A method for incubating and culturing of fertilized eggs of taractichthys steindachneri

Abstract

The present application relates to the field of aquaculture, and particularly relates to a method for hatching and cultivating fry of Takifugu obscurus, which comprises nine steps of concentrated hatching of fertilized eggs, separation of fertilized eggs, egg spreading, air control, water temperature control, water quality control, bait and feeding method, pool division, and desalination of fry. The present application creates a simple method for hatching and cultivating fry of Takifugu obscurus from fertilized eggs, and particularly changes the early larva carrying into the fertilized egg carrying in the technical scheme, breaks through the existing cognition, and creates a simple operation of moving the Takifugu obscurus from the conical hatching barrel into the flat bottomed fry cultivation pool before the membrane of the fertilized egg is broken, and a late embryo membrane breaking and fry cultivation technical scheme. The present application improves the Takifugu obscurus breeding efficiency and reduces the artificial breeding cost. The present application saves the breeding production cost, is simple to operate, and is easy to be accepted and popularized by people.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aquaculture, in particular to a simple method for fertilized egg hatching and fry cultivation of Takifugu obscurus. BACKGROUND

[0002] Takifugu obscurus belongs to the order of Tetraodontiformes, suborder of Tetraodontoidei, family of Tetraodontidae and genus of Takifugu, and is an important fishery resource in the Yangtze River of China, with high nutritional value and medicinal value. The muscle of Takifugu obscurus is white as frost, with delicious and tender taste, rich in protein and nutrients, and is honored as the first of the "Three Fresh" in the Yangtze River. There has been a tradition of eating puffer fish in China since ancient times, and puffer fish has always been regarded as a delicacy on the dining table. The liver and ovary of puffer fish can extract puffer toxin, which is used to treat neuralgia, spasm, nocturia and other diseases, so the economic value and medicinal value of puffer fish are very high. At present, the total annual output of domestic Takifugu obscurus reaches 20-50 million tons, and among the puffer fish species, Takifugu obscurus has the largest breeding area and the highest total output. In particular, in September 2016, the Office of the Ministry of Agriculture and the State Food and Drug Administration jointly issued the "Notice on Conditionally Opening the Cultivation of Redfin Takifugu and Dark Pattern Takifugu for Processing and Operation", and the safe consumption of cultivated Takifugu obscurus is protected by law. The breeding area of Takifugu obscurus is expanding, and the Takifugu obscurus breeding industry is booming, with a huge demand for Takifugu obscurus fry in the market.

[0003] At present, the conventional artificial propagation and fry cultivation technology of Takifugu obscurus is relatively mature, and the survival rate is relatively high. However, in the existing conventional artificial breeding technology of Takifugu obscurus, the artificial breeding of Takifugu obscurus is divided into fertilized egg hatching and fry cultivation, and the fertilized eggs after de-adhesion are usually placed in a hatching container for hatching. After the embryos are hatched out of the membrane, the fry is moved into the fry cultivation pool after 2-3 days of feeding or after 5-6 days of feeding. This causes certain difficulty in Takifugu obscurus breeding: the hatching density of fertilized eggs is relatively low, generally 20-30 million eggs / m 3 ; when hatched out of the membrane, the water space is small and the water quality is difficult to control due to the large amount of organic matter in the water; a large amount of foam appears in the water, and the newly hatched fry is adhered by the foam and dies; the fry density is high in the hatching barrel after hatching, and the water change operation is easy to cause damage to the fry; because the early stage of Takifugu obscurus is small and weak, it is not suitable for artificial operation, and it is very difficult and tedious to move the fry from the hatching pool to the fry cultivation pool. Therefore, there is an urgent need for a simple method for Takifugu obscurus from fertilized egg hatching to fry cultivation in the field of technology, to improve the breeding efficiency of Takifugu obscurus and reduce the labor cost of breeding. SUMMARY

[0004] The present application aims at solving the above technical problems and providing a simple method for hatching and breeding of fertilized eggs of Takifugu obscurus.

