Crayfish (Procambarus clarkii), English name Red swamp crayfish, commonly known as lobster, shrimp, etc., is a freshwater economy shrimp, because meat is delicious, cheap and popular. Now we will briefly introduce the basic situation collected and the actual situation of aquaculture in China.
1 Overview
1.1 Basic characteristics The whole shrimp of the genus Klebsiella is classified into arthropods, crustaceans, subclasses of soft carps, decapoda, and locusts. Originally produced in North America, it was introduced into Japan in 1918. In 1929, it was introduced into Japan by Japan. After decades of proliferation, it has formed a nationwide distribution and has become a common freshwater economy shrimp. It has a wide adaptability and a wide suitable growth temperature. It can grow and develop normally when the water temperature is 10-30 °C. It can also withstand high temperatures and cold temperatures, can tolerate high temperatures above 40°C, and can safely survive over winter temperatures below -14°C. The crayfish crayfish grow rapidly. Under the appropriate temperature and adequate feed supply, after more than two months of breeding, sexual maturity can be achieved and the shrimp specifications can be achieved. Generally, the male grows faster than the female shrimp, and the commercial shrimp Specifications are also larger than females. Like many crustaceans, the growth of crayfish is accompanied by clam shells. When clam shells are found, they are usually searched for hidden objects, such as in water plants or under the leaves of plants. After the oyster shell, the maximum weight gain can reach 95%. Generally, the pod can reach sexual maturity 11 times, and sexually mature individuals can continue to grow trichomes. Its life is not long, about 1 year. However, in the absence of food, low temperatures and relatively dry conditions, life expectancy can be up to 2-3 years.
1.2 Habit Crawfish crayfish like to live in shallow water, rich grass wetlands, lakes and rivers, breeding season hi burrowing. The cave is located about 20cm above the surface of the pond, with a depth of 60cm to 1.2m. There is a small amount of stagnant water inside to keep the humidity, and the caverns are generally sealed with mud caps to reduce water loss. After a summer night or after a heavy rain, it has the habit of climbing ashore to cross dams and into other bodies of water. The crayfish crayfish do not have high requirements for bait, and they are omnivorous animals. They mainly feed on organic debris on the bottom of the water, and they also eat aquatic animals, such as small crustaceans, aquatic insects, etc. In the culture ponds, they prefer feeding and feeding. Small trash fish and snail meat; individuals in natural waters, animal foods account for about 20%, and plant foods account for 80%. When there is a shortage of food, there is a habit of killing each other, mainly preying on soft-shelled shrimps that have just been shelled. The crayfish require low water quality and can grow in the water with a pH of 6.5-9.0. The optimum pH is 7.5-8.5. It is resistant to hypoxia and ammonia nitrogen. When the dissolved oxygen in water is 1.0 - 3.0mg / L, can be normal growth, when the dissolved oxygen decreased to 1.0mg / L below the activity weakened, below 0.5mg / L can cause a large number of death; under normal circumstances, in the ammonia nitrogen 2. 0-5.0mg/L, no significant effect on its growth, but the high ammonia nitrogen will inhibit the growth, and even cause a large number of deaths, this happens mostly in the summer, when a large number of organic matter in the water will sporadically occur. From the above perspectives, it is more suitable for aquaculture in China's vast areas, and is particularly suitable for rice-shrimp ecological farming in rice growing areas.
2 Breeding characteristics Crawfish crayfish can reproduce all year round, with peaks from May to September.
2.1 Both broodstock and male and female identify crayfish crayfish dioecious, and have a more pronounced secondary sexual characteristics. First of all, it can be distinguished from the abdominal swimmer's limb shape. The first swimmer's limb in the male is specialized as a commissural spine, and the first swimmer's limb in the female is specialized as a spermidine hole (Figure 1); The male crawfish had large feet and there was a bright red Shen-like protrusion on both sides of the entire foot. The female chewing feet were smaller and the Shen-like bulges were not obvious. Third, the chelipeds of the male prawn were larger than the female and the individuals were also larger than females. shrimp.
2.2 Gonadal development The ovary development of Crawfish crustaceans has a long duration. Usually after mating, depending on the water temperature, the ovaries need to develop for another 5 months before they mature. In production, we can observe from the junction of the head breast and the abdomen. According to the color of the ovary, judging the degree of gonadal maturity, the ovarian development can be divided into pale, yellow, orange, brown (brown) and dark brown (bean paste) phases. The pale white is the gonad of the immature juvenile. It takes several months to reach maturity. The orange is the mature ovary. It takes about 3 months after mating to ovulate. The brown and brown-black are the mature ovaries. The ideal type of broodstock.
