I. Pond Conditions Shrimp ponds should be equipped with a reliable water source, ensuring high-quality water that meets the standards outlined in GB11607. The water must be free from pollution and maintain good clarity. The pond bottom should be flat with minimal silt accumulation to facilitate efficient drainage. Ideal pond sizes range between 3 to 10 acres, with the optimal size being 3 to 5 acres. Water depth should be maintained at 1.8 to 2.5 meters, and each pond must have 2 to 3 aerators to ensure proper oxygenation and water circulation.
II. Pre-Stocking Preparation 1. Pond Cleaning and Disinfection: For new ponds, it is recommended to fill them with water and let them soak for a few days before applying disinfectants. If the pond is an old fish pond being converted into a shrimp farm, it should be dried for 20 to 25 days, then thoroughly cleaned by removing sludge and weeds before disinfection. Apply quicklime at a rate of 80 to 100 kg per mu to ensure effective disinfection.
2. Bait Cultivation: Five to seven days before seedlings are introduced, apply 1 to 1.5 kg of microbial composite preparation (EM) per mu. Two days prior to stocking, add a small amount of urea and superphosphate to promote plankton growth. This helps achieve a water transparency of 25 to 30 cm, with a dark brown or yellow-green color, ideal for shrimp development.
3. Salinity Adjustment: For freshwater ponds, add 150 to 200 kg of coarse salt or sea salt per acre one to two days before planting. This helps adjust the salinity to 1‰ to 1.5‰, which is suitable for shrimp acclimation and growth.
III. Shrimp Selection and Stocking 1. Shrimp Selection and Desalination: Choose healthy, disease-free Penaeus vannamei seedlings with a size larger than 1.0 cm. Before introduction, they must be quarantined to prevent the spread of diseases. For early stocking, when temperatures are low, keep the shrimps in a nylon greenhouse for 10 to 15 days. During desalination, reduce salinity gradually by no more than 1‰ per day until reaching 1‰ to 1.5‰. Once the larvae reach 1.0 to 1.5 cm, they can be moved to outdoor ponds. For the second batch, place the seedlings in a temporary holding pool or net cage for 7 to 8 days to adapt before transferring to the main pond.
2. Stocking Density: The first stocking should take place in mid-May when water temperatures stabilize above 20°C. A density of 3.8 to 4.0 million per mu is recommended. For the second batch, keep the density lower at 2.8 to 3.0 million per mu to avoid overcrowding, which could hinder growth and affect final marketable size.
IV. Feeding and Management 1. Water Quality Management: Water quality plays a crucial role in shrimp health and growth. In the early stages, focus on adding water. As the cultivation progresses, regularly change the water every 5 to 7 days, but never exceed 30% of the total volume. Use aerators as needed based on weather and water conditions. Every 15 to 20 days, apply photosynthetic bacteria or EM to improve sediment quality and maintain clean water.
2. Feeding Practices: Use high-quality, full-nutrient pellet feed. Ensure the feed is of good quality and appropriate particle size. Control the feeding amount based on shrimp weight, typically 30% to 5% of their body weight daily. However, in practice, adjust the quantity depending on feeding behavior, water quality, and temperature, using smaller, more frequent feedings if necessary.
V. Disease Prevention Adhere to the principle of “prevention and health management.†Every 15 to 20 days, alternate between environmental disinfectants like quicklime, dibromohydantoin, photosynthetic bacteria, and EM to maintain a clean environment. If artificial feed is used, add 1‰ to 2‰ of vitamin C and immune polysaccharides to boost shrimp immunity. When changing water, avoid large-volume irrigation to maintain stable water conditions.
VI. Harvesting Methods South American white prawns are mainly harvested using ground cage nets, followed by manual collection from dry ponds. Harvest timing depends on market demand, price, and shrimp growth. After 70 to 80 days of farming, shrimp reach a size of 60 to 90 tails per kilogram, making them ready for harvest. First crop is usually caught in late July to early August to avoid delaying the second crop’s stocking and growth. Harvest in batches and market accordingly, ensuring optimal yield and quality.
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