After desalination of Penaeus vannamei, they can be cultured in freshwater areas. In order to ensure a certain growth time, mentioning the market in the morning and making up for market vacancies, when the shrimps are cultivated in the northern areas, the use of greenhouses and simple water heaters for intermediate storage of their desalinated seedlings is a very important step. The technical points are now described as follows:
1 Preparation for cultivation of greenhouses
The cultivation pond is best to be excavated along the sun-facing slope of the pond, generally 5m~8m wide and 50m~80m in length. The excavation area depends on the amount of seedlings. After the cultivating pool is dug and compacted, the l0kg-15kg/500m2 quicklime is used to dilute the water evenly, and 15ppm-20ppm bleaching powder can be used for disinfecting.
The bamboo scaffold can be used as a scaffold for scaffolding, and E14mm wire steel can also be used as a scaffold and covered with a plastic film. In northern Jiangsu, if it is released in March, it needs to cover the double membrane to increase the insulation performance. With bamboo sticks tied into the bottom of the pool, or in the pool to cultivate water plants as attachments; and in the pool arranged in two rows of bulk gas aeration, scattered stone spacing 1.5m, hanging from the bottom of the pool 15cm.
2 Simple water heater installation
Generally 1t water heater can guarantee about 500m2 greenhouse water temperature. When purchasing or processing a water heater, it can be determined according to the area of ​​the cultivation pond. The method of warming with a hot water heater is to heat the pipe circulating hot water: the water heater is installed at one end of the pool, and a 2 cm plastic pipe is laid in the bottom of the pool as a hot water circulation pipe; the water outlet of the furnace A pipe pump is installed, one end of the circulation pipe is connected with the pump port, and the other end is connected with the water inlet of the furnace. When it is necessary to warm up, the water temperature is heated to 50°C to 60°C, and the pipeline pump is turned on to heat the hot water. This method has a good heating effect and saves energy. The second is open-type artesian water heating: According to the length of the cultivation pond, the furnace is elevated at one end or in the middle of the pond; two 2°C plastic tubes are laid 20cm above the bottom of the pool, and one end is sealed and the other end is connected with the furnace. The nozzles are connected and valves are added to control the speed of the water. In the plastic tube on both sides of the lateral hole, the distance between the hole lm, ranging from 1.5mm ~ 2mm aperture, the greater the farther the blast furnace aperture. When heating is required, the water can be heated to 40°C-50°C and the valve can be opened. The water pressure can be self-flowing through the furnace and the hot water can be directly heated in the pool through the small holes in the pipeline. When using this method, the water temperature in the furnace should not be too high. When the hot water in the furnace is dry, water can be added to the furnace by the water pump. The advantage of this method is that often there is fresh water injected into the pool, and there is no need to change the water frequently in the early stage.
3 Preparation before laying seedlings
About 10 days before planting, the ponds were repeatedly drained 2-3 times in order to eliminate the remaining poison in the pool. Cover the pool of dry water after the film, dry and cultivate the pond for 4-5 days to increase the ground temperature; then gradually fill the water and add the water level (60cm~80cm) within 2-3 days. When the water temperature exceeds 18°C, Fertilization. For the first fertilization, 5ppm urea plus 0.5ppm of Phosphate fertilizer is sprayed on the whole pond. After 3-5 days, the fertilizer is applied for the second time. The amount of fertilizer is half of the first time. Soaked soybean milk can also be used to cultivate zooplankton, 1kg soybeans/500m2 days. , Sprinkle for a week.
Since the desalted seedlings of Penaeus vannamei are gradually diluted, generally the seedlings still have a certain degree of salinity (0.5‰ to 1‰) at the time of seedling emergence, taking into account the adaptability of the shrimp seedlings after stocking, before the seedlings are released. 2-3 days should first sprinkle some coarse salt particles into the pool, or you can coarse salt into brine before spilling it into the pool, spilling 1kg of coarse salt/m3 of water. After the above work is ready, support a net cage of about lm2 in the pool, take 50 to 100 shrimps from the seedlings field and test the water in the cage 2-3 days before planting. If there is no abnormality, In response, you can consider letting go.
4 Stocking of shrimp
When the water temperature in the greenhouse is maintained at more than 20 strokes and the pH is stable at between 7.8-8.4, shrimp can be used. If the water heater is used for warming, the time for releasing the seedlings may be about 20 days earlier than the general greenhouse seedlings. Since shrimps are cultivated in greenhouses for 30-50 days, taking into account the difficulties of late management, it is recommended that the density of seedlings should not exceed 1000 tails/m2. In order to ensure the survival rate of shrimp after stocking, the conditions of the weather at that time should be fully considered when stocking the shrimp. Generally, it is required to ensure that the weather is fine for 2-3 days after release.
