoke nauplii in the later stage until the feeding of rotifers is stopped;

[0048] Specifically: from day 15 to day 20, the afternoon feeding amount of rotifers is reduced by 1 rotifer / ml, and the feeding amount of artemia is increased by 1 rotifer / ml; from day 20 to day 25, the afternoon feeding amount of rotifers is reduced by 2 rotifers / ml, and the feeding amount of artemia is increased by 2 rotifers / ml; from day 25 to day 30, the feeding amount of rotifers is 0, and the feeding amount of artemia is 5 rotifers / ml.

[0049] When feeding Artemia nauplii and formulated feed to seedlings 30-45 days after hatching, the feeding method is as follows: feed Artemia nauplii normally, reduce the amount of Artemia nauplii in the afternoon, and supplement with a small amount of formulated feed. Later, gradually advance the feeding time of formulated feed and increase the amount of formulated feed until feeding of Artemia nauplii is stopped. Specifically:

[0050] Reduce the amount of artichokes fed in the afternoon from day 30 to 35 by 1, reduce the amount of artichokes fed in the afternoon from day 35 to 40 by 2, and reduce the amount of artichokes fed in the afternoon from day 40 to 45 by 0. Feed the formulated feed in small amounts and frequently according to the degree of satiety.

[0051] Preferably, when the water temperature is >25℃, the amount of feed should be halved, and the remaining feed and feces should be siphoned off 2 hours after each feeding; maintain stable environmental conditions such as light, water temperature, and salinity to prevent stress reactions, and promptly clean up diseases and dead individuals in the aquaculture pond.

[0052] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for improving the quality of Scorpionfish fry, which has the following beneficial effects:

[0053] The aquaculture method provided by this invention involves pre-collecting broodstock from original breeding farms of Scorpionichthys schlegelii and artificially cultivating them in net cages at sea, then nourishing and strengthening them. Fry are obtained using artificial squeezing of fry, allowing for the control of fry numbers based on production needs. This avoids problems such as dystocia and abortion in first-time breeding broodstock, reduces the inconvenience of manual operation, and allows for control of pond density. The method also utilizes a combination of easily absorbed natural plant active ingredients and common microecological preparations, avoiding the need for disinfection and medication, thus improving the quality and dietary health of Scorpionichthys schlegelii fry. Furthermore, controlling the water flow rate at different growth stages ensures that the fry exhibit more natural behavior and achieve optimal growth performance. This method integrates nutritional rejuvenation, artificial spawning, pollution-free water quality control, and seedling behavior regulation. It focuses on solving technical problems in the breeding process of Scorpionfish schlegelii, such as poor parent stock quality, seedling mortality, insufficient seedling activity, slow growth, and poor stress resistance. The breeding period is highly controllable, resulting in a high seedling survival rate. The use of probiotics and water flow rate control have significant growth-promoting and immune-enhancing effects. It also has good prevention and control effects against bacterial diseases, achieving pollution-free seedling breeding, reducing disease incidence and mortality, lowering the feed conversion ratio, and effectively improving the economic benefits of aquaculture. Detailed Implementation

[0054] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0055] The following examples and comparative examples all took place between May and July.

[0056] Example 1

[0057] Step 1: Select a sea area with smooth, unpolluted waters and convenient transportation for the aquaculture farm. The water quality for aquaculture must meet the requirements of NY5052-2001, the standard for pollution-free seawater aquaculture water quality.

[0058] Step Two: Selecting Parent Stock

[0059] The broodstock of Scorpionfish were selected from filtered seawater at 13℃ and temporarily raised for more than one month with fresh and frozen small fish and shrimp for nutritional rejuvenation. After temporary rearing, individuals with uniform size, normal body color, no damage to the body surface, no disease or deformity, strong activity and good feeding were selected.

