CN105379650B - A kind of method for obtaining batch America hilsa herring fertilized eggs - Google Patents

Abstract

A method for obtaining fertilized eggs of shad shad in batches, which is characterized by adopting plastic greenhouse cement pools to carry out overwintering cultivation of backup parents, using local fresh water, gradually increasing the salinity when changing the water, until the final salinity reaches 12-15‰, and overwintering the cultivation water temperature Keep the temperature above 8°C. The bait is commercial freshwater fish extruded pellet feed No. 3. From the end of March to the beginning of April, the parents will enter spring to strengthen cultivation. As the temperature rises, use ventilation on both sides of the plastic greenhouse, remove the plastic film, and add shade. membrane to keep the water temperature in the cement pool at 16-18°C; each time the water is changed, the salinity is gradually reduced by 2-3‰ each time, until the salinity reaches the local river water at the end, in mid-May-early June, select to promote production Put the parents into the production-promoting ring, the stocking density of the production-promoting parents is 0.8-1 fish/m ² , adopt the natural oviposition fertilization method, collect the fertilized eggs in time after the parents oviposit, carry water for operation, and move them to the hatching pool after counting.

Description

A method for obtaining fertilized eggs of American shad in batches

technical field

The invention relates to aquaculture, in particular to a method for obtaining fertilized eggs of American shad in batches.

Background technique

American shad (Alosa sapidissima), commonly known as American shad, is mainly distributed in the rivers and oceans of the Atlantic west coast of North America from Quebec, Canada to Florida, the United States. American shad is a reproductive and migratory fish. It is plump and plump, with delicious meat and high economic value. It has been widely introduced all over the world. In China, the Shanghai Fisheries Research Institute took the lead in introducing fertilized eggs produced by wild shad from the Mississippi River in the United States in 1998, and then hatched fertilized eggs, cultivated seedlings and cultured them. Because American shad is similar to Chinese shad in appearance and comparable in meat quality, American shad is also very popular with people when the Yangtze River shad is on the verge of extinction, and the market price is also very high, 200-300 yuan/catties, and farmers have flocked. Breeding this fish, the seed of this fish has formed broad market prospect. Due to the unique reproductive habits of this fish, at present, American shad breeding farmers use deep well water below 150 meters underground and with a stable water temperature of 16-17°C in winter and spring to carry out parental breeding of the fish, and then directly in the parental breeding ponds. The method of collecting fertilized eggs, but the underground deep well water resources are limited, and there are also geographical limitations, and many coastal cities have restricted the use of underground deep well water for aquaculture, and the existing method of collecting fertilized eggs in American shad adult fish breeding ponds The parameters are relatively blind, and the chance is large, which limits the batch supply and large-scale production of American shad. Therefore, there is an urgent need for a set of technologies to use river water or estuary water from natural waters to complete parental breeding, natural mating and fertilization collection of American shad without deep well water to maintain water temperature, so as to obtain batches of fertilized eggs to adapt to the Americas. Bulk supply of shad seedlings.

Contents of the invention

The problem to be solved by the present invention is to provide a method for obtaining fertilized eggs of American shad in batches.

