1. Site Selection A high-yielding nursery should be built in an ideal location. The ideal nursery is first to have convenient transportation, access to electricity, and adequate water resources. Second, to examine the water retention performance of soil, choose muddy or sandy mudflats with good water retention as the site. Third, avoid as many as possible. The roots of developed plants (such as reeds, rice grass, etc.) grow where the decayed grass roots will affect the water quality of the nursery.
2. Pond Preparation A complete ecological nursery should include a rotifer culture and a larval rearing pond, both of which have an area ratio of 2:1 to 3:1. At present, the area of ​​high-yielding larval rearing ponds is between 1,300 and 2,000 square meters. The pool shape is rectangular or square, the aspect ratio does not exceed 3:2, the pool depth is not less than 2 meters, and the width of the crest is suitable for driving. The rotifer culture pond should satisfy the feeding of larvae at different time intervals. There are several pools with an area of ​​2000-6000 square meters. The pool shape is not limited, and the depth is about 1m. In the construction of a pond, usually three processes are used: the excavator catches the pool, the bulldozer pushes and presses hard, and the pit is manually finished. Make sure that the inside of the pond is flat and smooth. Before using the old pond, you must use a bulldozer to clear the bottom of the pool. If you can expose it for a few days, the effect will be better.
3, the inlet water according to the degree of difficulty of the water, decided to start the inlet time. Nursery ponds should, in principle, fill up the water at one time before the half-month of expected seedlings. It should not be too early, but it is easy to make the water spoiled when it is too early. It cannot be too late and too late will affect the disinfection effect. The proportion of influent water in nursery ponds is preferably around 1.015, and no water or water is changed during nursery. The rotifer cultivation pond must be filled with water earlier and adopt the method of adding water step by step in order to facilitate water quality and fertilization. All feed inlets shall be provided with two screen mesh bags (40 meshes in the inner layer and 100 meshes in the outer layer) to prevent the entry of impurities and predators.
4. The disinfected crab breeding pond must be sanitized three times: about 10 days before the seedlings, the trichlorfon powder should be fully dissolved and uniformly sprayed into the pond so that the content in the pond is 1.50.000001; before the seedlings are used 6 days, 30-40) 0.00001 bleach was re-sterilized once; between these two, 200.000001 tea seed cake was disinfected once. The rotifer culture pond was sterilized twice with trichlorfon and tea seed cake.
5. Control of fertilizer and water quality Water and fertilizer control of crab breeding ponds are the key to the entire nursery stage. The water quality is lean, and the initial production of Z1 has insufficient amount of bait, resulting in weak and diseased constitutions and affecting future development and metamorphosis. The water quality is too fat, and the water quality in the late stage of nursery is prone to deterioration, resulting in a large number of larvae dead and failure in nursery production. We usually start fertilization five days before the seedlings. The optimal amount of carbonic amine is 3 to 4 kg per 667 square meters, and 1 to 1 kg of urea. During the larval rearing period, if the water quality is too fat, the rotifers can be over-fed in the early morning of each day to control, but the rotifers should not be over-fed and flooded. The amount of rotifer feeding should also be strictly controlled. Before each feeding, the person in charge of technology should be aware of the number, size, and feeding speed of the larvae in the pond in order to accurately determine the amount of feeding.
6. The method of seedling seedlings for ecological breeding of Brachyspira spicata is not the same as industrialized seedling raising. Usually, the seedlings are first collected in a pool and then divided into cages. When individual crabs cultivated in the same batch are discharged individually, the crabs are immediately sterilized. The method of disinfection of the crabs is the same as that of industrialized seedlings. The disinfected crabs are first hung in the top of a pond and observed continuously. When a large amount of discharge is found, they are sorted immediately to find out the amount of crabs that have been discharged, and then the crabs are not produced. Twelve percent of the crabs required for the pool were allocated to the pool to be produced. The number of species of crabs required for ecological seedlings per pond is calculated based on the amount of Z1 discharged from the water body, and is preferably 8,000 to 10,000 cubic meters per cubic meter. If the larvae have not yet been fully produced in the initial production pool, several more species of crabs can be produced.
