Aquaculture raises water first, and good water raises good fish. In recent years, with the improvement of the degree of intensive fisheries in aquaculture, the water quality has also worsened and the number of difficult diseases has increased. Water quality management has become the most concerned issue for farmers.
1 Characteristics of water quality management in aquaculture in summer The change in water quality in summer is a continuous process. In the early stage of aquaculture, the biomass in the pond is small, organic matter is small, and the dissolved oxygen is sufficient. The organic matter is under aerobic microbial decomposition and the pond is relatively benign. Ecological balance. With the growth of the breeding period, there are more and more organic matters in the pond. With the increase of the water temperature, we continue to feed in the whole process from seeding to harvesting. The fish continuously feed and continuously excrete. Algae continue to grow and die. High breeding density results in excessive feeding. A large number of residual baits, feces and excrement diffuse and dissolve in water and deposit on the bottom. Excess feed, fish and shrimp excrement, dead algae, and other dead animals and plants Accumulated in water and cultured one day, these substances accumulate day by day, and the total amount accumulates to a certain extent, resulting in changes in the pH of the water body. The ammonia, nitrite content in the water rises, the transparency of the water body decreases, the organisms multiply and the algae As a result of the changes, overall water quality deteriorated and bacterial pathogens developed. The peak of death of a fish disease usually occurs in July-August.
2 Control of Several Key Points in Water Quality Management in Summer Farming
1) pH is an important indicator of water quality pH (pH) is an important indicator of water quality. Aquaculture pH is generally controlled between 7.5 and 8.5, and freshwater aquaculture pH is generally controlled between 6.5 and 9.0. If the pH is too high or too low, it will have direct damage to aquaculture animals and even cause death. Water with a pH of less than 6.5 can lower the pH in the blood of aquaculture animals, weakening their ability to carry oxygen in blood and causing aquaculture animals to suffer from physiological anoxia. Despite the high dissolved oxygen in the water, aquaculture animals such as fish and shrimp still often float. If the pH value is too high, the water may corrode the tissues of the fish and shrimps, causing the fish and shrimps to lose their breathing capacity and die in large numbers.
2) Dissolved Oxygen is the Life Factor of Aquaculture Animals Aquaculture animals need to breathe oxygen in water, and oxygen deficiency can cause them to float. Severe lack of oxygen can also cause death of aquaculture animals. The dissolved oxygen in the aquaculture waters of fish, shrimp, and crab aquaculture animals should be maintained at 5 to 8 mg/L, and should be kept at least 4 mg/L. Mild oxygen-deficient fish and shrimps do not die, but fish and shrimp appear irritated, breathing fast, the growth rate of fish and shrimp will slow down; too high dissolved oxygen in water will cause fish and shrimp to suffer from bubble disease.
3) Control of the toxicity of ammonia nitrogen The ammonia nitrogen in aquaculture mainly comes from the bait, excrement of aquatic animals, fertilizers, and animal and plant remains. The toxicity of ammonia to aquatic animals varies according to their concentration. At low concentrations of 0.01 to 0.02 mg/L, aquatic animals can chronically poison and inhibit their growth; at concentrations of 0.02 to 0.05 mg/L, ammonia can Other causes of aquatic animal diseases have a common additive effect that accelerates their death. At a high concentration of 0.05 to 0.2 mg/L, they damage the skin, stomach, and intestine mucosa of aquatic animals, resulting in surface and internal organs. Bleeding; At a lethal concentration of 0.2 to 0.5 mg/L, aquatic animals will die of acute poisoning.
Measures to prevent high concentration of ammonia nitrogen in aquaculture water: Clear ponds and dredging in the initial stage of breeding; Establish a reasonable stocking density according to the actual bearing capacity of the water body; Choose appropriate feeds, reasonably feed baits, avoid bait waste and bait accumulation Deterioration of water quality due to spoilage; early attention to the use of organic fertilizers during fertilization; frequent activation of aerators to promote the natural conversion of bait and reduce accumulation; use of moderate amounts of zeolite powder to improve sediment, adsorption of ammonia nitrogen , Degradation of organic matter; In order to prevent the non-ionic ammonia in the aquaculture water area is too high, in addition to the indicators of regular detection of water in the water, but also promptly clean up the removal of the bottom of the aquaculture waters and aquaculture animals excreted fecal and other measures.
4) Nitrosonitrogen is a key factor in triggering fish diseases Nitrite is an intermediate product of ammonia in the process of converting to nitrate. The process of converting ammonia into nitrate is hindered, and the nitrite of the intermediate product will be Accumulated in water. The presence of nitrite in the aquaculture waters makes it possible for the ferrous hemoglobin in the blood of fish, crabs and crabs to be oxidized to methemoglobin, thereby inhibiting the oxygen carrying capacity of the blood. Fish, shrimp, and crabs are exposed to high concentrations of nitrite in water for a long time and yellow blood disease can occur. Nitrite in water should generally be controlled below 0.1 mg/L.