The technical scheme of the present invention is composed of backup parent overwintering cultivation, parent spring intensive cultivation, production-promoting parent selection, parent production promotion, natural oviposition fertilization and fertilized egg collection production steps, which is characterized in that artificially bred American shad over 2 years old Adult fish are used as backup parents for artificial reproduction. From November to December each year, commercial adult fish that are strong, plump, and weigh 0.75-1.5Kg are selected to enter the backup parents for overwintering cultivation. The backup parents are cultivated in cement pools in plastic greenhouses. Smooth, ^square or round cement pond with an area of 150-250m2, 1.2-1.8m deep, with a bow-shaped ring top above the cement pond, covered with a light-transmitting and heat-preserving plastic film, and covered with a shading film with a shading rate of 90% on the plastic On the film, adjust the light, reduce the light transmittance, and adjust the covering rate of the shade film according to the water color of the pool, and maintain the covering rate at 30%-40%; place air heads in the cement pool, and the air head density is 0.2-0.3 pieces/m ² , use a Roots blower to inflate continuously for 24 hours, and the air volume is boiling; before stocking, disinfect the cement pool, enter 20cm of water, dissolve it with 20PPm bleaching powder, sprinkle the whole pool, soak for 48 hours, drain and rinse, and dry for 3-4 days Reuse; when the selected backup parent is put in a suitable place to breed, adopt local fresh water, one week after putting in a suitable place to breed, when changing water at every turn, increase salinity gradually, rise salinity 2-3‰ each time, reach 12-15‰ to final salinity, raise The water used for salt and overwintering cultivation uses local estuary water with a salinity of 10-15‰. All water is used for primary sedimentation in ponds, natural sunlight preheating and secondary sedimentation in cement pools in plastic greenhouses, and then 80-mesh sieve tulle Filter, change the water once a week, 2/3 each time, turn over the pond once every 25-35 days, keep the water temperature for overwintering cultivation above 8°C, change the water temperature difference less than 2°C, and turn the pond water temperature difference less than 1°C; The bait is No. 3 commercial freshwater fish extruded pellet feed, with a crude protein content of 38%. It is fed once a day, subject to 1-2 hours of ingestion; in order to alleviate water pollution caused by excrement and residual bait deposition at the bottom of the cultivation pond , stocking white prawns in the breeding pond, the stocking amount is 5-10 kg/pond; from the end of March to the beginning of April, it enters the stage of intensive cultivation of the parents in spring. As the outside temperature rises, ventilate on both sides of the plastic greenhouse, remove the plastic film, cover the first layer of shading film, and then cover the second layer of shading film to keep the water temperature in the cement pool at 16-18°C; Reduce the salinity by 2-3‰ each time until the salinity reaches the local river water. The water used for salt reduction and intensive cultivation uses local river water, and all water is used for natural cooling in cement pools that have undergone first-level sedimentation in ponds and shady greenhouses. and secondary sedimentation, and then filter with 80-mesh sieve silk, change the water once every 5-6 days, 2/3 each time, turn the pool once every 2 weeks, change the temperature difference of water less than 2°C, and turn the water temperature difference less than 1°C; the bait is No. 3 commercial seawater fish extruded pellet feed, with a crude protein content of more than 40%, and it is fed twice a day, subject to 1-2 hours of ingestion; other management is the same as before; until mid-May-6 At the beginning of the month, at this time the shade greenhouse The water temperature in the breeding pond is 17-19°C, and the abdomen of the parent female fish gradually expands. At this time, the parent for production promotion can be selected. The selection criteria: the rear abdomen of the female fish is swollen and soft, the cloaca is reddish, and some eggs flow out when the abdomen is lightly pressed; For male fish, a small amount of semen flows out of the cloacal hole after light pressure, and it does not disperse when it meets water; the selected parents are transported in 100L drums and put into the birth promotion ring, and 2-3 parents are placed in each bucket; during the whole selection and transportation process The operation should be gentle and not separated from the water; the production promotion ring adopts a 30.0m×5.0m×1.2m rectangular cement pool with a water depth of 1.0m. After constructing the middle separation wall and rounding the corners of the pool, a 60.0m×2.4m×1.1m oval closed For the ring road, a 0.75KW water wheel aerator is used to increase oxygen and form water flow, and a 10KW air-energy heat pump hot water unit is used to maintain the stability of the water temperature in the ring road through cold and hot heat dissipation pipes. A bow-shaped ring top is set above the cement pool. Covered with three layers of shading film with a shading rate of 90%, to ensure that the light intensity during the day is lower than 300Lux, the stocking density of the production-promoting parents is 0.8-1 tail/m ² , the ratio of male to female is 1:1.1-1:1.3, and the water temperature for production-promoting 17.5-19°C; after the parent enters the labor-inducing circuit, keep absolutely quiet around the labor-inducing pool, use natural spawning and fertilization methods, keep the water velocity in the closed circuit at 0.07-0.11m/s, and the water temperature for promoting labor at 17.5-19 ℃; Feed a small amount of extruded compound feed in the production promotion pool to reduce the intake of fertilized eggs by the parents, but the residual bait should be removed in time, otherwise the extruded feed will sink to the bottom after soaking in water for a long time, and the fertilized eggs will be mixed, causing the fertilized eggs to be washed and separated Impurities are difficult; American shad parents have the habit of ingesting fertilized eggs. After the parents lay eggs, they should collect fertilized eggs in time. At the bottom of the pool at the dead corner of the net and flat copying loop, the American shad egg membrane is very thin, and the fertilized eggs cannot be squeezed out of the water. The eggs should be collected with water. After each egg copying, turn on the aerator for 3-5 minutes to let The eggs are automatically flipped to the dead corner of the ring, and then the eggs are copied. After repeating 3 times, more than 95% of the eggs can be collected, then cleaned, counted, and then moved to the hatching pool.