[0005] To achieve the above-mentioned purpose, the present application provides a method for hatching and breeding of fertilized eggs of Takifugu obscurus, which comprises the following steps: concentration of fertilized eggs, separation of fertilized eggs, egg spreading, air control, water temperature control, water quality control, bait and feeding method, sub-pool, and desalination of fry.

[0006] Further, the method for hatching and breeding of fertilized eggs of Takifugu obscurus specifically comprises the following steps:

[0007] A) Concentration of fertilized eggs: the fertilized eggs obtained according to the conventional artificial breeding method of Takifugu obscurus are placed in indoor conical hatching barrels separately according to the eggs produced by each female fish. The upper half of the hatching barrel is cylindrical, and the lower half is conical. After the eggs are brushed and debonded, static water aeration is used for hatching. The water is made to be boiling by aeration. The hatching barrel is placed in a cement pool water bath, and the water temperature is maintained at 21.5-22.0℃. The density of fish eggs is controlled at 10-20 million per barrel (i.e. 60-120 million per m 3 ); the light intensity during the day is 800-1000lx, and the light is turned on at night; 60-mesh mesh is used to change water 3 times a day, each time 4 / 5, and the water is local freshwater, which is precipitated for 48 hours and filtered with a 120-mesh silk screen;

[0008] Further, in step A), the hatching barrel is a conical hatching barrel made of stainless steel, the upper half of which is a cylindrical shape with a diameter of 580mm and a depth of 550mm, and the lower half of which is a conical shape with a diameter of 580mm and a depth of 60mm. The volume is 180L, and the practical water volume is 170L.

[0009] B) Separation of fertilized eggs: fish eggs with a fertilization rate of 30%-80% need to be separated. The bad eggs that are yellow or moldy are separated and disposed of, so that the fertilized egg rate reaches more than 85%. The operation time for separating fertilized eggs is selected within the range of 80-90 hours after the fertilization of Takifugu obscurus eggs;

[0010] Further, the step B) in the method of separating bad eggs: first take out the inflatable head of the hatching cone-shaped barrel, stir the water body to form small whirlpools, after 5-10 minutes, all the fish eggs sink into the conical bottom, then use the siphon method to suck the fish eggs into the 80-mesh soft strainer, the frame of the strainer is exposed above the water surface, the net of the strainer is suspended in the water, collect the good fish eggs, turn them into a circular basin, gently stir the water body in the basin, the fish eggs concentrate at the bottom of the center of the basin, the bad eggs are lighter than the fertilized eggs, generally, use a small air pipe to siphon the yellow eggs and moldy eggs on the surface of the egg layer, then stir the water body again, repeat the siphoning of bad eggs, after 4-5 times of repetition, put the fertilized eggs back into the hatching barrel, there are still a small amount of fertilized eggs in the siphoned fish eggs, separate them again according to the above method, and put the fertilized eggs back into the hatching barrel; the whole operation does not separate the fish eggs from the water.

[0011] C) Egg distribution: about 96 hours after fertilization, the fertilized eggs start to break the membrane, at this time, pay attention to observation, as soon as you see the initial hatched fry, move them into the fry cultivation pond, the water level for egg distribution is 60 cm, the egg distribution density is 20-30 thousand eggs / m 3 (ie 2.4-3.6 million eggs / pool), the temperature difference between the water temperature in the hatching barrel and the target pool should not exceed 0.5℃.

[0012] Further, in step C), the area of the fry cultivation pond is 20m 2 , the pool depth is 1.5m, the effective water depth is 1.4m, the water body is 30m 3 , and the effective water body is 28m 3 .