7. Accelerated and extended ripening of species of crabs is achieved by artificially controlling the time for female crabs to discharge larvae in advance or delayed, thereby opening the marketing period and reducing the contradiction between supply and demand caused by concentrated consumption of rotifers. The method of promoting ripening is relatively simple. A plastic greenhouse can be set up on the earth pond where crabs are cultivated, and the crabs can also be directly heated in the cement pool. There are three methods for extending ripening crabs:
The first is to delay the mating time of the crabs, that is, from the original autumn mating to postponed to the spring of the following year. However, the unoccupied female crabs must be allowed to overwinter in a pure fresh water environment to prevent the female crabs from affecting their mating rate and holding eggs due to excessive maturity. Quantity: Secondly, a bamboo frame is erected on the rearing crab crab pool, above which a straw or shade net is placed. Third, before the water temperature of 10°C in the early spring, the egg-bearing crabs are moved into the low-temperature storage and the cold storage is cooled by the refrigerator or ice cubes. The water temperature is controlled at 7～9°C, and the water is changed completely once every 10 days. The feed is fed once every 3 days. The feeding amount is about 5% of the total weight of the overwintering crabs. This method can delay the discharge time of the holding crabs in February. Left and right, while the previous two methods can only postpone about one week.
8. Rotifer culture and feeding In the larval rearing process, whether or not rotifers can supply sufficient quantities is a key factor in determining nursery yield. The rotifer cultivation process includes water intake, disinfection, fertilization, inoculation, and appropriate amount of capture. Inflow and disinfection have been briefly introduced in the previous section. The fertilization in the rotifer cultivation pond is generally done by the side of the water, and the amount of fertilization is slightly higher than that of the larval rearing pond. When the water quality has a certain degree of fertility, organic fertilizer can be splashed. The rotifer inoculation time and inoculum amount are flexibly controlled according to the initial feeding time. Under normal circumstances, one week in advance, 5 kg per mu can be used to catch food. The feeding time of rotifers is usually in the morning and evening, when the temperature is relatively low, the collected rotifers are not easy to degenerate. Feeding amount is subject to no remaining before the next feeding.
9. The arrest and desalination of bigeye larvae There are two types of arrests currently available: one is nighttime light trapping. This method takes a long time and is labor intensive and cannot meet the requirements of large-scale production and has basically been eliminated; Another method is to pull the net method, that is, use a 20-mesh sieve net to make a trawl net, a float ball for every meter on the top row, and a drop stone for every 50 cm in the bottom outline. The length of the net is not less than 170% of the width of the pond. The width is not less than 2 times the water depth. This kind of net can play 95% of the seedlings in the catch pool for the first time. The large-eyed larvae harvested by grazing nets are packed in crab boxes and then desalted in desalination ponds. The larval density in the desalination ponds is strictly controlled at 1.5 kg/cubic meter or less, and the big eye larvae are desalinated for 3 to 4 days. The salinity is reduced to Up to 4 inches can be sold.
10, seedlings of the packaging and transportation of earthen pond seedlings out of the pool late, a large number of market temperature has been higher, with crab seedlings packaging can not guarantee the survival rate of long-distance transport. We are now using the method of adding ice cubes in the foam box, which has a high survival rate. The specific method is to use a small wooden bar to make a bracket according to the size of the foam box, and use a 20-mesh sieve to sew a crab seedling bag. When it emerges, put two bottles of frozen mineral water in the bottom of the foam box first, and then put the two-layer bracket on the top. The good big-eyed larvae were put into a 20-mesh sieve bag, laid flat and fixed on the holder, and then the lid was closed. This method can guarantee the survival rate of 99% after 30 hours. First, the whole process of breeding fry seedlings can be divided into four stages:
1. Free feeding period: the fish just emerged from the membrane and was about 0.7-0.8 cm in length. At this time, the yolk sac of the fry has not disappeared. The fry are clustered at the bottom corner of the pool and tremble slightly. The fishes are yellowish. Only a few fishes leave the bottom of the pool and have no purpose to swim. The dark moving ability is weak and the fry are absorbed by the yolk sac. Nutrients grow and develop without feeding bait. After 2-6 days of development, the yolk sac of the fry was gradually absorbed, the yolk sac disappeared, the area of ​​the fish distribution increased, and the fish appeared greenish black. Some fish fry began to feed on the bottom, and the darkening ability changed. Strong, this time should be timely feeding appropriate, palatable bait. Mastering the opening time of the fry is one of the key links in the success of nursery.
