With the rapid development of the aquaculture seedling industry and the continuous increase in intensification, water quality conditions have continuously deteriorated and harmful algae and bacteria have proliferated in large numbers. As a result, the output of aquatic product breeding has been low or even unsuccessful in recent years. How to obtain high yield has become an urgent need. solved problem. Here to talk about a few aquatic breeding work should pay attention to production problems.
1, the choice of pro-crab health, no disability, back green and white, clean, strong struggle, male and female crabs best off-site selection, so as not to inbreeding. The size of the pro-crab is generally 90-115g for females and 115-150g for males. The size is too small (especially the female crabs), and the amount of spawning is small; individuals are large and the amount of eggs is large, but the embryos are often deprived of oxygen due to weakness in the abdominal fan, and development is not synchronized or even stops development.
2, cloth pool when the embryo heart rate of 180 / min do not rush to "hanging the cage", because the first hatched larvae are often poor vitality, no culture value. Always use a beaker to draw water to observe. When a beaker can reach 4-5 larvae, then disinfect the pro-crab and then “hang the cageâ€. In order to obtain a high yield of nursery, the larvae pool is very important. In the case of early seedlings, the natural temperature and water temperature are both low, pathogenic organisms are few, and the density of the cloth pool can be relatively large. Generally, 30-40 million juveniles/m3 is more appropriate. In the case of late seedlings (May), the natural water temperature is relatively high and the density can be controlled at 15-20 million juveniles/m3. If we do not scientifically determine the density of the pool, it will lead to failure of the nursery. Because the density is too high, the larvae will be fed unevenly and the development will be out of step. When the larvae are mostly metamorphosis to the big eye larvae, the unmetamorpha zoea will be caught in the big eye larvae. Slaughter; the density of the cloth pool is too small, the bait density is not well grasped during the breeding process, and the feeding is excessive, and the feeding of the larvae is not finished, which will lead to deterioration of water quality, too little feeding, and the bait in the water cannot reach a certain density. Food eventually causes larval insufficiency, physical weakness, and increased risk of disease.
3, too high temperature water temperature will affect the quality of seedlings, too low to affect the development of larvae. The water temperature in the general cloth pool is 19-20°C. After each metamorphosis, the temperature increases by 1-1.5°C.
4. Regularly measure the PH value of the PH value, preferably between 7.5-8.3. Above this range, the most direct adjustment method is to change the water.
5. Salinity can be controlled at 20-21‰ for general salinity, and 1.5-2‰ for each subsequent period. After the larvae become metamorphosed on day 2, the daily salt reduction rate is 5 ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰.
6, water quality In order to water quality, the most direct way is to add water. Changing water is the same as feeding, it is best to adhere to the principle of "a small number of times". If too much water is exchanged at one time, the growth environment of the larvae will change too much, beyond the adaptive capacity of the larvae, it will also increase the incidence of larvae, resulting in a low survival rate.
7. On the basis of strengthening the quality of conventional feed, the bait should ensure the quantity of bait to maintain the normal metabolism and development of the larvae, and avoid the larval development, high incidence and low survival rate due to lack of bait. Feeding must follow the principle of "less frequent casting, few times". If the amount of one shot is too large, the larvae will not eat enough, the bait will sink, causing the bottom of the pool to deteriorate, and produce toxic substances such as ammonia and hydrogen sulfide, which will ultimately cause adverse phenomena such as high larval rate and low survival rate.
1, the choice of pro-crab health, no disability, back green and white, clean, strong struggle, male and female crabs best off-site selection, so as not to inbreeding. The size of the pro-crab is generally 90-115g for females and 115-150g for males. The size is too small (especially the female crabs), and the amount of spawning is small; individuals are large and the amount of eggs is large, but the embryos are often deprived of oxygen due to weakness in the abdominal fan, and development is not synchronized or even stops development.
2, cloth pool when the embryo heart rate of 180 / min do not rush to "hanging the cage", because the first hatched larvae are often poor vitality, no culture value. Always use a beaker to draw water to observe. When a beaker can reach 4-5 larvae, then disinfect the pro-crab and then “hang the cageâ€. In order to obtain a high yield of nursery, the larvae pool is very important. In the case of early seedlings, the natural temperature and water temperature are both low, pathogenic organisms are few, and the density of the cloth pool can be relatively large. Generally, 30-40 million juveniles/m3 is more appropriate. In the case of late seedlings (May), the natural water temperature is relatively high and the density can be controlled at 15-20 million juveniles/m3. If we do not scientifically determine the density of the pool, it will lead to failure of the nursery. Because the density is too high, the larvae will be fed unevenly and the development will be out of step. When the larvae are mostly metamorphosis to the big eye larvae, the unmetamorpha zoea will be caught in the big eye larvae. Slaughter; the density of the cloth pool is too small, the bait density is not well grasped during the breeding process, and the feeding is excessive, and the feeding of the larvae is not finished, which will lead to deterioration of water quality, too little feeding, and the bait in the water cannot reach a certain density. Food eventually causes larval insufficiency, physical weakness, and increased risk of disease.
3, too high temperature water temperature will affect the quality of seedlings, too low to affect the development of larvae. The water temperature in the general cloth pool is 19-20°C. After each metamorphosis, the temperature increases by 1-1.5°C.
4. Regularly measure the PH value of the PH value, preferably between 7.5-8.3. Above this range, the most direct adjustment method is to change the water.
5. Salinity can be controlled at 20-21‰ for general salinity, and 1.5-2‰ for each subsequent period. After the larvae become metamorphosed on day 2, the daily salt reduction rate is 5 ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰.
6, water quality In order to water quality, the most direct way is to add water. Changing water is the same as feeding, it is best to adhere to the principle of "a small number of times". If too much water is exchanged at one time, the growth environment of the larvae will change too much, beyond the adaptive capacity of the larvae, it will also increase the incidence of larvae, resulting in a low survival rate.
7. On the basis of strengthening the quality of conventional feed, the bait should ensure the quantity of bait to maintain the normal metabolism and development of the larvae, and avoid the larval development, high incidence and low survival rate due to lack of bait. Feeding must follow the principle of "less frequent casting, few times". If the amount of one shot is too large, the larvae will not eat enough, the bait will sink, causing the bottom of the pool to deteriorate, and produce toxic substances such as ammonia and hydrogen sulfide, which will ultimately cause adverse phenomena such as high larval rate and low survival rate.