There are more than 100 kinds of freshwater maggots in China, but the only suitable oysters for cultured pearls are swiftlet breams, crested crown pythons, and no gingivae. At present, the most widely used and the highest value of the cultured pearls are the scallops and pleated crowns.
I. The ecology and living habits of freshwater pearls
(I) Living habits
Pearl tadpoles generally live in sediments in rivers, lakes, ponds, and other bodies of water. The depth of the body's sneak into the mud varies with the seasons. When the water temperature is low in winter, most of the carcasses sneak into the sediment, with the front ventral edge down and the dorsal edge up, only exposing some of the rear edge of the shell to ingest food. Most of Hawaii is exposed outside the sand. Different types of earthworms have different requirements on the environment. For example, the crested crested ibis inhabits the slow or steady sediments, and the water with good fertilizer is suitable for PH of 5-7. The spinnaker cocoon perches on the sandy bottom sediments. In addition, the water quality is relatively clear, and the PH is stable at 7-8.
(B) Intake habits
Cockroaches usually feed on bacteria, phytoplankton, protozoa, rotifers, small horns, small copepods, and organic debris in water. Different types of quail feeding vary. Such as crested cress more than algae feeding. The food intake depends on the amount of feed in the water, the degree of palatability, and the physical condition of the baby.
(III) Reproductive habits
When the water temperature is appropriate, the mature male and female gonads gradually become full and mature. The gonads of female eels are changed from light yellow to orange, indicating that the gonads are mature, the fertilized hole is tightly attached to the egg membrane, and fertilization occurs in the case of sperm. Spinnaker quail eggs 40 to 500,000 grains/only. Pleurotus plicata 50 to 700,000 grains per animal. The gonads of the baboon mature gradually and have multiple ovulation habits. The spinnaker ovulates 5 to 8 times during the breeding season, and the pleated crown ovulates 2 to 3 times. Therefore, the hooked larvae can be collected multiple times when the quail is farmed. Old fleas and sick fleas have a low fertility. Although the amount of eggs is high, due to the complex development of metamorphosis, the survival rate of larvae is only about 10%.
(d) Development of embryos and larvae
Fertilized eggs develop hatching in the external iliac crest. After the cleavage period, blastocyst stage, gastrulation stage (closed shell, heart, primordial shell, primitive intestine, hook teeth, bristles, full thread), the clerodendial larvae are formed.
After the hooked larval larvae leave the mother's body, the fish is caught on the larvae with full thread and shell hooks. In the parasitic stage, the fish secrete mucus to form cysts and entrap the larvae. The larvae absorb the nutrients of the fish and develop metamorphosis. The larvae finally breaks down and enter the benthic free-living habitat. Juveniles have the organs of the stomach, the adductor muscles, the intestines, the axe and other organs. Morphologically, it has a cocoon shape, and the full-featured foot hooks and hooks of the hooked larvae have disappeared.
(v) Breeding season
Different species of crickets have different breeding seasons. When the water temperature reaches 18C (in late April and early May), the gonads begin to mature, and the gonads begin to fertilize from May to June. In a good environment, each female can spawn and cleave larvae 7-8 times. In low-temperature water bodies, larvae can be delayed until September.
The pleated crown reproduces twice a year. Every year from March to April, at a water temperature of 10~20C, fertilized eggs develop into hooked larvae in the pupa. The ovulation stopped in June. In the fall, and in early September, ovulation begins again, and the fertilized eggs develop into larvae, which are excreted in the first ten to the first ten months of the month. If the environment is suitable, the female baboons begin to spawn again after ten days.
Second, artificial reproduction of freshwater pearls
(I) Intimate Choice and Cultivation
1. The choice of intimacy when choosing a pro-benefit is to consider the age, physical fitness, sex ratio, etc. Intimate requirements of up to 4 to 5 years of age, it is best to have spawned eggs on the physique and body shape is correct, bright shell color, thick shell quality, pearl layer color luster is beautiful, the body is robust and plump, the outer iliac flap complete without injury, spray Strong, closed shell strength, male to female ratio should be 1:1.
