Practical technology Aquaculture of crayfish
2018-04-26 17:00:11
The crustacean crawfish superfamily is divided into crayfish, river shrimp, mimicry shrimp, and langoustine shrimps. Among them, the crayfish family, river shrimp family, and mimetic river shrimp family belong to freshwater species. Freshwater crayfish have large individuals, strong adaptability, high reproduction rate, short breeding cycle, and generally short life span. For example, the life span of crayfish is 4 to 5 years. Marine crawfish are large in size, have a slow growth, and have a long breeding cycle. For example, the life span of American crayfish can reach 50 years. The currently cultivated crawfish are mainly crayfish.
Crayfish are generally mated in the fall and fertilized and hatched in the second year of spring and summer. The incubation period is related to the water temperature. For example, the Procambarus clarkii incubation period is from 30 days to 40 days at 18°C ​​to 20°C, and only 15 days to 20 days at 25°C. Crayfish eggs hatch directly from the clams. The first and second larvae of freshwater crayfish still adhere to the maternal appendages and leave the mother independently after several moltings. The entire larval develops and needs to undergo more than ten times of molting to become juveniles.
The newly hatched crayfish larvae are nutritious for their own yolks. They began to ingest phytoplankton, small larval larvae, rotifers, etc. after the first oyster shells. After four or five times of molting, they can ingest small branches and pods. Category; larval metamorphosis end to omnivorous. Adult crayfish are spawned and eaten mainly on small crustaceans, mollusks, aquatic insect larvae, algae, fish, and organic debris. In the case of starvation, the same type of food is also eaten.
Crayfish Camp benthic crawl life. It has strong adaptability and can grow and reproduce in rivers, lakes, ditches, ponds and rice fields. During the day, they sneaked into the caves. At night, they went out for food, shells, and mating. Same-sex crawfish are aggressive, so crawfish should be raised and kept at a distance from each other, so that tentacles cannot be touched.
The culture technology of crayfish is not complicated and the breeding cycle is short. It can also be mixed with fish, without special feeding and special management, but also can play a role in three-dimensional utilization and improve water productivity. It has been proved that polyculture of freshwater crayfish and adult fish can increase the total pond production by more than 10%, and the profit increases by about 30%.
Crawfish farming is mainly based on pond culture:
1. Pond conditions require sufficient water, good water quality, and easy access to water. The area is suitable from 3 mu to 5 mu, with a water depth of 0.8 to 1.2 meters. About 25% to 30% of the bottom of the pond is planted with water and grass for their habitat inhabitation. When the early plants are not grown, they can be planted with terrestrial plants and placed at 1.5 meters above the fish pond, every 3 to 5 meters. One, put 20 to 30 per mu.
2. Qingtang Fertilizer Appropriate water 0.2 to 0.3 meters in mid-April, with 8 kg to 10 kg of bleaching powder and 70 to 80 kg of quicklime diluted and diluted in Quanchipi to kill enemy pests. In mid-May, fertilizing and breeding feed organisms were used to improve the survival rate and growth rate of early crayfish rearing.
3. The stocking rate of stocked shrimp depends on the stocking size and size of the mixed fishes and is flexible. For ponds that cultivate one-year old fingerlings, 10,000 to 15,000 shrimps should be stocked for each acre. Note the water temperature difference when stocking.
4. Daily management After the shrimps are stocked for one week, they must be top-dressed to cultivate plankton for feeding shrimps. From June to August, they are the growth period of the crawfish, and the feed should be sufficient. After mid-September, the weight gain of the crawfish is increased. , To increase the amount of animal feed feed. In the early stage of cultivation, appropriate amount of fresh water is added once a month. If diseases are found in the breeding process, Chinese herbal medicines are generally used to prevent diseases through soaking and bait-repelling methods, and chemical drugs are used as little as possible to avoid killing crawfish. In early October, when the temperature drops to 18°C, fishing can begin. In addition to pond cultivation, paddy field cultivation and water channel aquaculture can also be carried out in various places based on actual water conditions. Cultured crayfish can also be developed as ornamental species in addition to being edible.