[0060] Step 3: Parent Breeding

[0061] After the fish underwent the rearing treatment in step two, male and female broodstock were placed in a rearing tank at a 1:1 ratio. After mating, the fertilized female broodstock were removed and placed in a breeding tank to await spawning (1 fish / m²). 3 After the seedlings are produced, the newly hatched seedlings are placed in a seedling cultivation pond for further cultivation.

[0062] The cultivation tank contains naturally filtered seawater at a temperature of 13℃. During the cultivation period, the temperature is increased by 0.5℃ daily, and the tank is temporarily kept at a constant temperature when the temperature reaches 17℃.

[0063] Fresh, frozen small fish and shrimp were fed in the rearing ponds, while no feeding was given to the female broodstock in the breeding ponds.

[0064] In the breeding pond, female fish awaiting birth lie still in the dark at the bottom, with their heads often facing downwards and their pectoral, pelvic, and caudal fins swaying slowly. Select female fish that are about to give birth, wrap their bodies with a cloth soaked in seawater and cover their eyes, and gently squeeze the abdomen of the fish towards the genital opening. The mature fry will slowly flow into the prepared circular tank. After that, gently squeeze the abdomen of the parent fish to slow down the flow of fry, then stop squeezing the fry and put the parent fish back into the marked net cage in the pond. Depending on the production needs, squeeze the fry again 2 to 4 hours later.

[0065] Step 4: Seedling Propagation

[0066] (4.1) Adjust the stocking density in a timely manner according to the size of the seedlings. The stocking density is:

[0067] 2500 seedlings ≤1cm in diameter / m 3 ;

[0068] 2000 seedlings / m² (1-3cm) 3 ;

[0069] 1500 seedlings / m² (3-5cm) 3 ;

[0070] 700 seedlings (5-8cm) per m 3 ;

[0071] 500 scorpionfish (over 8cm) per m 3 ;

[0072] During the breeding period, individuals with uneven growth in size are selected and cultured in separate ponds to ensure that the seedlings in the same breeding pond are of uniform size.

[0073] (4.2) Feeding of seedlings, i.e.:

[0074] Feed the newly hatched fry with rotifers from day 1 to day 15, and sprinkle live Chlorella until the water turns a light algae color. Change 50% of the water daily with fresh seawater.

[0075] Feed the water with rotifers and Artemia nauplii from day 15 to day 30, and sprinkle live Chlorella until the water shows a slight algal color. Change 50% of the water daily with fresh seawater.

[0076] The feeding method for rotifers and Artemia nauplii is as follows: feed rotifers normally, reduce the amount of rotifers in the afternoon, and supplement with a small amount of Artemia nauplii. In the later stage, gradually advance the feeding time of Artemia nauplii and increase the amount of Artemia nauplii until rotifers are stopped.

[0077] Specifically: from day 15 to day 20, the afternoon feeding amount of rotifers is reduced by 1 rotifer / ml, and the feeding amount of artemia is increased by 1 rotifer / ml; from day 20 to day 25, the afternoon feeding amount of rotifers is reduced by 2 rotifers / ml, and the feeding amount of artemia is increased by 2 rotifers / ml; from day 25 to day 30, the feeding amount of rotifers is 0, and the feeding amount of artemia is 5 rotifers / ml.

[0078] From day 30 to 45, feed the fish with Artemia nauplii and formulated feed for juvenile sea bream (particle size 0.25-0.36mm), sprinkle or mix with microecological preparations, feed additives and disease prevention drugs, and change the water volume by 50% to 100% daily.

[0079] The feeding method for Artemia nauplii and formulated feed is as follows: Feed Artemia nauplii normally, reduce the amount of Artemia nauplii in the afternoon, and supplement with a small amount of formulated feed. Later, gradually advance the feeding time of the formulated feed and increase the amount of formulated feed until feeding of Artemia nauplii is stopped. Specifically:

[0080] Reduce the amount of artichokes fed in the afternoon from day 30 to 35 by 1, reduce the amount of artichokes fed in the afternoon from day 35 to 40 by 2, and reduce the amount of artichokes fed in the afternoon from day 40 to 45 by 0. Feed the formulated feed in small amounts and frequently according to the degree of satiety.