Identifying males and females is important for selecting parental pairs. Sexually mature ticks are distinguished from the gonad color and can be identified based on the characteristics of money and silk. The two shells of female and pupa are relatively bulging, the shell width is larger, the trailing edge is more rounded, and the distance between the outer silk is relatively dense. Male cicada shell is smaller in width, slightly more pointed at the back end, and sparsely spaced at outside.
2, the requirements of the pro-culture pond
(1) The area of ​​the pond is more than 1000 meters. It is ventilated and sunny, and it has slow flowing water conditions.
(2) The water quality should not be too thin or too fat. The water quality is too thin and the feed is insufficient, which affects the development; the water quality is too fat and easy to be hypoxic, which results in the incomplete or sexual reversal of male and female germ cells. The water color is yellow-green, and the transparency is about 30 centimeters. Ensure that the water is fat and live, so as to provide sufficient natural feed to facilitate the normal development of the gonads and embryos.
(3) Sludge sludge is generally about 10 cm; 10 to 15 days before decoction, clear lime ponds are used.
3. After the Chinese New Year, the pro-sisters started to choose the pro-taste. They were marked with male and female on the oyster shell, and then they were raised in the pool in a space of 30-35 cm. This facilitates the natural fertilization of the male and female and improves the fertilization rate. After pro-tucking in the water, it is necessary to observe carefully and strengthen management.
(b) Manual picking
After fertilized eggs develop into hooked larvae in the external iliac crest of females, they must be parasitized on silk or fins of money to absorb nutrients and complete metamorphosis. Artificial seedlings artificially parasitize the larvae to parasites in the fish.
1. Selection of host fish The host fish requires mild temperament and slow swimming. Otherwise, the larvae will fall off prematurely and the metamorphosis will not be completed. Physique requires a strong, disease-free, injury-free, complete fins, otherwise, the clerodial larvae die without completing the metamorphic host fish. In addition, it is convenient to draw materials.
In actual production, yellow trout and salmon are usually selected as host fish. Stingray prefers quietness, fears of interference, strong patience, and high seedling rate (200 to 300 larvae attached to the right of a stingray with a body length of 15 cm), and it is found in rivers, lakes, reservoirs, and ponds. The growth can be caught all year round. The carp is moderate in temperament and convenient in feeding and management. It is also an ideal host fish. After the host fish are caught, they need to be held for a short period of time to drain the body surface, fins, and urine, while recovering their physical strength. Holding density should not be too high, generally 150 ~ 200 / m water body. Keep the fish as quiet as possible during the holding period without interference. When the holding time is long, appropriate amount of feed should be fed daily. Stingrays are preferred for feeding sturgeon or clam meat, and sturgeons are mainly cultivated with fertilizer.
2. Identification of larval mating larvae maturation Mutation of larval mating larvae is to be identified before picking, because immature hooked larvae have no parasitic ability. The signs of mating of larval mating larvae are: The egg membrane has been removed, and the full thread and hook have adhesion. When identifying, open the river raft with an opener and first look at the color of the raft. The crepuscular folds are plump and full of dark purple; the spinnakers are full of fleas, showing brownish yellow or purple black and greyish-yellow, and the eggs are clearly visible from the outside, indicating that the females have matured. Followed by the oocyte retrieval observation, when the external hemorrhoids were acupunctured, the hooked larvae of the larvae adhered to each other in a line, indicating that the larvae had broken the membrane and had a good maturity. The third step is to use the needle to pick out the eggs and place them on a glass slide. The visible double-shelled eggs start slightly, indicating that the larvae have matured.
Under normal conditions, the hooked larvae at the posterior end of the iliac crest are maturated and the front end is matured. Mature a batch, release a batch, exhausted in batches. Therefore, at the time of examination, sampling should be performed at the end of two years of the zygomatic valve. For example, most of the eggs mature, indicating that the membrane-breaking larvae break through more than half of the larvae.
