Generally speaking, shrimp is generally referred to as shrimp in the genus Penaeus and New Shrimp, and belongs to the order Arthropoda, Crustacea, and Decapoda. The following is a description of the main breeds of Chinese prawn (also known as Oriental prawn): China's prawn is mainly distributed in the Yellow Sea and Bohai Sea in China, and it can sometimes be seen in the East China Sea and South China Sea. However, it is rare. First, the breeding habits and life history of shrimp. The maturation period of male and female shrimp is not the same. Males can reach sexual maturity at that time, and females need to mature in April and May of the following year. After maturation, the males mate with females from about mid-October to early November. During mating, the male spermatozoa are sent to the female seminal vesicles before the new shells have hardened after the shells are repelled. After mating, the female seminal vesicle becomes plump and opaque from the original flat and transparent. From April to June in the second year after mating, female gonads matured and spawned. The spawning water temperature of Chinese shrimp in the natural sea area was 13-18°C. Artificial rearing can be performed early in March under conditions of temperature control. Prawns have many (batch) spawning habits. The female lays eggs while spawning, releasing the sperm in the seminal vesicles and binding the eggs. Chinese shrimps hatch from spawning to baby shrimp through three stages of completely different shapes, with nine shellings, ie no hatchlings, zoea, and shrimp larvae. After 14-22 shelling, the juveniles reached sexual maturity and mated and progenied. Second, the environmental factors of shrimp rearing shrimp rearing in the south are generally taken in the cement pool, the suitable environmental factors for shrimp rearing in China are: 1, water temperature: spawning and fertilized egg hatching the most suitable water temperature is 18-20 °C, no Festival The larval stage is 20-22°C, the zoea 22-24°C, the prawn larvae are 23-25°C, but when bred to the larval stage, the larvae are gradually reduced to 2-3 days before they are ready to go out of the pond. The temperature of the water in the aquaculture pond is similar. In order to avoid death after leaving the pond and the culture pond temperature difference is too large. 2. The pH is generally between 7.8-8.6. 3, salinity is generally about 25 。. 4, dissolved oxygen above 4 milliliters. Third, prawn cultivation techniques l Qingqing injure. After the ponds are built or old ponds are restored, clear ponds and clear ponds must be cleared of silt, algae, and animal predator organisms 20 days before development. The method of clearing the hostile creatures is: Ponds that do not accumulate water, drain the pond water after the shrimps have been harvested, and expose them to a winter heat, so as to achieve the purpose of clearing. However, the exposed ponds cannot be drained and need to be cleared with drugs. Commonly used drugs are tea seed cake, bleach, fish rattan, quicklime and so on. 2, bait biological culture. After clearing, it can be used to incubate biological feed. It is the basic bait for prawns, has the advantages of simple method, high nutritional value, low labor and production cost. A basic bait cultivating a good shrimp pond, shrimp can be stocked within half a month without bait. 3, shrimp transportation and precautions. The proper transport of shrimps and shrimps has a great impact on their survival rate. Dissolved oxygen and water quality are major factors in transportation. Most of the current use of polyethylene bags oxygen transport. This method is light, safe and adaptable to various tools. In a polyethylene bag with a volume of 10 liters, about 1/4 of the fresh seawater is filled, about 20,000 shrimps are replenished, about 3/4 of the oxygen is recharged, and the bag is tightly closed. The transport time is not within 10 hours. There will be problems if it is safer to put bags in the trays. The precautions for transportation of shrimps and shrimps include: 1 The seedlings cannot be used for nursery water in nursery ponds, but fresh seawater is used, and seawater that is cloudy or contaminated cannot be used. 3 The best seedling time is to arrange in the early morning or late afternoon to avoid the intense heat at noon. The best transportation water temperature can be controlled at the same temperature as the seedling nursery, and try to avoid exceeding 20°C. 4. Matters needing attention when laying seedlings. When laying seedlings, pay attention to whether the physical and chemical factors in shrimp ponds are suitable for shrimp seedlings. When stocking in April, the water temperature should be kept stable above 14°C. When the seedlings are released, the water depth should not be less than 40cm, and the salinity should be 20‰. 30 ‰, pH value of 7-8.6 is appropriate. 