Rotifera is one of the small-scale zooplankton which is widely used as a live bait during the artificial breeding of fish, shrimp, and crab. Especially in recent years, with the development of the shrimp and crab breeding industry and aquaculture, rotifers have become more and more used as high quality live feeds. The cultivation of rotifers can bring huge profits, so many farmers or nursery families have also turned their attention to rotifer culture, but in the rotifer culture process there are always some or all problems that make rotifer culture The output is not stable enough and increases costs. Therefore, on the basis of how to reduce the cost of breeding, it can stabilize the output and even increase the output, becoming a difficulty faced by rotifer breeding. The author has accumulated a number of successful experiences in cultivating rotifers (Cultivated rotifers) for several years and is summarized below.
First, preparatory work
1. Pond condition culture pool should be built near the nursery, with convenient transportation, convenient water source (freshwater, seawater) and shelter from the sun. The location is higher for construction and drainage. The area of ​​the earthen pond is preferably 2000-3000 square meters, and the depth of the pool is 80-120cm. The pool is rectangular. The soil quality should be muddy or sandy, and the bottom and the pool wall are not leaky. The number of earthen ponds is generally 3-5 or more, and it is convenient to divide the pools at the same time, incubate in batches, and harvest them alternately.
2. The new pond in Qingchi water can directly enter the water. If the old pond should drain the water, apply drugs to the remaining water to kill fish and crustaceans. Clearing agents commonly used are (1) bleaching powder, chlorine content should be detected before use, bleaching powder containing 30% chlorine, the amount of 25-30g / square meter, the general efficacy of 3-5 days disappeared. 1 rattan fine: dosage 2g/cubic meter.
After clear ponds can be filtered into the sea water, filter sieve with 160-200 mesh, to prevent enemy pests mixed. The initial water intake is 40-60cm, and the salinity is adjusted to 10-20 ‰. Fertilizer is applied to make the water eutrophic.
3. Fertilizer commonly used organic fertilizers and inorganic fertilizers, the amount of application based on the situation of pool water, should be a small amount of ground facilities. The amount of chemical fertilizer is generally 20-25g/m3 of sulfuric acid hinge, 15-20g/m3 of nitric acid hinge and 3g/m3 of superphosphate, and 15g-20g/m3 of urea. The amount of human urine 200g/m3, chicken and duck dung, because of its large efficiency and long-lasting, dosage 200g/m3, should be fermented before use, you can dig a small hole in the pool, down the manure, the It can be poured into the pool around noon every day after fermentation.
After fertilization, the water color is usually light green or light brown after 3-5 days under normal light and temperature conditions. In order to make the pond water become fat as quickly as possible, it is also possible to purchase a variety of effective feed algae from the scientific research institutes or other places, such as Algae, Platymonas palustris, Chlorella, Dunaliella, Nannochloropsis, P. tricornutum , Nissl, etc.) mixed together (called complex algal fluid), poured into the pool, the amount of 3-5L/m3. With the deepening of the water, the amount of water can be added in a timely manner.
Second, vaccination rotifers when the natural water temperature reaches 10 °C or so, the pool water can be timely vaccinated when the rotifers, if the soil terrapin cultured rotifers can be used to pull the bottom of the mud, the dormant eggs can be stirred up. Vaccinated rotifers can also purchase live rotifers from nearby greenhouses, but require high egg-laying rates. When inoculating, select the highest temperature in sunny afternoon. Inoculation density: Ordinary live rotifer 10 / L, or as high density seeding.
Third, training management
1. Fertilization: In the early stage of cultivation, due to the large amount of base fertilizer being applied at one time, and the lower temperature of the water, no additional fertilizer or a small amount of supplemental fertilizer is generally required. In the later period, algae reproduction is accelerated as the water temperature rises, and rapid nutrient consumption in the water body requires timely supplementation. Supplementing fertilizer is generally performed before and after noon, and the amount depends on the quality of the water. Usually a small amount of ground facilities.
2. Adding water: In the early days, water is mainly used to add water. With the deepening of the algae breeding water, water is added at a proper time. The circulation of substances in the higher temperature pool in the later period is accelerated. As the rotifers are continuously produced and some of the trace elements in the water lose their balance, fresh seawater needs to be replenished. Supplemental seawater needs to be filtered, preferably it is disinfected with drugs. The water exchange volume is generally changed by 1/5-1/3 every 10 days, and changing water can be carried out simultaneously with the harvest.
3. Feeding: When the rotifer density is too large, in order to prevent the pool water from filtering out in a short time, the rotifers need to be harvested in time, and at the same time, in order to make the population grow continuously, feeds may be fed, mainly yeast, soy milk, wheat and the like. The unicellular algae were maintained at a suitable density by means of round-rotation control of rotifer density, supplementation of bait, and the like.
4. Daily inspection: Check whether the pool wall leaks. Whether there is a change in the water color, if the water becomes lighter, the density of the algae may be reduced, and timely fertilization is needed. If the water color changes may be a change of a dominant species, the impact is not significant. Check the rotifer's density and ovulation rate (the number of female eggs and the total number of females). When the ovum rate drops below 13%, the rotifer population will decline, and the pool can be emptied and re-entered. Water inoculation.
