Crab breeding technology
2018-06-06 10:02:42
Improving the survival rate of purchasing crab seedlings
1. Some farmers who purchased Miao seedlings went south to north and purchased seedlings from other river systems and coastal estuaries. The mortality rate was often high. Therefore, the farmers in our province should purchase the seedlings of the Yangtze River system from the farms on both banks of the Yangtze River and the Huaihe River. It is not advisable to purchase the Liaohe species, and the Zhejiang and Zhejiang species.
2. Purchasing desalinated crabs There are a small number of units and individuals that cultivate crabs at present, and they are quick to gain instant benefits. The sale of desalination to farmers is not long (2-3 days), and the quality of large-eyed larvae is so low that crabs cannot adapt to the new environment and die. Therefore, seedlings with longer desalination (more than 5 days) should be purchased. When purchasing, in addition to the detailed understanding of the nursery households, the following methods can be used for identification:
(1) High-quality desalted crab seedlings are tan, not mixed with white or brownish red, and hold the crab seedlings for 3-5 seconds by hand. The hand feels hard, and after being put down, it is still moving freely, crawling quickly, and moving near the water's edge.
(2) If possible. The pH of the cultivating desalination tank should be measured, as well as the salt content. The salt content of the pool water can also be determined by the mouthfeel method.
3, transport crab seedlings (1) when buying seedlings is best to use professional buy seedling box, or use plastic bags with water oxygenation, not cloth bags, bamboo and other. (2) Crab seedlings like to gather and huddle, and should prevent crab seedlings from suffocating and suffocating. (3) To reduce vibration, keep the container for crabs away from the driver's cab, beware of the influence of gasoline and high temperature; the temperature difference between inside and outside when getting off is not more than 5°C. (4) Sprinkle water once in 2-3 hours to maintain a certain humidity; be careful not to spray with tap water at the station, because there is chlorine in the water.
4. Before investing in the preparation of crab seedlings, it is imperative to clear the pond and remove the predators. Crabs generally have only a grain size, and are often targets of water snakes, frogs, crickets, and carnivorous fish. Delivery time should be sunny at noon. If conditions permit, they can be put into Datang for a week and this can significantly increase the survival rate.
River crab cultivation technology River crab breeding is an important part of river crab production. It has cultivated a robust crab crab, which is conducive to high yield and efficiency. If the crab bigeye larvae are directly put into the crab pool, not only the early spring temperature is low, the crab seedlings can not survive, but also due to the lack of food to kill each other, resulting in survival rate, in the 3-5 months need to build crab breeding seedlings Plastic greenhouses, according to the biological characteristics of juvenile crabs, provide the environmental conditions required for their growth and shelling, and sufficient food to develop five young crabs of the same size, suitable size, and high survival rate.
First, build a pool. Crab breeding ponds are based on the amount of crabs, generally 0.5-1 mu. The pool depth is 0.8-1 meters, the water depth is 0.4-0.8 meters, and the slope ratio is about 1:1.5. The water is abundant, the water quality is good, the bottom of the pool is rigid and the pool is solid and does not leak. The bottom of the pool is inclined towards the outlet. The pond is rectangular and arranged in the east-west direction with an aspect ratio of 5:3.
Second, Qingchi disinfection. Qingchi can kill enemy creatures in the pool. Before restocking crabs, the silt in the nursery pond should be removed and holes and cracks should be filled. Newly built crab ponds or crab ponds that have been converted from fish ponds should be disinfected with drug clearing ponds prior to stocking, and bleaching powders should be used for clearing ponds. The method of using the bleaching pond: first calculate the volume of the pool water, use 20 grams of bleaching powder (20ppm) per cubic meter of water, and dissolve the bleaching powder required in the nursery pond immediately after the water is added. Usually, the whole pond will be splashed, usually after 5 days seedling. Pay attention to the fact that the alkali water in the saline-alkaline pond is alkaline and has a high PH value. Therefore, alkaline lime cannot be used as a clear pond drug.
Third, the arrival of crab seedlings. To achieve "human seedlings, cars and other seedlings, ponds and other seedlings", after the crabs are transported to Tangkou, the crab seedlings should be placed in the pool water for 2 minutes, and then lifted, so reciprocated 2-3 times to make the crab The seedlings are adapted to the pond water temperature and water quality, and then put into the cage for raising. After the crab seedlings are put into cages, the live crabs will automatically swim out and the cages will be removed. After the crabs were normal, they were given medications for leeches.
