Culture techniques of Monopterus Albus

Eel belongs to the genus Monopterus, also known as Monopterus Albus, Monopterus Albus

Construction of eel pond

1. Cement pool area

It is appropriate to take 30 square meters to 50 square meters, the surface and bottom of the pool should be polished and smooth, so as to avoid the infection of bacteria and viruses caused by the skin scraped by eels during activities. The top of the pool should be about 30 centimeters above the water level, and a natural overflow outlet should be set. The outlet is fixed with a net to prevent the rice field eel from escaping. There are two ways of raising eels in cement ponds: soilless and soilless, both of which should be planted with water peanuts or water hyacinth, adjust the water temperature and provide rest for eels in the hot season, but only a small part of the eel can be left in the whole pond. If there is soil culture, it is suitable to spread 20 cm ~ 30 cm soil, and the water level above the mud layer should be kept at 20 cm ~ 25 cm. If the water is too deep, the eel will consume too much energy in the activity, and if the water is too shallow, the water body will be easy to become turbid and the water temperature will change greatly. If the water level of soilless culture is kept at 30 cm ~ 40 cm, the advantage of this culture model is that the disinfection effect of water body is good, while in soil culture, it is difficult to act on the bottom of soil during disinfection, and it is easy to breed various parasites and their intermediate hosts, such as leeches, flat leaf snails, vertebral snails and so on.

2. Rice field culture

First dig up the soil of the paddy field, bury the cage, and then put the soil back into the cage, fix the four corners of the cage, and plant water peanuts or water hyacinth with an area of 20 ~ 30 square meters. Rice and other crops with rough and developed roots should not be planted in cages, because eels have the habit of drilling soil and are easy to scratch the epidermis.

3. Net culture in various ponds, lakes and reservoirs

That is, the cage soilless culture, the area of 15 square meters to 20 square meters is appropriate, so as to facilitate disinfection, treatment, disease can be directly put into the cage and fish in a large disinfection container. Aquatic plants such as water peanuts or water hyacinth should also be cultivated in the cage for eels to rest.

The area of the above culture models should not be too large, which will easily increase the difference in the size of eels in the process of culture, which is disadvantageous to the growth.

Eel seedling selection

Should choose yellow and black spots large and dense eel species, this kind of eel species grows fastest; yellow, small and irregular spots grow generally; yellow and black grow slowly; black or black grow the slowest, but this kind of seedling is relatively ferocious.

When selecting seedlings, we should pay attention not to select the seedlings with injury, electric shock, fishing and trap, but choose the seedlings with health, strong vitality, strong swimming ability against the current and quick reaction by gently touching its tail end. The seedlings with the same size and specification should be selected when selecting seeds, because the eels eat each other, especially when the bait is insufficient.

Effects of water temperature and ph on eel

Monopterus Albus is very sensitive to the change of water temperature. The suitable water temperature for growth is 15 ℃ ~ 30 ℃. The activity is the strongest, the growth rate is fast and the feed utilization rate is high at 28 ℃. During this period of time, we should pay attention to the feeding of feed so that the eels are full. When the water temperature is lower than 15 ℃, Monopterus Albus does not feed and goes into hibernation. Therefore, in the north of the Yangtze River, when the water temperature is unstable in April, do not add water or bait to the pond to lure the eel out of the hole, so as not to cause eel disease due to great changes in water temperature. The eel can spend the winter by wet method, which is as follows: first, dry the water and keep the soil wet; when it is cold and snowing, a layer of straw or hay can be added to keep warm to prevent icing; the method of overwintering in deep water can also be used, but there is a disadvantage. When the weather warms up in the second year, the eel will come out of the hole to look for food, but the eel is easy to catch cold and other diseases because of the unstable weather and water temperature at this time.

The pH value is also called pH. In the process of feeding, if the dissolved oxygen is insufficient, the oxidation process is inhibited, and the food residue, organic matter and excreta gradually accumulate and decompose insufficiently, the pH value decreases due to the accumulation of organic acid, which affects the growth of eel. Therefore, in the process of culture, we should pay attention to change fresh and clean water. Because eels like clean water quality, we should pay attention to changing water frequently and determining pH value at ordinary times. Eels are generally suitable to live in neutral or weakly acidic waters (pH values are between 6, 5 and 7, 2). Pay attention to the weather and water temperature when changing water. 3 cm ~ 5 cm is suitable for each change of water, and it is appropriate to slowly put in fresh water and then slowly discharge old water. The season of onset should also be treated in the same way. Because the water is changed too quickly, it is easy to cause a large temperature difference, which makes the eel catch a cold.

Fish pond management

1. Disinfect the fish pond before releasing the fry.

The disinfection time should be about 10 days before the fry is released, because there may be residual poison in the fish pond too late, and it is easy to re-breed bacteria too early. During disinfection, the pool water is kept 5 cm ~ 6 cm high and sterilized with 90 g / m2 ~ 120 / m2 of quicklime. The next day after disinfection, it is best to mix the mud and lime milk with a rake to make it play a full role. During disinfection, new water is put in every 1-2 days, and the old water is discharged.