[0013] D) Air supply control: the density of the air diffuser stone is 1.5 / m 2 when distributing eggs, after the first bottom suction, the density of the air diffuser stone is reduced to 1 / m 2 , when distributing eggs, the air supply is boiling, as the water level rises, the air supply is flat;

[0014] E) Water temperature control: the water temperature when releasing eggs is 22.0-22.5℃, after releasing eggs, the temperature is increased by 0.5℃, and after 6 hours, it is increased by another 0.5℃, until the water temperature is 22.5-23.5℃; on the third day after releasing eggs, the natural water temperature is maintained at 22-25℃, and the water temperature changes by no more than 1℃ per day;

[0015] F) Water quality control: the water depth when releasing eggs is 60cm, and the water used is fresh water, from the second day, add water in four times, each time adding 20cm, among which, the first two times of water addition use local fresh water, the third time of water addition uses local seawater (salinity 11-12) after first using fresh water, and the fourth time directly gradually adds seawater until full, and the water used after that is seawater, on the fifth day, replace 1 / 3 of the water with 60-mesh, on the sixth day, replace 1 / 3 of the water and clean the bottom twice with 60-mesh, on the seventh day, replace 2 / 3 of the water and clean the bottom once, and after that, clean the bottom once a day and replace 2 / 3 of the water every other day, the temperature difference of the water added for replacement should not exceed 1℃.

[0016] G) bait and feeding method: starting from the third day after spawning, feeding egg yolk, 5 times a day, 4-5 egg yolks per pool per day, sieving with 100 mesh silk gauze, and spraying the whole pool; starting from the 5th to 6th day after spawning, feeding brine shrimp nauplii, requiring just hatched brine shrimp nauplii, 80 mesh sieving, maintaining a density of 500-1000 / L, supplementing 2 times a day; stopping feeding egg yolk on the 8th to 9th day after spawning; starting from the 8th to 9th day after spawning, the feeding of brine shrimp nauplii does not need to be sieved, and the feeding amount of brine shrimp nauplii is gradually increased; starting from the 15th to 16th day after spawning, freshwater cladocerans sieved with 40 mesh can be increased, and the feeding amount of brine shrimp nauplii is reduced;

[0017] Further, in step G), on the first day of feeding brine shrimp, 5%-15% of the fry feed on brine shrimp nauplii, on the second day of feeding brine shrimp, 50%-60% of the fry feed on brine shrimp nauplii, and on the third day of feeding brine shrimp, more than 90% of the fry feed on brine shrimp nauplii.

[0018] H) Pooling: The egg laying density is more than 250,000 eggs / m 3 Generally, the fish fry is pooled once on the 14th day after spawning, the density is reduced by half, and the soft mesh silk gauze net is used to pull the net in the pool; the egg laying density is less than 200,000 eggs / m 3 Generally, no pooling is needed;

[0019] I) Freshwater hatching: starting from the 17th to 18th day after spawning, freshwater hatching is started, and the freshwater is pumped out in two times and added in four times to complete, i.e., on the first day, the water in the whole pool is pumped out by 1 / 2, the morning is added with freshwater to 1 / 4 of the whole pool, and the afternoon is added with freshwater again to 1 / 4 of the whole pool, on the second day, the water in the whole pool is pumped out by 2 / 3, the morning is added with freshwater to 1 / 3 of the whole pool, and the afternoon is added with freshwater again to 1 / 3 of the whole pool, then the water is changed with freshwater; after the 20th day after spawning, the fish fry is 0.7-0.8 cm in total length, and can be put into the pond for summer grouper seed cultivation, before hatching, the bottom is first sucked, then the water level is lowered to 30 cm by siphoning, and the low water level is pulled by the 30 mesh soft mesh silk gauze net.

[0020] From the fertilized egg hatching to the 0.7-0.8 cm fish fry, the total hatching rate is 65%-70%.

[0021] Compared with the prior art, the present application has the following outstanding advantages:

[0022] 1. A simple method for culturing dark striped puffer from fertilized egg hatching to fry is created, especially the technical scheme of changing the early fry carrying to the fertilized egg carrying, which breaks the existing cognition (dark striped puffer sink eggs must be hatched in a conical barrel), and creates a simple operation of carrying the fertilized egg from the conical hatching barrel to the flat bottom fry cultivation pool before the membrane breaking, and a late embryo membrane breaking and fry cultivation technical scheme.

