Artificial breeding technology for the marbled eel (Anguilla marmorata), its price per jin, and whether it is a protected animal
Practical Still-Water Breeding Techniques for the Marbled Eel
The marbled eel is a national second-class protected animal, but only wild ones are; artificially bred ones do not count as protected animals. Around 200 per jin.
1 Water quality regulation for marbled eel breeding
The marbled eel has high water quality requirements. Before breeding, the pond should be disinfected, generally using quicklime; about 150-250 kg of quicklime per 667 sq m of pond is appropriate, which can also raise the pH value of the pond water. If the pH value reaches above 11, it can also eliminate wild trash fish, insects, etc. in the water and improve the acidity of the pond bottom soil. After disinfection, let the pond water stand for 15-20 d; once its pH value remains between 8 and 9, trial stocking can be carried out. For trial stocking, other fish species are generally used; after the lime toxicity disappears and the trial stocking shows no problems, the marbled eels are introduced.
During the breeding process, the water quality should be kept clear and tender green, and an appropriate amount of blue-green algae should be ensured in the water body. Algae can provide shade, increase oxygen and stabilize water quality. If there is too little algae in the water, the water body will become lean and clear, thereby affecting the feeding and growth of the marbled eel. Therefore, in breeding, introduction or fertilization methods can be used to promote the reproduction of algae in the water. In addition, regular inspections should be carried out. If zooplankton are found in the water, they should be dealt with promptly to prevent pollution of the water quality and effects on the growth of the marbled eel. For zooplankton, Kechong b1 preparation can be used to kill them, sprinkled along a range of about 2 m around the pond edge, to control the zooplankton in the water and ensure sufficient algae in the water. In addition, the dissolved oxygen, ammonia nitrogen, nitrite, pH value, etc. of the water quality should also be tested, and problems should be dealt with promptly once found. If the dissolved oxygen level in the water is found to be low, the number of aerators should be increased and the operating time of the aerators extended to ensure that the oxygen concentration in the water meets the requirements.
2 Feeding management for the marbled eel
The water quality environment affects the feeding situation of the marbled eel, among which the effect of water temperature is relatively serious. If the temperature difference between morning and evening is large, it will affect the feed intake of the marbled eel. Generally, the temperature difference between morning and evening in the pond should be controlled within 3°C. If the daily temperature difference exceeds 4°C, it will cause the marbled eel to eat less; at this time, the feeding amount should be reduced as much as possible, preferably by 30%-50%. During the breeding process, temperature control during temperature difference changes must be strengthened. For example, when spring and summer alternate, the insulation shed can be removed later, and when autumn and winter alternate, the insulation shed can be covered earlier, to avoid too large a temperature difference during seasonal changes affecting the feed intake of the marbled eel. To ensure the food intake of the marbled eel, the feeding amount is generally controlled according to the water temperature in the pond. For example, when the temperature in the pond is between 24-29°C, the feeding amount is 2.5%-3%; when the water temperature exceeds 30°C, the feeding amount should be reduced accordingly, preferably to 2.2%-2.6%.
In addition, as the marbled eel continues to grow, its feeding amount should increase accordingly. During the white fry stage, the feeding amount of white fry feed should be 5%-6% of the eel body weight. After growing for a period and entering the black fry stage, the feeding rate should drop to between 5% and 3.5%. The feed intake of the marbled eel is also closely related to water quality. During breeding, the water exchange volume generally cannot be too large; too great a change in water quality will cause a serious decline in the feed intake of the marbled eel, and may even cause a phenomenon of no feeding. Substances such as ammonia nitrogen and nitrite nitrogen in the water must not exceed standards; excessive harmful substances will cause abnormal oxygen transport in the marbled eel itself, thus causing irregular feeding by the marbled eel.
3 Breeding methods for the marbled eel
In China, the most commonly used breeding method for the marbled eel is open-air still-water breeding. Generally, the scale of a marbled eel farm is suitable to be controlled within 3.33 hm2. During breeding, various infrastructure facilities should be improved, such as ponds, water injection systems and ancillary facilities, and natural water sources should be used for breeding as much as possible. To keep the water quality clean during breeding, moderate water exchange should be carried out, with each water exchange kept at 1/10-1/7 of the pond water. To improve water quality, reliance is generally placed on planktonic blue-green algae, water wheels and aerators to ensure that the oxygen in the water meets demand. This breeding method has low cost, does not require too much time when building ponds, and uses equipment for aeration with low power consumption, but the overall yield is relatively low, generally 1,000-2,000 kg per 667 sq m.
During breeding, marbled eel ponds should be classified, generally into 4 categories. The adult eel pond has the largest area, and the first-grade pond is generally mainly used for feeding training of young marbled eels.