The outstanding features of the present invention relative to the prior art are: 1) During the overwintering cultivation period of the backup parent, the water temperature of the cultivation water is raised by sunlight and plastic film under natural conditions, and the culture water temperature is maintained at 8.5°C without energy heating. When the natural water temperature is higher than 18°C during the intensive cultivation period of the parents in spring, use ventilation and shade film to reduce the water temperature of the cultivation water and keep the cultivation water temperature below 18°C; during the production promotion period, use air energy units To reduce and maintain the water temperature of the water; therefore, during the whole parental cultivation and reproduction period, deep well water (16-17°C in winter and spring) is not used to cool down to maintain the water temperature of the parental cultivation water, nor is deep well water used as breeding water, This has protected precious clean underground deep well water resource, also saved energy; Fresh water resources; 3) In the case of long-term net-pull and pool-moving exercise during the parental cultivation period, the method of selecting and moving the parents with better gonad development to concentrate on the production-promoting ring for natural oviposition, mating and fertilization, which is better than the existing method of directly The method of collecting fertilized eggs in the parent breeding pond has many advantages, such as; in the production-promoting ring, the better-developed male and female parents have a higher encounter rate, and the probability of natural mating is relatively higher, and it also prevents the interference of gonads with undeveloped fish The parents naturally mate and ingest the fertilized eggs produced; at the same time, it also avoids the difficulty of cleaning and separating the fertilized eggs collected due to the relatively large amount of pollutants and residual bait in the conventional parent breeding pond; 4) adopting this technical scheme can obtain large quantities The American shad fertilized egg is easier to operate, the method is more practical, and the quality of the fertilized egg and larvae is indirectly improved. It is suitable for large-scale breeding and production of American shad, and is easy to be accepted and popularized by people.

Description of drawings

Figure 1 is a schematic diagram of the structure of the production-promoting loop of American shad parents.

Detailed ways

The present invention consists of the following production steps:

