Winter protection technology for tilapia sheds
2018-06-07 10:02:07
Tilapia is a tropical fish. Its cold resistance is relatively poor. When the water temperature drops to 12°C, tilapia will suffer frostbite or death. Tilapia fish is relatively resistant to cold. However, it is not possible to overwinter in low-temperature environments for a long period of time. In China, except in Hainan, Taiwan, Yunnan, and Guangdong, where natural wintering occurs, tilapia in most regions cannot overwinter under natural conditions. Overwintering measures to ensure the successful wintering of parents and seedlings.
There are many wintering methods for tilapia, depending on the differences in climate and overwintering conditions in different regions, such as the overwintering of cover film, the wintering of hot springs, the deep water wells, the residual heat of factories, the heating of boilers, and the heating of electric heaters. As a production base for tilapia seedlings, I used the overwintering method of combining the cover film Datang shed and the iron frame cover film overwintering in accordance with the overwintering experience over the past few years. Practice has proved that this is a relatively successful wintering technique. Preparation before winter
1. Selection and Preparation of Overwintering Ponds
The wintering pond requires a higher choice of terrain, good water retention capacity, good leewardness, and an area that should not be too large. It is generally advisable to use it within 6 mu. It should be east-west and the span should not be too large. The wintering ponds should dry the pool water two months before the winter, remove the fish, weeds, and miscellaneous materials at the bottom of the pond, and strictly repair the ponds and drainage outlets, especially the outlet filter. Conditional units allow the exposure of Datang to cracks, then backwater 10-15 cm for disinfection. Disinfection can be combined with quicklime and tea bream. The scope of disinfection includes pond bottoms and pond larvae to thoroughly destroy trash fish and bacteria. When returning water, it is best to use fresh river water or well water. The wintering pond water does not require the cultivation of fertilizer and water, because the water quality is not conducive to the management of wintering during the winter, increasing the difficulty of management. After 5-7 days of disinfection, the fish can be tested and put in water.
2. Preparation and construction of wintering materials
It is mainly used as a shed support frame. In the middle of Datang, a row of support frames is built with wooden piles, and then a small steel wire is placed on the top, and the pond is fixed with a wooden stake. After the film is covered, the steel wire rope is pressurized and fixed with a small wire. Upper and lower wire ropes. When the film is covered, it should be leveled to prevent the rain from accumulating on the shed. During the winter, it is necessary to inspect the film for loopholes and take appropriate measures.
3, preparation for wintering equipment
According to different wintering methods, the heating, oxygenation, and effluent facilities required during wintering should be ready before winter, such as heaters, boilers, temperature controllers, water pumps, and aerators.
Prepare the wintering fish before entering the pond
1. Fertilizer before winter
In winter months before winter, the fish that will be overwinter will be raised in a special pool to strengthen and nurture, which will promote the cultivation of their fat and strengthen their overwintering and cold resistance so that they can gradually adapt to the living environment during the winter and advance some frail or injured fishes. Eliminated.
2, the election of overwintering fish
There are two types of overwintering fish: broodstock and fry:
(1) Broodstock: When the broodstock enters the pond, it must be rigorously selected according to the requirements of the production seedlings to ensure that each broodstock meets the requirements. The ratio of male to female of broodstock is selected as 3:1 or 4:1, and wintering of male and female ponds is facilitated to facilitate the mating operation in the coming year. The number of requisitions will be increased by 15% to 20% based on the planned amount of growing fry, so as to ensure the successful production of seedlings in the coming year.
(2) Fish species: Overwintering species are 4-6 cm in diameter. Generally wintering species require the same specification when entering the pond. Over utilization of the wintering pond will be reduced if the wintering species are used. Oversized wintering species will have poor adaptability during wintering. Survival rate is low and there will be different sizes of overwinter seedlings in the same pond. The selected fish species must also pay attention to individuals who are physically strong, have no injuries, are free from disease, have a smooth body surface, and have no frostbite.
