Biological characteristics 1) The main characteristics of China's prawns Chinese prawns have no frontal stomach, with no more than half of the frontal sulcus in the frontal horn, no hepatic dorsal and frontal ridges, and central sulcus. The third step is generally no more than the second antennal squama. Male The third Banyan knuckle and the palm festival are of equal length. 2) Internal Organs The whole body of Chinese shrimp is also a complete organism composed of neurology, circulation, digestion, respiration, excretion, endocrinology, reproduction, and muscle and bones. The various systems cooperate to maintain their life activities. 3) Living habits Chinese shrimp are mainly distributed on the coast of the Yellow Sea and Bohai Sea, occasionally on the Hanxi West Coast, East China Sea and South China Sea. Its optimum temperature range is 18-30°C. It is salty and has a wide diet. It is a carnivorous animal with larvae and dinoflagellates. Floating animals and plants dominate. Most prawns mature for a year and breed offspring, dioecious. Economic traits Prawn is a world-famous marine product, especially Chinese shrimp, which has many advantages such as large individual, good taste, high value, rapid growth, wide appetite, and strong adaptability to the environment, not only in marine fishery. Important position, but also as an important species of marine aquaculture has received much attention. The shrimp industry has become a pillar industry in China's coastal fisheries economy. Aquaculture Status The development of large-scale shrimp farming was initiated in the 1970s and 1980s. Prawn culture was widely practiced across the entire country from the south to the north, which has greatly promoted the development of the coastal economy. The development of aquaculture production has enabled the country’s highest annual output to reach 200,000 tons, and it has become one of the largest shrimp farming countries. Our city is one of the areas where shrimp farming started earlier and has a history of Hui. The county has emerged as the first place in the country to win the first place in the country in terms of unit production, total output, efficiency, and export earnings, and Xishu High Yield Pond, which has produced more than one ton per kilogram in the country. Since the occurrence of the epidemic shrimp virus disease in 1993, the output has greatly decreased. After continuous efforts in recent years, the breeding units and shrimp farmers have achieved certain results in the exploration of breeding methods, aquaculture varieties, and disease prevention. By 1997, the shrimp aquaculture area was stable at 16.5 million mu, and shrimp aquaculture production recovered to 3040T, which laid a solid foundation for the further recovery and development of shrimp aquaculture. Economic Analysis Shrimp aquaculture is an industry with high investment, short cycle, and quick results. The rise of shrimp culture in the 1980s created a new road for rapid enrichment in coastal areas. After the outbreak of shrimp virus disease, the economic benefits of shrimp farming are greatly affected. Many shrimp farmers use greatly reduce the density of transplanting seedlings, change the intensive culture to extensive culture, and implement the second shrimp farming or mixed with fish, crab, shellfish and algae. support. As a result, the profits of such farming have gradually increased, and farmers and shrimp farmers have gradually resumed confidence in shrimp farming. At the same time, we have also witnessed the emergence of a number of healthy high-yield shrimp varieties that have emerged after exploration. For example, 500 acres of joint-produced 500 mu per mu in Tianjin's Hangu District can be as high as 1,000 kg, and the benefits of Mu can exceed RMB 10,000, making shrimp culture highly risky. The amount of profit, which will certainly play a significant role in promoting the development of shrimp aquaculture. It is believed that in the near future, shrimp virus disease will eventually be overcome and the road to healthy shrimp farming will be wider and wider. Conditions for Seedling Rearing of Chinese Prawn Seedlings 1) Basic Facilities for Nursery Farming The building structure of the nursery room must meet the requirements for daylighting, heat preservation, and ventilation. The room should be provided with a light curtain, or a white lacquer on the glass section to regulate light intensity. In addition, the basic facilities for a complete nursery include food culture ponds, spawning hatcheries, larval rearing ponds, outdoor prawn cultivation ponds, and power supply, water supply, and heating systems. In order to improve the survival rate and economic benefits of nursery, the water for nursery, nursery ponds, nursery equipment and other facilities must be strictly disinfected. 2) Broodstock harvesting and wintering Breeding Broodstock breeding usually uses two sources: the first is to catch mature broodstock from the shrimp spawning ground, and the second is to raise the broodstock. The broodstock should be selectively full-filled, robust, disease-free, and several individuals whose ovaries are yellow-brown or brownish green. They can be transported using live water and inflatable canvas buckets and are to be raised for production. The broodstock should be moved into the house during winter in our city, and the temperature should be maintained at 9-10°C, and should be properly mixed with 1/4?