The mother's time to check is shorter and lighter. The time is too long to stimulate the mother-fever abortion caused by the General Assembly. The so-called abortion refers to the fact that the female larvae are immature and excreted.
3, the method of artificial seedlings
(1)Hydrostatic water-collecting method The mother-flies mating with the larvae of the larvae are used for drying and solar stimulation and then put into a basin. It is advisable to submerge the oyster shell in the basin water. Soon, the larvae of the larvae are seen. It is like a cluster of cotton wool sinking into the bottom of the water. At this time, it is immediately put into the host fish, and the water in the pot is properly agitated to increase the chance of contact between the fish and the hooked larvae, increase the seedling attachment rate, increase the dissolved oxygen in the water, and prevent the host. Fish floating head. After 10 to 20 minutes, the host fish is moved into the flow basin.
The length of time the seedlings are taken is related to the temperature, the temperature is high, the activity of the hooked larvae is strong, and the picking time should be short; otherwise the time can be longer. At a water temperature of 18 to 20, in a container with a bottom diameter of 40 cm and a water depth of 20 cm, two females can be placed. After the female larvae expel the larvae, the female quail is placed in another container containing fresh water. Then put the fish separately, and it is appropriate to parasitize 200 to 300 hooked larvae on each fin and cocoon, and the hooked larvae parasitize on the fish body as white dots.
Pleurotus plicosa larvae often linger for several hours. Therefore, it is inconvenient to produce, and sometimes it can be used to collect seedlings.
(2) Flowing seedlings method Use a large basin with a bottom diameter of 40 to 50 cm. Place 2 to 3 females in each container. Place the host fish at the same time. Cover the net cloth on the container to prevent the fish from jumping out; The water keeps the water in the container constantly flowing and renewing, keeping the water fresh and the oxygen being sufficient. After one night, the hooked larvae discharged from the female worms are parasitized on the fish body. Then the seedlings will be stocked in a timely manner.
The benefits of this method are sufficient oxygen, high survival rate of parasitic fish, and convenient seedlings for large-scale production. However, the rate of loss of larvae was high.
(2) The method of collecting seedlings from cages is a 39-mesh polyethylene cage with a height of 1.2 meters, a width of 0.8 meters and a height of 0.6 meters on a wide surface of the water. Each box contains 10 to 20 females and 400 to 500 host fish. The natural discharge of the female lice is mediated by the larvae for 2 to 3 hours. About 200 larvae are caught on the larvae and fins of the fish, and the harvesting is completed once. The host fish is then dispersed and diluted.
(3) The pond directly collects seedlings with 200-300 m2 of seedling pool, 0.5 m water depth, hard mud sediment, no shade around, sufficient water supply, convenient drainage and irrigation, and appropriate fertilizer. Mature females are selected for the breeding season, and 20 to 30 parasites are released for each female. After the mother lice discharge the larvae, remove the mother lice. Careful management is then performed to properly feed soya milk to keep the water fresh and parasites grow well, thus ensuring the development of hooked larvae.
4, picking seedling matters needing attention
(1) When selecting mature mothers, the action should be light to prevent miscarriage.
(2) To control the parasitic density, generally one fish parasitoid larvae 150 to 200 are in excess, malnutrition, and will cause the death of host fish in severe cases.
(3) Appropriate flow, not too large, too fast, so as to avoid loss of larvae.
5, the cultivation of parasitic fish
After the hooked larvae parasitize the fish body, it takes a certain amount of parasitism to complete the metamorphosis. The parasitic time is related to water temperature.
Parasitized larval fish should be cultured with live water and fertilized appropriately. As long as they are well-fed, more than 100 calves can be obtained per parasite.