Whether it is selected broodstock or fingerlings, the operation must be performed quickly and carefully when selecting the leaves to avoid injury to the fish body and to enter the pool immediately after selection. The fish species should not be concentrated in the pool for a long time during grading and screening. The water in the net pool can be divided into two hours after the screening, count into the pond, the longest time should not exceed five hours, but also not suitable for high-density long-distance transport, otherwise it will cause serious fish injuries, resulting in low survival rate overwintering.
3. When the fish body is sterilized, the broodstock will pass through the winter and the fish species will have different degrees of damage during transportation and operation. The fish body should be disinfected before entering the pool, and 2% -3% salt solution (without iodine) can be used to soak the fish. After 5 to 10 minutes of incubation, ponds can be used. When all the fish are introduced into the pond, 0.3 ppm of chlorine dioxide can be used to disinfect the ponds to prevent disease. Within one week after entering the pond, it is necessary to pay close attention to the activities of the fish species in the pond, especially if the wounds of fish fingerlings operated at low water temperatures are infected, and take corresponding measures in time. A week after entering the pond, the fish species were basically stable, and they managed to enter the wintering period.
Wintering fish into the pool time and density
1, into the pool time
It is advisable to enter the pond at a water temperature of 18-20 °C. It must be completed before the first cold current. Once the water temperature is lower than 16 °C, the catching fish cannot be used as overwintering species because the water temperature will cause frostbite, After entering the pool will continue to die. When fishing into the pond, we should choose the weather is stable, there is a strong sun, usually after 9:30 in the morning to open the net fishing, to the end before 4:30 in the afternoon, so the water temperature is higher during the period, is conducive to operation.
2, stocking density
The density of overwintering fish into the pond depends on the conditions of overwintering environment, fish size and management level. When the film is overwintering in Datang, the hydrostatic water increases oxygen, generally 5-8 kilograms of broodstock per cubic metre of water can be released. However, broodstock should be intensively cultivated before and after seedling cultivation in the late winter, so the conditional unit should reduce the parental stocking density. Acre stocking 500-600 tail, specifications for 500-600 g / tail. If paired production and seedlings are conducted in the original overwintering greenhouse, the number and weight of the female and male parent should also be considered. The stocking densities of overwintering fry are 3-4 cm in size, with 10-12 million tails per acre; 4-5 cm in size; 8-10 million tails per acre; and 70-80,000 fry over 5 cm in size. Small size seedlings are overwintering, because of their smaller size and lower survival rate, they should be properly increased into ponds, after deducting the survival rate to reach the general level of overwintering, and after strengthening the cultivation, they can reach the size of 5-7 cm when going out of pond; Specification seedlings, because of the higher survival rate after entering the pool, so the large-size seedling density should be denser when entering the pool, in order to maintain the uniform specifications, the most stable in the 5-7 cm specification.
Feeding management during wintering
The wintering period of tilapia is longer, generally from late October to late March, and lasts about half a year. In the production, the overwintering is generally divided into three stages of management. The water temperature in the early stage of entering the pool and the soon to be out of the pool are all relatively high. The amount of water should be appropriately adjusted to adjust the water quality. In the middle period, the temperature should be reduced appropriately to prevent the deterioration of water quality. The management of the late winter is particularly important. Before going out of the pond, we must strengthen the quantity and quality of the feed, promote the recovery of the body and the gonad development of the broodstock, so that the quality of the seed after the pool can be guaranteed. Throughout the winter, there must be someone responsible for doing a good job of recording, controlling water temperature, regulating water quality, feeding materials, and preventing diseases.