[0023] 2. The hatching density of the fertilized eggs of the Takifugu obscurus is improved, from 20-30 million eggs per m 3 to 60-120 million eggs per m 3 ;

[0024] 3. When the embryos are hatched out of the membrane, the fertilized eggs have been moved into the fry rearing pool, the water space is large, the water quality is easy to control, and there is no foam in the water body, and the initial hatched fry will not be killed by the foam adhesion;

[0025] 4. The fertilized eggs are hatched in the fry rearing pool, the density of the early Takifugu obscurus fry is reduced, and the water change and other human operations rarely contact the fry, reducing the damage of human operation to the fry;

[0026] 5. The Takifugu obscurus breeding efficiency is improved, and the total survival rate of the fry from the hatching of the fertilized eggs to the 0.7-0.8 cm Takifugu obscurus fry is 65%-70%. The present application saves the breeding production cost, and is simple to operate, easy to be accepted and popularized by people. DETAILED DESCRIPTION

[0027] The specific embodiment provided by the present application will be described in detail below in combination with examples.

[0028] Example 1:

[0029] The Takifugu obscurus fertilized egg hatching and fry rearing method of the present application, the specific production technical steps include:

[0030] 1) Concentrated hatching of fertilized eggs: the fertilized eggs obtained according to the conventional artificial breeding method of Takifugu obscurus are separately placed into indoor hatching barrels for hatching, the hatching barrel is a conical hatching barrel made of stainless steel, the upper half is cylindrical (diameter 580 mm x depth 550 mm), the lower half is conical (diameter 580 mm x depth 60 mm), the volume is 180 L, and the practical water body is 170 L. After brushing the eggs to remove the adhesion, static water aeration hatching is adopted, the aeration makes the water boiling, the hatching barrel is placed in a cement pool water bath, the water temperature is maintained at 21.5-22.0℃, and the hatching density of the fish eggs is controlled at 10-20 million eggs per barrel (i.e. 60-120 million eggs per m 3 ); the light intensity during the day is 800-1000 lx, and the light is turned on at night; 60 mesh screen is used to change water 3 times a day, each time 4 / 5, and the water is local freshwater, 48 hours of sedimentation, and 120 mesh screen silk net filtration.

[0031] 2) Fertilized egg separation: Fertilization rate of 30% to 80% of fish eggs need to be separated, and bad eggs that are yellow or moldy are separated and disposed of to make the fertilized egg rate reach more than 85%. The time for separating the fertilized eggs is selected within the range of 80 to 90 hours after fertilization of the fish eggs, and the specific operation is as follows: first, the air inlet of the hatching conical barrel is taken out, the water body is stirred to form small whirlpools, after 5 to 10 minutes, the fish eggs are all sunk to the conical bottom, then the fish eggs are sucked into a 80-mesh soft strainer with water by using a siphon method, the frame of the strainer is exposed to the water surface, and the net of the strainer is suspended in the water. The collected fish eggs are turned into a circular basin, the water body in the basin is stirred gently, the fish eggs are concentrated and sunk at the bottom of the center of the basin, and the bad eggs have a lower specific gravity than the fertilized eggs. Generally, the yellow eggs and moldy eggs on the surface of the egg layer are siphoned out by using a small air pipe, then the water body is stirred again, and the bad eggs are siphoned out repeatedly. After 4 to 5 times of repetition, the fertilized eggs are put back into the hatching barrel, and there are still a small amount of fertilized eggs in the siphoned-out fish eggs. The fertilized eggs are separated again according to the above method, and the fertilized eggs are put back into the hatching barrel. The whole operation is performed without separating the fish eggs from the water.

[0032] 3) Egg laying: About 96 hours after fertilization, the fertilized eggs start to break the membrane. At this time, attention should be paid to observation. As soon as the first hatched fry is seen, the fry is moved into a fry cultivation pond (area 20 m 2 , pond depth 1.5 m, effective water depth 1.4 m, water body 30 m 3 , effective water body 28 m 3 ), the egg laying water level is 60 cm, the egg laying density is 20,000 to 30,000 eggs per m 3 (24,000 to 36,000 eggs per pond), and the temperature difference between the water temperature in the hatching barrel and the target pond should not exceed 0.5℃.