Average water temperature 18°C ​​20~21°C 23°C 26~28°C 30~35°C
Parasite time 15 days or so 13 days or so 10 days or so 6~8 days 4 to 6 days
Relationship between larval parasitism and water temperature in pleurotus plicata
Average water temperature 12~13°C15°C17°C19°C
Parasite time 15 days or so 13 days or so 10 days or so 6 to 8 days
I. The ecology and living habits of freshwater pearls
(I) Living habits
Pearl tadpoles generally live in sediments in rivers, lakes, ponds, and other bodies of water. The depth of the body's sneak into the mud varies with the seasons. When the water temperature is low in winter, most of the carcasses sneak into the sediment, with the front ventral edge down and the dorsal edge up, only exposing some of the rear edge of the shell to ingest food. Most of Hawaii is exposed outside the sand. Different types of earthworms have different requirements on the environment. For example, the crested crested ibis inhabits the slow or steady sediments, and the water with good fertilizer is suitable for PH of 5-7. The spinnaker cocoon perches on the sandy bottom sediments. In addition, the water quality is relatively clear, and the PH is stable at 7-8.
(B) Intake habits
Cockroaches usually feed on bacteria, phytoplankton, protozoa, rotifers, small horns, small copepods, and organic debris in water. Different types of quail feeding vary. Such as crested cress more than algae feeding. The food intake depends on the amount of feed in the water, the degree of palatability, and the physical condition of the baby.
(III) Reproductive habits
When the water temperature is appropriate, the mature male and female gonads gradually become full and mature. The gonads of female eels are changed from light yellow to orange, indicating that the gonads are mature, the fertilized hole is tightly attached to the egg membrane, and fertilization occurs in the case of sperm. Spinnaker quail eggs 40 to 500,000 grains/only. Pleurotus plicata 50 to 700,000 grains per animal. The gonads of the baboon mature gradually and have multiple ovulation habits. The spinnaker ovulates 5 to 8 times during the breeding season, and the pleated crown ovulates 2 to 3 times. Therefore, the hooked larvae can be collected multiple times when the quail is farmed. Old fleas and sick fleas have a low fertility. Although the amount of eggs is high, due to the complex development of metamorphosis, the survival rate of larvae is only about 10%.
(d) Development of embryos and larvae
Fertilized eggs develop hatching in the external iliac crest. After the cleavage period, blastocyst stage, gastrulation stage (closed shell, heart, primordial shell, primitive intestine, hook teeth, bristles, full thread), the clerodendial larvae are formed.
After the hooked larval larvae leave the mother's body, the fish is caught on the larvae with full thread and shell hooks. In the parasitic stage, the fish secrete mucus to form cysts and entrap the larvae. The larvae absorb the nutrients of the fish and develop metamorphosis. The larvae finally breaks down and enter the benthic free-living habitat. Juveniles have the organs of the stomach, the adductor muscles, the intestines, the axe and other organs. Morphologically, it has a cocoon shape, and the full-featured foot hooks and hooks of the hooked larvae have disappeared.
(v) Breeding season
Different species of crickets have different breeding seasons. When the water temperature reaches 18C (in late April and early May), the gonads begin to mature, and the gonads begin to fertilize from May to June. In a good environment, each female can spawn and cleave larvae 7-8 times. In low-temperature water bodies, larvae can be delayed until September.
The pleated crown reproduces twice a year. Every year from March to April, at a water temperature of 10~20C, fertilized eggs develop into hooked larvae in the pupa. The ovulation stopped in June. In the fall, and in early September, ovulation begins again, and the fertilized eggs develop into larvae, which are excreted in the first ten to the first ten months of the month. If the environment is suitable, the female baboons begin to spawn again after ten days.
Second, artificial reproduction of freshwater pearls
(I) Intimate Choice and Cultivation
1. The choice of intimacy when choosing a pro-benefit is to consider the age, physical fitness, sex ratio, etc. Intimate requirements of up to 4 to 5 years of age, it is best to have spawned eggs on the physique and body shape is correct, bright shell color, thick shell quality, pearl layer color luster is beautiful, the body is robust and plump, the outer iliac flap complete without injury, spray Strong, closed shell strength, male to female ratio should be 1:1.
