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Recycling Submerged Salinized Water to Breed Penaeus vannamei
The use of underground salinized water for the cultivation of white shrimp in South America, using closed-cycle technology, can cut off the horizontal transmission pathways of pathogens and greatly reduce the incidence of shrimp disease. At the same time, due to the recycling of aquaculture water, it can avoid environmental pollution. Aquaculture health, sustainable development requirements, the real realization of healthy breeding, and the technology is operable, easy to promote the application. First, materials and methods Experiment time and place. The experiment began in 2001 and ended in 2002, after two production years. The experiment site is located at the experimental and practice base in the Yunshan Township of Lianyungang City, School of Marine and Fisheries of Huaihai Institute of Technology. 2. Ponds and disinfection. The aquaculture ponds are rectangular, extending from north to south, with a total of 7 earthen ponds, a depth of 2.4m, and a flat bottom, which can maintain an effective water depth of 2.0m. Among them, 4 ponds have an area of ​​2.6 mu, and 3 ponds have an area of ​​3 mu. The pond is sterilized with 80 kg/mu of quick lime pond before entering the pond. 3. Water and water treatment. The underground salinized water was applied to the high-density culture of shrimp. Before the use, the treatment measures such as oxidation ditch circular aeration and monocytic algae culture were adopted in the water treatment tank. The treated water body reached the index of aquaculture water use. There are two circulating water treatment tanks, covering an area of ​​25 mu, composed of a biological pool, a stream-type oxidation ditch and a sedimentation tank. In the early stage of cultivation, underground salinized water was used. The salinity was 16 ‰, which was increased to 8 cm. Fresh water (including rain water) was gradually added after the larvae were released. The salinity of the water body gradually decreased to 6 ‰. The degree of salinity of shallow groundwater in coastal plains of Jiangsu Province has gradually increased from 1g/L to over 10g/L, and the type of water chemistry is chloride type, but the chemical composition is different from that of seawater, and certain ions (such as iron) are often formed. The combination of enrichment, ammonia nitrogen indicators even up to 10 (the negative 6th power) above. The semi-closed circulating water technology is used in the aquaculture production process, and chlorine dioxide is used to disinfect the water body every 5 days in the middle and later stages of the breeding. 4. Support facilities. It is equipped with 2 deep wells and 2 deep well pumps (2x25 m3/h). Each breeding pond is equipped with a 1.5kW jet aerator and a 1.1kW spray aerator. The circulating water is completed by 4 submersible pumps with a total water transmission capacity of 400 cubic meters/h. The daily maximum amount of circulation in aquaculture ponds can reach 35% - 40%. 5. Seedlings. Seedlings are from the Luyi base of the Jiangsu Provincial Institute of Oceanography. The seed size is 0.6cm. Seed quarantine using PCR technology specific pathogens (white spot syndrome virus WSSV) on shrimp seedlings were examined, negative. The release date was May 31, 2001. The average seedling density is 60,000/mu. 6. Feed and feed. During the cultivation period, all artificial compound feeds were used, which were fed 5 times a day, and the feeding amount in the middle and late stages of the culture increased by 10%-20%. 7. Water cycle and ecological regulation. The internal circulation is formed between the aquaculture pond and the water treatment pond water body, and its main role includes two aspects: First, the safety protection function (isolation of pathogens, maintain the stability of the water environment, reduce the stimulation of cultured organisms); second, the role of purified water body (Reducing organic pollution, increasing the dissolved oxygen content in the pool, and reducing the concentration of metabolic poisons). Exploring “eco-control†in the project is to set up a filter with a suitable pore size by means of the in-and-out drainage channel in the internal circulation system. In accordance with the relationship between phytoplankton and zooplankton in the food web, isolation and removal of large and medium-sized planktons during the circulation process. Animals regulate the phytoplankton stocks by controlling the feeding pressure of macro-and zooplankton on microzooplankton and regulating the micro-lake zooplankton stock. The "grazing-food chain" that begins with phytoplankton is the main route for the circulation of organic matter in the pond water. 8. Monitoring and diagnosis. Due to rapid changes in environmental conditions in high-density culture ponds, environmental factors such as water temperature, salinity, transparency, pH value, dissolved oxygen, ammonia nitrogen, nitrates, and nitrites are regularly monitored according to different requirements in the early, mid and late stages of cultivation. Indicators, and at any time pay attention to the observation of plankton species, quantity, to take appropriate technical measures. During the aquaculture process, specific etiological examinations of the shrimp body were also regularly performed. Abnormal conditions were encountered and technical measures were improved. Second, the breeding results from the beginning of September 4th, 2001, to September 31 was completed, the average yield of 485kg per mu, the total output of 9700kg, the average size of 11.45cm, survival rate of about 64.7%, bait coefficient of 1. 81. On September 10, 2002, the market began to be harvested. By the end of the 26th, a total of 1060.4kg shrimp was harvested. The average size was 11.90cm, the survival rate was 72.1%, and the feed coefficient was 1.6. Third, discuss 1. No specific pathogen shrimp is the basis for healthy breeding. Scientific breeding methods are the key. Strict management measures are the guarantee of successful breeding. 2. The application of subsurface salinization water to factory seedlings has been successfully implemented in Lianyungang area. If submerged salinized water can be applied to shrimp aquaculture, the contradiction of invading pathogens can be avoided, and new breeding areas can be developed. This opens up new areas for the healthy breeding of shrimp. 3. The project will be completed by narrowing the width of the oxidation ditch, extending the oxidation ditch process to more than three times the current level, and increasing the use of halophytes for water treatment. 4. In the practice of healthy shrimp and intensive shrimp farming, the role and impact of plankton in the aquaculture process are increasingly attracting attention. It is necessary to increase the quantitative detection and analysis of plankton in culture ponds and establish control indicators and early warnings. Indicators, target-oriented indicators and other work. 5. In the first year of implementation of this project, due to the power supply, the phenomenon of floating heads of prawn in individual ponds occurred, and further experiments should be conducted to increase the effects of mechanical oxygenation and the increase of circulation ratio.