[0033] 4) Air supply control: The density of the air diffuser stone is 1.5 per m 2 when the eggs are laid. After the first bottom suction, the density of the air diffuser stone is reduced to 1 per m 2 . When the eggs are laid, the air supply is boiling, and with the rising of the water level, the air supply is flat.

[0034] 5) Water temperature control: The water temperature when the eggs are laid is 22.0 to 22.5℃, after the eggs are laid, the temperature is increased by 0.5℃, and after 6 hours, the temperature is increased by another 0.5℃, until the water temperature is 22.5 to 23.5℃. On the third day after the eggs are laid, the natural water temperature is maintained at 22 to 25℃, and the water temperature changes by no more than 1℃ per day.

[0035] 6) Water quality control: water depth is 60 cm at the time of releasing eggs, and fresh water is used. From the second day, water is added 4 times, each time adding 20 cm. The first two times, local fresh water is used. At the third time, first local fresh water is used, then about 5-8 cm of local seawater (salinity 11-12) is added. At the fourth time, seawater is gradually added until full. From the fifth day, 1 / 3 of the water is replaced with 60 mesh water, and on the sixth day, 1 / 3 of the water is replaced and 2 times of bottom cleaning is performed with 60 mesh suction. On the seventh day, 2 / 3 of the water is replaced and 1 time of bottom cleaning is performed. From then on, 1 time of bottom cleaning is performed every day, and 2 / 3 of the water is replaced every other day. The temperature difference of the water added for replacement does not exceed 1°C.

[0036] 7) Bait and feeding method

[0037] From the third day after releasing eggs, egg yolks are fed, 5 times a day, 4-5 egg yolks per day per pool, sieved with 100 mesh silk gauze, and spread throughout the pool.

[0038] From the fifth to sixth day after releasing eggs, Artemia nauplii are introduced for feeding. The Artemia nauplii are required to have just hatched and broken membranes, sieved with 80 mesh, and maintained at a density of 500-1000 per liter, with 2 times of replenishment per day. Generally, on the first day of feeding Artemia nauplii, 5%-15% of the fry feed on Artemia nauplii. On the second day of feeding Artemia nauplii, 50%-60% of the fry feed on Artemia nauplii. On the third day of feeding Artemia nauplii, more than 90% of the fry feed on Artemia nauplii. On the eighth to ninth day after releasing eggs, egg yolks are stopped.

[0039] From the eighth to ninth day after releasing eggs, Artemia nauplii do not need to be sieved, and the amount of Artemia nauplii fed is gradually increased.

[0040] From the fifteenth to sixteenth day after releasing eggs, 40 mesh sieved freshwater branch crustaceans can be increased, and the amount of Artemia nauplii fed is reduced.

[0041] 8) Pooling: the egg distribution density exceeds 25,000 per m 3 Generally, the eggs are pooled once on the fourteenth day after releasing, the density of the fry is reduced by half, and the pool is netted with a 40-60 mesh soft silk gauze net. When the egg distribution density is less than 20,000 per m 3 Generally, no pooling is needed.

[0042] 9) Weakening of the emergence: 17-18 days after the eggs are laid, the weakening begins, and the fresh water is pumped out twice and added four times, i.e., on the first day, the water in the whole pool is pumped out by 1 / 2, and in the morning, fresh water is added to 1 / 4 of the water in the whole pool, and in the afternoon, fresh water is added again to 1 / 4, on the second day, the water in the whole pool is pumped out by 2 / 3, and in the morning, fresh water is added to 1 / 3 of the water in the whole pool, and in the afternoon, fresh water is added again to 1 / 3, and then the water is changed with fresh water; after 20 days after the eggs are laid, the fish fry is 0.7-0.8 cm in total length, and can be released to the pond for summer flower seed cultivation, before the emergence, the bottom is first sucked, and then the water level is lowered to 30 cm by siphon, and a 30-mesh soft gauze net is used for low-water-level netting. From the fertilized eggs to the 0.7-0.8 cm black juvenile fish fry, the overall emergence rate is 65%-70%.