1. Overwintering breeding of backup parents: artificially bred American shad adult fish over 2 years old are used as backup parents for artificial breeding, and commercial adult fish with strong body, plump body and weight of 0.75-1.5Kg are selected for entry in November-December of each year. The reserve parents are cultivated in winter, and the reserve parents are cultivated in a simple plastic greenhouse cement pool. The area of the square or round cement pool is 150-250m ² , the depth is 1.2-1.8m, and the pool wall is smooth; Light insulation plastic film, cover the plastic film with a shading film with a shading rate of 90%, adjust the light, reduce the light transmittance, and adjust the shading rate of the shading film according to the water color of the pool, generally maintained at 30%-40%; Air head is placed in the cement pool, the air head density is 0.2-0.3 pieces/m ² , and the Roots blower is used to inflate continuously for 24 hours, and the air volume is boiling. Disinfect the cement pool before stocking, enter 20cm of water, dissolve the whole pool with 20PPm bleaching powder, sprinkle it, soak it for 48 hours, drain it, rinse it, and let it dry for 3-4 days before using it. When the selected backup parents are stocked, use local fresh water. One week after stocking, each time the water is changed, the salinity is gradually increased, and the salinity is increased by 2-3‰ each time, until the final salinity reaches 12-15‰. The water used for cultivation is estuary water with a local salinity of 10-15‰. All water is used for primary sedimentation in ponds, natural sunlight preheating and secondary precipitation in cement pools in plastic greenhouses, and then filtered with 80-mesh silk screen. Change the water once a week, 2/3 each time, turn over the pond once every 25-35 days, keep the water temperature above 8°C for winter cultivation, change the water temperature difference less than 2°C, and turn the pond water temperature difference less than 1°C; the bait is commercial No. 3 freshwater fish extruded pellet feed, with a crude protein content of 38%, is fed once a day, subject to 1-2 hours of ingestion; the breeding pond is stocked with white prawns, and the stocking amount is 5-10 kg/pond;

2. Intensive cultivation of parents in spring: from the end of March to the beginning of April, it enters the stage of intensive cultivation of parents in spring. Remove the plastic film, cover the first layer of shading film, and then cover the second layer of shading film to keep the water temperature in the cement pool at 16-18°C; every time the water is changed, the salinity is gradually reduced, and the salinity is reduced by 2- 3‰, until the final salinity reaches the local river water, the water used for desalinization and intensive cultivation uses local river water (fresh water). Filter with mesh sieve and tulle, change the water once every 5-6 days, 2/3 each time, turn over the pool once every two weeks, the temperature difference between changing the water is less than 2°C, and the temperature difference between turning the pool is less than 1°C; the bait is commercial sea fish Extruded pellet feed No. 3, with a crude protein content of more than 40%, is fed twice a day, subject to 1-2 hours of ingestion; other management is the same as before;

3. Selection of parents for production promotion: From mid-May to early June, when the water temperature in the shady greenhouse cultivation pool is 17-19°C, the abdomen of the parent female fish gradually expands, and the parents for production promotion can be selected at this time. Selection criteria: female fish The hind abdomen is swollen and soft, the cloaca is reddish, and some eggs flow out when the abdomen is gently pressed; in male fish, a small amount of semen flows out when the cloaca is lightly pressed, and it does not disperse when it meets water; the selected parents are transported in drums (100L) Put it into the production-promoting ring, and put 2-3 parents in each bucket; the whole selection and transportation process should be handled gently without leaving the water;

4. Promoting the production of the parents: The production-promoting ring road (referring to Fig. 1) adopts a rectangular cement pool (30.0m * 5.0m * 1.2m) 1, and the water depth is 1.0m, and forms an ellipse through building the middle separation wall 2 and rounding the corners of the pool Closed loop (60.0m×2.4m×1.1m) 3, using 0.75KW waterwheel type aerator 4 to increase oxygen and form water flow 5, using 10KW air energy heat pump hot water unit 6 to maintain The water temperature in the ring road is stable, and a bow-shaped ring top is set above the cement pool. The top is covered with three layers of shading film with a shading rate of 90% to ensure that the light intensity during the day is lower than 300Lux ^. , the ratio of male to female is 1:1.1～1:1.3, and the water temperature for promoting production is 17.5～19℃;

5. Natural spawning and fertilization: After the parent enters the production-promoting ring, keep the surroundings absolutely quiet, adopt the natural spawning and fertilization method, keep the closed-loop water velocity at 0.07-0.11m/s, and the production-stimulating water temperature at 17.5-19°C ; Feed a small amount of extruded compound feed in the production promotion pond, and remove the residual bait in time;

6. Collection of fertilized eggs: American shad parents lay eggs and mate in the early morning at dawn, usually at 5:00-6:00, and the collection of fertilized eggs usually starts at 7:00. After the water flow rate drops, use a 24-mesh soft sieve silk triangular copying net to level the bottom of the pool at the dead corner of the loop, collect eggs and operate with water. After each copying of eggs, turn on the aerator for 3-5 minutes to let the eggs turn automatically Go to the dead corner of the ring road, and then copy the eggs. After repeating 3 times, more than 95% of the eggs can be collected, then cleaned, counted, and then moved to the hatching pool.