The testis is smaller, and it is generally synchronized with the ovaries in the culture pond. In the United States, the main crayfish production areas, the general method of gradually draining the pool water to stimulate the crayfish gonad maturation, promote mating prawn production more than p [2,3].
2.3 The mating crayfish can be mated almost all the year round, but peaks every spring. Mating is generally carried out in open areas in water, and the mating water temperature is relatively large, ranging from 15°C to 31°C. During mating, the males inject sperm into the seminal vesicles of the female crabs by means of a cross-thorn. The spermatozoa are stored in the seminal vesicles for 2 to 8 months and the eggs can still be fertilized. After mating, the females dig into the hole one after another. When the eggs mature, the process of ovulation, fertilization and larval development is completed within the cave.
2.4 Spawning and larval development The reproduction of crayfish is rather special. Most of the breeding process is done in caves, so it is difficult to see spawning shrimp in normal production. After mating, the ovaries take 2-3 months to finally mature and undergo ovulation and fertilization. The fertilized egg is a purple sauce that adheres to the bristles of the abdomen's swimmer's limbs (Fig. 2). The egg-bearing shrimp often keeps the abdomen close to the water in the hole to keep the egg moist. Kwok whole shrimps have a small amount of fleshy eggs. According to different specifications, the amount of fleshy eggs is generally 100-700 grains, with an average of 300 grains. The hatching time of eggs is about 14-24 days, but under low temperature conditions, the incubation period can be as long as 4-5 months. During the development of the crayfish crayfish larvae do not require any external nutrient supply, newly hatched prawns need to stay in the abdomen of the broodstock for about 10 days before being removed from the mother. If the conditions are not suitable, you can eat or drink for a few weeks in the cave. When the pond is irrigated, baby shrimp and brooders gradually climb out of the cave and naturally spread in the pond. Sometimes the broodstock will carry the larvae into the water body, and then Release larvae. Although the crayfish crayfish hold less eggs, the survival rate of hatching larvae is very high. Due to the decentralized breeding habits of the crayfish, the scale production of the seed is limited, which has an adverse effect on intensive production.
3 Main farming methods of crayfish crayfish have been used for decades in the United States and are commonly cultivated in combination with food production or feed crop production. It is recommended to use a rice-crawfish-rice rotation, a rice-crawfish-soybean rotation, a crayfish-catch-crawling rotation, etc.[7]. Although aquaculture technology continues to improve, commercial production of shrimps has not yet been established, and shrimps rely mainly on broodstock feeding to ponds. At the same time, due to little research on the nutrient requirements of the crayfish, only certain areas of Australia, piglet feed is recommended as the feed for crayfish and Cherax quadrinatus. General farming uses natural foodstuffs completely, and mainly uses the straws of crops and forage crops as the source of the feed, so the cost of breeding feeds is low. Based on the experience gained in China, the culture mode of Crawfish crayfish is further discussed.
3.1 Pond construction and water requirements require that the terrain be gentle and that clay soils are preferred. The pond slope ratio is 1:3 and the depth is 30-100cm.
The water source is non-polluting, the lowest pH is 6.5, and the total alkalinity of the water is not less than 50mg/L. In order to ensure that there are enough places for brooding shrimp and burrowing, and for convenience of drainage and drainage, a large area of ​​water can be built in the middle of the pool with multiple pools. One of them is not connected to the pool to make it accessible. . In this way, when the culture density is high, the entire pool of water can be in a state of microcirculation through a water injection port (Figure 3), which is easy to manage. In order to ensure sufficient water, a 30-40cm deep ditch can be excavated at a depth of 2m from the pool to ensure that the soil is moist.
3.2 Broodstock Restocking The best season for laying broodstock every March and May is to disinfect the pond with quicklime before stocking and 300kg/mu of organic fertilizer. The broodstock can be released after 10 days. The selection criteria for broodstock is that the physique is robust and the appendages are intact. The time to leave the water is within 5 hours and the average size is 25-30 pieces/kg. The stocking capacity is 10-20kg/mu for newly opened ponds, with a ratio of 1:1 for males and females, and 5-10kg/mu for ponds that have been reared. The ponds that catch relatively late can not feed broodstock, and the natural broodstock can meet production needs. The requirement for gonadal development is that female gonads are orange to dark brown in color, and at least 40% of them are dark brown to ensure that there are enough broodstock to lay eggs. This is the key to ensuring that there are no gains in the year. After broodstock is stocked, in order to promote broodstock mating and burrowing, pool water should be gradually drained and drained within 2-4 weeks so that most of the broodstock have been mated into the hole. Drained ponds can be used to grow various crops or grow forage grasses.