1, the water temperature control
When the wintering fish enter the pool within 10 days, the water temperature should be controlled between 20-25 °C. This will help the fish body's wounds heal as soon as possible and inhibit the occurrence of watery mildew. After the situation is basically stable, the water temperature can be controlled between 18-20 °C. The water temperature must not be too high or low, it cannot be cooled down suddenly, nor can it be controlled for more than 20°C for a long period of time. Long-term high temperature is not conducive to wintering management, but it also increases the input of feed. Because the water temperature is high, the fish's vitality is strong and it consumes more energy. Food intake will also increase. If ultra-thin material film greenhouses are used, the temperature in the pool may be as high as 30°C during the day due to the increasing sunlight temperature. At this time, the film should be partially opened to let the air circulate, and the temperature in the shed should be controlled at about 21°C. The water temperature should be controlled at 18-. At 19 °C, in the event of sudden changes in the weather or cold currents, the film should be covered in time to prevent a sudden drop in temperature.
2, the adjustment of water quality
Overwintering ponds should keep fresh water and adequate dissolved oxygen. Overwintering big ponds, because of their large area, are difficult to change water, so under normal circumstances they do not change water, and only add some new water. During the winter, the water quality can be adjusted and the vitality of water can be increased by regularly using a number of microbial preparations (such as vitamins, fish breeding, etc.). When the water becomes dark, some of the old water can be replaced, and new water can be injected. However, changing the water should not be excessive, and it should be controlled between 1/4 and 1/5. When the water is added, the water flow should be leveled into the pool and the outlet must be covered with a filter to prevent weeds from entering or the species from swimming backwards. The time for flushing during the day should not exceed four hours, especially the seedling pool, should be controlled in 2-3 hours or so to prevent fish fry long-term consumption of excess water or intensive increase in fish damage.
3, oxygen increase equipment
Due to the higher wintering density of the winter shed of Datang, the water quality is generally more fat, so the overwintering pool must be equipped with aeration equipment. In the low temperature season, due to the lower surface water temperature, the fish exposed to water after anoxic flotation, easily frostbite, prone to S. solani, leading to ulceration and death; in the late winter, due to the increase of water temperature, feeding increased, parents in the prenatal training In the process, the water quality becomes fat and it will cause severe hypoxia and affect the cultivation. Therefore, oxygenation during the winter is very important.
4, reasonable feeding
Tilapia must be fed with nutrient-rich concentrate during the winter. Usually take more than two, in the middle less feeding method, that is, after a certain period of time into the pool, more than appropriate feeding, broodstock control at about 2%, fish species control at about 5% -6%, once a day feeding, feeding all fish It's better to eat. For Miaochi, one or two overdose feeds are arranged every week. The purpose is to maintain the energy consumption of some weak seedlings because they cannot be eaten due to the low feed rate, and they can be eaten once or twice a week. As for thin and dead. Feeds for fingerlings can be powdered or small-caliber compound feeds. Feeding should be carried out evenly throughout the pond so that most of the fry can be eaten. The broodstock feed should be made into buoyant granular material, and the desiccant material should be set appropriately, and It is advisable to finish eating within 1.5 hours. When you are finished eating, you must remove the residual materials in time and reduce the amount of feed to prevent deterioration of feed quality. During the winter, the quantity and quality of the feed are adjusted at any time with the water temperature, the quality of the water, and the feeding conditions of the fish. Daily management
1, pay attention to changes in water temperature
Always measure the temperature and temperature of the water, usually twice a day, and make a record.
2, insist on early, middle and late patrol pond
Check whether the overwintering greenhouses are firm, observe the fish’s vitality, food intake, and monitor the water quality. If necessary, we should regularly monitor several indicators such as dissolved oxygen, ammonia chloride, and organic matter in the pool, and make records to detect problems in time and take measures to prevent An accident occurred.
3, pay attention to ventilation, ventilation
In the late winter, due to the increase of water temperature, it is necessary to pay attention to the ventilation and ventilation of wintering sheds, and the temperature of the water is stable. Then, the shed can be cooled, and fresh water can be added. When the temperature of the overwintering shed is equal to the outside world, preparations can be made before the pond.
4, pay attention to disease prevention
In the winter season, due to the small area of ​​wintering ponds, high density, relatively poor water quality, low water temperature, coupled with less activity and less feeding, tilapia is more susceptible to disease. Fish disease mainly adopts the principle of combination of prevention and treatment. In the wintering period, quicklime is used once every half month, and the dosage is 10-15 kg. After using quicklime for 7-10 days, disinfect with 0.2 5-0.3 ppm of chlorine dioxide and use pesticides once a month. Note that all drugs should be used separately and alternately. Always check the fish's activity and find that there are abnormal conditions.