[0081] After 45 days, feed the juvenile sea bream with a suitable particle size feed, sprinkle or mix in microecological preparations, feed additives and disease prevention drugs, and raise them in fresh seawater with constant flow.

[0082] The above baits have been thoroughly rinsed and are free of pathogens;

[0083] Instructions for use of probiotics, feed additives, and disease control drugs: Use EM probiotics (such as brown sugar) once a week, at a dosage of 3-5 g / m² each time. 3 ; 0.2% multivitamins, once a week, diluted at 2g / kg feed; bile acids, 4-6g / kg feed each time, prevention once a week, treatment for 5 consecutive days; poplar flower extract, 10mL / kg each time, mixed with 5g / kg enteritis remedy, fed to the feed, prevention once a week, treatment for 3-5 consecutive days;

[0084] When the seedlings are ≤2cm in length, feed them small amounts frequently, 4-5 times a day. When the seedlings are >2cm in length, they show obvious phototaxis, so feed them intensively, 2-3 times a day.

[0085] In the aforementioned culture using fresh seawater with constant flow, the flow rate of the constant flow is adjusted according to the actual body length of the seedlings, and the flow rate is controlled at 1BL / s;

[0086] Rotifers should be fed at a rate of 5 per mL of culture water, and Artemia nauplii should be fed at a rate of 3-5 per mL. Nutritional fortification should be carried out before feeding.

[0087] The rotifer enhancer is Schizochytrium powder; the rotifer culture density is 500 rotifers / ml, the amount of enhancer is 0.25g / L (water volume), the enhancement is carried out for 12 hours, the water temperature is about 28℃, the salinity is 28-30, the pH is 8.0-8.4, the light intensity is about 1000Lx, and sufficient aeration is provided to maintain the dissolved oxygen content in the water above 5mg / L;

[0088] The Artemia nauplii enhancer is Schizochytrium powder. The culture density of Artemia nauplii is 150 nauplii / ml. The amount of enhancer is 0.4g / L (water volume). Enhancement is carried out for 12 hours. The water temperature is about 28℃, the salinity is 28-30, the pH is 8.0-8.4, the light intensity is about 1000Lx, and sufficient aeration is provided to maintain the dissolved oxygen content in the water above 5mg / L.

[0089] (4.3) Control the light intensity of the aquaculture environment, namely:

[0090] The light intensity is below 1000 Lx, the light is uniform, and the light cycle is light:dark = 12h:12h;

[0091] (4.4) Control the breeding environment, namely:

[0092] The aquaculture water temperature is 17–25℃, salinity is 25–32‰, pH is 7.8–8.3, with micro-aeration and dissolved oxygen above 5 mg / L. Water quality is monitored daily, and the ponds are emptied monthly. Before emptying the ponds, astaxanthin is administered for 5 consecutive days at a dosage of 10 mL / kg mixed with feed. Astaxanthin administration is stopped before and after emptying the ponds, and a vitamin C stress reliever is applied at a dosage of 0.5 g / m³. 3 ;

[0093] When the water temperature is above 25℃, reduce the amount of feed by half. Siphon off any remaining feed and feces 2 hours after each feeding. Maintain stable environmental conditions such as light, water temperature, and salinity to prevent stress reactions. Clean up any diseased or dead individuals in the aquaculture pond in a timely manner.

[0094] Let it be denoted as S1.

[0095] Example 2

[0096] The difference from Example 1 is as follows:

[0097] (4.1) Adjust the stocking density in a timely manner according to the size of the seedlings. The stocking density is:

[0098] 2000 seedlings ≤1cm in diameter / m 3 ;

[0099] 1500 seedlings / m² (1-3cm) 3 ;

[0100] 1000 seedlings per m (3-5cm) 3 ;

[0101] 600 seedlings (5-8cm) per m 3 ;

[0102] 400 scorpionfish (over 8cm) per meter 3 ;

[0103] During the breeding period, individuals with uneven growth in size are selected and cultured in separate ponds to ensure that the seedlings in the same breeding pond are of uniform size.