According to past experience, the length of fry development from hatching to the disappearance of the yolk sac is closely related to the temperature: 17 days at 17-18°C, 6 days at 19-18°C, 5 days, and 4 days at 21-23°C. It takes 3 days at 24-26°C and the water temperature above 28°C is 2 days. However, for more than 4 days, the fry of this process will be completed, and the constitution will become thin and the survival rate will decline. Therefore, when the water temperature of the fish shade pool is lower than 21°C, temperature raising measures shall be taken in time.
2. First-stage cultivation stage: When the fry size is below 1 cm, it is a first-stage cultivation stage. Nursery ponds should be equipped with an indoor hatchery with a specification of 2-3 m2, a water depth of 12-20 cm, and a stocking density of 4000-5000 tails/meter:. Immediately after the yolk sac of fry was absorbed, a sufficient amount of rotifers filtered by 80-mesh larvae should be used as open bait, and the transparency of the pool water should be controlled at about 24 cm. When the fish fry have ingested a large amount of rounds of blood, the density of the rotifers in the water body is reduced, and the water body becomes transparent gradually. At this time, fertilizer and water containing a large number of rotifers should be promptly exchanged. In this way, after two days of cultivation, it is possible to change the water oysters as bait. It is necessary to pay attention to the feeding of leeches which must be filtered through a 40-mesh sieve. When the fry size reaches 1 cm or more, it is transferred to the secondary culture stage.
3. Secondary cultivation stage: Nursery ponds can choose outdoor nursery ponds, with an area of ​​5-6 m 2, a water depth of 25-30 m, and a stocking density of about 2,000 Ni/m 2. At this stage, healthy fry always live in dark places. Few fry swims. In the evening, they only scramble around for food, so the surface of the pool is covered with materials with better heat-resistant properties such as cement tiles to cover the pool surface 1/ The area of ​​3, on the one hand to prevent the sun from rising when the temperature is fierce, on the other hand to provide dark shading habitat for fry to facilitate the growth of fry. Fry in the pool, after feeding the blisters two days later, grow to 1.5 cm or more, you can change feeding silkworms. After three days of silkworm feeding, the fry size reached 2 cm or more and was transferred to tertiary culture.
4. Tertiary incubation stage: The tertiary cultivation tank is 15-30 m2 in size, the water depth should be about 50 cm, the stocking density should be 400-500/m2, and a small amount of water lotus should be placed in the pool, covering about 1/4 of the water surface. In order to purify water, shading and for fry. Feed is mainly silk pupa. When silk pupa is not available, you can use cooked boiled snail meat instead of chopped meat or fish. The fry can grow up to 5 cm in 12-15 days to reach the sale specification.
Second, feeding and management
1. Feeding: In the course of fry cultivation, the fry is multiplied daily with its own body weight, so the amount of its feeding changes every day. Each feeding should pay attention to observe the feeding conditions of the fry, according to the observation results of appropriate adjustment of feeding amount. Feeding should be a small amount of meals, each feeding should pay attention to the appropriate interval for a period of time, feeding the amount of fish just about half an hour is appropriate.
2. Changing water and removing residual baits and feces: At nightfall, the oxygen content of the pool water begins to drop, and in the morning, the time when the amount of dissolved oxygen in the water body is the minimum, both of which will float to the surface in succession. So change the water sooner or later; remove the bait and feces once. On cloudy days, the fry is more likely to float, and the number of new water flushes should be increased.
3. Dividing the pool: The water temperature is appropriate, and the fry grows very quickly. It is very easy to form a dense “top mouthâ€. To determine whether to “topâ€, according to the fry all surfaced at 12 o'clock in the evening or in the morning when the sun did not come out, when people approached the nursery pond, the fish group issued a “summer†sound. When they drilled into the water, they said they would not If the fry is unresponsive, it still shakes its head and flicks on the surface of the water, and if it swims casually, it means “top mouthâ€. According to such a situation, the degree of "top mouth" can be judged, and it can be known when delivering. The division must be carried out in the morning and in the evening. The operation must be meticulous to avoid injury to the fry.
III. Disease Prevention
1. Gastrointestinal disease: The vomiting of this disease is caused by the ingestion of diuretic pupa with a diseased virus (virus). The belly of the diseased fish was red and congested and the mortality rate was high. Faster, most of the dead fish are big and big. Control methods: Add peony or oxytetracycline to the silkworms that are to be fed, let silkworms absorb them after one hour, and the dosage is 1 kg. Silkworms add 4 grams, for several days, the effect is significant.