The implementation site of the project is in the pond along the Pearl River Estuary. The pollution of the water in the Pearl River estuary is becoming increasingly serious. Therefore, how to control the niche of the pond itself from the perspective of sustainable development has become the main technical measure of the project. For this reason, water quality management during the breeding period actually controls several important indicators of the pond within a certain limit standard, including water transparency of 30-40 cm, pH value of 7.2-8.2, and dissolved oxygen of more than 3 mg/L. The oxygen consumption of organic matter is 8-12 mg/l, ammonia is less than 0.1 mg/l, the total biomass of phytoplankton is 20-30 mg/l, and the total zooplankton biomass is 8 mg/l. In order to make the water quality of the rearing pond relatively stable, besides adding the appropriate water and starting the aerator, it is possible to use complex microbial flora, ammonia nitrogen and nitrite nitrogen in the nitrification water to make the beneficial colonies become dominant populations and maintain a good and stable ecology. surroundings. The use of beneficial microbial ponds in Doumen’s test ponds was 25%–30% lower than in control ponds. In addition, you can also use the bottom modifier, which can not only purify water, adsorb all kinds of residues, but also precipitate and chelate various toxic substances, such as heavy metal ions.
The disease prevention and control of the diseases and insect pests that occur in the larvae of salty water in enclosed ponds are both universal and specific. In terms of universality, the occurrence of farmed fish is often the result of the simultaneous action of multiple pathogens. Parasitic diseases generally endanger the juvenile period, especially early juvenile fish. Infectious diseases mainly threaten adult fish; In the case of high salinity, most pathogenic pathogens are seawater types, such as Cryptocaryon irritans, Round scale insects, Oriental oysters, Vibrio and seawater flexor bacteria. The salinity is low during the flood season, and most pathogenic pathogens are Freshwater type, such as ringworm, Chinese sturgeon and Aeromonas etc. Therefore, the ponds where brackish water meets are particularly complicated in terms of disease.
Disease prevention and control In addition to doing a good job in the ecological regulation of aquaculture waters, adopting a scientific breeding model and paying attention to the fish's feed and nutrient composition, it should be based on prevention and control. This project promotes the use of oligosaccharide molecular vaccines for prevention and control. In total, 80,000 pigs were immersed in the Jianzi vaccine, Dongguan, 80,000 vaccines were taken from the Doumen flower bud seedling vaccine, and 80,000 were immersed in the Longjimiao vaccine. It plays a role in preventing bacterial diseases. The application of genetic engineering vaccines is also underway and observed. The full use of vaccines, including tissue vaccines, chemical vaccines, and engineering vaccines, will be the goal of this project and the only path that must be taken toward healthy breeding.
Due to traditional practices, many disease prevention measures cannot be fully implemented at once, and only active treatment measures can be taken after illness. In addition to pathogen detection in Dongguan, the focus is on water disinfection. The disinfected drugs are mainly trichloroisocyanuric acid and compound stable chlorine dioxide, which are almost completely enclosed in pond culture; Doumen tablets and Longxuedao tablets are replaced by chlorine dioxide or quaternary amine salts after water exchange; More use of antibiotics drugs, including Dongguan tablets through drug susceptibility testing, more targeted use of high-sensitivity drugs.
Crayfish are generally mated in the fall and fertilized and hatched in the second year of spring and summer. The incubation period is related to the water temperature. For example, the Procambarus clarkii incubation period is from 30 days to 40 days at 18°C ​​to 20°C, and only 15 days to 20 days at 25°C. Crayfish eggs hatch directly from the clams. The first and second larvae of freshwater crayfish still adhere to the maternal appendages and leave the mother independently after several moltings. The entire larval develops and needs to undergo more than ten times of molting to become juveniles.
The newly hatched crayfish larvae are nutritious for their own yolks. They began to ingest phytoplankton, small larval larvae, rotifers, etc. after the first oyster shells. After four or five times of molting, they can ingest small branches and pods. Category; larval metamorphosis end to omnivorous. Adult crayfish are spawned and eaten mainly on small crustaceans, mollusks, aquatic insect larvae, algae, fish, and organic debris. In the case of starvation, the same type of food is also eaten.
Crayfish Camp benthic crawl life. It has strong adaptability and can grow and reproduce in rivers, lakes, ditches, ponds and rice fields. During the day, they sneaked into the caves. At night, they went out for food, shells, and mating. Same-sex crawfish are aggressive, so crawfish should be raised and kept at a distance from each other, so that tentacles cannot be touched.
The culture technology of crayfish is not complicated and the breeding cycle is short. It can also be mixed with fish, without special feeding and special management, but also can play a role in three-dimensional utilization and improve water productivity. It has been proved that polyculture of freshwater crayfish and adult fish can increase the total pond production by more than 10%, and the profit increases by about 30%.
Crawfish farming is mainly based on pond culture:
1. Pond conditions require sufficient water, good water quality, and easy access to water. The area is suitable from 3 mu to 5 mu, with a water depth of 0.8 to 1.2 meters. About 25% to 30% of the bottom of the pond is planted with water and grass for their habitat inhabitation. When the early plants are not grown, they can be planted with terrestrial plants and placed at 1.5 meters above the fish pond, every 3 to 5 meters. One, put 20 to 30 per mu.