Identifying males and females is important for selecting parental pairs. Sexually mature ticks are distinguished from the gonad color and can be identified based on the characteristics of money and silk. The two shells of female and pupa are relatively bulging, the shell width is larger, the trailing edge is more rounded, and the distance between the outer silk is relatively dense. Male cicada shell is smaller in width, slightly more pointed at the back end, and sparsely spaced at outside.
2, the requirements of the pro-culture pond
(1) The area of ​​the pond is more than 1000 meters. It is ventilated and sunny, and it has slow flowing water conditions.
(2) The water quality should not be too thin or too fat. The water quality is too thin and the feed is insufficient, which affects the development; the water quality is too fat and easy to be hypoxic, which results in the incomplete or sexual reversal of male and female germ cells. The water color is yellow-green, and the transparency is about 30 centimeters. Ensure that the water is fat and live, so as to provide sufficient natural feed to facilitate the normal development of the gonads and embryos.
(3) Sludge sludge is generally about 10 cm; 10 to 15 days before decoction, clear lime ponds are used.
3. After the Chinese New Year, the pro-sisters started to choose the pro-taste. They were marked with male and female on the oyster shell, and then they were raised in the pool in a space of 30-35 cm. This facilitates the natural fertilization of the male and female and improves the fertilization rate. After pro-tucking in the water, it is necessary to observe carefully and strengthen management.
(b) Manual picking
After fertilized eggs develop into hooked larvae in the external iliac crest of females, they must be parasitized on silk or fins of money to absorb nutrients and complete metamorphosis. Artificial seedlings artificially parasitize the larvae to parasites in the fish.
1. Selection of host fish The host fish requires mild temperament and slow swimming. Otherwise, the larvae will fall off prematurely and the metamorphosis will not be completed. Physique requires a strong, disease-free, injury-free, complete fins, otherwise, the clerodial larvae die without completing the metamorphic host fish. In addition, it is convenient to draw materials.
In actual production, yellow trout and salmon are usually selected as host fish. Stingray prefers quietness, fears of interference, strong patience, and high seedling rate (200 to 300 larvae attached to the right of a stingray with a body length of 15 cm), and it is found in rivers, lakes, reservoirs, and ponds. The growth can be caught all year round. The carp is moderate in temperament and convenient in feeding and management. It is also an ideal host fish. After the host fish are caught, they need to be held for a short period of time to drain the body surface, fins, and urine, while recovering their physical strength. Holding density should not be too high, generally 150 ~ 200 / m water body. Keep the fish as quiet as possible during the holding period without interference. When the holding time is long, appropriate amount of feed should be fed daily. Stingrays are preferred for feeding sturgeon or clam meat, and sturgeons are mainly cultivated with fertilizer.
2. Identification of larval mating larvae maturation Mutation of larval mating larvae is to be identified before picking, because immature hooked larvae have no parasitic ability. The signs of mating of larval mating larvae are: The egg membrane has been removed, and the full thread and hook have adhesion. When identifying, open the river raft with an opener and first look at the color of the raft. The crepuscular folds are plump and full of dark purple; the spinnakers are full of fleas, showing brownish yellow or purple black and greyish-yellow, and the eggs are clearly visible from the outside, indicating that the females have matured. Followed by the oocyte retrieval observation, when the external hemorrhoids were acupunctured, the hooked larvae of the larvae adhered to each other in a line, indicating that the larvae had broken the membrane and had a good maturity. The third step is to use the needle to pick out the eggs and place them on a glass slide. The visible double-shelled eggs start slightly, indicating that the larvae have matured.
Under normal conditions, the hooked larvae at the posterior end of the iliac crest are maturated and the front end is matured. Mature a batch, release a batch, exhausted in batches. Therefore, at the time of examination, sampling should be performed at the end of two years of the zygomatic valve. For example, most of the eggs mature, indicating that the membrane-breaking larvae break through more than half of the larvae.