When choosing shrimp, we must choose healthy and lively, transparent body, body length 1.5cm above the shrimp seedlings; identification of shrimp seedlings can be good or bad in the hatchery field to take more than a dozen shrimp seedlings pool, with The squeezed wet towel wraps the shrimp seedlings for 10 min, and then puts them back into the original pool water. If the shrimp seedlings survive, they are good seedlings. When transporting shrimp, double-layer nylon bags can be used, with 10L of clean fresh water, 10L of oxygenated water, 10,000 to 20,000 shrimps (depending on the size of the shrimp and the length of transport time), and the insulation truck. Transport time is within 12h.
Before the pool of shrimp seedlings, the seedling bags should be placed in the pool for a period of time. When the temperature of the water in the seedling bags is fully consistent with the pool water temperature, the shrimps are poured into the drums in the pool in batches, and then the shrimps are slowly added. The seedlings were floated into the pool, and at the same time, the seedlings at the bottom of the barrel were discarded and the survival rate of the shrimp seedlings was estimated.
5 Daily management
(1) Water quality regulation. The color of the water in the cultivation pond is yellow-brown, and the transparency is 35cm-50cm. The level of transparency can be adjusted by fertilization; the pH value should be stabilized at 7.8-8.4, and the pH level can be adjusted by changing the water. . The first three days after the first seedling placement, there is no need to change the water. At this time, the shrimp seedlings should be less likely to be disturbed due to the new water. After 3 days, fresh water can be added in good weather. After one week, change the water every 2-3 days depending on the water quality. The water exchange volume is generally 1/5-1/3 of the pool water, ie 10cm-20cm; It should be done at noon on fine weather. The dissolved oxygen in the cultivation pond should always be kept above 5mg/L, and the dissolved oxygen in the bottom water should not be lower than 3mg/L; when the dissolved oxygen is low, the aerator can be used to inflate oxygen.
In the middle and later stages of cultivation, the pH of the cultivation pond water will increase, which may cause unstable shrimps and even parade along the pool. At this time, attention should be paid to the ventilation of the greenhouse, and at the same time, the daily water exchange volume should be increased to improve water quality. When changing the water, if the external water temperature and the pool water temperature are too different, it is necessary to pay attention to changing the water speed should not be too fast. Subei areas generally do not need to burn boilers after mid-April; in May, as long as the weather is fine, around 9:00 am, the area around the greenhouses will be opened and the air temperature will be controlled and controlled. At this time, special attention should be paid to controlling the temperature of the water in the greenhouse within 30°C to improve the survival of the shrimp seedlings, and also to facilitate the management of water quality in the later period. When the bottom moss surfaced, always remove it.
(2) Feeding of bait. In the first week after releasing, if there are more zooplankton in the pool, some fish paste, cakes, shrimp slices, etc. can be fed in a small amount; after one week, gradually matching the grain feed, the grain size of the feed is 0. 05mm~0.5mm. The daily feeding amount was: 80g to 110g/million of shrimp seedlings within 2cm; 170g-220g/million tails of 2cm-3cm seedlings; 250g-330g/million tail shrimp of 3cm to 4cm. Daily feeding 4-6 times, after the evening the amount of feeding should exceed the amount of feeding during the day; feeding should avoid deep water areas and bamboo sticks and other attachments, evenly spilled on both sides of the pool, after each feeding Lh~2h Take a certain amount of shrimp to check its stomach fullness, and observe the remaining bait in the pool to adjust the amount of feed.
(3) Disease prevention and control. The desalted seedlings of Penaeus vannamei need to be healthy and lively. During the cultivation process, attention should be paid to the regulation of water quality and sediment quality. The prevention and treatment of shrimp disease should follow the principle of “prevention from prevention, prevention from prevention, and prevention from over controlâ€. Before the seedlings are planted, disinfection of the cultivation ponds should be done. During the holding process, a certain amount of antibiotics (0.5ppm of oxytetracycline or furazolidone, etc.) can be periodically spilled into the pool or fed regularly for prevention.
Ciliary diseases are more common during the cultivation of shrimps, and most of them occur in the middle and late stages of cultivation (after 30 days). If this disease occurs, it needs to be dealt with promptly. Otherwise, it will cause skin problems in shrimps, affecting growth and even causing the death of shrimps. In the treatment, the water quality can be improved with talcum powder, bottom net, etc., and then the fibrin net is 1.2g/m3. The ciliate can also be killed by pungent disinfectants such as quaternary ammonium salts or chlorine dioxide.
The main predators during the cultivation of temporary seedlings are snakes and frogs, which will swallow the shrimp seedlings and should be promptly removed when found.
6 Baby shrimp out of the pool
After a period of 30 days to 50 days, the juveniles usually reach a body length of 4 cm or more. When the outside water temperature is stable for more than 20°C for several days, the juveniles can be out of the pond and cultured in the outer pond. When juveniles are out of the pond, a 20-mesh cage should be set at the outlet to collect seedlings.
