What are the methods of raising eel?

Monopterus albus has strong adaptability, hypoxia tolerance, hunger tolerance, convenient transportation, simple breeding method, low cost and high economic benefit, and is suitable for small-scale family farming. The following are the methods I have carefully arranged for you to raise eels. Let's have a look.

Method of raising eels

1, cage culture of Monopterus albus

Cage culture of Monopterus albus is still in the technical development stage. Cage culture is suitable for large water bodies. The main advantage is that the water flows through the mesh to form a living water environment in the box, so the water quality is fresh and the dissolved oxygen is rich, and high-density intensive culture can be implemented. The main cultivation techniques are as follows:

The net cage covers an area of about 20 square meters, with a net length of 5m, a net width of 4m and a net height of 1m, with a surface part of 40cm and an underwater part of 60cm. Mesh quality should be good, mesh should be dense and mesh should be tight to prevent eels from escaping from being bitten by rats. The cage is set in a pond with a water depth of more than 0.8m, and the harmful substances emitted by the newly made cage will disappear only after being put into the water for 35 days. A few days before stocking eel species, the water quality should be cultivated properly, so that the water color is thick and the transparency is about 15cm, which can control or reduce the invasion of ant mites on eel in the pond. Cages can be placed side by side in the pond, and a bamboo frame can be built between two rows of cages for people to walk and feed. The installation area of cages should not exceed 50% of the total area of ponds, otherwise it will easily lead to the deterioration of water quality. Aquatic plants, preferably Alternanthera philoxeroides, should be placed in the cage, covering 90-95% of the cage area, providing a good environment for the growth and habitat of Monopterus albus.

Monopterus albus has the habit of eating each other, so it is advisable to keep the specifications basically the same when stocking. Generally, 20 kilograms of eel species can be raised per square meter, and 400 kilograms can be raised per cage.

It is difficult for Monopterus albus to change its habits after eating one kind of feed. It is necessary to fix several kinds of feed, such as earthworm, small fish, clam meat or animal viscera, to improve its growth rate. Live bait can be put when conditions permit. Because of its high utilization rate, there is no need to remove residual bait, which has little pollution to the cage and is beneficial to the growth of Monopterus albus.

The most critical stage of cage culture of Monopterus albus is within one month after stocking. This period is a process in which Monopterus albus changes its original living habits and adapts to the new environment. If the method is proper, the survival rate of eel species can reach more than 90%. If the method is improper, the survival rate is sometimes below 30% or even completely dead. This month is the key to the success of cage culture of Monopterus albus. In addition to disinfection and domestication of Monopterus albus species, the occurrence of diseases should also be effectively controlled. The specific method is to disinfect water alternately with strong disinfectant and quicklime to prevent the generation of pathogens.

2, Monopterus albus plastic greenhouse soilless flowing water culture

Traditional pond culture is prone to diseases, and the hibernation of Monopterus albus affects perennial culture. Monopterus albus can be continuously produced in plastic greenhouse all year round, and soilless flowing water culture can effectively control diseases and multiply benefits.

The optimum growth temperature of Monopterus albus is 27℃ ~ 30℃. Using plastic greenhouse, no special heating device is needed, and the temperature in the greenhouse is easy to maintain in spring, summer and autumn. Even in cold winter, the average temperature in the greenhouse can reach 20℃.

The feeding pond keeps running water, and the water quality will not deteriorate.

There are two main ways of soilless flowing water cultivation in plastic greenhouses:

1 is already open. Suitable for building pools in places with warm running water all the year round. Its advantages are stable flow and suitability for large-scale operation. The feeding pond is a brick cement pond with an area of10 ~ 20m2, a depth of 40cm, a width of12m and a ridge width of 20 ~ 40cm. Two water inlet pipes and water outlet pipes with diameters of 3-4cm are arranged at the opposite positions of the pool. The inlet pipe is equal to the bottom of the pool; One drain pipe is as high as the bottom of the pool, and the other is 5 cm higher than the bottom of the pool. The inlet and outlet pipes are equipped with metal mesh to prevent escape. Arrange several feeding ponds side by side into a unit, and the area of each unit shall not exceed 500 square meters.

2 closed-loop filter type. Suitable for use in big cities or places lacking water. Its advantages are that the feed water can be reused, the water consumption is less, and the temperature is easy to control, but the investment is slightly larger. The construction method of the feeding pond is the same as that of the open type. In addition, it is necessary to build aeration tanks and sedimentation tanks, and add some water purification devices, pumping devices and heating devices.