[0104] It is denoted as S2.

[0105] Example 3

[0106] The difference from Example 1 is as follows:

[0107] (4.1) Adjust the stocking density in a timely manner according to the size of the seedlings. The stocking density is:

[0108] 1500 seedlings ≤1cm in diameter / m 3 ;

[0109] 1000 seedlings (1-3cm) per m 3 ;

[0110] 800 seedlings per m (3-5cm) 3 ;

[0111] 500 seedlings (5-8cm) per m 3 ;

[0112] 300 scorpionfish over 8cm in length / m 3 ;

[0113] During the breeding period, individuals with uneven growth in size are selected and cultured in separate ponds to ensure that the seedlings in the same breeding pond are of uniform size.

[0114] It is denoted as S3.

[0115] Comparative Example 1

[0116] Step 1: Select a sea area with smooth, unpolluted waters and convenient transportation for the aquaculture farm; use sand-filtered natural seawater for aquaculture.

[0117] Step 2: Selection of artificially bred broodstock for Scorpionfish. Select broodstock that are uniform in size, have normal body color, no damage to the body surface, and are free from disease and deformities. Place the mated and fertile female fish into a 15℃ naturally filtered seawater breeding pond for breeding. After the fry are born, promptly remove them and place them into a fry rearing pond.

[0118] Step 3: Adjust the stocking density according to the size of the seedlings. The stocking density is as follows:

[0119] 2500 seedlings ≤1cm in diameter / m 3 ;

[0120] 2000 seedlings / m² (1-3cm) 3 ;

[0121] 1500 seedlings / m² (3-5cm) 3 ;

[0122] 700 seedlings (5-8cm) per m 3 ;

[0123] 500 scorpionfish (over 8cm) per m 3 During the cultivation period, individuals with uneven growth in size are selected and cultured in separate ponds to ensure that the seedlings in the same breeding pond are of uniform size.

[0124] The breeding environment uses natural light, and the light cycle is the natural day-night cycle.

[0125] The aquaculture water temperature is 15-25℃, the salinity is 25-32‰, the pH is 7.8-8.3, micro-aeration is provided, the dissolved oxygen is above 5mg / L, the water quality is monitored daily, and the water is drained once a month.

[0126] Feed newly hatched fry with rotifers from day 1 to day 15, and change 50% of the water daily with fresh seawater;

[0127] Feed rotifers and Artemia nauplii from day 15 to 30, and change 50% of the seawater daily with fresh seawater.

[0128] Feed the nauplius larvae and formulated feed on days 30 to 45, and change 50% to 100% of the water daily.

[0129] Feed the animals with formulated feed after day 45, and raise them in fresh seawater with constant flow. All feed should be thoroughly rinsed to ensure it is free of pathogens.

[0130] When the seedlings are ≤2cm in length, feed them small amounts frequently, 4-5 times a day. When the seedlings are >2cm in length, their phototaxis becomes obvious, and feed them intensively, 2-3 times a day.

[0131] Feed rotifers at a rate of 5 rotifers / mL of culture water, and Artemia nauplii at a rate of 3-5 rotifers / mL. Before feeding, nutritional fortification should be carried out. The fortifier for rotifers is fortified yeast. The culture density of rotifers is 500 rotifers / mL, the amount of fortifier is 0.25 g / L (water volume), fortification is carried out for 12 hours, the water temperature is about 28℃, the salinity is 28-30, the pH is 8.0-8.4, the light intensity is about 1000 Lx, and sufficient aeration is provided.

[0132] The Artemia nauplii were enhanced with Schizochytrium powder at a culture density of 150 nauplii / ml, with an enhancement amount of 0.4 g / L (water volume). The enhancement was carried out for 12 hours at a water temperature of approximately 28℃, a salinity of 28–30, a pH of 8.0–8.4, a light intensity of approximately 1000 Lx, and adequate aeration.