Fourth, stocking density. Generally, 80-150 (5-10 kg) crabs are stocked on each acre. The specifications are large, the quality is good, and the density can be thinned. On the contrary, it is denser.
Fifth, planting plants. To plant water peanuts, duckweed, and bitter grass, first rinse the water peanuts, duckweed, and bitter grass with river water, wash off most of the attached shrimp seeds and fish eggs, and disinfect them with 20 ppm potassium permanganate solution. Bacteria, which can purify water quality, can also use water peanuts, duckweed, and bitter grass as habitats and young crab feed.
Six, intensive fine feed.
(1) Temperature: The adaptation range of Crab crabs and crabs stage is 15°C～30°C, the optimum water temperature is 25°C or so, and the water temperature drops below 12°C, crab seedlings will be frozen to death. Therefore, we must strictly control the water temperature in the pool, if the water temperature is low, we must try to increase temperature.
(2) Feeding: Use fresh wild fish and appropriate amount of salt, stir and dehydrate bones and stir into fish gizzards, then mix well with wheat flour to make pellets and feed them directly. The mixing ratio is 0.8 kg of fish and 1 kg of wheat flour, and the daily bait is calculated as 100%-150% of the body weight of the crab. Crabs were introduced into the pond 3-5 times a day, and after 7 days, once a day, sooner or later, a portion of the bait was thrown in the shallow water area of ​​the pool, and the other part was sprinkled in the dense area of ​​aquatic plants.
(3) Control the water level of the pond: When the crab is just under the pond, the water depth should be maintained at 20-30 cm. After the first phase of larvae was removed, 15 cm of water was added, and after the second phase of larvae, 15 cm of water was added. Turn to the third stage of crabs, add water 25 centimeters to reach the maximum water level 70-80 centimeters.
Seventh, strengthen management.
(1) Timely inspection of crab pond escape prevention facilities. It was found that the damage prevention facilities must be promptly repaired, and that predator organisms (frogs, water mice, snakes, etc.) must be promptly killed.
(2) To inspect the pond three times a day, so that “three inspections and three inspections†means that crabs will be eaten in the morning to kill the enemy’s harmful organisms; the growth of crabs (developmental stage) will be checked at noon; , Analyze the water quality situation.
(3) A certain amount of floating plants in the pond should generally account for about one-half of the water surface. Too few plants should be planted, and too much water must be taken out of the pool.
Eight, prevention and treatment of diseases. The crab seedlings are susceptible to disease during the crab breeding period. Therefore, the disease prevention and control work must be done. The crabs can be disinfected with formaldehyde before entering the pool. To prevent and treat diseases of crab seedlings, at this stage, the main drugs are crabs landing ashore and crab speed Kang (Bao 009).
The management of crabs in the shelling period is an inherent characteristic of their physiology and an important indicator of the growth, development, and metamorphosis of crabs. It can be said that in the life cycle of crabs, the more shells they have, the faster the growth gains. Crab shelling is a "rebirth" process. The sturdy crabs can be completed within 5-10 minutes, while the weak ones require about one hour. The shell crab is the most frail when it is shelled, and it is also the most dangerous period to be attacked by pathogens, enemy enemies and even the same kind. Therefore, routine management should pay attention to the shelling of crabs, and it is advisable to change the water one week before the crab shelling. Disinfection measures to ensure smooth shelling of crabs. In the life of the crab, it takes more than 28-30 times to uncrusting: the pod-like larvae are shelled once in about 3 days; the big-eyed larvae are 4-6 days in the early stage and 7-10 days in the later stage; Crabs shelled about 15-20 days; autumn and crab species reached sexual maturity from winter to autumn, and shelled about 7-9 times. It is worth noting that in the absence of feed, crab growth rate is slow, not only the number of shelling less, and no step. How to determine the shelling period of crabs, first, from the feeding situation, under normal circumstances, crab shelling food intake will be significantly reduced, and the second is that the back shell of the shelled crab is yellow. The food bait of river crab is the material basis of crab breeding. Its species, quality and abundance directly affect the breeding effect of river crab. Knowing the crab's feeding habits will help to optimize its ecological environment and rational preparation of food during crab breeding.