[0043] Example 2

[0044] According to the above method, in 2022, 2.46 million fertilized eggs of the dark-striped puffer fish were obtained at the Shanghai Fisheries Research Institute Fengxian Research Base from May 1 to 4, and were placed in a conical stainless steel hatching barrel with a volume of 180 L for centralized hatching. After brushing the eggs to remove adhesion, static water aeration hatching was used, the density of fish eggs was 10-20 million per barrel (i.e. 60-120 million per m 3 ), the water temperature was 21.5-22.0℃, and 80-90 hours after fertilization of the eggs, the fertilized eggs were separated and the bad eggs were removed. 96 hours after fertilization, the fertilized eggs were observed to break the membrane, and the eggs were then placed in 8 30m 3 breeding ponds on May 5-8, with a density of 2.0-3.0 million per m 3 (24-36 million per pool). On May 21, two pools with a density of 3.0 million per m 3 on May 8 were separated, and the eggs were gradually weakened from May 21 according to the time of placement, and 161.2 million 0.7-0.8 cm black juvenile fish fry were released from May 23 to May 28, and the overall emergence rate from fertilized eggs to fry was 65.52%.

[0045] The preferred embodiments of the present application have been specifically described above, but the present application is not limited to the described embodiments, and those skilled in the art can make various equivalent modifications or replacements without deviating from the spirit of the present application, and these equivalent modifications or replacements are all included within the scope defined by the claims of the present application.