3.3 Feeding Grass Planting C. cuspidatum After the mating of the females into the hole, no additional management is required, and various crops can be planted in the pond. The main varieties currently planted are rice, soybeans and forage grass. The main species selected for forage grass are Sudan grass, hybrid pennisetum, and the first plant. Before the autumn larvae are produced, water is injected into the pond and the grass is partially submerged. The rotted feed grass can be used as bait for crawfish. Need to feed the bait again.
3.4 Management From the time the broodstock enters the pool to the beginning of September, there is basically no need for daily management work, but it is necessary to ensure that the soil is moist and that the broodstock in the cave has sufficient water supply. From mid-September, the ponds can be filled with water. At this time, most of the egg-holding shrimps will hatch baby shrimps. About 1-2 weeks later, the water quality of the ponds will become fat. The juvenile shrimps also gradually emerge from the hole and start to feed on the aquatic life in the pond. And plant debris. At this point, attention should be paid to the change in water quality, so that the water quality is not too concentrated. By mid-November, some crawfish can reach the market specifications. However, most of the crawfish will reach commercial specifications in March-May next year and can be sold for sale. Unacquired individuals will be mated successively in the process of draining pool water, entering the cave, and immature individuals will continue to grow in the ring ditch of the pond. Fisheries are caught in cages or cages.
3.5 Other breeding modes At present, the mode of foreign crayfish farming is mainly ecological farming. In some areas, special pool intensive breeding is started, but the technology is not mature enough. In many regions of China, the polyculture mode of crayfish and fish is used, which also has a good effect. Now a brief introduction to various breeding modes.
Rice-crawfish rice cultivation model: In the spring from March to May, the first rice was planted and planted. After the seedlings survived, the water depth was kept at 20cm, and the crawfish broodstock was 5-7.5kg per acre, and then the water level was slowly lowered until all rows were reached. Dry, mating brooding brooding people hatch ovulation incubation, after the harvest of autumn rice, the water filled the pool, about 2 months later, some individuals up to product specifications, can be captured and listed, most of them in the following year 3-5 months successively Up to product specifications, shrimps that are not caught can be reared for breeding, and the average yield per mu can reach 150-200kg.
Rice-crawfish-soybean aquaculture model: This model is based on a two-year cycle of cultivation. The first year of rice cultivation and whole shrimp stocking is the same as that of a whole shrimp-rice model. However, the following year crawfish breeding and fishing period extended to the beginning of June, then the pool water drained, planting soybeans, after the harvest of autumn soybeans, and then irrigation into the next round of farming. As the value of soybean straw on crawfish feed is much higher than that of rice straw, the yield of the second round of aquaculture will increase greatly, and the average yield per mu can reach more than 200kg.
Crawfish - rice - crayfish model: This model is based on crawfish farming, taking into account the cultivation of rice. The immature whole shrimps can be released in April, with 100kg per acre, and they can be harvested and marketed by the beginning of June. When the fishing is over, the pool water is slowly drained to promote the mating of the crayfish into the hole, and then the rice is planted. After the rice is harvested in late autumn, the rice will be harvested. Filling the pond with water, the large-scale crawfish can be caught from May to June in the spring of the following year. Generally, the yield per mu can reach more than 200kg, and the size of the crawfish is large. The farming model can be suitable for the area north of the Huaihe River in China.
Since Crawfish crawfish can use the straw of the crop as feed, the ecological farming model generally does not require additional feed costs, so the input cost is very low. According to information provided by the Alabama Agricultural Technology Extension Department in the United States [2], in the United States, 80% of the cost of crayfish farming is the fishing cost, due to the long fishing time of the crayfish crayfish and the high cost of labor in the United States. There is a large amount of surplus labor in rural areas in China, and the development of whole shrimp farming has a unique advantage. In addition, due to the low requirements for water quality and site requirements of the crawfish crayfish, many regions in China have the tradition of fish farming in rice paddies. Under the circumstance that the benefits of fish farming are declining, the ecological farming technology of crawfish crayfish can be greatly promoted and can be effectively utilized. China's rural land resources and human resources.