Plastic greenhouses are built the same as ordinary greenhouses. It is best to put all units in the same shed for easy management.

The feeding method of soilless running water culture in plastic greenhouse was adopted. Because the water is clear, as long as there is enough feed, Monopterus albus generally won't escape. But we should pay attention to prevent the harm of natural enemies such as rats and snakes. After feeding for a period of time, the size of Monopterus albus in the same pond is uneven, so it is necessary to feed separately in time.

3. Rice field culture of Monopterus albus

Using rice fields to cultivate Monopterus albus has the advantages of low cost, convenient management, rice production and fish culture, and is an effective way for farmers to get rich and increase their income.

Selection and requirements of rice fields

Paddy fields with good water conservation benefits, low terrain and convenient water intake and drainage should be selected for breeding Monopterus albus.

First, heightening and reinforcing the ridge to prevent water leakage; Secondly, dig a group of ditches around the site, with a width of 5m and a depth of 1m, and dig a "+"or "well"-shaped ditch in the middle of the site, with a width of 50 cm and a depth of 30cm, so as to communicate with the surrounding ditches; Third, do a good job in the water inlet and outlet system, and install solid fish blocking facilities at the inlet and outlet to prevent fish from escaping.

Put in seedlings

The time is concentrated in the middle and late April, and the fish species are soaked in 3%-4% salt solution 10 minute to prevent skin abrasion and kill water mold and body surface parasites.

Feeding and management

First, do a good job in feeding feed. Monopterus albus is an omnivorous fish whose main food is animal bait. While preying on natural bait in rice fields, pig blood, small fish and shrimp should be properly fed according to the feeding situation to meet their feeding and growth needs; Second, do a good job in water quality management. The water level of paddy field should be kept at about 10cm, and fresh water should be replenished regularly, usually once every 3-5 days in the early stage and once in summer, and the water depth should be increased by 3-5 cm each time to prevent hypoxia. The third is to prevent and treat diseases regularly. Sprinkle quicklime or bleaching powder around the ditch once every half month, and feed it with furazolidone or fish blood powder regularly to prevent enteritis and other diseases.

Catch the winter

After more than five months of feeding and management, the standard tail weight of eel fry with a standard tail weight of about 50 grams can reach about 150 grams, and the big one can reach more than 200 grams. Grasping is relatively simple. In the early stage, eel cages woven with bamboo strips can be trapped with bait such as earthworms, released in the evening and harvested in the early morning of the next day. After winter, Monopterus albus has the habit of lurking in caves and shallow mud or aquatic plants. If you want to take it, first remove the aquatic plants, then raise the water level to lure the eel out of the hole, and then release the dry field water to catch it. If it is stored in the field for overwintering, the surrounding ditches should be kept at a certain depth or humidity, or the surface of the layer should be covered with a layer of soft grass to safely overwinter.

sex control

Sex control of fish is an effective method to increase yield. Generally speaking, sex hormones can induce the sex of Monopterus albus to develop in the desired direction.

More than 99% male fish can be obtained by treating eel fry with testosterone. The treated fish not only grows fast, but also can increase production by about 30% because of its single sex, fixed density and low cost.

The technology of gender control has been developed for many years abroad, and the technology is very mature. However, in China, this technology only stays at the laboratory level, there is no relevant report on production, and the corresponding national standards are not perfect.

Matters needing attention

1. Selection of fry: We must choose eel varieties with strong and harmless physique, lively swimming, neat specifications, large muscles, no parasites on the body surface and bright yellow body color. White skin, broken skin, broken tail and scars on the mouth and cheeks are not suitable for stocking.

2. Preparation before stocking: After disinfection and water injection in the eel pond, when the water temperature reaches above 15℃, eel species can be put in. Before stocking, eel species should be soaked in 10ppm bleaching powder or 3%-4% salt solution15-20min to kill their surface pathogens.

3, disease prevention and control:

1 "cold" disease. Because the temperature difference between fresh water and raw water is too large. As long as the water temperature is adjusted and stabilized, diseases can be prevented and treated.

Capillary nematodiasis Parasitic in eels, causing fish to emaciate and die, accompanied by edema and redness. Use 0. 1g 90% crystal trichlorfon per kilogram of Monopterus albus, mix it into feed, and feed it continuously for 6 days.

Plum blossom spot disease Eels have many plum blossom-shaped festering spots the size of soybeans.