Claims

1. A method for hatching and rearing of fertilized eggs of Takifugu obscurus, characterized by, The method comprises the following steps: 1) Concentrated hatching of fertilized eggs: The fertilized eggs obtained according to the conventional artificial breeding method of T. nudus were divided and placed into indoor hatching barrels for hatching, the hatching barrels were conical and made of stainless steel, the upper half was cylindrical with a diameter of 580 mm x depth of 550 mm, the lower half was conical with a diameter of 580 mm x depth of 60 mm, the volume was 180 L, and the practical water volume was 170 L; after brushing the eggs to remove the adhesion, static water was used for aeration hatching, the water was boiling after aeration, the hatching barrel was placed in a cement pool water bath, the water temperature was maintained at 21.5-22.0℃, and the density of fish egg hatching was controlled at 10-20 million eggs / barrel, i.e. 60-120 million eggs / m 3 ; the light intensity during the day was 800-1000 lx, and the light was turned on at night; 60 mesh screen was used to change water 3 times a day, 4 / 5 each time, and the water was local freshwater, 48 hours of sedimentation, and filtered with 120 mesh silk screen; 2) Fertilized egg separation: fish eggs with a fertilization rate of 30% to 80% need to be separated, and bad eggs that are yellow or moldy are separated and disposed of, so that the fertilized egg rate reaches more than 85%, and the operation time of separating the fertilized eggs is selected to be within the range of 80 to 90 hours after the fertilization of the fish eggs of the T. nudus, and the specific operation is as follows: first, the inflatable head of the hatching conical barrel is taken out, the water body is stirred to form small whirlpools, after 5 to 10 minutes, the fish eggs are all sunk to the conical bottom, then the fish eggs are sucked into a 80-mesh soft strainer by using a siphon method, the frame of the strainer is exposed to the water surface, and the net of the strainer is suspended in the water, the collected fish eggs are turned into a circular basin, the water body in the basin is stirred gently, the fish eggs are concentrated and sunk at the bottom of the center of the basin, the bad eggs have a lower specific gravity than the fertilized eggs, the yellow eggs and the moldy eggs on the surface of the egg layer are siphoned out by using a small air pipe, then the water body is stirred again, the bad eggs are siphoned out again, and the operation is repeated for 4 to 5 times, the fertilized eggs are put back into the hatching barrel, and there are still a small amount of fertilized eggs in the fish eggs siphoned out, the fertilized eggs are separated again according to the above method, and the fertilized eggs are put back into the hatching barrel; and the whole operation is performed without taking the fish eggs out of the water; 3) Spawning: about 96 hours after fertilization, the fertilized eggs begin to break the membrane, at this time, pay attention to observation, as soon as you see the initial hatched fry, hatch into the fry culture pool, area 20 m 2 , pool depth 1.5 m, effective water depth 1.4 m, water body 30 m 3 , effective water body 28 m 3 , the water level for spawning is 60 cm, the spawning density is 20-30 thousand particles / m 3 , that is, 240-360 thousand particles / pool, the temperature difference between the water temperature in the hatching barrel and the target pool should not exceed 0.5℃; 4) Air control: the density of air stone is 1.5 / m when spreading eggs 2 , the density of air stone is reduced to 1 / m after the first suction 2 , the air is boiling when spreading eggs, and the air is flat as the water level rises 5) Water temperature control: the water temperature is 22.0 to 22.5 ℃ when the eggs are put in, after the eggs are put in, the water temperature is increased by 0.5 ℃, and the water temperature is increased by 0.5 ℃ every 6 hours until the water temperature is 22.5 to 23.5 ℃; starting from the third day after the eggs are put in, the natural water temperature is kept at 22 to 25 ℃, and the water temperature changes by no more than 1 ℃ per day; 6) Water quality control: the water depth is 60 cm when the eggs are put in, and fresh water is used, starting from the second day, the water is added to the full capacity in four times, the water added in the first two times is local fresh water, when the water is added in the third time, the local seawater with a salinity of 11 to 12 is added after the fresh water, and the water is directly added to the full capacity by gradually adding seawater in the fourth time, and the water used after the fifth day is seawater, the water is changed by 1 / 3 by using a 60-mesh strainer on the sixth day, the water is changed by 1 / 3 and the bottom is cleaned by using a 60-mesh strainer twice, the water is changed by 2 / 3 and the bottom is cleaned once on the seventh day, and the bottom is cleaned once and the water is changed by 2 / 3 every other day after that, and the water temperature difference of the added water is no more than 1 ℃; 7) Feeds and feeding method Starting from the third day after the eggs are put in, egg yolk is fed, 4 to 5 egg yolks are fed to each pond every day, the egg yolk is sieved by using a 100-mesh silk screen, and the egg yolk is sprayed in the whole pond; Starting from the fifth to sixth day after the eggs are put in, Artemia nauplii are introduced and fed, the Artemia nauplii are required to be just hatched and broken, the Artemia nauplii are sieved by using a 80-mesh screen, the density of the Artemia nauplii is maintained at 500 to 1,000 pieces per liter, and the Artemia nauplii are supplemented twice a day; on the first day of feeding the Artemia nauplii, 5% to 15% of the fry feed on the Artemia nauplii, on the second day of feeding the Artemia nauplii, 50% to 60% of the fry feed on the Artemia nauplii, on the third day of feeding the Artemia nauplii, more than 90% of the fry feed on the Artemia nauplii, and the egg yolk is stopped feeding on the eighth to ninth day after the eggs are put in; Starting from the eighth to ninth day after the eggs are put in, the Artemia nauplii do not need to be sieved when the Artemia nauplii are fed, and the feeding amount of the Artemia nauplii is gradually increased; Starting from the fifteenth to sixteenth day after the eggs are put in, the feeding amount of the Artemia nauplii is reduced, and 40-mesh sieved freshwater branch crustaceans are added; 8) Ponds: the density of eggs exceeds 250,000 eggs / m 3 , 14 days after the eggs are laid, the density of eggs is reduced by half, and the 40-60 mesh soft screen silk net is used to pull the net to fill the water; the density of eggs is less than 200,000 eggs / m 3 , no division of ponds; 9) Weakening of the emergence: in the 17th ~ 18th day after oviposition, start to weaken, 2 times of water 4 times of water to complete, namely, the first day, 1 / 2 of the pool water, add water to 1 / 4 of the pool water in the morning, add water to 1 / 4 in the afternoon, the second day, 2 / 3 of the pool water, add water to 1 / 3 of the pool water in the morning, add water to 1 / 3 in the afternoon, then use fresh water to replace water; 20 days after oviposition, fish fry full length 0.7~0.8 cm, put into the pond to carry out summer flower seed cultivation, before the emergence, first suction bottom, then siphon to reduce water level to 30 cm, use 30 mesh soft screen gauze to carry out low water level net.