(1) Natural bait crabs are omnivorous, mainly feeding on aquatic plants and small fish, shellfish and benthic organisms, and consuming organic detritus when consuming food. After sampling and analysis of the river crabs released from the lake, 65% of the stomach contents of the river crabs are mainly plant foods. However, under the conditions of artificial rearing, when the animals' bait (carcasses, small fishes) and aquatic plants are present at the same time, the crabs are ingested first. It is an animal food, and its food group only accounts for 35% of the total food intake. Aquatic plants serve as the main bait for crabs in natural conditions because they are easily eaten, because in the breeding season of snails and shrimps, animal foods can reach 60%-70% of the food in river crabs. Crabs have a certain selectivity for the uptake of aquatic plants. During the annual breeding period, the alfalfa (spring) and the black algae (summer and autumn) are two different seasons of eating types, golden algae, yellow silk grass, and bittergrass are alternative foods, Malay's sub-grass, and grass ( Foxtail algae is a food-eating species. Of course, this sorting is not a fixed model. The selection of aquatic species by crabs is related to the population structure of aquatic plants and their respective biomass. The food composition of crabs is diverse. Experiments have confirmed that crabs' intake of diverse foods is significantly higher than that of single foods. If crabs need to be transplanted in ponds for raising crabgrass, special attention should be paid to the transplanting of alfalfa grass in addition to collecting diversity grass species. Commonly known as "grass yellowgrass", the grass is the kind of food that crabs prefer in the early spring.
(2) The research on artificial compound feedstuffs for artificial crabs is quite different in different regions. However, the general principle is that the formula must first be formulated according to the nutrient components of crabs: the approximate content of protein and amino acids, combined with artificial feed sources. It cannot be ignored that the best source of artificial compound feed must take into account the reasonable proportions of binders, trace elements, and tropins (dehuminates), as well as the differences between juvenile, juvenile and adult crabs, and develop palatability and nutrition. Good foods with good digestibility and stability meet the feeding characteristics of crabs.
1. Some farmers who purchased Miao seedlings went south to north and purchased seedlings from other river systems and coastal estuaries. The mortality rate was often high. Therefore, the farmers in our province should purchase the seedlings of the Yangtze River system from the farms on both banks of the Yangtze River and the Huaihe River. It is not advisable to purchase the Liaohe species, and the Zhejiang and Zhejiang species.
2. Purchasing desalinated crabs There are a small number of units and individuals that cultivate crabs at present, and they are quick to gain instant benefits. The sale of desalination to farmers is not long (2-3 days), and the quality of large-eyed larvae is so low that crabs cannot adapt to the new environment and die. Therefore, seedlings with longer desalination (more than 5 days) should be purchased. When purchasing, in addition to the detailed understanding of the nursery households, the following methods can be used for identification:
(1) High-quality desalted crab seedlings are tan, not mixed with white or brownish red, and hold the crab seedlings for 3-5 seconds by hand. The hand feels hard, and after being put down, it is still moving freely, crawling quickly, and moving near the water's edge.
(2) If possible. The pH of the cultivating desalination tank should be measured, as well as the salt content. The salt content of the pool water can also be determined by the mouthfeel method.
3, transport crab seedlings (1) when buying seedlings is best to use professional buy seedling box, or use plastic bags with water oxygenation, not cloth bags, bamboo and other. (2) Crab seedlings like to gather and huddle, and should prevent crab seedlings from suffocating and suffocating. (3) To reduce vibration, keep the container for crabs away from the driver's cab, beware of the influence of gasoline and high temperature; the temperature difference between inside and outside when getting off is not more than 5°C. (4) Sprinkle water once in 2-3 hours to maintain a certain humidity; be careful not to spray with tap water at the station, because there is chlorine in the water.
4. Before investing in the preparation of crab seedlings, it is imperative to clear the pond and remove the predators. Crabs generally have only a grain size, and are often targets of water snakes, frogs, crickets, and carnivorous fish. Delivery time should be sunny at noon. If conditions permit, they can be put into Datang for a week and this can significantly increase the survival rate.