When nitrite is too high, only slow water changes and good water application can be used. Then take the liver protection medicine or fish multidimensional for a week, increase anti-stress ability and degrade blood nitrite.
Treatment of nitrite: Displace water, mainly to reduce the concentration of nitrite and discharge some garbage. So it is best to drain the bottom of the water, discharge the sewage; disinfection and zeolite powder for sucking. The necessary bactericidal treatment is carried out first to use a bactericidal disinfectant that stimulates a small effect, and then the natural zeolite powder is used for sucking again the next day.
5) Treatment of poor water color The main cause of water whitening is that in the early stage of culture, due to excessive zooplankton or a large number of deaths of phytoplankton, a single cell algae cannot grow normally. In this case, if the content of ammonia nitrogen or nitrite in the water is too high, ammonia-removing water purifiers such as zeolite powder and aluminum chloride should be used first, and the feed should be controlled or stopped at the same time until most of the zooplankton are ingested. Or after death, introduce some new water and apply live biological fertilizers for fertilizer and water. In the middle and later stages of breeding, due to weather changes, the abnormal death of algae resulted in high oxygen consumption of fish and shrimp in the middle and later stages, and the amount of feed was large. Degradation and transformation processes of excrement and residual feed required large amounts of oxygen, and planktonic unicellular algae. Unnatural death will lead to deterioration of water quality. In this case, the first step is to open the aerator, then drain part of the bottom water and introduce some new water. Use ammonia-removing water purifiers in time and oxygen booster to relieve the lack of oxygen. At the same time, use dehydrin to decompose the algae. The use of photosynthetic bacteria to decompose small molecules of organic matter and ammonia nitrogen, nitrite, hydrogen sulfide and other harmful substances, and then sprinkle the fertilizer to restore the normal growth of algae. Due to the sudden changes in water quality, fish or viscera of live fish often suffer varying degrees of damage. When eating normally, health care medicines such as vitamins and allicin should be given to promote the recovery of damaged organs. After a sudden change in water quality, the growth rate of farmed fish is significantly reduced, and the anti-stress ability is reduced. Most of them require a week to recover, so water changes should be avoided as much as possible.
1 Characteristics of water quality management in aquaculture in summer The change in water quality in summer is a continuous process. In the early stage of aquaculture, the biomass in the pond is small, organic matter is small, and the dissolved oxygen is sufficient. The organic matter is under aerobic microbial decomposition and the pond is relatively benign. Ecological balance. With the growth of the breeding period, there are more and more organic matters in the pond. With the increase of the water temperature, we continue to feed in the whole process from seeding to harvesting. The fish continuously feed and continuously excrete. Algae continue to grow and die. High breeding density results in excessive feeding. A large number of residual baits, feces and excrement diffuse and dissolve in water and deposit on the bottom. Excess feed, fish and shrimp excrement, dead algae, and other dead animals and plants Accumulated in water and cultured one day, these substances accumulate day by day, and the total amount accumulates to a certain extent, resulting in changes in the pH of the water body. The ammonia, nitrite content in the water rises, the transparency of the water body decreases, the organisms multiply and the algae As a result of the changes, overall water quality deteriorated and bacterial pathogens developed. The peak of death of a fish disease usually occurs in July-August.
2 Control of Several Key Points in Water Quality Management in Summer Farming
1) pH is an important indicator of water quality pH (pH) is an important indicator of water quality. Aquaculture pH is generally controlled between 7.5 and 8.5, and freshwater aquaculture pH is generally controlled between 6.5 and 9.0. If the pH is too high or too low, it will have direct damage to aquaculture animals and even cause death. Water with a pH of less than 6.5 can lower the pH in the blood of aquaculture animals, weakening their ability to carry oxygen in blood and causing aquaculture animals to suffer from physiological anoxia. Despite the high dissolved oxygen in the water, aquaculture animals such as fish and shrimp still often float. If the pH value is too high, the water may corrode the tissues of the fish and shrimps, causing the fish and shrimps to lose their breathing capacity and die in large numbers.
2) Dissolved Oxygen is the Life Factor of Aquaculture Animals Aquaculture animals need to breathe oxygen in water, and oxygen deficiency can cause them to float. Severe lack of oxygen can also cause death of aquaculture animals. The dissolved oxygen in the aquaculture waters of fish, shrimp, and crab aquaculture animals should be maintained at 5 to 8 mg/L, and should be kept at least 4 mg/L. Mild oxygen-deficient fish and shrimps do not die, but fish and shrimp appear irritated, breathing fast, the growth rate of fish and shrimp will slow down; too high dissolved oxygen in water will cause fish and shrimp to suffer from bubble disease.