2. Bad rotten lice disease: diseased fish and roaches ulcers, the early onset of fish song decreased food intake, swim out of the grid across the pool crowded with each other, into a group of rubbing each other, or rubbing the pool edges with the kiss, The attitude is extremely disturbing. In severe cases, the snouts and lumbos rotted white and struggled to die. Control methods: healthy disease-free fry, hidden during the day in the shady corners of the pool, once the fish out of the dark barrage, it is necessary to remove all fry as soon as possible, with Sichuan Mg / elevated potassium manganate dip 30 minutes The free pool is best transferred to other empty pools, and the original pool needs to be cleaned after being returned to the original pool. Put fish back into the water and then sprinkling formalin at a concentration of 20 ml/m3. Then change the water every afternoon and then spill 20 ml/m3 of formalin for 3 consecutive days. The effect is excellent. The disease is caused mainly by worms, which are caused by parasitism and green hyphae.
3. Black body disease: The diseased fish body is darkened, and the food intake is significantly reduced. The fish body is thinner and thinner than a day, and some fish fry become turbulent when disturbed. False death lies at the bottom of the pool. The severely-fed fry muscles are inflamed and the fish is still dead. When the muscles are dissected, they smell rancid. The cause of the disease is unknown and there is no cure.
IV. Discussion
1. After the development of carp fry to the disappearance of the yolk sac, it should have a strong ability to darken, and the fry without the darkening ability is a stunted fry, which needs to be sucked away with a straw.
2. When the yolk sac of the fry disappeared, the rotifer was the most suitable bait. Because the fry at this time can't swallow the large blisters, it is easy to be harmed by the blisters, and other easily soluble powders such as egg yolks can cause water corruption.
3. When using snail meat or fish gizzard as feed, during the feeding process, it should be noted that the water should be agitated and fed again so that the feed can be uniformly dispersed and turned in the water. Because the eel fry only eat the food that floats in the water, but ignores and does not eat the fixed feed. In addition, grasping the amount of feed and method of feeding is also the key to improving the survival rate of nursery.
2. Pond Preparation A complete ecological nursery should include a rotifer culture and a larval rearing pond, both of which have an area ratio of 2:1 to 3:1. At present, the area of ​​high-yielding larval rearing ponds is between 1,300 and 2,000 square meters. The pool shape is rectangular or square, the aspect ratio does not exceed 3:2, the pool depth is not less than 2 meters, and the width of the crest is suitable for driving. The rotifer culture pond should satisfy the feeding of larvae at different time intervals. There are several pools with an area of ​​2000-6000 square meters. The pool shape is not limited, and the depth is about 1m. In the construction of a pond, usually three processes are used: the excavator catches the pool, the bulldozer pushes and presses hard, and the pit is manually finished. Make sure that the inside of the pond is flat and smooth. Before using the old pond, you must use a bulldozer to clear the bottom of the pool. If you can expose it for a few days, the effect will be better.
3, the inlet water according to the degree of difficulty of the water, decided to start the inlet time. Nursery ponds should, in principle, fill up the water at one time before the half-month of expected seedlings. It should not be too early, but it is easy to make the water spoiled when it is too early. It cannot be too late and too late will affect the disinfection effect. The proportion of influent water in nursery ponds is preferably around 1.015, and no water or water is changed during nursery. The rotifer cultivation pond must be filled with water earlier and adopt the method of adding water step by step in order to facilitate water quality and fertilization. All feed inlets shall be provided with two screen mesh bags (40 meshes in the inner layer and 100 meshes in the outer layer) to prevent the entry of impurities and predators.
4. The disinfected crab breeding pond must be sanitized three times: about 10 days before the seedlings, the trichlorfon powder should be fully dissolved and uniformly sprayed into the pond so that the content in the pond is 1.50.000001; before the seedlings are used 6 days, 30-40) 0.00001 bleach was re-sterilized once; between these two, 200.000001 tea seed cake was disinfected once. The rotifer culture pond was sterilized twice with trichlorfon and tea seed cake.