There are many wintering methods for tilapia, depending on the differences in climate and overwintering conditions in different regions, such as the overwintering of cover film, the wintering of hot springs, the deep water wells, the residual heat of factories, the heating of boilers, and the heating of electric heaters. As a production base for tilapia seedlings, I used the overwintering method of combining the cover film Datang shed and the iron frame cover film overwintering in accordance with the overwintering experience over the past few years. Practice has proved that this is a relatively successful wintering technique. Preparation before winter
1. Selection and Preparation of Overwintering Ponds
The wintering pond requires a higher choice of terrain, good water retention capacity, good leewardness, and an area that should not be too large. It is generally advisable to use it within 6 mu. It should be east-west and the span should not be too large. The wintering ponds should dry the pool water two months before the winter, remove the fish, weeds, and miscellaneous materials at the bottom of the pond, and strictly repair the ponds and drainage outlets, especially the outlet filter. Conditional units allow the exposure of Datang to cracks, then backwater 10-15 cm for disinfection. Disinfection can be combined with quicklime and tea bream. The scope of disinfection includes pond bottoms and pond larvae to thoroughly destroy trash fish and bacteria. When returning water, it is best to use fresh river water or well water. The wintering pond water does not require the cultivation of fertilizer and water, because the water quality is not conducive to the management of wintering during the winter, increasing the difficulty of management. After 5-7 days of disinfection, the fish can be tested and put in water.
2. Preparation and construction of wintering materials
It is mainly used as a shed support frame. In the middle of Datang, a row of support frames is built with wooden piles, and then a small steel wire is placed on the top, and the pond is fixed with a wooden stake. After the film is covered, the steel wire rope is pressurized and fixed with a small wire. Upper and lower wire ropes. When the film is covered, it should be leveled to prevent the rain from accumulating on the shed. During the winter, it is necessary to inspect the film for loopholes and take appropriate measures.
3, preparation for wintering equipment
According to different wintering methods, the heating, oxygenation, and effluent facilities required during wintering should be ready before winter, such as heaters, boilers, temperature controllers, water pumps, and aerators.
Prepare the wintering fish before entering the pond
1. Fertilizer before winter
In winter months before winter, the fish that will be overwinter will be raised in a special pool to strengthen and nurture, which will promote the cultivation of their fat and strengthen their overwintering and cold resistance so that they can gradually adapt to the living environment during the winter and advance some frail or injured fishes. Eliminated.
2, the election of overwintering fish
There are two types of overwintering fish: broodstock and fry:
(1) Broodstock: When the broodstock enters the pond, it must be rigorously selected according to the requirements of the production seedlings to ensure that each broodstock meets the requirements. The ratio of male to female of broodstock is selected as 3:1 or 4:1, and wintering of male and female ponds is facilitated to facilitate the mating operation in the coming year. The number of requisitions will be increased by 15% to 20% based on the planned amount of growing fry, so as to ensure the successful production of seedlings in the coming year.
(2) Fish species: Overwintering species are 4-6 cm in diameter. Generally wintering species require the same specification when entering the pond. Over utilization of the wintering pond will be reduced if the wintering species are used. Oversized wintering species will have poor adaptability during wintering. Survival rate is low and there will be different sizes of overwinter seedlings in the same pond. The selected fish species must also pay attention to individuals who are physically strong, have no injuries, are free from disease, have a smooth body surface, and have no frostbite.
Whether it is selected broodstock or fingerlings, the operation must be performed quickly and carefully when selecting the leaves to avoid injury to the fish body and to enter the pool immediately after selection. The fish species should not be concentrated in the pool for a long time during grading and screening. The water in the net pool can be divided into two hours after the screening, count into the pond, the longest time should not exceed five hours, but also not suitable for high-density long-distance transport, otherwise it will cause serious fish injuries, resulting in low survival rate overwintering.