1 Overview
1.1 Basic characteristics The whole shrimp of the genus Klebsiella is classified into arthropods, crustaceans, subclasses of soft carps, decapoda, and locusts. Originally produced in North America, it was introduced into Japan in 1918. In 1929, it was introduced into Japan by Japan. After decades of proliferation, it has formed a nationwide distribution and has become a common freshwater economy shrimp. It has a wide adaptability and a wide suitable growth temperature. It can grow and develop normally when the water temperature is 10-30 °C. It can also withstand high temperatures and cold temperatures, can tolerate high temperatures above 40°C, and can safely survive over winter temperatures below -14°C. The crayfish crayfish grow rapidly. Under the appropriate temperature and adequate feed supply, after more than two months of breeding, sexual maturity can be achieved and the shrimp specifications can be achieved. Generally, the male grows faster than the female shrimp, and the commercial shrimp Specifications are also larger than females. Like many crustaceans, the growth of crayfish is accompanied by clam shells. When clam shells are found, they are usually searched for hidden objects, such as in water plants or under the leaves of plants. After the oyster shell, the maximum weight gain can reach 95%. Generally, the pod can reach sexual maturity 11 times, and sexually mature individuals can continue to grow trichomes. Its life is not long, about 1 year. However, in the absence of food, low temperatures and relatively dry conditions, life expectancy can be up to 2-3 years.
1.2 Habit Crawfish crayfish like to live in shallow water, rich grass wetlands, lakes and rivers, breeding season hi burrowing. The cave is located about 20cm above the surface of the pond, with a depth of 60cm to 1.2m. There is a small amount of stagnant water inside to keep the humidity, and the caverns are generally sealed with mud caps to reduce water loss. After a summer night or after a heavy rain, it has the habit of climbing ashore to cross dams and into other bodies of water. The crayfish crayfish do not have high requirements for bait, and they are omnivorous animals. They mainly feed on organic debris on the bottom of the water, and they also eat aquatic animals, such as small crustaceans, aquatic insects, etc. In the culture ponds, they prefer feeding and feeding. Small trash fish and snail meat; individuals in natural waters, animal foods account for about 20%, and plant foods account for 80%. When there is a shortage of food, there is a habit of killing each other, mainly preying on soft-shelled shrimps that have just been shelled. The crayfish require low water quality and can grow in the water with a pH of 6.5-9.0. The optimum pH is 7.5-8.5. It is resistant to hypoxia and ammonia nitrogen. When the dissolved oxygen in water is 1.0 - 3.0mg / L, can be normal growth, when the dissolved oxygen decreased to 1.0mg / L below the activity weakened, below 0.5mg / L can cause a large number of death; under normal circumstances, in the ammonia nitrogen 2. 0-5.0mg/L, no significant effect on its growth, but the high ammonia nitrogen will inhibit the growth, and even cause a large number of deaths, this happens mostly in the summer, when a large number of organic matter in the water will sporadically occur. From the above perspectives, it is more suitable for aquaculture in China's vast areas, and is particularly suitable for rice-shrimp ecological farming in rice growing areas.
2 Breeding characteristics Crawfish crayfish can reproduce all year round, with peaks from May to September.
2.1 Both broodstock and male and female identify crayfish crayfish dioecious, and have a more pronounced secondary sexual characteristics. First of all, it can be distinguished from the abdominal swimmer's limb shape. The first swimmer's limb in the male is specialized as a commissural spine, and the first swimmer's limb in the female is specialized as a spermidine hole (Figure 1); The male crawfish had large feet and there was a bright red Shen-like protrusion on both sides of the entire foot. The female chewing feet were smaller and the Shen-like bulges were not obvious. Third, the chelipeds of the male prawn were larger than the female and the individuals were also larger than females. shrimp.
2.2 Gonadal development The ovary development of Crawfish crustaceans has a long duration. Usually after mating, depending on the water temperature, the ovaries need to develop for another 5 months before they mature. In production, we can observe from the junction of the head breast and the abdomen. According to the color of the ovary, judging the degree of gonadal maturity, the ovarian development can be divided into pale, yellow, orange, brown (brown) and dark brown (bean paste) phases. The pale white is the gonad of the immature juvenile. It takes several months to reach maturity. The orange is the mature ovary. It takes about 3 months after mating to ovulate. The brown and brown-black are the mature ovaries. The ideal type of broodstock.
