Crayfish, commonly known as crawfish, have become a focus of artificial breeding due to the decline in natural resources, supply shortages, and rising market prices. To address these challenges, researchers have experimented with co-cultivating crayfish and crustaceans in the same pond, achieving impressive results that show great potential for broader application. Below is a detailed introduction of the technology:
The pond should be located in a quiet area with convenient transportation and reliable irrigation systems. The soil should be clay or loam, with good water retention and fertility. Water depth should range between 0.8 to 1.2 meters, and the slope ratio should be 1:2 to 1:3. A 60 cm high calcium plastic or aluminum board is installed around the pond to prevent escape. Bamboo and wooden poles are used as supports, while a 40 cm diameter cement culvert or plastic pipe serves as the water inlet. An identical pipe is placed in the opposite corner as an outlet, both sealed with dense barbed wire or plastic net to prevent crabs and other species from escaping. After harvesting, the pond is cleaned, and 50 kg of tea seed cake and 100 kg of quicklime per acre are applied to disinfect and eliminate predators, without affecting the crayfish in their burrows.
Aquatic plants and snails play a crucial role in successful breeding. Waterweed and snails serve as high-quality food sources for both crabs and crayfish, while also helping to maintain water quality and provide shade during hot summer months. A 5-meter-wide aquatic zone is set up around the pond, with bamboo poles and ropes used to fix water plants. Before the Qingming Festival, 300 to 500 kg of fresh snails per mu are introduced to breed naturally, providing a sustainable food source for the aquatic life.
Crab seedlings are purchased and raised in a designated holding area at the corner of the pond, which occupies 5% to 10% of the total surface area. These seedlings are kept for about a month until they reach approximately 6,000 per kilogram. They are then released into the main pond. Crabs from the Yangtze River system are preferred, ideally raised in a simulated natural environment. Each kilogram contains about 160,000 crabs. After desalination for over seven days, the salinity must be below 3 ppm before release. Healthy seedlings with uniform size, bright color, and active movement are selected, transported in air-conditioned vehicles.
Upon arrival, the seedling boxes are submerged in the pond water for 1–2 minutes, then lifted, repeated 2–3 times to acclimate them to the pond temperature. Feeding begins with egg yolk every 2–3 hours for newly hatched larvae. As they grow, they are transitioned to fish cakes, bean cakes, and bran, with feeding rates gradually reduced to 5–7%.
For shrimp stocking, two methods are commonly used: spring stocking of larvae or stocking of 2–4 cm shrimp from February to May. After 2–3 months of growth, they are caught using cages. Alternatively, mature shrimp are stocked in September–October at a 3:1 male-to-female ratio, with each shrimp weighing over 40 grams. From April to May, land cages are used to capture broodstock, allowing self-bred shrimp to grow in the pond. Stocking density is generally around 5,000 per acre.
In addition to natural food sources, feed is gradually increased from April onward, including water grass, wheat, corn, bean cakes, snails, oysters, and clams. A combination of fixed feeding and spraying ensures all animals can access food. From August to September, plant-based feeds are prioritized, while animal-based feeds are used from October to December. Water is changed every 10 days, with one-third of the water replaced each time. Daily patrols are conducted in the morning and evening to monitor water quality, feeding behavior, aquatic vegetation, and anti-escape facilities. Weather conditions are closely monitored to prevent escapes, especially from predators like rats, frogs, and birds. Lime is sprinkled every 15–20 days, with 5 kg of quicklime per acre.
Harvesting typically occurs from February to March of the following year. Crabs are captured using dip nets, and once most are collected, the pond is drained. Water peanuts are spread on the poolside, and the water is released in the evening. The next morning, crabs are gathered under the peanuts, capturing over 90% of the population in two rounds. Crawfish are harvested regularly throughout the year using ground cage nets. This method proves effective and sustainable for long-term aquaculture.
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"Black and White Ultrasound Scanner" is to emit ultrasonic waves, so that the ultrasonic waves encounter barriers to generate echoes, use the computer to collect these echoes, convert them into corresponding images and display them on the screen, and the images measured by the ultrasonic probe are black and white, so it is called " Black and White Ultrasound Scanner" is also the earliest diagnostic technology adopted by b-ultrasound.
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