Due to the high density of cage culture of Monopterus albus, when the feed is not enough, it will bite each other and cause mold infection, and "white hair" will grow on the body surface, and the sick fish will lose their appetite and die. The treatment method is to sprinkle a mixture of salt water and baking soda. In the case of sufficient feed, this phenomenon can not only be avoided, but also the phenomenon of mutual cannibalism will not occur even if the specifications of eel species raised in the same cage are quite different.

The feed for cage culture should be fresh, and the deteriorated feed should not be fed. Some rotten and smelly feed left in the cage should be removed in time, otherwise it will easily lead to enteritis. Treatment can be taken orally with sulfanilamide, furan or garlic. Before feeding, the feed should be washed, soaked in 200ppm potassium permanganate for 3 minutes, and then rinsed with clear water before feeding. If artificial compound feed is used, its protein content should reach more than 45%, and it is better to domesticate with fly maggots and earthworm meat.

6 In the process of fishing, transportation and stocking, eel species should avoid scratching as much as possible to prevent bacterial invasion from causing erythroderma. Symptoms are bleeding and inflammation on the body surface, especially on the abdomen and sides, which need to be disinfected by oral drugs and external drugs. Preventive measures: strictly disinfect eel fry when stocking. The specific method is to soak 50 ml disinfectant in 100 kg water for 30 minutes, or soak in 8% iodized salt water for 10 minutes, then put it in clear water for temporary cultivation 1 hour, then wash it with clear water and put it in a box.

In addition, water bodies should be disinfected frequently. For disinfection, quicklime can be used with the dosage of 100 ~ 150g/m3, malachite green copper sulfate 0.7g/m3 and bleaching powder 10g/m3.

4. When Monopterus albus is placed in a high-density container in cage culture, more and more mucus accumulates on the body surface, which rapidly consumes dissolved oxygen in the water through the decomposition of microorganisms in the water, leading to the death of Monopterus albus species. When eel species are put into cages, they sometimes intertwine with each other, and sometimes 100 kilograms of eel species intertwine together, causing a large number of eel species to die.

Preparations for breeding Monopterus albus

1, eel pond construction

It is necessary to choose a place with slightly higher terrain and convenient irrigation and drainage to build a pool, which can be built into an aboveground pool, an underground pool or a semi-underground pool. The area should be 30~50 m2, and the wall and bottom of the pond should be polished and smooth, so as to avoid the eel scratching the panel during the activity and causing various bacterial and virus infections; The depth of the pool is 80~ 100 cm, and the shape of the pool is generally rectangular, oval or square, and it runs east-west. Set up a natural overflow port, and the inlet and outlet pipes are firmly closed with barbed wire to prevent eels from fleeing. The top of the pool should be more than 30 cm above the water surface, and the top of the pool wall can be made into a "T" shape. The bottom layer should be paved with 20-30 cm river mud or loam made of grass and cow dung, and the water level above the mud layer should be kept at 20-25 cm. Aquatic plants such as Zizania latifolia, Alternanthera philoxeroides, Eichhornia crassipes and wormwood can be appropriately planted on the water surface of the pond13 to provide shade for eels, reduce the water temperature and improve the fish pond environment.

2. Seed selection and stocking

There are small wild eels caught in cages, which can also be bought from the market. However, to remove the eels with broken skin and tail, it is best to choose artificially propagated eels. The fry should be ricefield eel with strong physique, smooth body surface, strong activity and the same size. Generally speaking, large-sized eels weighing 20 g/ tail and 30~50 g/ tail can also be put in.

Before 15 d stocking, the mixed solution of 10mg/kg copper sulfate and 100mg/kg potassium permanganate was sprinkled on the whole pond, soaked for 7 d, and then replaced with clean water. Before stocking, in order to determine whether there is residual poison in the fish pond, bighead carp or silver carp fry with a body length of 5~ 10 cm can be used as "trial fish", and the ratio is 2~3 fish /m2. If the fish activities are normal, it means that the toxicity in the pond has disappeared, otherwise the stocking should be postponed. The stocking time is better in early spring and should be released within 1 week. The stocking amount is generally 1.5~3.0 kg/m2, and it can be put to 5~6 kg/m2 under good conditions. Before stocking the eel, soak it in 4% salt solution or 10 mg/kg bleaching powder 10~20 min to eliminate pathogens and parasites on the fry surface and increase the disease resistance. When stocking, attention should be paid to the temperature difference between the temporary breeding pool and the stocking pool, which should not be too large and should not exceed 3℃. If the difference is large, adjust the water temperature appropriately.