5. Control of fertilizer and water quality Water and fertilizer control of crab breeding ponds are the key to the entire nursery stage. The water quality is lean, and the initial production of Z1 has insufficient amount of bait, resulting in weak and diseased constitutions and affecting future development and metamorphosis. The water quality is too fat, and the water quality in the late stage of nursery is prone to deterioration, resulting in a large number of larvae dead and failure in nursery production. We usually start fertilization five days before the seedlings. The optimal amount of carbonic amine is 3 to 4 kg per 667 square meters, and 1 to 1 kg of urea. During the larval rearing period, if the water quality is too fat, the rotifers can be over-fed in the early morning of each day to control, but the rotifers should not be over-fed and flooded. The amount of rotifer feeding should also be strictly controlled. Before each feeding, the person in charge of technology should be aware of the number, size, and feeding speed of the larvae in the pond in order to accurately determine the amount of feeding.
6. The method of seedling seedlings for ecological breeding of Brachyspira spicata is not the same as industrialized seedling raising. Usually, the seedlings are first collected in a pool and then divided into cages. When individual crabs cultivated in the same batch are discharged individually, the crabs are immediately sterilized. The method of disinfection of the crabs is the same as that of industrialized seedlings. The disinfected crabs are first hung in the top of a pond and observed continuously. When a large amount of discharge is found, they are sorted immediately to find out the amount of crabs that have been discharged, and then the crabs are not produced. Twelve percent of the crabs required for the pool were allocated to the pool to be produced. The number of species of crabs required for ecological seedlings per pond is calculated based on the amount of Z1 discharged from the water body, and is preferably 8,000 to 10,000 cubic meters per cubic meter. If the larvae have not yet been fully produced in the initial production pool, several more species of crabs can be produced.
7. Accelerated and extended ripening of species of crabs is achieved by artificially controlling the time for female crabs to discharge larvae in advance or delayed, thereby opening the marketing period and reducing the contradiction between supply and demand caused by concentrated consumption of rotifers. The method of promoting ripening is relatively simple. A plastic greenhouse can be set up on the earth pond where crabs are cultivated, and the crabs can also be directly heated in the cement pool. There are three methods for extending ripening crabs:
The first is to delay the mating time of the crabs, that is, from the original autumn mating to postponed to the spring of the following year. However, the unoccupied female crabs must be allowed to overwinter in a pure fresh water environment to prevent the female crabs from affecting their mating rate and holding eggs due to excessive maturity. Quantity: Secondly, a bamboo frame is erected on the rearing crab crab pool, above which a straw or shade net is placed. Third, before the water temperature of 10°C in the early spring, the egg-bearing crabs are moved into the low-temperature storage and the cold storage is cooled by the refrigerator or ice cubes. The water temperature is controlled at 7～9°C, and the water is changed completely once every 10 days. The feed is fed once every 3 days. The feeding amount is about 5% of the total weight of the overwintering crabs. This method can delay the discharge time of the holding crabs in February. Left and right, while the previous two methods can only postpone about one week.
8. Rotifer culture and feeding In the larval rearing process, whether or not rotifers can supply sufficient quantities is a key factor in determining nursery yield. The rotifer cultivation process includes water intake, disinfection, fertilization, inoculation, and appropriate amount of capture. Inflow and disinfection have been briefly introduced in the previous section. The fertilization in the rotifer cultivation pond is generally done by the side of the water, and the amount of fertilization is slightly higher than that of the larval rearing pond. When the water quality has a certain degree of fertility, organic fertilizer can be splashed. The rotifer inoculation time and inoculum amount are flexibly controlled according to the initial feeding time. Under normal circumstances, one week in advance, 5 kg per mu can be used to catch food. The feeding time of rotifers is usually in the morning and evening, when the temperature is relatively low, the collected rotifers are not easy to degenerate. Feeding amount is subject to no remaining before the next feeding.
9. The arrest and desalination of bigeye larvae There are two types of arrests currently available: one is nighttime light trapping. This method takes a long time and is labor intensive and cannot meet the requirements of large-scale production and has basically been eliminated; Another method is to pull the net method, that is, use a 20-mesh sieve net to make a trawl net, a float ball for every meter on the top row, and a drop stone for every 50 cm in the bottom outline. The length of the net is not less than 170% of the width of the pond. The width is not less than 2 times the water depth. This kind of net can play 95% of the seedlings in the catch pool for the first time. The large-eyed larvae harvested by grazing nets are packed in crab boxes and then desalted in desalination ponds. The larval density in the desalination ponds is strictly controlled at 1.5 kg/cubic meter or less, and the big eye larvae are desalinated for 3 to 4 days. The salinity is reduced to Up to 4 inches can be sold.