River crab cultivation technology River crab breeding is an important part of river crab production. It has cultivated a robust crab crab, which is conducive to high yield and efficiency. If the crab bigeye larvae are directly put into the crab pool, not only the early spring temperature is low, the crab seedlings can not survive, but also due to the lack of food to kill each other, resulting in survival rate, in the 3-5 months need to build crab breeding seedlings Plastic greenhouses, according to the biological characteristics of juvenile crabs, provide the environmental conditions required for their growth and shelling, and sufficient food to develop five young crabs of the same size, suitable size, and high survival rate.
First, build a pool. Crab breeding ponds are based on the amount of crabs, generally 0.5-1 mu. The pool depth is 0.8-1 meters, the water depth is 0.4-0.8 meters, and the slope ratio is about 1:1.5. The water is abundant, the water quality is good, the bottom of the pool is rigid and the pool is solid and does not leak. The bottom of the pool is inclined towards the outlet. The pond is rectangular and arranged in the east-west direction with an aspect ratio of 5:3.
Second, Qingchi disinfection. Qingchi can kill enemy creatures in the pool. Before restocking crabs, the silt in the nursery pond should be removed and holes and cracks should be filled. Newly built crab ponds or crab ponds that have been converted from fish ponds should be disinfected with drug clearing ponds prior to stocking, and bleaching powders should be used for clearing ponds. The method of using the bleaching pond: first calculate the volume of the pool water, use 20 grams of bleaching powder (20ppm) per cubic meter of water, and dissolve the bleaching powder required in the nursery pond immediately after the water is added. Usually, the whole pond will be splashed, usually after 5 days seedling. Pay attention to the fact that the alkali water in the saline-alkaline pond is alkaline and has a high PH value. Therefore, alkaline lime cannot be used as a clear pond drug.
Third, the arrival of crab seedlings. To achieve "human seedlings, cars and other seedlings, ponds and other seedlings", after the crabs are transported to Tangkou, the crab seedlings should be placed in the pool water for 2 minutes, and then lifted, so reciprocated 2-3 times to make the crab The seedlings are adapted to the pond water temperature and water quality, and then put into the cage for raising. After the crab seedlings are put into cages, the live crabs will automatically swim out and the cages will be removed. After the crabs were normal, they were given medications for leeches.
Fourth, stocking density. Generally, 80-150 (5-10 kg) crabs are stocked on each acre. The specifications are large, the quality is good, and the density can be thinned. On the contrary, it is denser.
Fifth, planting plants. To plant water peanuts, duckweed, and bitter grass, first rinse the water peanuts, duckweed, and bitter grass with river water, wash off most of the attached shrimp seeds and fish eggs, and disinfect them with 20 ppm potassium permanganate solution. Bacteria, which can purify water quality, can also use water peanuts, duckweed, and bitter grass as habitats and young crab feed.
Six, intensive fine feed.
(1) Temperature: The adaptation range of Crab crabs and crabs stage is 15°C～30°C, the optimum water temperature is 25°C or so, and the water temperature drops below 12°C, crab seedlings will be frozen to death. Therefore, we must strictly control the water temperature in the pool, if the water temperature is low, we must try to increase temperature.
(2) Feeding: Use fresh wild fish and appropriate amount of salt, stir and dehydrate bones and stir into fish gizzards, then mix well with wheat flour to make pellets and feed them directly. The mixing ratio is 0.8 kg of fish and 1 kg of wheat flour, and the daily bait is calculated as 100%-150% of the body weight of the crab. Crabs were introduced into the pond 3-5 times a day, and after 7 days, once a day, sooner or later, a portion of the bait was thrown in the shallow water area of ​​the pool, and the other part was sprinkled in the dense area of ​​aquatic plants.
(3) Control the water level of the pond: When the crab is just under the pond, the water depth should be maintained at 20-30 cm. After the first phase of larvae was removed, 15 cm of water was added, and after the second phase of larvae, 15 cm of water was added. Turn to the third stage of crabs, add water 25 centimeters to reach the maximum water level 70-80 centimeters.
Seventh, strengthen management.
(1) Timely inspection of crab pond escape prevention facilities. It was found that the damage prevention facilities must be promptly repaired, and that predator organisms (frogs, water mice, snakes, etc.) must be promptly killed.
