The artificial seedlings of P. scallop include mainly the preservation of bait, the cultivation of bait, the harvesting and stocking of pro-shellfish, egg collection and hatching, the selection and breeding of larvae, the placement of attachment bases, and the management of attached juveniles.
(1) Pro-shellfish harvesting and stocking: Accurate mastering of the breeding period of E. scallop, breeding pro-scallops indoors during the breeding period. After nearly 10 years of observation, the breeding season of E. scallops in northern Yellow Sea of ​​China is at the end of March. By mid-April, the water temperature in the sea area is 3-5°C. In order not to miss the season, at the end of March, Chengbei, which has been raised on the raft of the sea area or the seabed for 2 years and has a body height of about 10 centimeters, should be stored indoors. However, in order to make full use of the nursery equipment, some production units carry out two trips. Nursery, in the early February of the breeding season before the breeding season, the pro-beads will be used indoors to warm up and ripen, and egg-laying and nursery will be advanced.
After the pro-beaten came back, remove the attachments in time and brush the sludge. Select healthy individuals and separate the male and female. Hang them in the pool with a lantern net cage, or directly on the bottom of the pool, for each cubic meter of water. Stocking 30-50.
During the process of feeding broods and worms, the total amount of water is changed by 1-2 times a day. When the water is changed, the dead worms are picked out and the bottom of the pool is removed. In the process of pro-feeding, if the temperature is increased, it must be fed enough cells. Algae.
(2) Obtaining eggs: Natural discharge is a good method for obtaining eggs in the process of parenting. Natural spawning not only has good egg hatching rate, but also larvae are robust, but can't do unplanned concentrated egg harvesting. In order to achieve a planned concentrated egg, it is also easy to collect egg through shady and warming stimulation. The method of obtaining eggs. However, this method must be done only when the gonads are fully mature. The net profit is usually during the stocking process and it is found when there is a sperm spawning. The practice is to pro-bellied fish on the bench for drying for about 1 hour, and then select individuals full of gonads, male and female separately placed in the water temperature than the temperature of the storage tank water temperature of 3 °C in the induced discharge, when the egg amounted to 100-200 / In milliliters, you can move pro-Bay to another pool to continue spawning, then take semen several times to perform artificial insemination, microscopic observation, control the appropriate number of sperm, this method of harvesting eggs can also get good results .
(3) Incubation: Divide the fertilized eggs with water or divide the cells to control the density at 50 cells per ml or so. In order to prevent the hatching effect of the fertilized eggs from accumulating at the bottom, the water is used every hour for the incubation process. Stirred once, until the development of the larval larval stage, at a water temperature of about 12 °C, about 70 hours more than the diameter can be developed to the face plate larvae.
(4) Larval breeding and breeding: When the larvae develop to the larvae of the faceplate, they can be cultured with trawl nets made of NX-103 sieves. If the number of larvae is small, they can be collected by concentrated drainage and the larval density. Directly affect the culture effect, the culture density of scallop spawning larvae should be 7/ml, and when it is newly bred, the water quality will be clean and the larvae will be small (general body length is only about 100 microns), so it is not necessary to fill the water. , only add 1/2, fill once or twice in the next day, the temperature of the culture pool should be consistent with the temperature of the hatching pool.
After the water is filled, the filter rod (drum) made of NX-103 sieve is used to change the water the next day. The water is changed twice a day, each time the water is changed by 1/2. After a period of incubation, the larvae die and die. The bait and suspended matters in the water gradually sink to the bottom of the pool, so in addition to changing the water frequently, it is necessary to take a breeding method once every five days or so to ensure the water quality is clean.
Appropriate bait species and density are the main factors for nursery success. The bait is best fed with the mixture of Zhanjiang fork algae and Pyramidophytes (or Platymonas olivaceus) (mostly Zhanjiang forkworm). The number of the above-mentioned monocytic algae is calculated to be 20,000-30,000 cells/ml according to the density in the culture pond, and this number can satisfy the needs of the growth and development of the larvae. The bait should be less frequently cast and not cast too much at one time. At the same time, the number of baits should be determined according to the different growth and development summers. For example, within a few days after breeding, due to smaller larvae, less food intake, larger cells It is also difficult to swallow. During this time, a small amount of the smaller cell Zhanjiang fork algae is fed separately. After that, as the larvae increase, the food intake increases. At this time, in addition to the golden algae, the algae (or cyanobacteria) should also be mixed (or Platymonas esculenta), and the amount of diet also gradually increased, the feed should be fresh, no or less protozoa.
The water temperature also directly affects the growth and development of larvae and the number of attachments. In order to improve the seedling raising effect, larvae must be raised (controlled) in temperature during the larval rearing process. The method is to first raise the water temperature in the preheating pool. Water temperature is required. When the water is changed, the warmed seawater is sent to the cultivation pond and the water temperature of the nursery is gradually increased. The daily temperature increase rate does not exceed 1°C. When the temperature is about 15°C, the named water temperature is constant within this range. When the water temperature of the sea area rises above 15°C No longer (actually impossible) temperature control.