[0133] When the water temperature is above 25℃, reduce the amount of feed by half. Siphon off any remaining feed and feces 2 hours after each feeding. Maintain stable environmental conditions such as light, water temperature, and salinity to prevent stress reactions. Clean up any diseased or dead individuals in the aquaculture pond in a timely manner.

[0134] It is denoted as D1.

[0135] Comparative Example 2

[0136] The difference from Comparative Example 1 is that:

[0137] Step 3: Adjust the stocking density according to the size of the seedlings. The stocking density is as follows:

[0138] 2000 seedlings ≤1cm in diameter / m 3 ;

[0139] 1500 seedlings / m² (1-3cm) 3 ;

[0140] 1000 seedlings per m (3-5cm) 3 ;

[0141] 600 seedlings (5-8cm) per m 3 ;

[0142] 400 scorpionfish (over 8cm) per meter 3 During the cultivation period, individuals with uneven growth in size are selected and cultured in separate ponds to ensure that the seedlings in the same breeding pond are of uniform size.

[0143] It is denoted as D2.

[0144] Comparative Example 3

[0145] The difference from Comparative Example 1 is that:

[0146] Step 3: Adjust the stocking density according to the size of the seedlings. The stocking density is as follows:

[0147] 1500 seedlings ≤1cm in diameter / m 3 ;

[0148] 1000 seedlings (1-3cm) per m 3 ;

[0149] 800 seedlings per m (3-5cm) 3 ;

[0150] 500 seedlings (5-8cm) per m 3 ;

[0151] 300 scorpionfish over 8cm in length / m 3 During the cultivation period, individuals with uneven growth in size are selected and cultured in separate ponds to ensure that the seedlings in the same breeding pond are of uniform size.

[0152] It is denoted as D3.

[0153] Experimental Example

[0154] After raising juvenile Scorpionfish using the methods provided in Examples 1-3 and Comparative Examples 1-3 for 90 days, the survival rates of individual Scorpionfish in different groups were statistically analyzed, and the results are shown in Table 1.

[0155] Table 1. Survival rate and body length of different groups of *Scorpionfish schlegelii*

[0156]

[0157] Table 1 above shows that the breeding method provided by the present invention can significantly improve the survival rate and growth rate of seedlings.

[0158] In summary, the aquaculture method provided by this invention selects lively and healthy individuals artificially cultivated in net cages at sea by the original breeding farm of *Scorpionichthys schlegelii* as stable broodstock. Through nutritional fortification, it improves the reproductive efficiency of the broodstock and the environmental adaptability of the seedlings. By controlling reasonable stocking densities according to different seedling sizes, and by optimizing the combination of microecological agents and feed additives, it reduces water pollution and disease incidence in the aquaculture environment. The disease incidence rate of *Scorpionichthys schlegelii* is generally below 5%, thereby improving the survival rate. Furthermore, by controlling the water flow rate in the seedling culture, it enhances the natural behavior and growth performance of the seedlings, increasing the growth rate by more than 5%, demonstrating promising application prospects. As shown in the examples, after 90 days of aquaculture using the above method, the survival rate and growth rate of individual *Scorpionichthys schlegelii* seedlings during the breeding period can be significantly improved.