1 Preparation for cultivation of greenhouses
The cultivation pond is best to be excavated along the sun-facing slope of the pond, generally 5m~8m wide and 50m~80m in length. The excavation area depends on the amount of seedlings. After the cultivating pool is dug and compacted, the l0kg-15kg/500m2 quicklime is used to dilute the water evenly, and 15ppm-20ppm bleaching powder can be used for disinfecting.
The bamboo scaffold can be used as a scaffold for scaffolding, and E14mm wire steel can also be used as a scaffold and covered with a plastic film. In northern Jiangsu, if it is released in March, it needs to cover the double membrane to increase the insulation performance. With bamboo sticks tied into the bottom of the pool, or in the pool to cultivate water plants as attachments; and in the pool arranged in two rows of bulk gas aeration, scattered stone spacing 1.5m, hanging from the bottom of the pool 15cm.
2 Simple water heater installation
Generally 1t water heater can guarantee about 500m2 greenhouse water temperature. When purchasing or processing a water heater, it can be determined according to the area of ​​the cultivation pond. The method of warming with a hot water heater is to heat the pipe circulating hot water: the water heater is installed at one end of the pool, and a 2 cm plastic pipe is laid in the bottom of the pool as a hot water circulation pipe; the water outlet of the furnace A pipe pump is installed, one end of the circulation pipe is connected with the pump port, and the other end is connected with the water inlet of the furnace. When it is necessary to warm up, the water temperature is heated to 50°C to 60°C, and the pipeline pump is turned on to heat the hot water. This method has a good heating effect and saves energy. The second is open-type artesian water heating: According to the length of the cultivation pond, the furnace is elevated at one end or in the middle of the pond; two 2°C plastic tubes are laid 20cm above the bottom of the pool, and one end is sealed and the other end is connected with the furnace. The nozzles are connected and valves are added to control the speed of the water. In the plastic tube on both sides of the lateral hole, the distance between the hole lm, ranging from 1.5mm ~ 2mm aperture, the greater the farther the blast furnace aperture. When heating is required, the water can be heated to 40°C-50°C and the valve can be opened. The water pressure can be self-flowing through the furnace and the hot water can be directly heated in the pool through the small holes in the pipeline. When using this method, the water temperature in the furnace should not be too high. When the hot water in the furnace is dry, water can be added to the furnace by the water pump. The advantage of this method is that often there is fresh water injected into the pool, and there is no need to change the water frequently in the early stage.
3 Preparation before laying seedlings
About 10 days before planting, the ponds were repeatedly drained 2-3 times in order to eliminate the remaining poison in the pool. Cover the pool of dry water after the film, dry and cultivate the pond for 4-5 days to increase the ground temperature; then gradually fill the water and add the water level (60cm~80cm) within 2-3 days. When the water temperature exceeds 18°C, Fertilization. For the first fertilization, 5ppm urea plus 0.5ppm of Phosphate fertilizer is sprayed on the whole pond. After 3-5 days, the fertilizer is applied for the second time. The amount of fertilizer is half of the first time. Soaked soybean milk can also be used to cultivate zooplankton, 1kg soybeans/500m2 days. , Sprinkle for a week.
Since the desalted seedlings of Penaeus vannamei are gradually diluted, generally the seedlings still have a certain degree of salinity (0.5‰ to 1‰) at the time of seedling emergence, taking into account the adaptability of the shrimp seedlings after stocking, before the seedlings are released. 2-3 days should first sprinkle some coarse salt particles into the pool, or you can coarse salt into brine before spilling it into the pool, spilling 1kg of coarse salt/m3 of water. After the above work is ready, support a net cage of about lm2 in the pool, take 50 to 100 shrimps from the seedlings field and test the water in the cage 2-3 days before planting. If there is no abnormality, In response, you can consider letting go.
4 Stocking of shrimp
When the water temperature in the greenhouse is maintained at more than 20 strokes and the pH is stable at between 7.8-8.4, shrimp can be used. If the water heater is used for warming, the time for releasing the seedlings may be about 20 days earlier than the general greenhouse seedlings. Since shrimps are cultivated in greenhouses for 30-50 days, taking into account the difficulties of late management, it is recommended that the density of seedlings should not exceed 1000 tails/m2. In order to ensure the survival rate of shrimp after stocking, the conditions of the weather at that time should be fully considered when stocking the shrimp. Generally, it is required to ensure that the weather is fine for 2-3 days after release.