(5) Attachment and attachment: At a water temperature of about 15°C, if the type of feed is suitable and the quantity meets the requirements, after about 20 days of cultivation, the larvae will be able to end their planktonic life and become abnormally attached. Appropriate attachment base depots are used for attachment of metamorphic juveniles. There are many materials suitable for attaching base materials, of which the brown shades made of a brown rope with a diameter of about 6 mm are effective. However, because the brown rope contains harmful substances such as tannin and pectin, if the treatment is not clean, it will be counterproductive. Can you handle the brown rope? The general treatment process is: Prepare the seedling curtain before using 1-2% (with a weight ratio of the cord) sodium hydroxide soaked in fresh water for a few days, then change the water for cleaning, to the lighter when the color is taken out to get beat on the rope machine Wash, then arrange the curtain, then prepare the seedlings and then cook them in an iron pot. Open the pot for 2 hours. The cooked seedlings curtains are then soaked in clean seawater. Always change the water during the soaking process. Basic colorless.
When the larvae are about to end their abnormal attachment to planktonic life, a black spot is created at the back of the mouth and ditch, and a black spot is called the eye point. The initial eye spot is small and irregular, and the second and third days become round and obvious. Afterwards, the swimming ability weakened, and the feet were formed one after the other. Therefore, the emergence of eye spots is a sign of the timing of the attachment of bases, due to differences in the growth and development of larvae. Occasionally there are eye-points too early and late, so the timing of the attachment should begin when the proportion of eye-larvae reaches 20% or more. It was too early to vote because of the sedimentation of floating sludge on the seedling screen, which affected the attached seedlings. At the same time, it was not convenient to manage. If it was too late, it would miss the chance of attachment.
Before putting on the seedling curtains, wash the pools first, apply a layer of curtains to the bottom of the washed pools, press the stone on the bottom curtains, add fresh seawater, then haul the larvae, concentrate, and collect them until the pool is covered. In the middle, on the same day or the next day, the curtain is hung or hung on a float welded with a polyvinyl chloride tube.
After changing the curtain, increase the amount of water change and the number of water changes. At the same time, increase the amount of feeding. Normally, the larvae can be attached one week after the curtain is lowered. When there is no planktonic larvae in the pool, they can be used without filter rods (drums). When the hose is drained, when the jumbo shell is attached to about 600 microns, the pool can be quantitatively counted and bred at sea. The water temperature in the room should be gradually reduced to the same level as the sea before leaving the pool.
(1) Pro-shellfish harvesting and stocking: Accurate mastering of the breeding period of E. scallop, breeding pro-scallops indoors during the breeding period. After nearly 10 years of observation, the breeding season of E. scallops in northern Yellow Sea of ​​China is at the end of March. By mid-April, the water temperature in the sea area is 3-5°C. In order not to miss the season, at the end of March, Chengbei, which has been raised on the raft of the sea area or the seabed for 2 years and has a body height of about 10 centimeters, should be stored indoors. However, in order to make full use of the nursery equipment, some production units carry out two trips. Nursery, in the early February of the breeding season before the breeding season, the pro-beads will be used indoors to warm up and ripen, and egg-laying and nursery will be advanced.
After the pro-beaten came back, remove the attachments in time and brush the sludge. Select healthy individuals and separate the male and female. Hang them in the pool with a lantern net cage, or directly on the bottom of the pool, for each cubic meter of water. Stocking 30-50.
During the process of feeding broods and worms, the total amount of water is changed by 1-2 times a day. When the water is changed, the dead worms are picked out and the bottom of the pool is removed. In the process of pro-feeding, if the temperature is increased, it must be fed enough cells. Algae.
(2) Obtaining eggs: Natural discharge is a good method for obtaining eggs in the process of parenting. Natural spawning not only has good egg hatching rate, but also larvae are robust, but can't do unplanned concentrated egg harvesting. In order to achieve a planned concentrated egg, it is also easy to collect egg through shady and warming stimulation. The method of obtaining eggs. However, this method must be done only when the gonads are fully mature. The net profit is usually during the stocking process and it is found when there is a sperm spawning. The practice is to pro-bellied fish on the bench for drying for about 1 hour, and then select individuals full of gonads, male and female separately placed in the water temperature than the temperature of the storage tank water temperature of 3 °C in the induced discharge, when the egg amounted to 100-200 / In milliliters, you can move pro-Bay to another pool to continue spawning, then take semen several times to perform artificial insemination, microscopic observation, control the appropriate number of sperm, this method of harvesting eggs can also get good results .
(3) Incubation: Divide the fertilized eggs with water or divide the cells to control the density at 50 cells per ml or so. In order to prevent the hatching effect of the fertilized eggs from accumulating at the bottom, the water is used every hour for the incubation process. Stirred once, until the development of the larval larval stage, at a water temperature of about 12 °C, about 70 hours more than the diameter can be developed to the face plate larvae.