The above-mentioned specific implementation methods have been tested at the base of the Seed Technology Center of the institute. During 2014-2015, American shad parents were cultivated and production was promoted, and a total of 177,600 fertilized eggs were obtained. The details are as follows:

On May 21, 2014, the parents were induced by hormones. On May 22 and 23, 110,000 eggs were obtained, and 40,000 fertilized eggs were obtained, with an average fertilization rate of 36.4%.

In May 2015, American shad parents were produced in two batches. A total of 563,200 eggs were obtained, and 137,600 fertilized eggs were obtained, with an average fertilization rate of 24.4%. The first batch, on May 18, selected 2-year-old progenitor parents and placed them in Dong 10 ^# , with 64 females and 76 males, and the ratio of male to female was 1:1.2. See Table 1 for the fertilization of eggs; the second batch, May 28 The 3-year-old progenitor parents were selected and put into Dong 9 ^# , with 71 females and 76 males. The ratio of male to female was 1:1.1.

Table 1 Oviposition and fertilization status of the first batch of pro-production parents in 2015 (East 10 ^# )

Table 2 Oviposition and Fertilization of the First Batch of Parents Stimulated in 2015 (East 9 ^# )

Claims (1)

1. A method for obtaining fertilized eggs of shad shad in batches, consisting of overwintering cultivation of backup parents, intensive cultivation of parents in spring, selection of parents for promoting production, promoting production of parents, fertilization of natural spawning, and collection of fertilized eggs. It is characterized in that artificial American shad adult fish over 2 years old are used as backup parents for artificial breeding. From November to December each year, commercial adult fish with a healthy body, plump body, and a weight of 0.75-1.5Kg are selected to enter the backup parents for overwintering cultivation, and plastic greenhouse cement is used. The pool is used to cultivate the reserve parents, and the ^square or round cement pool with a smooth wall and an area of 150-250m2 is used, and the depth is 1.2-1.8m. A bow-shaped ring top is set above the cement pool, and the top is covered with a light-transmitting thermal insulation plastic film, with a shading rate of 90. % of the shading film is covered on the plastic film to adjust the light and reduce the light transmittance, and at the same time adjust the covering rate of the shading film according to the water color of the pool, generally maintained at 30%-40%; place the air head in the cement pool, and the air head density is 0.2-0.3 pieces/m ² , use a Roots blower to inflate continuously for 24 hours, and inflate until boiling; before stocking, disinfect the cement pool, enter 20cm of water, dissolve it with 20PPm bleaching powder, sprinkle the whole pool, soak for 48 hours, drain and rinse. , dry for 3-4 days before use; when the selected backup parents are stocked, use local fresh water, and one week after stocking, when changing the water each time, gradually increase the salinity, and increase the salinity by 2-3‰ each time, until the final salinity It reaches 12-15‰, and the water used for salt raising and overwintering cultivation uses local estuary water with a salinity of 10-15‰. All the water is passed through primary sedimentation in ponds, preheating by natural sunlight in cement pools in plastic greenhouses, and secondary precipitation. Use 80-mesh sieve to filter, change the water once a week, 2/3 each time, turn over the pond once every 25-35 days, keep the water temperature above 8°C for overwintering cultivation, and change the water temperature difference less than 2°C. The temperature difference in the pool water is less than 1°C; the bait is No. 3 commercial freshwater fish extruded pellet feed, with a crude protein content of 38%, and it is fed once a day, subject to 1-2 hours of ingestion; The bait deposits are corrupted and pollute the water quality. White shrimps are stocked in cement ponds, and the stocking amount is 5-10 kg/pond; from the end of March to the beginning of April, it enters the stage of intensive cultivation of the parents in spring. At this time, the water temperature in the cement pond of the plastic greenhouse has just