(2) To inspect the pond three times a day, so that “three inspections and three inspections†means that crabs will be eaten in the morning to kill the enemy’s harmful organisms; the growth of crabs (developmental stage) will be checked at noon; , Analyze the water quality situation.
(3) A certain amount of floating plants in the pond should generally account for about one-half of the water surface. Too few plants should be planted, and too much water must be taken out of the pool.
Eight, prevention and treatment of diseases. The crab seedlings are susceptible to disease during the crab breeding period. Therefore, the disease prevention and control work must be done. The crabs can be disinfected with formaldehyde before entering the pool. To prevent and treat diseases of crab seedlings, at this stage, the main drugs are crabs landing ashore and crab speed Kang (Bao 009).
The management of crabs in the shelling period is an inherent characteristic of their physiology and an important indicator of the growth, development, and metamorphosis of crabs. It can be said that in the life cycle of crabs, the more shells they have, the faster the growth gains. Crab shelling is a "rebirth" process. The sturdy crabs can be completed within 5-10 minutes, while the weak ones require about one hour. The shell crab is the most frail when it is shelled, and it is also the most dangerous period to be attacked by pathogens, enemy enemies and even the same kind. Therefore, routine management should pay attention to the shelling of crabs, and it is advisable to change the water one week before the crab shelling. Disinfection measures to ensure smooth shelling of crabs. In the life of the crab, it takes more than 28-30 times to uncrusting: the pod-like larvae are shelled once in about 3 days; the big-eyed larvae are 4-6 days in the early stage and 7-10 days in the later stage; Crabs shelled about 15-20 days; autumn and crab species reached sexual maturity from winter to autumn, and shelled about 7-9 times. It is worth noting that in the absence of feed, crab growth rate is slow, not only the number of shelling less, and no step. How to determine the shelling period of crabs, first, from the feeding situation, under normal circumstances, crab shelling food intake will be significantly reduced, and the second is that the back shell of the shelled crab is yellow. The food bait of river crab is the material basis of crab breeding. Its species, quality and abundance directly affect the breeding effect of river crab. Knowing the crab's feeding habits will help to optimize its ecological environment and rational preparation of food during crab breeding.
(1) Natural bait crabs are omnivorous, mainly feeding on aquatic plants and small fish, shellfish and benthic organisms, and consuming organic detritus when consuming food. After sampling and analysis of the river crabs released from the lake, 65% of the stomach contents of the river crabs are mainly plant foods. However, under the conditions of artificial rearing, when the animals' bait (carcasses, small fishes) and aquatic plants are present at the same time, the crabs are ingested first. It is an animal food, and its food group only accounts for 35% of the total food intake. Aquatic plants serve as the main bait for crabs in natural conditions because they are easily eaten, because in the breeding season of snails and shrimps, animal foods can reach 60%-70% of the food in river crabs. Crabs have a certain selectivity for the uptake of aquatic plants. During the annual breeding period, the alfalfa (spring) and the black algae (summer and autumn) are two different seasons of eating types, golden algae, yellow silk grass, and bittergrass are alternative foods, Malay's sub-grass, and grass ( Foxtail algae is a food-eating species. Of course, this sorting is not a fixed model. The selection of aquatic species by crabs is related to the population structure of aquatic plants and their respective biomass. The food composition of crabs is diverse. Experiments have confirmed that crabs' intake of diverse foods is significantly higher than that of single foods. If crabs need to be transplanted in ponds for raising crabgrass, special attention should be paid to the transplanting of alfalfa grass in addition to collecting diversity grass species. Commonly known as "grass yellowgrass", the grass is the kind of food that crabs prefer in the early spring.
(2) The research on artificial compound feedstuffs for artificial crabs is quite different in different regions. However, the general principle is that the formula must first be formulated according to the nutrient components of crabs: the approximate content of protein and amino acids, combined with artificial feed sources. It cannot be ignored that the best source of artificial compound feed must take into account the reasonable proportions of binders, trace elements, and tropins (dehuminates), as well as the differences between juvenile, juvenile and adult crabs, and develop palatability and nutrition. Good foods with good digestibility and stability meet the feeding characteristics of crabs.