(4) Larval breeding and breeding: When the larvae develop to the larvae of the faceplate, they can be cultured with trawl nets made of NX-103 sieves. If the number of larvae is small, they can be collected by concentrated drainage and the larval density. Directly affect the culture effect, the culture density of scallop spawning larvae should be 7/ml, and when it is newly bred, the water quality will be clean and the larvae will be small (general body length is only about 100 microns), so it is not necessary to fill the water. , only add 1/2, fill once or twice in the next day, the temperature of the culture pool should be consistent with the temperature of the hatching pool.
After the water is filled, the filter rod (drum) made of NX-103 sieve is used to change the water the next day. The water is changed twice a day, each time the water is changed by 1/2. After a period of incubation, the larvae die and die. The bait and suspended matters in the water gradually sink to the bottom of the pool, so in addition to changing the water frequently, it is necessary to take a breeding method once every five days or so to ensure the water quality is clean.
Appropriate bait species and density are the main factors for nursery success. The bait is best fed with the mixture of Zhanjiang fork algae and Pyramidophytes (or Platymonas olivaceus) (mostly Zhanjiang forkworm). The number of the above-mentioned monocytic algae is calculated to be 20,000-30,000 cells/ml according to the density in the culture pond, and this number can satisfy the needs of the growth and development of the larvae. The bait should be less frequently cast and not cast too much at one time. At the same time, the number of baits should be determined according to the different growth and development summers. For example, within a few days after breeding, due to smaller larvae, less food intake, larger cells It is also difficult to swallow. During this time, a small amount of the smaller cell Zhanjiang fork algae is fed separately. After that, as the larvae increase, the food intake increases. At this time, in addition to the golden algae, the algae (or cyanobacteria) should also be mixed (or Platymonas esculenta), and the amount of diet also gradually increased, the feed should be fresh, no or less protozoa.
The water temperature also directly affects the growth and development of larvae and the number of attachments. In order to improve the seedling raising effect, larvae must be raised (controlled) in temperature during the larval rearing process. The method is to first raise the water temperature in the preheating pool. Water temperature is required. When the water is changed, the warmed seawater is sent to the cultivation pond and the water temperature of the nursery is gradually increased. The daily temperature increase rate does not exceed 1°C. When the temperature is about 15°C, the named water temperature is constant within this range. When the water temperature of the sea area rises above 15°C No longer (actually impossible) temperature control.
(5) Attachment and attachment: At a water temperature of about 15°C, if the type of feed is suitable and the quantity meets the requirements, after about 20 days of cultivation, the larvae will be able to end their planktonic life and become abnormally attached. Appropriate attachment base depots are used for attachment of metamorphic juveniles. There are many materials suitable for attaching base materials, of which the brown shades made of a brown rope with a diameter of about 6 mm are effective. However, because the brown rope contains harmful substances such as tannin and pectin, if the treatment is not clean, it will be counterproductive. Can you handle the brown rope? The general treatment process is: Prepare the seedling curtain before using 1-2% (with a weight ratio of the cord) sodium hydroxide soaked in fresh water for a few days, then change the water for cleaning, to the lighter when the color is taken out to get beat on the rope machine Wash, then arrange the curtain, then prepare the seedlings and then cook them in an iron pot. Open the pot for 2 hours. The cooked seedlings curtains are then soaked in clean seawater. Always change the water during the soaking process. Basic colorless.
When the larvae are about to end their abnormal attachment to planktonic life, a black spot is created at the back of the mouth and ditch, and a black spot is called the eye point. The initial eye spot is small and irregular, and the second and third days become round and obvious. Afterwards, the swimming ability weakened, and the feet were formed one after the other. Therefore, the emergence of eye spots is a sign of the timing of the attachment of bases, due to differences in the growth and development of larvae. Occasionally there are eye-points too early and late, so the timing of the attachment should begin when the proportion of eye-larvae reaches 20% or more. It was too early to vote because of the sedimentation of floating sludge on the seedling screen, which affected the attached seedlings. At the same time, it was not convenient to manage. If it was too late, it would miss the chance of attachment.
Before putting on the seedling curtains, wash the pools first, apply a layer of curtains to the bottom of the washed pools, press the stone on the bottom curtains, add fresh seawater, then haul the larvae, concentrate, and collect them until the pool is covered. In the middle, on the same day or the next day, the curtain is hung or hung on a float welded with a polyvinyl chloride tube.
After changing the curtain, increase the amount of water change and the number of water changes. At the same time, increase the amount of feeding. Normally, the larvae can be attached one week after the curtain is lowered. When there is no planktonic larvae in the pool, they can be used without filter rods (drums). When the hose is drained, when the jumbo shell is attached to about 600 microns, the pool can be quantitatively counted and bred at sea. The water temperature in the room should be gradually reduced to the same level as the sea before leaving the pool.