First, the desalination process is essential when purchasing shrimp from the nursery. The salinity should be between 2 to 5 parts per thousand before they can be transferred. Shrimp have a very low survival rate if directly introduced into fresh water, so a secondary desalination process is necessary. This step is crucial for the successful freshwater culture of *Penaeus vannamei*.
Before releasing the seedlings, a thin plastic film is used to create a temporary enclosure in the pond. Typically, an area of about 0.1 mu (approximately 66.7 square meters) per acre is sufficient, with a water depth of around 50 cm. Salt brine or coarse salt is then added to adjust the salinity to match that of the nursery. Based on our experience, about 50 kg of coarse salt is used per acre of water, and the shrimp are temporarily stocked in this area.
Second, feeding and management play a key role in shrimp cultivation. Before stocking, the pond should be disinfected by drying it to a depth of 10–15 cm and applying 200 kg of lime per acre. When filling the pond to a depth of 1 meter, 150 kg of lime per acre is used. After 7–10 days, the water level is raised to 30–60 cm. A 40-mesh filter is installed to prevent unwanted organisms and wild fish from entering. Then, fermented manure such as chicken or pig manure is added to enrich the water and cultivate natural food sources. About 100–150 kg of fermented manure per acre is recommended, aiming for water color to turn yellow, oil green, or tea brown, with a transparency of 25–35 cm. This ensures that shrimp have ample natural food after being stocked.
For water temperature management, the holding area should maintain a stable temperature around 20°C. Low temperatures can reduce survival rates. Once stocked, feed is prepared by mixing one egg, a tablespoon of milk powder, and a little salt with water, then steaming and diluting through a 40-mesh sieve. The mixture is evenly distributed across the pond, fed 4–5 times daily. After 4–5 days, soy milk and fish paste are introduced, along with specialized shrimp feed. Each 10,000 larvae receive 5–10 grams of feed, with quantities adjusted based on food availability and water quality. After about 15 days, when the shrimp reach 3 cm in size and the salinity matches the main pond, the plastic film is removed, and the two areas are connected. The survival rate typically reaches around 60%.
During the early stages, water is gradually increased by 3–5 cm daily to lower salinity. Once the water depth reaches 0.8–1 meter, water changes are performed every 2–3 days, with 10–15 cm of water replaced each time. Water quality management is critical due to high density and small volume. Regular monitoring of water conditions, timely aeration, and removal of leftover feed are essential. If moving shrimp to another pond, choose sunny, windless days. Netting should be removed in the morning, with gentle handling and similar water conditions between the two ponds to ensure survival.
Stocking time is usually between mid-May and mid-July. Initial stocking ranges from 1–15,000 larvae per acre, yielding about 75 kg. Intensive breeding can reach 6–80,000 larvae per acre within 10 acres, producing 300–400 kg. Healthy shrimp with a size of at least 1 cm should be used. To extend the growth period, some farmers hold seedlings early to increase their size and yield, even allowing for two harvests per year.
Feeding is divided into types and schedules. *Penaeus vannamei* primarily feeds on plankton and benthic organisms. In addition to fresh fish and shrimp, high-quality granulated feed with at least 35% protein, 4% fat, and 15–25% polysaccharides is ideal. Such feed supports growth over 70–80 days, reaching up to 15 grams per individual.
Feeding frequency is 3–5 times daily, depending on the stage. Early-stage shrimp (3 cm) are fed 8–9% of their body weight, while those 3–8 cm consume 6–6%. For shrimp over 8 cm, 4–5% of their weight is sufficient. Feeding is done evenly around the pond’s edge, with more feed given at night due to nocturnal feeding habits. During the seedling phase, uniform distribution is key. Bait trays help monitor consumption, and feeding should stop during aeration. Feed size and palatability must be appropriate to avoid waste. In later stages, fresh animal feed like fish and snails can be added 2–3 times weekly, especially before harvesting, ensuring freshness and cleanliness.
Finally, water quality management is vital throughout the process. Initially, fertilization increases natural food organisms, while later stages require higher transparency (30–40 cm). Dissolved oxygen levels should exceed 5 mg/L in surface water and 3 mg/L in the bottom. Water is added every 3–5 days initially, with gradual changes of 5–10 cm in later stages. Lime is applied every 20 days to adjust pH and improve bottom quality, avoiding use during molting periods. Environmentally friendly disinfectants and micro-ecological agents like photosynthetic bacteria are also used. Aerators are essential, with increased aeration time as the shrimp grow. Ammonia nitrogen and hydrogen sulfide levels must remain below 0.2 mg/L and 0.1 mg/L, respectively, to maintain a healthy environment.
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