5, aquaculture daily management (1) watch pond observation. After stocking the shrimp, it is necessary to carefully inspect the pond and carefully observe the dynamics of the shrimp pond and the changes of the environmental factors. To prevent accidents from happening. The observations of the patrol pond mainly include whether the gate and the filter are in good condition, whether the shrimp is active or ingested, whether the shelling is normal, whether the difference in environmental factors is too large, and whether the pool water has a strange smell. (2) change the water. Changing water is an essential measure to improve water quality in shrimp ponds. It can increase dissolved oxygen in water, regulate salinity, pH, and water temperature, control the proliferation of monocytic algae, remove metabolic waste, and improve environmental conditions. Increase food organisms and stimulate shrimp shelling. The specific operation is generally as follows: In the early stage (within half a month after the shrimp is put in), the water is mainly added, and a small amount is added every day until the shrimp pond is filled. After that, the amount of water is changed every day, and the amount of water in the middle and later days can be increased to about 30%. In the normal situation in the later period, the daily water exchange volume should preferably be controlled at about 50%, so as to avoid excessive changes in environmental factors when the water exchange volume is too large. (3) Feeding; At present, the prawn feeds in the south of Zhejiang Province are mainly bred with small nets and shrimps, and they are also partially fed with baits, cockroaches and snails. According to studies, shrimps have the following characteristics in their food intake. First, the central nervous system of shrimp is simple, it is difficult to form conditional reflexes, and conditional stimulation cannot be used as a feeding signal. Second, the range of sight and activity of shrimp is not large. It mainly depends on sniffing for food. Third, shrimps use chewing claws to catch food. They only hold food and then shred their food with small quails. The large chewing chew enters the stomach. Therefore, the food must have a certain shape, not too thin or too large, and the fourth is that the feeding of prawns changes regularly with the clam shell cycle. The prawns that had just been shelled did not eat anything because their bodies did not harden. Fifth, in the condition with good water quality, the healthy shrimps will increase their water supply as the water temperature rises within a suitable temperature range of 7-32°C. Therefore, the feeding amount and the size of the bait granules need to be determined based on the above characteristics and the individual size of the shrimp. Under normal circumstances, more than 70% of the shrimp should reach full stomach or half full after one hour after feeding. Fourth, shrimp feeds As the shrimp aquaculture area continues to expand, coupled with fishing season fishing management, in the breeding process must use compound feed to replace the natural bait, a good bait advantage is: able to adapt to different stages of nutritional needs of shrimp, In particular, the use of protein complementation to improve feed utilization, reduce food quality, low-quality food; reduce disease; easy to save and feed. Therefore, when the current disease seriously affects the shrimp aquaculture industry, the experts call for the use of compound feed to raise shrimp as much as possible, which can play a role in disease control and disease control. V. Diseases and Diseases Prevention Diseases of cultured shrimp can be divided into two major categories: biological diseases and non-biological diseases. Biological diseases include viral diseases caused by baculoviruses, Rickettsia bodies, and pathogens, etc. Bacterial diseases caused by bacteria, etc., fungal diseases caused by Fusarium, protozoan diseases caused by polyps, etc., worm diseases caused by nematodes, aphids, etc. Non-biological diseases, including malnutrition caused by malnutrition, environmental diseases caused by bad water quality, and toxic diseases caused by harmful chemical substances. The occurrence of shrimp disease is quite complicated. Despite the existence and invasion of biological and abiotic diseases, it is the direct cause of the disease. However, it is not necessarily the presence of pathogenic organisms that will affect the disease or even death. It also depends on shrimp. Physical health conditions and environmental conditions, so to protect the environment and enhance the physical fitness of shrimp can play a preventive role. At present, the disease epidemic during the development of shrimp has become a global problem. The devastating impact on the shrimp farming industry has yet to find an effective method of prevention and control.
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