3. When the fish body is sterilized, the broodstock will pass through the winter and the fish species will have different degrees of damage during transportation and operation. The fish body should be disinfected before entering the pool, and 2% -3% salt solution (without iodine) can be used to soak the fish. After 5 to 10 minutes of incubation, ponds can be used. When all the fish are introduced into the pond, 0.3 ppm of chlorine dioxide can be used to disinfect the ponds to prevent disease. Within one week after entering the pond, it is necessary to pay close attention to the activities of the fish species in the pond, especially if the wounds of fish fingerlings operated at low water temperatures are infected, and take corresponding measures in time. A week after entering the pond, the fish species were basically stable, and they managed to enter the wintering period.
Wintering fish into the pool time and density
1, into the pool time
It is advisable to enter the pond at a water temperature of 18-20 °C. It must be completed before the first cold current. Once the water temperature is lower than 16 °C, the catching fish cannot be used as overwintering species because the water temperature will cause frostbite, After entering the pool will continue to die. When fishing into the pond, we should choose the weather is stable, there is a strong sun, usually after 9:30 in the morning to open the net fishing, to the end before 4:30 in the afternoon, so the water temperature is higher during the period, is conducive to operation.
2, stocking density
The density of overwintering fish into the pond depends on the conditions of overwintering environment, fish size and management level. When the film is overwintering in Datang, the hydrostatic water increases oxygen, generally 5-8 kilograms of broodstock per cubic metre of water can be released. However, broodstock should be intensively cultivated before and after seedling cultivation in the late winter, so the conditional unit should reduce the parental stocking density. Acre stocking 500-600 tail, specifications for 500-600 g / tail. If paired production and seedlings are conducted in the original overwintering greenhouse, the number and weight of the female and male parent should also be considered. The stocking densities of overwintering fry are 3-4 cm in size, with 10-12 million tails per acre; 4-5 cm in size; 8-10 million tails per acre; and 70-80,000 fry over 5 cm in size. Small size seedlings are overwintering, because of their smaller size and lower survival rate, they should be properly increased into ponds, after deducting the survival rate to reach the general level of overwintering, and after strengthening the cultivation, they can reach the size of 5-7 cm when going out of pond; Specification seedlings, because of the higher survival rate after entering the pool, so the large-size seedling density should be denser when entering the pool, in order to maintain the uniform specifications, the most stable in the 5-7 cm specification.
Feeding management during wintering
The wintering period of tilapia is longer, generally from late October to late March, and lasts about half a year. In the production, the overwintering is generally divided into three stages of management. The water temperature in the early stage of entering the pool and the soon to be out of the pool are all relatively high. The amount of water should be appropriately adjusted to adjust the water quality. In the middle period, the temperature should be reduced appropriately to prevent the deterioration of water quality. The management of the late winter is particularly important. Before going out of the pond, we must strengthen the quantity and quality of the feed, promote the recovery of the body and the gonad development of the broodstock, so that the quality of the seed after the pool can be guaranteed. Throughout the winter, there must be someone responsible for doing a good job of recording, controlling water temperature, regulating water quality, feeding materials, and preventing diseases.
1, the water temperature control
When the wintering fish enter the pool within 10 days, the water temperature should be controlled between 20-25 °C. This will help the fish body's wounds heal as soon as possible and inhibit the occurrence of watery mildew. After the situation is basically stable, the water temperature can be controlled between 18-20 °C. The water temperature must not be too high or low, it cannot be cooled down suddenly, nor can it be controlled for more than 20°C for a long period of time. Long-term high temperature is not conducive to wintering management, but it also increases the input of feed. Because the water temperature is high, the fish's vitality is strong and it consumes more energy. Food intake will also increase. If ultra-thin material film greenhouses are used, the temperature in the pool may be as high as 30°C during the day due to the increasing sunlight temperature. At this time, the film should be partially opened to let the air circulate, and the temperature in the shed should be controlled at about 21°C. The water temperature should be controlled at 18-. At 19 °C, in the event of sudden changes in the weather or cold currents, the film should be covered in time to prevent a sudden drop in temperature.