10, seedlings of the packaging and transportation of earthen pond seedlings out of the pool late, a large number of market temperature has been higher, with crab seedlings packaging can not guarantee the survival rate of long-distance transport. We are now using the method of adding ice cubes in the foam box, which has a high survival rate. The specific method is to use a small wooden bar to make a bracket according to the size of the foam box, and use a 20-mesh sieve to sew a crab seedling bag. When it emerges, put two bottles of frozen mineral water in the bottom of the foam box first, and then put the two-layer bracket on the top. The good big-eyed larvae were put into a 20-mesh sieve bag, laid flat and fixed on the holder, and then the lid was closed. This method can guarantee the survival rate of 99% after 30 hours. First, the whole process of breeding fry seedlings can be divided into four stages:
1. Free feeding period: the fish just emerged from the membrane and was about 0.7-0.8 cm in length. At this time, the yolk sac of the fry has not disappeared. The fry are clustered at the bottom corner of the pool and tremble slightly. The fishes are yellowish. Only a few fishes leave the bottom of the pool and have no purpose to swim. The dark moving ability is weak and the fry are absorbed by the yolk sac. Nutrients grow and develop without feeding bait. After 2-6 days of development, the yolk sac of the fry was gradually absorbed, the yolk sac disappeared, the area of ​​the fish distribution increased, and the fish appeared greenish black. Some fish fry began to feed on the bottom, and the darkening ability changed. Strong, this time should be timely feeding appropriate, palatable bait. Mastering the opening time of the fry is one of the key links in the success of nursery.
According to past experience, the length of fry development from hatching to the disappearance of the yolk sac is closely related to the temperature: 17 days at 17-18°C, 6 days at 19-18°C, 5 days, and 4 days at 21-23°C. It takes 3 days at 24-26°C and the water temperature above 28°C is 2 days. However, for more than 4 days, the fry of this process will be completed, and the constitution will become thin and the survival rate will decline. Therefore, when the water temperature of the fish shade pool is lower than 21°C, temperature raising measures shall be taken in time.
2. First-stage cultivation stage: When the fry size is below 1 cm, it is a first-stage cultivation stage. Nursery ponds should be equipped with an indoor hatchery with a specification of 2-3 m2, a water depth of 12-20 cm, and a stocking density of 4000-5000 tails/meter:. Immediately after the yolk sac of fry was absorbed, a sufficient amount of rotifers filtered by 80-mesh larvae should be used as open bait, and the transparency of the pool water should be controlled at about 24 cm. When the fish fry have ingested a large amount of rounds of blood, the density of the rotifers in the water body is reduced, and the water body becomes transparent gradually. At this time, fertilizer and water containing a large number of rotifers should be promptly exchanged. In this way, after two days of cultivation, it is possible to change the water oysters as bait. It is necessary to pay attention to the feeding of leeches which must be filtered through a 40-mesh sieve. When the fry size reaches 1 cm or more, it is transferred to the secondary culture stage.
3. Secondary cultivation stage: Nursery ponds can choose outdoor nursery ponds, with an area of ​​5-6 m 2, a water depth of 25-30 m, and a stocking density of about 2,000 Ni/m 2. At this stage, healthy fry always live in dark places. Few fry swims. In the evening, they only scramble around for food, so the surface of the pool is covered with materials with better heat-resistant properties such as cement tiles to cover the pool surface 1/ The area of ​​3, on the one hand to prevent the sun from rising when the temperature is fierce, on the other hand to provide dark shading habitat for fry to facilitate the growth of fry. Fry in the pool, after feeding the blisters two days later, grow to 1.5 cm or more, you can change feeding silkworms. After three days of silkworm feeding, the fry size reached 2 cm or more and was transferred to tertiary culture.
4. Tertiary incubation stage: The tertiary cultivation tank is 15-30 m2 in size, the water depth should be about 50 cm, the stocking density should be 400-500/m2, and a small amount of water lotus should be placed in the pool, covering about 1/4 of the water surface. In order to purify water, shading and for fry. Feed is mainly silk pupa. When silk pupa is not available, you can use cooked boiled snail meat instead of chopped meat or fish. The fry can grow up to 5 cm in 12-15 days to reach the sale specification.