5. Disease prevention and treatment: Disease organisms commonly found in rotifer cultures fall into two categories: one is food pests, mainly small-scale fish, shrimp, crab larvae, aquatic insects, mosquitoes and flies, and the like, as well as larvae. Hey.
Control methods: filter the water, use 120-150 mesh nets to collect aquatic insects, etc., to eliminate the poolside weeds, so that no predators are breeding ground. In the breeding season, you can hold the egg crab in the evening with a lamp in your hand. The other type is the competitive predators, such as the insects in the original animal, swim traps, and amoeba. Once contaminated, the rotifers do not die, but because they devour unicellular algae, the yield of rotifers does not increase. The main control measures: control the pollution of water sources, add water consumption is good to eliminate the poison. In addition, clean all around the pool walls to reduce the impact of rainstorms and bring protozoa. When a large number of protozoa appear in the culture pool, the pool water is generally drained and re-inoculated.
Fourth, the early harvest water temperature is low, rotifer breeding slowly, at this time, although the market demand is large and the price is high, only a small amount of harvest. When the general water temperature is 10-15°C, the daily harvest is about 1/10 of the amount of the reservoir. The higher water temperature in the later period, rapid reproduction can be harvested in large quantities. The general daily harvest is 1/6-1/3 of the storage volume. In addition, when the rotifer production peak occurs, a large number of rotifers should be timely harvested and supplemented with fertilizer and water to maintain the continuous growth of the population.
Harvesting method: Use a 240-mesh sieve to grow into a cylindrical shape, length 6-10m, diameter 40cm, and fix the electric floating pump on the middle boat of the pool. One end of the sieve cup is set on the pump port, so that it is fully stretched, and the other end is fixed. At the edge of the pool, use live ligature. Check the mesh bag before use.
Harvest time: Generally better in the early morning, because the water temperature in the afternoon is higher than that of rotifers, spawning eggs, water, viscous substances in the water, at the same time due to the dissolved oxygen in the water often oversaturated in the afternoon, easy to reduce the permeability of Sieve Siphon during filtration, As a result, a large amount of foam is formed in the bag, affecting the efficiency and product quality.
V. Discussion
1. Sometimes the rotifer's density and ovum rate drop rapidly. The reason for this is probably due to the high NH3-N in the water, and water change measures are usually taken.
2. Due to the low natural water temperature during the early breeding of fish, shrimp, crabs, and the low yield of earthen pond culture, it is unable to meet the needs of the nursery industry. In the future, we should vigorously develop greenhouses to cultivate rotifers to meet market demand.
3. Individuals with small rotifers can only meet the needs of fish, shrimp and crab larvae. In the later culture process, they should be dedicated to large-scale individual rotifer culture and research.
First, preparatory work
1. Pond condition culture pool should be built near the nursery, with convenient transportation, convenient water source (freshwater, seawater) and shelter from the sun. The location is higher for construction and drainage. The area of ​​the earthen pond is preferably 2000-3000 square meters, and the depth of the pool is 80-120cm. The pool is rectangular. The soil quality should be muddy or sandy, and the bottom and the pool wall are not leaky. The number of earthen ponds is generally 3-5 or more, and it is convenient to divide the pools at the same time, incubate in batches, and harvest them alternately.
2. The new pond in Qingchi water can directly enter the water. If the old pond should drain the water, apply drugs to the remaining water to kill fish and crustaceans. Clearing agents commonly used are (1) bleaching powder, chlorine content should be detected before use, bleaching powder containing 30% chlorine, the amount of 25-30g / square meter, the general efficacy of 3-5 days disappeared. 1 rattan fine: dosage 2g/cubic meter.
After clear ponds can be filtered into the sea water, filter sieve with 160-200 mesh, to prevent enemy pests mixed. The initial water intake is 40-60cm, and the salinity is adjusted to 10-20 ‰. Fertilizer is applied to make the water eutrophic.
3. Fertilizer commonly used organic fertilizers and inorganic fertilizers, the amount of application based on the situation of pool water, should be a small amount of ground facilities. The amount of chemical fertilizer is generally 20-25g/m3 of sulfuric acid hinge, 15-20g/m3 of nitric acid hinge and 3g/m3 of superphosphate, and 15g-20g/m3 of urea. The amount of human urine 200g/m3, chicken and duck dung, because of its large efficiency and long-lasting, dosage 200g/m3, should be fermented before use, you can dig a small hole in the pool, down the manure, the It can be poured into the pool around noon every day after fermentation.
After fertilization, the water color is usually light green or light brown after 3-5 days under normal light and temperature conditions. In order to make the pond water become fat as quickly as possible, it is also possible to purchase a variety of effective feed algae from the scientific research institutes or other places, such as Algae, Platymonas palustris, Chlorella, Dunaliella, Nannochloropsis, P. tricornutum , Nissl, etc.) mixed together (called complex algal fluid), poured into the pool, the amount of 3-5L/m3. With the deepening of the water, the amount of water can be added in a timely manner.