The mother's time to check is shorter and lighter. The time is too long to stimulate the mother-fever abortion caused by the General Assembly. The so-called abortion refers to the fact that the female larvae are immature and excreted.
3, the method of artificial seedlings
(1)Hydrostatic water-collecting method The mother-flies mating with the larvae of the larvae are used for drying and solar stimulation and then put into a basin. It is advisable to submerge the oyster shell in the basin water. Soon, the larvae of the larvae are seen. It is like a cluster of cotton wool sinking into the bottom of the water. At this time, it is immediately put into the host fish, and the water in the pot is properly agitated to increase the chance of contact between the fish and the hooked larvae, increase the seedling attachment rate, increase the dissolved oxygen in the water, and prevent the host. Fish floating head. After 10 to 20 minutes, the host fish is moved into the flow basin.
The length of time the seedlings are taken is related to the temperature, the temperature is high, the activity of the hooked larvae is strong, and the picking time should be short; otherwise the time can be longer. At a water temperature of 18 to 20, in a container with a bottom diameter of 40 cm and a water depth of 20 cm, two females can be placed. After the female larvae expel the larvae, the female quail is placed in another container containing fresh water. Then put the fish separately, and it is appropriate to parasitize 200 to 300 hooked larvae on each fin and cocoon, and the hooked larvae parasitize on the fish body as white dots.
Pleurotus plicosa larvae often linger for several hours. Therefore, it is inconvenient to produce, and sometimes it can be used to collect seedlings.
(2) Flowing seedlings method Use a large basin with a bottom diameter of 40 to 50 cm. Place 2 to 3 females in each container. Place the host fish at the same time. Cover the net cloth on the container to prevent the fish from jumping out; The water keeps the water in the container constantly flowing and renewing, keeping the water fresh and the oxygen being sufficient. After one night, the hooked larvae discharged from the female worms are parasitized on the fish body. Then the seedlings will be stocked in a timely manner.
The benefits of this method are sufficient oxygen, high survival rate of parasitic fish, and convenient seedlings for large-scale production. However, the rate of loss of larvae was high.
(2) The method of collecting seedlings from cages is a 39-mesh polyethylene cage with a height of 1.2 meters, a width of 0.8 meters and a height of 0.6 meters on a wide surface of the water. Each box contains 10 to 20 females and 400 to 500 host fish. The natural discharge of the female lice is mediated by the larvae for 2 to 3 hours. About 200 larvae are caught on the larvae and fins of the fish, and the harvesting is completed once. The host fish is then dispersed and diluted.
(3) The pond directly collects seedlings with 200-300 m2 of seedling pool, 0.5 m water depth, hard mud sediment, no shade around, sufficient water supply, convenient drainage and irrigation, and appropriate fertilizer. Mature females are selected for the breeding season, and 20 to 30 parasites are released for each female. After the mother lice discharge the larvae, remove the mother lice. Careful management is then performed to properly feed soya milk to keep the water fresh and parasites grow well, thus ensuring the development of hooked larvae.
4, picking seedling matters needing attention
(1) When selecting mature mothers, the action should be light to prevent miscarriage.
(2) To control the parasitic density, generally one fish parasitoid larvae 150 to 200 are in excess, malnutrition, and will cause the death of host fish in severe cases.
(3) Appropriate flow, not too large, too fast, so as to avoid loss of larvae.
5, the cultivation of parasitic fish
After the hooked larvae parasitize the fish body, it takes a certain amount of parasitism to complete the metamorphosis. The parasitic time is related to water temperature.
Parasitized larval fish should be cultured with live water and fertilized appropriately. As long as they are well-fed, more than 100 calves can be obtained per parasite.
Average water temperature 18°C ​​20~21°C 23°C 26~28°C 30~35°C
Parasite time 15 days or so 13 days or so 10 days or so 6~8 days 4 to 6 days
Relationship between larval parasitism and water temperature in pleurotus plicata
Average water temperature 12~13°C15°C17°C19°C
Parasite time 15 days or so 13 days or so 10 days or so 6 to 8 days