The testis is smaller, and it is generally synchronized with the ovaries in the culture pond. In the United States, the main crayfish production areas, the general method of gradually draining the pool water to stimulate the crayfish gonad maturation, promote mating prawn production more than p [2,3].
2.3 The mating crayfish can be mated almost all the year round, but peaks every spring. Mating is generally carried out in open areas in water, and the mating water temperature is relatively large, ranging from 15°C to 31°C. During mating, the males inject sperm into the seminal vesicles of the female crabs by means of a cross-thorn. The spermatozoa are stored in the seminal vesicles for 2 to 8 months and the eggs can still be fertilized. After mating, the females dig into the hole one after another. When the eggs mature, the process of ovulation, fertilization and larval development is completed within the cave.
2.4 Spawning and larval development The reproduction of crayfish is rather special. Most of the breeding process is done in caves, so it is difficult to see spawning shrimp in normal production. After mating, the ovaries take 2-3 months to finally mature and undergo ovulation and fertilization. The fertilized egg is a purple sauce that adheres to the bristles of the abdomen's swimmer's limbs (Fig. 2). The egg-bearing shrimp often keeps the abdomen close to the water in the hole to keep the egg moist. Kwok whole shrimps have a small amount of fleshy eggs. According to different specifications, the amount of fleshy eggs is generally 100-700 grains, with an average of 300 grains. The hatching time of eggs is about 14-24 days, but under low temperature conditions, the incubation period can be as long as 4-5 months. During the development of the crayfish crayfish larvae do not require any external nutrient supply, newly hatched prawns need to stay in the abdomen of the broodstock for about 10 days before being removed from the mother. If the conditions are not suitable, you can eat or drink for a few weeks in the cave. When the pond is irrigated, baby shrimp and brooders gradually climb out of the cave and naturally spread in the pond. Sometimes the broodstock will carry the larvae into the water body, and then Release larvae. Although the crayfish crayfish hold less eggs, the survival rate of hatching larvae is very high. Due to the decentralized breeding habits of the crayfish, the scale production of the seed is limited, which has an adverse effect on intensive production.
3 Main farming methods of crayfish crayfish have been used for decades in the United States and are commonly cultivated in combination with food production or feed crop production. It is recommended to use a rice-crawfish-rice rotation, a rice-crawfish-soybean rotation, a crayfish-catch-crawling rotation, etc.[7]. Although aquaculture technology continues to improve, commercial production of shrimps has not yet been established, and shrimps rely mainly on broodstock feeding to ponds. At the same time, due to little research on the nutrient requirements of the crayfish, only certain areas of Australia, piglet feed is recommended as the feed for crayfish and Cherax quadrinatus. General farming uses natural foodstuffs completely, and mainly uses the straws of crops and forage crops as the source of the feed, so the cost of breeding feeds is low. Based on the experience gained in China, the culture mode of Crawfish crayfish is further discussed.
3.1 Pond construction and water requirements require that the terrain be gentle and that clay soils are preferred. The pond slope ratio is 1:3 and the depth is 30-100cm.
The water source is non-polluting, the lowest pH is 6.5, and the total alkalinity of the water is not less than 50mg/L. In order to ensure that there are enough places for brooding shrimp and burrowing, and for convenience of drainage and drainage, a large area of ​​water can be built in the middle of the pool with multiple pools. One of them is not connected to the pool to make it accessible. . In this way, when the culture density is high, the entire pool of water can be in a state of microcirculation through a water injection port (Figure 3), which is easy to manage. In order to ensure sufficient water, a 30-40cm deep ditch can be excavated at a depth of 2m from the pool to ensure that the soil is moist.
3.2 Broodstock Restocking The best season for laying broodstock every March and May is to disinfect the pond with quicklime before stocking and 300kg/mu of organic fertilizer. The broodstock can be released after 10 days. The selection criteria for broodstock is that the physique is robust and the appendages are intact. The time to leave the water is within 5 hours and the average size is 25-30 pieces/kg. The stocking capacity is 10-20kg/mu for newly opened ponds, with a ratio of 1:1 for males and females, and 5-10kg/mu for ponds that have been reared. The ponds that catch relatively late can not feed broodstock, and the natural broodstock can meet production needs. The requirement for gonadal development is that female gonads are orange to dark brown in color, and at least 40% of them are dark brown to ensure that there are enough broodstock to lay eggs. This is the key to ensuring that there are no gains in the year. After broodstock is stocked, in order to promote broodstock mating and burrowing, pool water should be gradually drained and drained within 2-4 weeks so that most of the broodstock have been mated into the hole. Drained ponds can be used to grow various crops or grow forage grasses.