3) Control of the toxicity of ammonia nitrogen The ammonia nitrogen in aquaculture mainly comes from the bait, excrement of aquatic animals, fertilizers, and animal and plant remains. The toxicity of ammonia to aquatic animals varies according to their concentration. At low concentrations of 0.01 to 0.02 mg/L, aquatic animals can chronically poison and inhibit their growth; at concentrations of 0.02 to 0.05 mg/L, ammonia can Other causes of aquatic animal diseases have a common additive effect that accelerates their death. At a high concentration of 0.05 to 0.2 mg/L, they damage the skin, stomach, and intestine mucosa of aquatic animals, resulting in surface and internal organs. Bleeding; At a lethal concentration of 0.2 to 0.5 mg/L, aquatic animals will die of acute poisoning.
Measures to prevent high concentration of ammonia nitrogen in aquaculture water: Clear ponds and dredging in the initial stage of breeding; Establish a reasonable stocking density according to the actual bearing capacity of the water body; Choose appropriate feeds, reasonably feed baits, avoid bait waste and bait accumulation Deterioration of water quality due to spoilage; early attention to the use of organic fertilizers during fertilization; frequent activation of aerators to promote the natural conversion of bait and reduce accumulation; use of moderate amounts of zeolite powder to improve sediment, adsorption of ammonia nitrogen , Degradation of organic matter; In order to prevent the non-ionic ammonia in the aquaculture water area is too high, in addition to the indicators of regular detection of water in the water, but also promptly clean up the removal of the bottom of the aquaculture waters and aquaculture animals excreted fecal and other measures.
4) Nitrosonitrogen is a key factor in triggering fish diseases Nitrite is an intermediate product of ammonia in the process of converting to nitrate. The process of converting ammonia into nitrate is hindered, and the nitrite of the intermediate product will be Accumulated in water. The presence of nitrite in the aquaculture waters makes it possible for the ferrous hemoglobin in the blood of fish, crabs and crabs to be oxidized to methemoglobin, thereby inhibiting the oxygen carrying capacity of the blood. Fish, shrimp, and crabs are exposed to high concentrations of nitrite in water for a long time and yellow blood disease can occur. Nitrite in water should generally be controlled below 0.1 mg/L.
When nitrite is too high, only slow water changes and good water application can be used. Then take the liver protection medicine or fish multidimensional for a week, increase anti-stress ability and degrade blood nitrite.
Treatment of nitrite: Displace water, mainly to reduce the concentration of nitrite and discharge some garbage. So it is best to drain the bottom of the water, discharge the sewage; disinfection and zeolite powder for sucking. The necessary bactericidal treatment is carried out first to use a bactericidal disinfectant that stimulates a small effect, and then the natural zeolite powder is used for sucking again the next day.
5) Treatment of poor water color The main cause of water whitening is that in the early stage of culture, due to excessive zooplankton or a large number of deaths of phytoplankton, a single cell algae cannot grow normally. In this case, if the content of ammonia nitrogen or nitrite in the water is too high, ammonia-removing water purifiers such as zeolite powder and aluminum chloride should be used first, and the feed should be controlled or stopped at the same time until most of the zooplankton are ingested. Or after death, introduce some new water and apply live biological fertilizers for fertilizer and water. In the middle and later stages of breeding, due to weather changes, the abnormal death of algae resulted in high oxygen consumption of fish and shrimp in the middle and later stages, and the amount of feed was large. Degradation and transformation processes of excrement and residual feed required large amounts of oxygen, and planktonic unicellular algae. Unnatural death will lead to deterioration of water quality. In this case, the first step is to open the aerator, then drain part of the bottom water and introduce some new water. Use ammonia-removing water purifiers in time and oxygen booster to relieve the lack of oxygen. At the same time, use dehydrin to decompose the algae. The use of photosynthetic bacteria to decompose small molecules of organic matter and ammonia nitrogen, nitrite, hydrogen sulfide and other harmful substances, and then sprinkle the fertilizer to restore the normal growth of algae. Due to the sudden changes in water quality, fish or viscera of live fish often suffer varying degrees of damage. When eating normally, health care medicines such as vitamins and allicin should be given to promote the recovery of damaged organs. After a sudden change in water quality, the growth rate of farmed fish is significantly reduced, and the anti-stress ability is reduced. Most of them require a week to recover, so water changes should be avoided as much as possible.