[0159] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the quality of Scorpionfish fry, characterized in that, Includes the following steps: Step 1: Select a breeding farm and adjust the quality of the water used for breeding; Step 2: Select broodstock of *Scorpionfish schlegelii*; Select lively, healthy, mature 2-year-old parent fish that were artificially cultured and raised in net cages at sea ahead of the original breeding farm of Xu's Scorpionfish; Step 3: Breeding of broodstock of Scorpionfish Xu; After the parent fish have undergone the second breeding treatment, they are placed in a culture pond at a ratio of female to male of 1:

1. After the parent fish mate, the fertilized female broodstock is removed and placed in a breeding pond to give birth. After the fry are born, the newly hatched fry are placed in a fry rearing pond for cultivation. Step 4: Seedling Propagation (4.1) Control the stocking density, that is: When the fry are larvae ≤1cm in length, the stocking density is 2000-2500 fish / m². 3 ; When the fry are larvae with a length >1cm and ≤3cm, the stocking density is 1500-2000 fish / m². 3 ; When the fry are larvae with a length >3cm and ≤5cm, the stocking density is 1000-1500 fish / m². 3 ; When the fry are larvae with a length >5cm and ≤8cm, the stocking density is 700-800 fish / m². 3 ; When the seedlings are longer than 8cm, the stocking density is 500-600 fish / m². 3 ; (4.2) Feeding of seedlings, i.e.: Feed the seedlings with rotifers from day 1 to day 15 after they hatch, and sprinkle fresh Chlorella until the water has a slight algal color. Feed the seedlings with rotifers and artichoke nauplii from day 15 to 30 after hatching, and sprinkle fresh Chlorella until the water has a slight algal color. From the 30th to the 45th day after hatching, feed the fry with Artemia nauplii and formulated feed for juvenile sea bream with a particle size of 0.25 to 0.36 mm, and sprinkle or mix in microecological preparations, feed additives and disease prevention drugs. For fry that are ≥45 days old, feed them with appropriate particle size formulated feed for juvenile sea bream based on the fry's mouth diameter, and sprinkle or mix in microecological preparations, feed additives, and disease prevention drugs. Among them, based on the volume of the culture water, the feeding amount of rotifers is 6-8 per mL, and the feeding amount of Artemia nauplii is 3-5 per mL; The microecological preparations, feed additives, and disease control drugs, along with their application methods, are as follows: Sugar-free EM probiotics, once a week, 3-5g / m² each time. 3 ; 0.2% multivitamins, once a week, diluted 2g / kg of feed each time; bile acids, 4-6g / kg of feed each time, preventive once a week, treatment for 5 consecutive days; poplar flower extract, 10mL / kg each time, mixed with 5g / kg of enteritis remedy, feed, preventive once a week, treatment for 3-5 consecutive days; When the seedlings are ≤2cm in length, feed them 4-5 times a day; when the seedlings are >2cm in length, feed them 2-3 times a day. When feeding rotifers and artichoke nauplii to seedlings 15-30 days after hatching, the feeding method for rotifers and artichoke nauplii is as follows: feed rotifers normally, reduce the amount of rotifers in the afternoon, and supplement with a small amount of artichoke nauplii. In the later stage, gradually advance the feeding time of artichoke nauplii and increase the amount of artichoke nauplii until feeding rotifers is stopped. Specifically: from day 15 to day 20, the afternoon feeding amount of rotifers is reduced by 1 rotifer / ml, and the feeding amount of artemia is increased by 1 rotifer / ml; from day 20 to day 25, the afternoon feeding amount of rotifers is reduced by 2 rotifers / ml, and the feeding amount of artemia is increased by 2 rotifers / ml; from day 25 to day 30, the feeding amount of rotifers is 0, and the feeding amount of artemia is 5 rotifers / ml. When feeding Artemia nauplii and formulated feed to seedlings 30-45 days after hatching, the feeding method is as follows: feed Artemia nauplii normally, reduce the amount of Artemia nauplii in the afternoon, and supplement with a small amount of formulated feed. Later, gradually advance the feeding time of formulated feed and increase the amount of formulated feed until feeding of Artemia nauplii is stopped. Specifically: Reduce the amount of artichokes fed in the afternoon from day 30 to 35 by 1, reduce the amount of artichokes fed in the afternoon from day 35 to 40 by 2, and reduce the amount of artichokes fed in the afternoon from day 40 to 45 by 0. Feed the formulated feed in small amounts and frequently according to the degree of satiety. (4.3) Control the light intensity of the aquaculture environment, namely: The intensity of the light is below 1000 Lx, and the light cycle is light:dark = 12h:12h; (4.4) Control the breeding environment, namely: The aquaculture water temperature is 17℃~25℃, with the water temperature ≥17℃ in spring and ≤25℃ in summer. The salinity of the water used in the aquaculture farm is 25‰–32‰, the pH is 7.8–8.3, and the dissolved oxygen content is ≥5mg / L. The ponds are emptied monthly. Before emptying the ponds, astaxanthin is administered for 5 consecutive days at a dosage of 10mL / kg mixed with feed. Astaxanthin administration is stopped before and after emptying the ponds, and a vitamin C stress reliever is applied at a dosage of 0.5g / m³. 3 .

