**Broiler Selection and Feeding**
Most of the broodstock used for producing seedlings of *Penaeus monodon* in Guangdong is imported from countries like Malaysia, Indonesia, and Thailand. These shrimp are transported over long distances and must be handled carefully upon arrival. Once they reach the farm, they should be acclimated to the lower pool as soon as possible. The process involves opening the transport boxes, separating males and females into fresh seawater (using a large basin), and removing any dead individuals. Live shrimp are then counted and placed into healthy oyster shell ponds or simple oyster shell environments, avoiding any diseased specimens.
After 1-2 days of recovery, the broodstock can undergo eyelid surgery and maturation. This procedure should take place near the maturation pond, and the shrimp should be quickly moved into the prepared maturation tank. The maturation process includes:
1. **Preparation of the Maturation Tank**
Maturation tanks are typically cemented pools located in dark rooms or nursery areas with black-painted walls or covered with black cloth to create a dim, quiet environment. The tank is filled with standard seawater to about 40 cm depth, heated to 28.5°C using titanium heating rods, and kept at a constant temperature until the shrimp are ready to enter.
2. **Feeding**
High-quality live feed is provided four times daily—morning, afternoon, and twice during the night. Before each feeding, leftover food is removed. All operations are done by one person to ensure consistency and care. Live feed includes crabs, sandworms, small shellfish, squid, and cuttlefish, which are washed and cut into small pieces for easier consumption. The maturation period starts after three days, and water changes should not exceed half, with matching temperatures to prevent stress.
After 3–5 days, most broodstock reach gonad maturity. At this stage, regular observation is crucial, and a Taiwanese-made "shrimp mother lamp" can help determine maturity. Once mature, the broodstock should be moved to spawning tanks promptly.
Local broodstock can also be captured using specialized nets and methods. Captured shrimp are kept in live water tanks on board. When sold, buyers should check for sexual maturity by observing under sunlight or using a flashlight from the abdomen. Mature shrimp are larger, with dark green shells and full, developed eggs. Their ovaries weigh 11–15% of their body weight. Selection should focus on individuals with intact limbs, no injuries, and strong activity.
After capture, shrimp are placed in buckets with a small air pump for short transport. For longer trips, 3–5 shrimp per 20-liter plastic bag with seawater and crushed ice are used to maintain a temperature of 18–21°C. Upon arrival, the bags are slowly introduced into the spawning pool, allowing temperature and salinity to equalize before releasing the shrimp.
**Spawning and Hatching**
Mature, fast-producing broodstock are selected and placed in spawning tanks. Spawning usually occurs at night. After transportation, most females spawn in the evening. If no eggs are produced within three days, they likely won’t spawn again. Spawning tanks should be spacious enough to allow free movement without collisions. A density of 1–3 shrimp per ton of water is ideal, with a temperature of 26–29°C, salinity of 28–33 ppt, and a water depth of 60–70 cm.
After spawning, foam and mucus appear on the surface. These should be removed, and water changed appropriately. In Taiwan, the spawning rate is around 70%. Each female can lay 600,000 to over 1 million eggs. On the second day, the broodstock is removed, and the eggs are hatched in the spawning tank. Under optimal conditions (26–29°C), hatching takes 12–13 hours, with a hatching rate of 70–80%. The nauplii are then counted and transferred to the rearing pools.
**Shrimp Cultivation**
1. **Infertile Larval Stage**
Newly hatched larvae are 0.32–0.33 mm long, have swimming ability, and are phototactic. No feeding is needed during this phase, and water depth should be 70 cm. The culture density is 80–200 thousand nauplii per ton. After six dehydration stages, larvae develop into cysts. At 27–29°C, this takes about 50 hours; at 21–22°C, it takes 110 hours. Survival rates are high, reaching up to 90%.
2. **Larval Stage Management**
Pod larvae go through three molting phases. First-stage larvae are about 0.91 mm and avoid light. Exposure to direct light causes them to stop feeding, become deformed, and die within 2–3 days. From the third stage, oxygen demand increases, so aeration is essential. Survival rates during this phase are low, ranging from 30–60%, making this a major challenge in artificial breeding. Food consists mainly of single-cell diatoms.
3. **Larval Development**
After three to four days of molting, sickle-shaped larvae transform into squid-like forms. During this time, their heads and tails bend at right angles, and they move back and forth. Survival improves significantly after 3–4 days, and they begin feeding on zooplankton such as rotifers and copepods.
4. **Late Larval Stage**
Late-stage larvae molt three times and grow to about 5 mm. They resemble adult shrimp and start to settle on the bottom or attach to the walls. Water depth increases, and aeration becomes more intense. The ideal temperature is 25–30°C, with salinity between 14‰ and 25‰. By day 5–10, they can be moved outdoors. Food includes Artemia larvae, rotifers, and copepods in early stages, and larger prey later.
**Shrimp Wintering**
Large, well-developed black-shelled shrimp can be wintered in deep aquaculture ponds with salinity between 15–25‰ and stocking density of 100–150 per square meter. Feeding during winter is reduced due to lower water temperatures and decreased appetite. Overfeeding should be avoided to prevent water quality issues. Shrimp may stay at the bottom, so regular monitoring of dissolved oxygen, temperature, and salinity is necessary.
**Shrimp Transportation**
For short-distance transport, shrimp are packed in plastic bags with seawater and transported by car or boat. For long-distance shipping, 15–20 liters of seawater per 2040120 cm plastic bag is used, containing 3000–5000 shrimp. Oxygenation and sealing are required. In summer, crushed ice is added to keep the water temperature between 15–18°C. Upon arrival, water is slowly added to the bag to match the pool’s temperature and salinity before releasing the shrimp. Healthy shrimp will swim quickly and settle at the bottom of the pond.
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