Second, vaccination rotifers when the natural water temperature reaches 10 °C or so, the pool water can be timely vaccinated when the rotifers, if the soil terrapin cultured rotifers can be used to pull the bottom of the mud, the dormant eggs can be stirred up. Vaccinated rotifers can also purchase live rotifers from nearby greenhouses, but require high egg-laying rates. When inoculating, select the highest temperature in sunny afternoon. Inoculation density: Ordinary live rotifer 10 / L, or as high density seeding.
Third, training management
1. Fertilization: In the early stage of cultivation, due to the large amount of base fertilizer being applied at one time, and the lower temperature of the water, no additional fertilizer or a small amount of supplemental fertilizer is generally required. In the later period, algae reproduction is accelerated as the water temperature rises, and rapid nutrient consumption in the water body requires timely supplementation. Supplementing fertilizer is generally performed before and after noon, and the amount depends on the quality of the water. Usually a small amount of ground facilities.
2. Adding water: In the early days, water is mainly used to add water. With the deepening of the algae breeding water, water is added at a proper time. The circulation of substances in the higher temperature pool in the later period is accelerated. As the rotifers are continuously produced and some of the trace elements in the water lose their balance, fresh seawater needs to be replenished. Supplemental seawater needs to be filtered, preferably it is disinfected with drugs. The water exchange volume is generally changed by 1/5-1/3 every 10 days, and changing water can be carried out simultaneously with the harvest.
3. Feeding: When the rotifer density is too large, in order to prevent the pool water from filtering out in a short time, the rotifers need to be harvested in time, and at the same time, in order to make the population grow continuously, feeds may be fed, mainly yeast, soy milk, wheat and the like. The unicellular algae were maintained at a suitable density by means of round-rotation control of rotifer density, supplementation of bait, and the like.
4. Daily inspection: Check whether the pool wall leaks. Whether there is a change in the water color, if the water becomes lighter, the density of the algae may be reduced, and timely fertilization is needed. If the water color changes may be a change of a dominant species, the impact is not significant. Check the rotifer's density and ovulation rate (the number of female eggs and the total number of females). When the ovum rate drops below 13%, the rotifer population will decline, and the pool can be emptied and re-entered. Water inoculation.
5. Disease prevention and treatment: Disease organisms commonly found in rotifer cultures fall into two categories: one is food pests, mainly small-scale fish, shrimp, crab larvae, aquatic insects, mosquitoes and flies, and the like, as well as larvae. Hey.
Control methods: filter the water, use 120-150 mesh nets to collect aquatic insects, etc., to eliminate the poolside weeds, so that no predators are breeding ground. In the breeding season, you can hold the egg crab in the evening with a lamp in your hand. The other type is the competitive predators, such as the insects in the original animal, swim traps, and amoeba. Once contaminated, the rotifers do not die, but because they devour unicellular algae, the yield of rotifers does not increase. The main control measures: control the pollution of water sources, add water consumption is good to eliminate the poison. In addition, clean all around the pool walls to reduce the impact of rainstorms and bring protozoa. When a large number of protozoa appear in the culture pool, the pool water is generally drained and re-inoculated.
Fourth, the early harvest water temperature is low, rotifer breeding slowly, at this time, although the market demand is large and the price is high, only a small amount of harvest. When the general water temperature is 10-15°C, the daily harvest is about 1/10 of the amount of the reservoir. The higher water temperature in the later period, rapid reproduction can be harvested in large quantities. The general daily harvest is 1/6-1/3 of the storage volume. In addition, when the rotifer production peak occurs, a large number of rotifers should be timely harvested and supplemented with fertilizer and water to maintain the continuous growth of the population.
Harvesting method: Use a 240-mesh sieve to grow into a cylindrical shape, length 6-10m, diameter 40cm, and fix the electric floating pump on the middle boat of the pool. One end of the sieve cup is set on the pump port, so that it is fully stretched, and the other end is fixed. At the edge of the pool, use live ligature. Check the mesh bag before use.
Harvest time: Generally better in the early morning, because the water temperature in the afternoon is higher than that of rotifers, spawning eggs, water, viscous substances in the water, at the same time due to the dissolved oxygen in the water often oversaturated in the afternoon, easy to reduce the permeability of Sieve Siphon during filtration, As a result, a large amount of foam is formed in the bag, affecting the efficiency and product quality.
V. Discussion
1. Sometimes the rotifer's density and ovum rate drop rapidly. The reason for this is probably due to the high NH3-N in the water, and water change measures are usually taken.
2. Due to the low natural water temperature during the early breeding of fish, shrimp, crabs, and the low yield of earthen pond culture, it is unable to meet the needs of the nursery industry. In the future, we should vigorously develop greenhouses to cultivate rotifers to meet market demand.
3. Individuals with small rotifers can only meet the needs of fish, shrimp and crab larvae. In the later culture process, they should be dedicated to large-scale individual rotifer culture and research.
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