The practice of eel farming in cages has emerged as a promising aquaculture method in recent years. Known for its low investment and quick returns, this technique has spread rapidly across the country, delivering significant economic benefits. To further enhance and promote this technology, we have gathered insights from experienced farmers, leading to the development of an effective "eight-level" management system for yellow croaker cage culture.
1. **Pond Selection and Preparation**
Astragalus prefers warm, sheltered, and dark environments. Therefore, it is essential to select a sunny, wind-protected pond with convenient water access and minimal external disturbances. The ideal pond size ranges from 3 to 5 mu, with a depth of about 1.5 meters and a stable water level. Before stocking, the pond should be thoroughly disinfected using 100–120 kg of quicklime per mu to eliminate harmful microorganisms and improve the substrate quality.
2. **Cage Installation**
Each cage should cover an area of 15–20 square meters, constructed from polyethylene mesh. The rectangular structure is typically 1.5 meters high, positioned in the center of the pond. The four corners are secured with bamboo, while the sides are tied tightly to ensure stability and allow for proper water flow. The cage should be submerged about 1 meter deep, with the top edge 0.5 meters above the water surface to prevent escape. The total cage area should not exceed 50% of the pond’s surface. One week before stocking, the cages are placed in the water to allow algae to grow on them, reducing damage from rubbing. Aquatic plants like water hyacinth and peanuts are also introduced to create a favorable environment for seedlings, covering 80–95% of the cage area. If growth is slow, fertilizers like Feishuibao can be used to improve water quality and support early feeding.
3. **Seedling Stocking**
Currently, most seedlings come from wild catches, which are preferred over those caught by electric methods or with pink anal coloration, as they may carry diseases. Healthy seedlings have a yellowish body with dark spots on the back, followed by blue and gray ones. Stocking should occur between April and July, when temperatures range from 20–25°C, with June to July being optimal. Stocking above 30°C can reduce survival rates. Seedlings should be stocked at 20–40 tails per kilogram, with uniform sizes within each cage. Stocking density is recommended at 1–2 kg per square meter. Before entering the cage, seedlings are soaked in 20g/m³ of Shencaodan for 20 minutes to repair mucus and boost immunity, improving survival and feeding behavior.
4. **Feeding Management**
Before stocking, the first batch of Fish must be acclimated. This involves withholding food for three days and starting feeding at night once they adjust. Suitable feed includes alfalfa, small fish, and clams, given in small quantities and gradually increasing over time. During this period, additives like Pioneer, Liweisan, and Jinweisu can be mixed into the feed to enhance uniformity. Once feeding habits are established, artificial feed is introduced gradually, replacing part of the live bait. The final ratio is 1kg of fresh bait to 1–2kg of feed, fed twice daily at 6–7 and 17–18 hours. Daily feed amounts start at 2–3% of body weight and increase to 6% over time. Fresh bait should be washed and soaked in 1mL of Shencaodan per kg for 30 minutes to remove pathogens.
5. **Daily Management**
Water clarity should be maintained between 15–20cm to support healthy growth. Regularly introducing species like snails, oysters, and grass carp outside the cage helps improve water quality. Observing the pond regularly and removing dead fish promptly is crucial. In case of cage damage or signs of jaundice, immediate repairs and treatments are necessary. During summer, frequent feeding leads to rapid waste accumulation, so regular cleaning and water changes are essential. For poor water quality, products like Haibinbao can be used. Aquatic plants should be pruned to promote new growth and enhance water purification. In autumn, aging plants should be removed, and 1/7 of the water surface should be left open. In winter, water temperature drops, and plants decay, so adding immune-boosting drugs like Aureus and Baogan Granules is important. Disinfectants such as strong poison net and antivirus should be used to maintain water hygiene.
6. **Disease Prevention**
Adhering to the principle of “prevention first,†regular use of health supplements like Baogan Granules and Liweisan is essential. Disinfectants like glutaraldehyde and antivirus should be used to clean the water. Treatments include oral medications such as sepsis granules and bactericide granules. Common disease causes include unstable water quality, sudden temperature changes, toxic substances, improper feeding, and incorrect drug use.
7. **Disease Diagnosis**
Symptoms of illness include abnormal activity, skin bleeding, bluish discoloration, loss of appetite, and refusal to eat. Visual inspection, on-site observation, and internal examination are key diagnostic methods.
8. **Disease Treatment**
For conditions like "craziness," caused by overcrowding and poor water quality, treatment involves disinfectants and oral medicines. For hemorrhagic disease, antibiotics and antiseptics are used. Preventive measures include regular disinfection and monitoring.
This comprehensive approach ensures better survival rates, healthier fish, and sustainable aquaculture practices.
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Zhoushan Haiwang Seafood Co., Ltd. , https://www.haiwangseafoods.com