/3 males. The appropriate stocking density should be 3-5/m2. Good can be put to 10-20 tail/m2. Process Flow Precipitating Mesh Filtering Broiler Breeding Pond Algae Species Expanding Culture Pond Rotiferous Breeding Ponds Artemia Winter Egg Hatchery Pool │ │ ↓ â”—â”â”â”â”â”â”â”› │ │ Single Cell Algae Cultivation Pool │ │ │ â”â”â”â” â”â”â”â” â”â”â”┓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ Water-injection temperature control → Spawning, hatching → Nauplii → Zombie larvae → ç³ shrimp → larvae → saplings Out of counting bait Shrimp non-mother larvae do not eat, rely on egg yolk Own, enter the zoea larvae began to eat tiny dynamics, to increase the ability to feed during the squid period, post larvae can eat oyster meat and other artificial feed. Commonly used baits: 1) Skeletonema algae, Chaetoceros japonicus, Nitzschia closterium, Phaeodactylum tricornutum. 2) Brachionus rotifer, Artemia, bivalve eggs and larvae. 3) Soybean milk, tofu and soy flour; egg yolk, cake; shrimp powder, artificial ingredients. Disease prevention and control 1) There are two types of bacterial disease pathogens, one is solitary bacteria, and the other is solitary bacteria and Aeromonas. Symptoms: The viability of the larvae is significantly reduced, the swimming is not lively, the phototaxis is weak, the abdomen is bowed, swirling in the water, no feeding, the body color turns white, and it will die in a long time. Prevention: Thoroughly clear the pond, strict disinfection and filtration of water, reasonable feeding, reasonable density. Treatment: (1) Quanchiposa 3-5 ppm oxytetracycline or 2-3 ppm chloramphenicol once a day for 3 days. (2) Add 1 g/kg oxytetracycline or chloramphenicol to the young bait (such as soy milk and egg yolk) and feed them for three days. (3) with 2-3ppm sulfathiazole or sulfathiazole Quanchiposa; can also be used 0.5-1.5ppm nitrofurazone, furazolidone, furanese Quanchiposa, splashing for three days. 2) Pathogens of fungal diseases: Fungi (mold), mainly streptochyrium, chytrid, and cyanobacteria. Symptoms: The pathogenic egg and larvae are full of hyphae and the egg ceases to develop and quickly die. The larvae are inactive, their phototaxis is weakened, they do not eat, they sink and die. Treatment: (1) Quanchiposa 0.00610-6-0.0110-6 peacock, generally only once. (2) Nystatin 810-6-1010-6 Quanchiposa, 1-2 times in a row. (3) Quanchiposa 0.0110-6 trifluralin. 3) Pathogens of ciliated ciliate diseases: Protozoa ciliates of the protozoan species, mainly insects such as bell insects, polychaetes, monodentes, and slugs. Symptoms: Slow swimming, impeding feeding, slowing growth, falling out of the shell, eventually sinking. Prevention: When it is discovered early, replace the new water quickly. 4) Pathogens of filamentous bacterial diseases: Occurrence of Mucor bacterium is more common. Symptoms: After the bacteria are attached, the egg cannot continue to develop, and the larvae lose their vitality and die. Prevention: Clean water should be kept. In addition, there are many diseases during the nursery, such as malformation (hairpin atrophy), bubble disease, necrotic gland disease, and Chinese prawn baculovirus disease. At present, some viruses do not have good treatment methods. The key is to pay attention to the improvement of water quality and bait conditions, and to prevent them mainly. The cultivation conditions of shrimp cultivation techniques in China The shrimp farms are selected to be located in the intertidal and saline-alkaline areas of the small, smooth inner bay and estuary coast; the bottom of the pool is preferably impermeable clay, sandy clay or sandy loam; sea salinity In 5-35 ‰, no industrial pollution, ponds with 20-30 acres, water depth of 2 meters is appropriate. Shrimp transport shrimp can be transported by land, water and air transport. Transportation containers are mainly made of cloth and plastic bags. The density of seedlings depends on the size of the shrimp, the length of transportation time and the water temperature. The general time for transporting 10cm shrimp seedlings is about 6 hours, and 1m canvas bucket (about 1/3 water) is used. The density is 200,000 to 300,000. The density of the inflated nylon bag is 0.6-110,000 bags per bag. Pay attention to avoid hot noon transportation, so as to protect against sun and rain. Intermediate culture refers to the cultivation of large-scale shrimp seedlings. When the artificially-cultivated juvenile shrimp is cultivated to have a strong adaptability, it is stocked again. At present, plastic greenhouses are widely used for raising seedlings in advance. Chinese prawn is mostly cultivated to 2-3 cm in length, so the survival rate when cultivated is generally more than 80%. Process flow Clearance → Influent → Breeding basic bait → Take seedlings → Breeding management → Harvesting ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ æ•´ç† Finishing drug filtration Fertilization Inoculation Intermediate holding Water changing Feeding prevention Food bait Cultivation of bait Fresh shellfish and small junk fish are the best. After the meat and fish are ground, they are washed and put into the pool. The daily feeding amount is 200-300% of the prawn weight. Prawn has a very wide appetite, so it can also be used as a bait for shrimp, such as shellfish, crustaceans, a variety of fresh fish, frozen fish, dry miscellaneous fish, fish meal to vegetable feed such as peanut cake, bean cake, gluten bran, Mi Fu and so on. In addition, marine yeast, brewer's yeast, various blood meal, brine brine and artificial diet can be used as shrimp feed. At present, due to the frequent occurrence of viral diseases of shrimps, widespread circulation, and long propagation time, the requirements for shrimp bait have been increased, and artificial diets have been used. Disease prevention and control Shrimp aquaculture is regulated by the sea in the country. Due to the long history of breeding, the scale of breeding is large. Therefore, there are also quite a lot of diseases in breeding, especially the continuous occurrence of the viral epidemic of shrimp in 1993. The high mortality rate of the spread of shrimp almost extinguished shrimp culture. The following can only summarize the diseases of shrimp culture in China and briefly introduce several major diseases. 