With a plastic greenhouse, astragalus can be cultivated all year round, ensuring continuous production. By adopting landless water aquaculture, disease control becomes more effective, and profitability can double. The ideal growth temperature for astragalus is 27–30°C, which can be easily maintained in greenhouses without the need for additional heating equipment. During spring, summer, and autumn, the temperature inside the shed remains suitable, and even in winter, the average temperature can reach around 20°C. Maintaining a micro-flowing water system in the rearing pond helps prevent water quality degradation.
The construction of the breeding ponds involves two main types: open feeding ponds and closed-loop filter ponds. Open feeding ponds are ideal for areas with consistent warm water supply. They offer stable flow rates and are suitable for large-scale operations, though they are regionally limited. These ponds are built using bricks and cement, with each pool measuring 10–20 square meters, 40 cm deep, and 1–2 m wide. A 20–40 cm wide channel runs between pools, with two 3–4 cm diameter inlet and outlet pipes. The inlet pipe aligns with the pool bottom, while the outlet is slightly higher to prevent escape, equipped with metal mesh. Units should not exceed 500 square meters for efficient management.
Closed-loop filter ponds are better suited for urban areas or regions with limited water resources. They allow water reuse, reduce consumption, and make temperature control easier, although they require a larger initial investment. The construction is similar to open ponds, but additional components like aeration tanks, sedimentation basins, and pumping systems must be included.
Plastic greenhouses are constructed similarly to traditional sheds, and it's best to house each unit in the same structure for ease of management. Once the seed tanks are in place, the total water outlet is sealed, and the pools are filled and soaked for 5–7 days before draining. The bottom drainage holes are then plugged, and a small amount of water is kept flowing at a depth of 5 cm. Before stocking, the oyster species are soaked in a 10 ppm malachite green solution for 20–30 minutes to disinfect and remove parasites. The soaking time depends on the fish’s tolerance. After sterilization, the fish are stocked at a rate of 35–50 pieces per square meter, with each fish weighing 4–5 kg. All fish in the pool should be of similar size to avoid competition for food.
Astragalus is a carnivorous fish that prefers fresh feed. After stocking, chopped snails, frogs, and other protein-rich foods are placed at feeding stations, and the water flow is adjusted. The initial feeding amount is 1–2% of the total weight, increasing gradually to 5% as the fish grow. Over time, the diet can include silkworm pupae, fly larvae, cooked organs, fishmeal, soybean cake, and rice bran, eventually transitioning to artificial feed to reduce costs. The feed should contain 35–40% protein. Feeding is done once daily, preferably between 8–9 AM and 2–3 PM.
Daily management in plastic greenhouses is relatively straightforward. With clear water and sufficient feed, astragalus rarely escapes, but precautions must be taken against predators like rats and snakes. When fish sizes within a pool become uneven, they should be separated promptly. After 5–6 months of rearing, the fish can be harvested, typically at 6–10 pieces per kilogram, with a survival rate exceeding 90%.
Disease prevention is crucial. Although this method results in fewer diseases, some conditions still require attention. Cold disease occurs when new water is introduced too quickly, causing a drastic temperature change. Adjusting the temperature gradually prevents it. Capillary nematode disease, caused by parasites, leads to weight loss and swelling. Treating with 0.1% trichlorfon (90%) mixed into the feed for six consecutive days helps control it. For plum spot disease, characterized by dark spots on the fish, regular disinfection with 10 grams of bleach per cubic meter of water, or lime and malachite green, is recommended.
Spicy Taste Dried Alaska Pollack
Russian Dried Fish Snack,Pollock Alaska Fish Delicious,Seasoned Dried Fish Delicious
yanbian zhenxiang foods , https://www.driedpollock.com