2. Qingtang Fertilizer Appropriate water 0.2 to 0.3 meters in mid-April, with 8 kg to 10 kg of bleaching powder and 70 to 80 kg of quicklime diluted and diluted in Quanchipi to kill enemy pests. In mid-May, fertilizing and breeding feed organisms were used to improve the survival rate and growth rate of early crayfish rearing.
3. The stocking rate of stocked shrimp depends on the stocking size and size of the mixed fishes and is flexible. For ponds that cultivate one-year old fingerlings, 10,000 to 15,000 shrimps should be stocked for each acre. Note the water temperature difference when stocking.
4. Daily management After the shrimps are stocked for one week, they must be top-dressed to cultivate plankton for feeding shrimps. From June to August, they are the growth period of the crawfish, and the feed should be sufficient. After mid-September, the weight gain of the crawfish is increased. , To increase the amount of animal feed feed. In the early stage of cultivation, appropriate amount of fresh water is added once a month. If diseases are found in the breeding process, Chinese herbal medicines are generally used to prevent diseases through soaking and bait-repelling methods, and chemical drugs are used as little as possible to avoid killing crawfish. In early October, when the temperature drops to 18°C, fishing can begin. In addition to pond cultivation, paddy field cultivation and water channel aquaculture can also be carried out in various places based on actual water conditions. Cultured crayfish can also be developed as ornamental species in addition to being edible.
The implementation site of the project is in the pond along the Pearl River Estuary. The pollution of the water in the Pearl River estuary is becoming increasingly serious. Therefore, how to control the niche of the pond itself from the perspective of sustainable development has become the main technical measure of the project. For this reason, water quality management during the breeding period actually controls several important indicators of the pond within a certain limit standard, including water transparency of 30-40 cm, pH value of 7.2-8.2, and dissolved oxygen of more than 3 mg/L. The oxygen consumption of organic matter is 8-12 mg/l, ammonia is less than 0.1 mg/l, the total biomass of phytoplankton is 20-30 mg/l, and the total zooplankton biomass is 8 mg/l. In order to make the water quality of the rearing pond relatively stable, besides adding the appropriate water and starting the aerator, it is possible to use complex microbial flora, ammonia nitrogen and nitrite nitrogen in the nitrification water to make the beneficial colonies become dominant populations and maintain a good and stable ecology. surroundings. The use of beneficial microbial ponds in Doumen’s test ponds was 25%–30% lower than in control ponds. In addition, you can also use the bottom modifier, which can not only purify water, adsorb all kinds of residues, but also precipitate and chelate various toxic substances, such as heavy metal ions.
The disease prevention and control of the diseases and insect pests that occur in the larvae of salty water in enclosed ponds are both universal and specific. In terms of universality, the occurrence of farmed fish is often the result of the simultaneous action of multiple pathogens. Parasitic diseases generally endanger the juvenile period, especially early juvenile fish. Infectious diseases mainly threaten adult fish; In the case of high salinity, most pathogenic pathogens are seawater types, such as Cryptocaryon irritans, Round scale insects, Oriental oysters, Vibrio and seawater flexor bacteria. The salinity is low during the flood season, and most pathogenic pathogens are Freshwater type, such as ringworm, Chinese sturgeon and Aeromonas etc. Therefore, the ponds where brackish water meets are particularly complicated in terms of disease.
Disease prevention and control In addition to doing a good job in the ecological regulation of aquaculture waters, adopting a scientific breeding model and paying attention to the fish's feed and nutrient composition, it should be based on prevention and control. This project promotes the use of oligosaccharide molecular vaccines for prevention and control. In total, 80,000 pigs were immersed in the Jianzi vaccine, Dongguan, 80,000 vaccines were taken from the Doumen flower bud seedling vaccine, and 80,000 were immersed in the Longjimiao vaccine. It plays a role in preventing bacterial diseases. The application of genetic engineering vaccines is also underway and observed. The full use of vaccines, including tissue vaccines, chemical vaccines, and engineering vaccines, will be the goal of this project and the only path that must be taken toward healthy breeding.
Due to traditional practices, many disease prevention measures cannot be fully implemented at once, and only active treatment measures can be taken after illness. In addition to pathogen detection in Dongguan, the focus is on water disinfection. The disinfected drugs are mainly trichloroisocyanuric acid and compound stable chlorine dioxide, which are almost completely enclosed in pond culture; Doumen tablets and Longxuedao tablets are replaced by chlorine dioxide or quaternary amine salts after water exchange; More use of antibiotics drugs, including Dongguan tablets through drug susceptibility testing, more targeted use of high-sensitivity drugs.