1) Disease types: 1 Chinese prawn baculovirus disease, infectious subcutaneous hematopoietic necrosis, and almost enterovirus. 2 Bacterial shrimp disease, red limb disease (red leg disease), rotten eye disease, gill disease, brown spot disease (crustacean disease), aeromonas disease, filamentous bacterial disease, white spot disease. 3 Fungal shrimp disease: white spot disease. 4 Protozoal diseases: microsporidia, cimic ciliate disease, pseudo-cerebellar disease, and piperculosis. 5 non-parasitic shrimp disease: muscle necrosis, rickets, soft shell disease, black shank disease. 2) Several major cases: 1 Chinese prawn baculovirus disease (PCBV disease) Source: Chinese prawn baculovirus. Symptoms: Shrimp first stop eating, slow action, weak bouncing, roaming on the water surface or lying on the bottom of the pool. Moved and died soon. Epidemic situation: This disease occurs in China's prawn, shrimp larvae to shrimp, in the middle of the month in mid-93 occurred in Fujian, and soon spread to the country, the general occurrence of shrimp pond 2-3 days, up to less than a week can be the whole pool The shrimp died. Prevention and treatment: There are no effective treatment methods for the viral disease of all shrimps so far, mainly prevention. 2 Red-leg disease (red-limb disease) Source of the disease: mainly solitary solitary pathogens and solitary bacteria, as well as algae solitary bacteria. Symptoms: The main symptom is that the appendages turn red, especially in the swimming feet; the palatal area in the head and chest is pale yellow. Shrimp are generally swimming slowly around the pool, while others spin in the water or swim up and down vertically, stop eating, and die shortly afterwards. Epidemiological situation: Red-leg disease is endemic in shrimp farming areas along the coast of China. It mainly occurs in Chinese prawn. The morbidity and mortality rate can reach more than 90%. It is the disease most harmful to baculovirus except for baculovirus. Treatment: A, norfloxacin 0.05% or furazolidone 0.1-0.15 or chloramphenicol 0.1% or oxytetracycline 0.2% was mixed into the feed to make a bait and fed continuously for 5 days. B, garlic 1-2% by weight of feed, peeled mash, add a small amount of water, mix well, mix in the compound feed, until the liquid is completely inhaled, you can feed, continuous 3-5 days. C. At the same time as oral administration of the above-mentioned drugs, bleaching powder fine 0.3-0.5ppm or trichloroisocyanuric acid 0.2ppm or bleaching powder 1-2ppm can be used to spray the entire pool, and the effect is better. 3 Ciliate-type pathogens of the phylum: Many species of the suborder of the ciliate ciliate. Symptoms: Shrimp swimming is slow, feeding capacity is reduced, growth and development stop, can not peel, it will promote the attachment and proliferation of fixed ciliates, resulting in a large number of shrimp death. Epidemic situation: The main pathogen of the prawn rearing period is the polypene, so it is also called polydenodecosis, and it mostly occurs in the pool of organic matter. Prevention and control: 1) The occurrence of polydeficiency disease is generally solved by a large number of water changes. 2) The tea pot can be splashed in the whole pool to make the pool water 10-15ppm. Chinese shrimp harvesting and processing methods Harvesting of shrimp in normal years in Lianyungang is usually in the upper and middle, and the key depends on the water temperature. At present, the cultured shrimps are harvested timely due to the disease. There are two main shrimp harvesting methods, namely, the use of a sealing net to collect and drain shrimp, which is more common. The method is to install a taper hanging net on the drainage gate and a pocket-shaped long net bag on the tail of the net. During the tide, it is sufficient to collect water and collect it. Finally, it can be collected through repeated irrigation. Processing technology The shrimp cultured in that year was mostly processed by cold storage into headless shrimps. The processing method was based on certain export specifications, and then weighed and frozen, fresh and fresh, and most of the current harvests were listed directly or frozen. Shrimp listing. Reference Shandong Marine University 1985 Maritime Aquaculture Manual Shanghai Science and Technology Press Ministry of Agriculture Workers Technical Training Textbooks Editorial Committee 1995 Artificial breeding of marine fish, shrimp, crab and shellfish Chinese Agriculture Press Xu Wei 1989 Operation guidelines for shrimp rearing in China, Jiangsu Provincial Bureau of Standards Meng Qingxian Yu Kaikang 1996 Fish Disease diagnosis and control of shrimp, crab, shellfish China's agriculture publishing house Zhu Guangding Senior Lecturer Lianyungang Fisheries School, Jiangsu Province 222042 Lv Lisen's engineer Lianyungang Municipal Tidal Flat Resource Development Bureau. Zhao Tiezhu Senior Engineer Jixian Fisheries Bureau
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