2. The method for improving the quality of Scorpionfish fry according to claim 1, characterized in that, The aquaculture farms mentioned in Step 1 are located in areas with smooth, unpolluted waters and convenient transportation; the water quality for aquaculture meets the requirements of NY5052-2001, the standard for pollution-free food seawater aquaculture water quality.

3. The method for improving the quality of Scorpionfish fry according to claim 1, characterized in that, The parent stock mentioned in step two is ≥2kg. The temperature of the parent stock culture area is 13℃. During the culture period, the parent stock is fed fresh and frozen small fish and shrimp until it is full. The uneaten feed is cleaned up in time the next day.

4. The method for improving the quality of Scorpionfish fry according to claim 1, characterized in that, In step three, the density of fertilized female broodstock in the breeding pond is 1 fish / m². 3 The production process is as follows: Select a female fish that is about to give birth. Wrap the fish's body with a cloth soaked in seawater and cover the female fish's eyes. Gently squeeze the fish's abdomen towards the genital opening. The mature fry will slowly flow into the prepared tank. Stop squeezing the fry when the outflow of the fry slows down. Put the parent fish back into the marked net cage in the pond. Squeeze the fry again 2-4 hours later until the birth is over. The culture tank contains naturally filtered seawater at a temperature of 13°C. The temperature is increased by 0.5°C daily during the culture period, and the seawater is kept at a constant temperature when it reaches 17°C.

5. A method for improving the quality of Scorpionfish fry according to claim 1, characterized in that, From day 1 to day 15 after hatching, 50% of the water in the seedlings is replaced with fresh seawater daily; from day 15 to day 45 after hatching, 50% to 100% of the water in the seedlings is replaced with fresh seawater in a constantly flowing system; after day 46 after hatching, the seedlings are cultured in a constantly flowing system of fresh seawater.

6. A method for improving the quality of Scorpionfish fry according to claim 5, characterized in that, In fresh seawater aquaculture with constant flow, the flow rate is controlled at 1BL / s.

7. A method for improving the quality of Scorpionfish fry according to claim 1, characterized in that, The rotifers and artichoke nauplii described in step (4.2) need to be nutritionally fortified before being fed.

8. A method for improving the quality of Scorpionfish fry according to claim 7, characterized in that, The rotifer culture method includes the following steps: The culture density was 500 cells / mL, the water temperature was 28℃, the salinity was 28-30, the pH was 8.0-8.4, the light intensity was 1000 Lx, and sufficient aeration was provided to maintain the dissolved oxygen content in the water above 5 mg / L. The rotifer nutrient enhancement treatment was performed using Schizochytrium powder at a dosage of 0.25 g / L based on water volume, and the nutrient enhancement time was 12 h. The method for culturing Artemia nauplii includes the following steps: The culture density was 150 cells / mL, the water temperature was 28℃, the salinity was 28-30, the pH was 8.0-8.4, the light intensity was 1000 Lx, and sufficient aeration was provided. The fortifying agent for the Artemia nauplii nutrient fortification treatment includes Schizochytrium powder, and the amount of fortifying agent is 0.4 g / L based on the water volume, and the nutrient fortification time is 12 h.

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