begun to reach 15 -16°C, as the outside temperature rises, use ventilation on both sides of the plastic greenhouse, remove the plastic film, cover the first layer of shading film, and then cover the second layer of shading film to keep the water temperature in the cement pool at 16-18°C; During the first water change, the salinity is gradually reduced, and the salinity is reduced by 2-3‰ each time, and finally reaches the salinity of the local river water. The water used for salt reduction and intensive cultivation is local river water, and all water is used for first-level sedimentation and shading The greenhouse cement pool is naturally cooled and secondary sedimentation, and then filtered with 80-mesh sieve silk screen, the water is changed once every 5-6 days, 2/3 each time, and the pool is turned once every 2 weeks, and the temperature difference between water changes is less than 2°C , the water temperature difference in turning over the pond is less than 1°C; the bait is No. 3 commercial seawater fish puffed pellet feed, with a crude protein content of more than 40%, and it is fed twice a day, subject to 1-2 hours of ingestion; other management is the same as before; From mid-May to early June, the When the water temperature in the cement pool in the shady greenhouse is 17-19 ℃, the abdomen of the parent female fish gradually expands. At this time, the parent for production promotion can be selected. The selection criteria: the rear abdomen of the female fish is enlarged and soft, the cloaca is slightly red, and some abdomen is lightly pressed Eggs flow out; for male fish, a small amount of semen flows out when the cloaca is lightly pressed, and it does not disperse when it meets water; the selected parents are transported in 100L drums and put into the production-promoting ring, and 2-3 parents are placed in each bucket; the whole selection During transportation and transportation, the operation should be gentle and not separated from the water; the production promotion ring adopts a 30.0m×5.0m×1.2m rectangular cement pool with a water depth of 1.0m. After constructing the middle partition wall and rounding the corners of the pool, an elliptical closed loop is formed. The 0.75KW waterwheel type aerator is used to increase oxygen and form water flow. A 10KW air source heat pump hot water unit is used to keep the water temperature in the loop stable through cold and hot heat dissipation pipes. A bow-shaped ring top is set above the cement pool, and the top is covered with three layers of shade The shading film with a rate of 90% ensures that the light intensity during the day is lower than 300Lux, the stocking density of the progeny-promoting parents is 0.8-1 tail/m ² , the ratio of male to female is 1:1.1-1:1.3, and the water temperature for procreative production is 17.5-19°C ; After the parents enter the birth promotion ring, keep absolutely quiet around the birth promotion ring, adopt natural spawning and fertilization methods, keep the water flow velocity of the closed ring at 0.07-0.11m/s, and the birth-stimulation water temperature at 17.5-19°C; Feed a small amount of extruded compound feed in the production ring to reduce the intake of fertilized eggs by the parents, but the residual bait should be removed in time, otherwise the extruded feed will sink to the bottom after soaking in water for a long time, and the fertilized eggs will be mixed, making it difficult to clean the fertilized eggs and separate impurities American shad parents have the habit of ingesting fertilized eggs. After the parents lay eggs, they should collect fertilized eggs in time. Before collecting fertilized eggs, stop the waterwheel type aerator, let the water flow rate drop, and use a 24-mesh soft sieve silk triangular net At the bottom of the pool at the dead corner of the flat copying ring road, the American shad egg membrane is very thin, and the fertilized eggs cannot be squeezed out of the water. The eggs should be collected with water. After each egg copying, turn on the aerator for 3-5 minutes to let the eggs automatically Flip to the dead corner of the ring, and then copy the eggs. After repeating 3 times, more than 95% of the eggs can be collected, then cleaned, counted, and then moved to the hatching pool.