When choosing shrimp, we must choose healthy and lively, transparent body, body length 1.5cm above the shrimp seedlings; identification of shrimp seedlings can be good or bad in the hatchery field to take more than a dozen shrimp seedlings pool, with The squeezed wet towel wraps the shrimp seedlings for 10 min, and then puts them back into the original pool water. If the shrimp seedlings survive, they are good seedlings. When transporting shrimp, double-layer nylon bags can be used, with 10L of clean fresh water, 10L of oxygenated water, 10,000 to 20,000 shrimps (depending on the size of the shrimp and the length of transport time), and the insulation truck. Transport time is within 12h.
Before the pool of shrimp seedlings, the seedling bags should be placed in the pool for a period of time. When the temperature of the water in the seedling bags is fully consistent with the pool water temperature, the shrimps are poured into the drums in the pool in batches, and then the shrimps are slowly added. The seedlings were floated into the pool, and at the same time, the seedlings at the bottom of the barrel were discarded and the survival rate of the shrimp seedlings was estimated.
5 Daily management
(1) Water quality regulation. The color of the water in the cultivation pond is yellow-brown, and the transparency is 35cm-50cm. The level of transparency can be adjusted by fertilization; the pH value should be stabilized at 7.8-8.4, and the pH level can be adjusted by changing the water. . The first three days after the first seedling placement, there is no need to change the water. At this time, the shrimp seedlings should be less likely to be disturbed due to the new water. After 3 days, fresh water can be added in good weather. After one week, change the water every 2-3 days depending on the water quality. The water exchange volume is generally 1/5-1/3 of the pool water, ie 10cm-20cm; It should be done at noon on fine weather. The dissolved oxygen in the cultivation pond should always be kept above 5mg/L, and the dissolved oxygen in the bottom water should not be lower than 3mg/L; when the dissolved oxygen is low, the aerator can be used to inflate oxygen.
In the middle and later stages of cultivation, the pH of the cultivation pond water will increase, which may cause unstable shrimps and even parade along the pool. At this time, attention should be paid to the ventilation of the greenhouse, and at the same time, the daily water exchange volume should be increased to improve water quality. When changing the water, if the external water temperature and the pool water temperature are too different, it is necessary to pay attention to changing the water speed should not be too fast. Subei areas generally do not need to burn boilers after mid-April; in May, as long as the weather is fine, around 9:00 am, the area around the greenhouses will be opened and the air temperature will be controlled and controlled. At this time, special attention should be paid to controlling the temperature of the water in the greenhouse within 30°C to improve the survival of the shrimp seedlings, and also to facilitate the management of water quality in the later period. When the bottom moss surfaced, always remove it.
(2) Feeding of bait. In the first week after releasing, if there are more zooplankton in the pool, some fish paste, cakes, shrimp slices, etc. can be fed in a small amount; after one week, gradually matching the grain feed, the grain size of the feed is 0. 05mm~0.5mm. The daily feeding amount was: 80g to 110g/million of shrimp seedlings within 2cm; 170g-220g/million tails of 2cm-3cm seedlings; 250g-330g/million tail shrimp of 3cm to 4cm. Daily feeding 4-6 times, after the evening the amount of feeding should exceed the amount of feeding during the day; feeding should avoid deep water areas and bamboo sticks and other attachments, evenly spilled on both sides of the pool, after each feeding Lh~2h Take a certain amount of shrimp to check its stomach fullness, and observe the remaining bait in the pool to adjust the amount of feed.
(3) Disease prevention and control. The desalted seedlings of Penaeus vannamei need to be healthy and lively. During the cultivation process, attention should be paid to the regulation of water quality and sediment quality. The prevention and treatment of shrimp disease should follow the principle of “prevention from prevention, prevention from prevention, and prevention from over controlâ€. Before the seedlings are planted, disinfection of the cultivation ponds should be done. During the holding process, a certain amount of antibiotics (0.5ppm of oxytetracycline or furazolidone, etc.) can be periodically spilled into the pool or fed regularly for prevention.
Ciliary diseases are more common during the cultivation of shrimps, and most of them occur in the middle and late stages of cultivation (after 30 days). If this disease occurs, it needs to be dealt with promptly. Otherwise, it will cause skin problems in shrimps, affecting growth and even causing the death of shrimps. In the treatment, the water quality can be improved with talcum powder, bottom net, etc., and then the fibrin net is 1.2g/m3. The ciliate can also be killed by pungent disinfectants such as quaternary ammonium salts or chlorine dioxide.
The main predators during the cultivation of temporary seedlings are snakes and frogs, which will swallow the shrimp seedlings and should be promptly removed when found.
6 Baby shrimp out of the pool
After a period of 30 days to 50 days, the juveniles usually reach a body length of 4 cm or more. When the outside water temperature is stable for more than 20°C for several days, the juveniles can be out of the pond and cultured in the outer pond. When juveniles are out of the pond, a 20-mesh cage should be set at the outlet to collect seedlings.
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