2, the adjustment of water quality
Overwintering ponds should keep fresh water and adequate dissolved oxygen. Overwintering big ponds, because of their large area, are difficult to change water, so under normal circumstances they do not change water, and only add some new water. During the winter, the water quality can be adjusted and the vitality of water can be increased by regularly using a number of microbial preparations (such as vitamins, fish breeding, etc.). When the water becomes dark, some of the old water can be replaced, and new water can be injected. However, changing the water should not be excessive, and it should be controlled between 1/4 and 1/5. When the water is added, the water flow should be leveled into the pool and the outlet must be covered with a filter to prevent weeds from entering or the species from swimming backwards. The time for flushing during the day should not exceed four hours, especially the seedling pool, should be controlled in 2-3 hours or so to prevent fish fry long-term consumption of excess water or intensive increase in fish damage.
3, oxygen increase equipment
Due to the higher wintering density of the winter shed of Datang, the water quality is generally more fat, so the overwintering pool must be equipped with aeration equipment. In the low temperature season, due to the lower surface water temperature, the fish exposed to water after anoxic flotation, easily frostbite, prone to S. solani, leading to ulceration and death; in the late winter, due to the increase of water temperature, feeding increased, parents in the prenatal training In the process, the water quality becomes fat and it will cause severe hypoxia and affect the cultivation. Therefore, oxygenation during the winter is very important.
4, reasonable feeding
Tilapia must be fed with nutrient-rich concentrate during the winter. Usually take more than two, in the middle less feeding method, that is, after a certain period of time into the pool, more than appropriate feeding, broodstock control at about 2%, fish species control at about 5% -6%, once a day feeding, feeding all fish It's better to eat. For Miaochi, one or two overdose feeds are arranged every week. The purpose is to maintain the energy consumption of some weak seedlings because they cannot be eaten due to the low feed rate, and they can be eaten once or twice a week. As for thin and dead. Feeds for fingerlings can be powdered or small-caliber compound feeds. Feeding should be carried out evenly throughout the pond so that most of the fry can be eaten. The broodstock feed should be made into buoyant granular material, and the desiccant material should be set appropriately, and It is advisable to finish eating within 1.5 hours. When you are finished eating, you must remove the residual materials in time and reduce the amount of feed to prevent deterioration of feed quality. During the winter, the quantity and quality of the feed are adjusted at any time with the water temperature, the quality of the water, and the feeding conditions of the fish. Daily management
1, pay attention to changes in water temperature
Always measure the temperature and temperature of the water, usually twice a day, and make a record.
2, insist on early, middle and late patrol pond
Check whether the overwintering greenhouses are firm, observe the fish’s vitality, food intake, and monitor the water quality. If necessary, we should regularly monitor several indicators such as dissolved oxygen, ammonia chloride, and organic matter in the pool, and make records to detect problems in time and take measures to prevent An accident occurred.
3, pay attention to ventilation, ventilation
In the late winter, due to the increase of water temperature, it is necessary to pay attention to the ventilation and ventilation of wintering sheds, and the temperature of the water is stable. Then, the shed can be cooled, and fresh water can be added. When the temperature of the overwintering shed is equal to the outside world, preparations can be made before the pond.
4, pay attention to disease prevention
In the winter season, due to the small area of ​​wintering ponds, high density, relatively poor water quality, low water temperature, coupled with less activity and less feeding, tilapia is more susceptible to disease. Fish disease mainly adopts the principle of combination of prevention and treatment. In the wintering period, quicklime is used once every half month, and the dosage is 10-15 kg. After using quicklime for 7-10 days, disinfect with 0.2 5-0.3 ppm of chlorine dioxide and use pesticides once a month. Note that all drugs should be used separately and alternately. Always check the fish's activity and find that there are abnormal conditions.