Culture techniques and matters needing attention of eels with serpentine appearance

Eel is a general term for species belonging to the order Anguilla. Also known as eel, it is a kind of fish with the appearance similar to long snake, which has the basic characteristics of fish. In addition, eels have migratory characteristics similar to salmon. Eel is a fish, like snakes, but without scales, generally produced in brackish and fresh water boundary waters.

In recent years, eel prices continue to rise to present a stable state, eel aquaculture is one of the high-efficiency breeding species. Specific farming techniques and precautions are as follows:

I. Water quality environment

It is advisable to select open water surface, good water quality, low wind speed and water depth of more than 4 meters at low tide to set up net cages near the estuary. The water temperature is required to range from 8℃ to 30 ℃, and the current velocity is less than 1 m/s. The water area with the current velocity of 0.5 m/s is the best.

II. Net cage specifications

The suitable size for eel culture is 3 m ×3 m ×3 m or 6 m ×3 m ×3 m seamless net cage. Its mesh specification is: raise black eel, young eel 0.5 cm, cultivate eel 0.8 cm. A 1m × 0.5m × 1m multi-layer net rack is placed in the net cage as an eel rest platform, and a 15cm anti-escape net brim is reserved at the opening of the net cage to prevent the eel from escaping when the water is tight.

III. Seed throwing

Eel larvae are the best for stocking, and the density of feeding is 150 eels per square meter. If there are no young eels and black eel larvae are released, the density is 500 eels per square meter. Eel seedlings should be disinfected with a medicated bath before being put in to prevent infection.

IV. Feeding management

a. Water quality management

Water quality management for eel farming is particularly important, requiring seawater specific gravity of 1.01-1.02, dissolved oxygen of more than 5 mg per life, and pH of 7-8.5. In recent years, some aquaculture farms have obtained successful experience in regulating water quality, soaking feed, preventing fish diseases, etc. by using EM original dew produced by Sino-Japanese cooperation, and have obtained good economic benefits.

b. Feeding

Eel feeding should be done "four fixed". That is, timing: feeding once at 8:00 p.m. every day in early spring and winter, feeding once at 5:00 a.m. and 8:00 p.m. every day at other times; positioning: feeding on a fixed bait platform; quality: feeding complete compound feed added with special vitamins for eel; quantitative: the total amount of diet is calculated as the percentage of the total weight of eel, and the adult eel stage is 15%, the juvenile eel stage is 3%, the black eel stage is about 5%, and the high temperature and winter stage is 0.5%-1%.

c. timely box division

After a month or so of rearing, the density of eel increases greatly, and the individual differences are even greater. It must be screened in time and raised in boxes, separated according to physical strength and individual size. In the process of screening and box separation, careful operation should be carried out to avoid scratching fish bodies, prevent infection, and disinfect them with medicinal bath.

d. Replace the cage

In order to keep the net cage clean and hygienic, prevent diseases and ensure the smooth exchange of water bodies, the net cage should be replaced in time. It is replaced every 10 days in summer and autumn, and every 50 days in early spring and winter. The replaced net should be cleaned immediately for next use.

e. Daily management

The net cage shall be managed in groups. Check the water quality every day, and record the weather, water temperature, pH value, bait feeding, disease prevention and control details. Observe eel feeding and growth, find problems and deal with them in time.