3.3 Feeding Grass Planting C. cuspidatum After the mating of the females into the hole, no additional management is required, and various crops can be planted in the pond. The main varieties currently planted are rice, soybeans and forage grass. The main species selected for forage grass are Sudan grass, hybrid pennisetum, and the first plant. Before the autumn larvae are produced, water is injected into the pond and the grass is partially submerged. The rotted feed grass can be used as bait for crawfish. Need to feed the bait again.
3.4 Management From the time the broodstock enters the pool to the beginning of September, there is basically no need for daily management work, but it is necessary to ensure that the soil is moist and that the broodstock in the cave has sufficient water supply. From mid-September, the ponds can be filled with water. At this time, most of the egg-holding shrimps will hatch baby shrimps. About 1-2 weeks later, the water quality of the ponds will become fat. The juvenile shrimps also gradually emerge from the hole and start to feed on the aquatic life in the pond. And plant debris. At this point, attention should be paid to the change in water quality, so that the water quality is not too concentrated. By mid-November, some crawfish can reach the market specifications. However, most of the crawfish will reach commercial specifications in March-May next year and can be sold for sale. Unacquired individuals will be mated successively in the process of draining pool water, entering the cave, and immature individuals will continue to grow in the ring ditch of the pond. Fisheries are caught in cages or cages.
3.5 Other breeding modes At present, the mode of foreign crayfish farming is mainly ecological farming. In some areas, special pool intensive breeding is started, but the technology is not mature enough. In many regions of China, the polyculture mode of crayfish and fish is used, which also has a good effect. Now a brief introduction to various breeding modes.
Rice-crawfish rice cultivation model: In the spring from March to May, the first rice was planted and planted. After the seedlings survived, the water depth was kept at 20cm, and the crawfish broodstock was 5-7.5kg per acre, and then the water level was slowly lowered until all rows were reached. Dry, mating brooding brooding people hatch ovulation incubation, after the harvest of autumn rice, the water filled the pool, about 2 months later, some individuals up to product specifications, can be captured and listed, most of them in the following year 3-5 months successively Up to product specifications, shrimps that are not caught can be reared for breeding, and the average yield per mu can reach 150-200kg.
Rice-crawfish-soybean aquaculture model: This model is based on a two-year cycle of cultivation. The first year of rice cultivation and whole shrimp stocking is the same as that of a whole shrimp-rice model. However, the following year crawfish breeding and fishing period extended to the beginning of June, then the pool water drained, planting soybeans, after the harvest of autumn soybeans, and then irrigation into the next round of farming. As the value of soybean straw on crawfish feed is much higher than that of rice straw, the yield of the second round of aquaculture will increase greatly, and the average yield per mu can reach more than 200kg.
Crawfish - rice - crayfish model: This model is based on crawfish farming, taking into account the cultivation of rice. The immature whole shrimps can be released in April, with 100kg per acre, and they can be harvested and marketed by the beginning of June. When the fishing is over, the pool water is slowly drained to promote the mating of the crayfish into the hole, and then the rice is planted. After the rice is harvested in late autumn, the rice will be harvested. Filling the pond with water, the large-scale crawfish can be caught from May to June in the spring of the following year. Generally, the yield per mu can reach more than 200kg, and the size of the crawfish is large. The farming model can be suitable for the area north of the Huaihe River in China.
Since Crawfish crawfish can use the straw of the crop as feed, the ecological farming model generally does not require additional feed costs, so the input cost is very low. According to information provided by the Alabama Agricultural Technology Extension Department in the United States [2], in the United States, 80% of the cost of crayfish farming is the fishing cost, due to the long fishing time of the crayfish crayfish and the high cost of labor in the United States. There is a large amount of surplus labor in rural areas in China, and the development of whole shrimp farming has a unique advantage. In addition, due to the low requirements for water quality and site requirements of the crawfish crayfish, many regions in China have the tradition of fish farming in rice paddies. Under the circumstance that the benefits of fish farming are declining, the ecological farming technology of crawfish crayfish can be greatly promoted and can be effectively utilized. China's rural land resources and human resources.
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