How to use cage to cultivate eel

In recent years, although the price of eel market fluctuates, eel species such as European eel with rich resources and low price are selected for marine cage culture, the prospect is still good, and the economic benefit is also very considerable.

In the water quality environment, it is appropriate to set up cages near the estuary where the water surface is open, the water quality is good, the wind speed is small, and the water depth can be maintained more than 4 meters at low tide. It is required that the range of water temperature is 8 ℃ ~ 30 ℃, the velocity of ocean current is less than 1 m / s, and the water area with velocity of 0.5 m / s is the best. The net cage size eel mariculture should adopt 3 m × 3 m × 3 m or 6 m × 3 m × 3 m unjointed net cage. The mesh specifications are as follows: raising black eel, young eel 0.5 cm, cultivated eel 0.8 cm. A 1m × 0.5m × 1m multi-layer grid is placed in the cage as the eel rest table, and the cage is opened with 15cm anti-escape eaves to prevent the eel from escaping from the box. Young eel is the best for seedling release, and its release density is 150 eels per square meter. If the black eel is released without young eel, the density is 500 eels per square meter. Eel seedlings should be disinfected by medicine bath before release to prevent infection. Feeding and management 1. Water quality management the water quality management of eel culture is particularly important, requiring that the specific gravity of sea water is 1.01-1.02, dissolved oxygen is more than 5 mg / L, and pH value is 7-8.5. In recent years, some aquaculture farms have achieved successful experience in regulating water quality, soaking and mixing feed and preventing fish diseases by using the microbial preparation EM produced jointly by China and Japan, and achieved good economic benefits. two。 Feed eel should be "four fixed". That is, timing: except that feed is fed at 8 pm every day in early spring and winter, it is fed once at 5 am and 8 pm every day. Positioning: feeding on a fixed bait table. Quality: feed the full-price compound feed with special multi-vitamins for eel. Quantitative: the total amount of diet is calculated as a percentage of the total body weight of eels, which is 15% in the adult stage, 3% in the young stage, about 5% in the black eel stage, and 0.5% in the high temperature and overwintering period. 3. After raising eels in boxes for about a month, the density of eels increases greatly, and the individual differences are more disparate, so the eels must be selected and reared in boxes in time and separated according to physical strength and individual size. In the process of screening the sub-box, the operation should be careful to avoid bruising the fish, prevent infection, and disinfect the medicine bath. 4. Change the cage in order to keep the cage clean and hygienic, the cage should be replaced in time. Change every 10 days in summer and autumn, and every 50 days in early spring and winter. The replaced cage should be cleaned immediately for next use. 5. Daily management carries out group management to the cage. Check the water quality every day and record the meteorology, water temperature, pH value, bait, disease prevention and so on. Observe the feeding and growth of eels, find problems and deal with them in time. Good water quality is the key to prevent the disease of eel. If the water quality in the cage is polluted and not ruled out, rotten gills, rotting tail and high temperature period of "crazy running disease" and various parasitic diseases may break out. Keeping the water body under the effective control of beneficial microbiota is a necessary condition for the success of eel culture. When there are symptoms such as bacterial Gill rot disease, the diseased fish can be diluted with 100 times high concentration of EM, or the affected part can be directly rubbed with 10 ~ 50 times of ultra-high concentration of EM, which can be cured in 4 ~ 5 days. When bacterial enteritis occurs, high concentration EM dilution can be used to mix feed immediately, and the effect is very good.