Second, feeding and management
1. Feeding: In the course of fry cultivation, the fry is multiplied daily with its own body weight, so the amount of its feeding changes every day. Each feeding should pay attention to observe the feeding conditions of the fry, according to the observation results of appropriate adjustment of feeding amount. Feeding should be a small amount of meals, each feeding should pay attention to the appropriate interval for a period of time, feeding the amount of fish just about half an hour is appropriate.
2. Changing water and removing residual baits and feces: At nightfall, the oxygen content of the pool water begins to drop, and in the morning, the time when the amount of dissolved oxygen in the water body is the minimum, both of which will float to the surface in succession. So change the water sooner or later; remove the bait and feces once. On cloudy days, the fry is more likely to float, and the number of new water flushes should be increased.
3. Dividing the pool: The water temperature is appropriate, and the fry grows very quickly. It is very easy to form a dense “top mouthâ€. To determine whether to “topâ€, according to the fry all surfaced at 12 o'clock in the evening or in the morning when the sun did not come out, when people approached the nursery pond, the fish group issued a “summer†sound. When they drilled into the water, they said they would not If the fry is unresponsive, it still shakes its head and flicks on the surface of the water, and if it swims casually, it means “top mouthâ€. According to such a situation, the degree of "top mouth" can be judged, and it can be known when delivering. The division must be carried out in the morning and in the evening. The operation must be meticulous to avoid injury to the fry.
III. Disease Prevention
1. Gastrointestinal disease: The vomiting of this disease is caused by the ingestion of diuretic pupa with a diseased virus (virus). The belly of the diseased fish was red and congested and the mortality rate was high. Faster, most of the dead fish are big and big. Control methods: Add peony or oxytetracycline to the silkworms that are to be fed, let silkworms absorb them after one hour, and the dosage is 1 kg. Silkworms add 4 grams, for several days, the effect is significant.
2. Bad rotten lice disease: diseased fish and roaches ulcers, the early onset of fish song decreased food intake, swim out of the grid across the pool crowded with each other, into a group of rubbing each other, or rubbing the pool edges with the kiss, The attitude is extremely disturbing. In severe cases, the snouts and lumbos rotted white and struggled to die. Control methods: healthy disease-free fry, hidden during the day in the shady corners of the pool, once the fish out of the dark barrage, it is necessary to remove all fry as soon as possible, with Sichuan Mg / elevated potassium manganate dip 30 minutes The free pool is best transferred to other empty pools, and the original pool needs to be cleaned after being returned to the original pool. Put fish back into the water and then sprinkling formalin at a concentration of 20 ml/m3. Then change the water every afternoon and then spill 20 ml/m3 of formalin for 3 consecutive days. The effect is excellent. The disease is caused mainly by worms, which are caused by parasitism and green hyphae.
3. Black body disease: The diseased fish body is darkened, and the food intake is significantly reduced. The fish body is thinner and thinner than a day, and some fish fry become turbulent when disturbed. False death lies at the bottom of the pool. The severely-fed fry muscles are inflamed and the fish is still dead. When the muscles are dissected, they smell rancid. The cause of the disease is unknown and there is no cure.
IV. Discussion
1. After the development of carp fry to the disappearance of the yolk sac, it should have a strong ability to darken, and the fry without the darkening ability is a stunted fry, which needs to be sucked away with a straw.
2. When the yolk sac of the fry disappeared, the rotifer was the most suitable bait. Because the fry at this time can't swallow the large blisters, it is easy to be harmed by the blisters, and other easily soluble powders such as egg yolks can cause water corruption.
3. When using snail meat or fish gizzard as feed, during the feeding process, it should be noted that the water should be agitated and fed again so that the feed can be uniformly dispersed and turned in the water. Because the eel fry only eat the food that floats in the water, but ignores and does not eat the fixed feed. In addition, grasping the amount of feed and method of feeding is also the key to improving the survival rate of nursery.
5A grade Huangjiu is adopted for Aged Wine ,i.e. A grade raw materials, A grade timing, A grade pottery jar, A grade storage and A grade brewers. Using Huangjiu of the most representative years as base, aged wine is bottled in green porcelain for banquet and gift-giving. Glass-bottled-wine is mainly used for 3-5 years of ordinary wine, with superior cost performance, suitable for people who drink at home frequently.Shaoxingtian Chun Wine,Yellow Wine Without Caramel Colour, etc..Shaoxing Wine without caramel is naturally fermented, with lighter color, purer and more attractive. The wine tastes fresh and mellow.
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