2. Disinfection and stocking of fish fry

In order to determine whether there is residual poison in the fish pond before stocking, 5 cm ~ 10 cm bighead carp or silver carp fry can be used as "test water fish" according to 2 / m2 ~ 3 / m2. If the fish activity is normal, the toxicity has disappeared, otherwise the stocking should be postponed. Disinfecting fish fry with 3% salt at 5% concentration for 10 to 15 minutes before stocking, or potassium permanganate of 2ppm~5ppm, can eliminate some pathogens and parasites and increase disease resistance. When disinfecting, it is best to carry out disinfection in a cool place to avoid sunlight exposure, and the time may depend on the appropriate increase or decrease in the physique of eel fry to see whether the fry is abnormal or not. after disinfection, it should be temporarily reared in clean water for stocking, and should be divided into ponds according to specifications when stocking, so as not to kill each other. It should also be noted that the water temperature of the temporary culture pond should be equal to that of the large fish pond (that is, the stocking pond), and the temperature difference between them should be less than 3 ℃. If the difference is large, the water temperature should be adjusted properly.

3. Feeding, management and growth

The eel begins to add some new water in the lower pond for about a week, and then add water once every 2 to 3 days, with 3 cm ~ 5 cm each time, so as to keep the water level at about 25 cm. When it is hot in summer, it is appropriate to increase the times of changing water. It is appropriate to discharge 3 cm ~ 5 cm each time, so as not to cause excessive temperature difference.

Keep patrolling the pool every day and find out the sick eels in time to analyze the cause (usually the sick fish do not enter the hole and float on the surface). Adhere to intensive breeding, feeding at a fixed time, fixed point, qualitative and quantitative. Usually disease prevention can be sprinkled with 1PPM bleach or trichlorfon 0, 2PPM whole pool (90% crystal type), disease prevention drugs should be prepared several varieties, often replaced, so as to avoid pathogens producing drug resistance.

The growth rate of eel is closely related to the nutritional composition, species and quality of bait. When small fish, shrimp, earthworm, clam and field snail are used in traditional culture, the freshness of eel is difficult to guarantee, and the eel is easy to deteriorate and get sick. Nutrients are relatively simple, basically protein-based, and the introduction of wild miscellaneous fish and other protein content is not high. The digestive organs of eels are weak, and eels are easy to get sick because of their weak digestive organs. Nutrients are relatively simple, basically protein-based, and the protein content of these wild fish is not high. The digestive organ of eel is weak, so it is not easy to digest and absorb, so it is not suitable for the growth of eel. In particular, chilled fish and clams are more difficult to digest and absorb, and are very easy to cause enteritis. Feeding earthworms is prone to a variety of parasitic diseases. Because earthworms live in wet, fertile soil, and all kinds of parasites like to reproduce and lay eggs in this environment, earthworms become intermediate infections of eels.

In order to improve the economic benefit, the larger size of eel seedlings should be selected to achieve the purpose of listing in the same year, so eels should choose to feed full-price compound feed with comprehensive nutrition and easy digestion and absorption. At present, there are three types of rice field eel formula feed on the market, namely, powder, granule and expanded feed, which inevitably have some shortcomings, such as easy to lose, pollute water quality, not easy to observe food intake, and so on. on the other hand, the expanded feed has good buoyancy, high stability in water, light degree of polluted water quality, easy to observe food intake, and the expanded material is sterilized at high temperature in the puffing process without carrying bacteria. It is the first choice in aquaculture feed. Farmers should choose good feed manufacturers and well-known brands to ensure product quality. at present, the expanded feed of Monopterus Albus "Yinxiang" and "Fuxing" on the market has been recognized by the majority of farmers.

Major diseases and their treatment

1. Hemorrhagic disease: the etiology is unknown and belongs to the nature of septicemia. Eels fed with earthworms are more likely to develop the disease, and it is easy to develop blood disease and enteritis because of parasitic diseases.

[symptoms] there is a blood-like fluid in the mouth, and the inverted fluid will flow out, especially after death. The body surface is covered with bleeding spots of different sizes, especially in the abdomen, the anus is red and swollen, valgus bleeding, sick fish often surface to take a deep breath, Hubei local farmers known as "vertical piles", constantly turning in circles, cutting open the belly, it can be seen that liver bleeding is enlarged, splenomegaly is purple, rectal bleeding.

[treatment] ① furazolidone 0, 2ppm~0, 35ppm were sprinkled in the whole pool (using furazolidone powder). ② take norfloxacin 5g / 100kg fish, mix with ingredients. ③ tobacco leaves were soaked in 250g warm water for 5 to 8 hours and sprinkled in the whole pool with 30cm / mu water depth. ④ Erythromycin 250000 units were washed with diseased eel. The above An and B can be used at the same time, and An and C can be used alternately every other day for 3 ~ 5 days.

2. Red skin disease

[symptoms] the sick fish move slowly and weakly, with their head sticking out of the water all day, local bleeding and inflammation, red plaques, most of the abdomen, severe epidermis decay, intestinal congestion and inflammation, which is different from hemorrhagic disease in that they do not know how to circle.

[treatment] ① 1ppm bleach solution was sprinkled in the whole pool for 3 days. ② Erythromycin to wash the diseased eel.

3. Enteritis: mainly caused by feeding spoiled ice fish clams or due to insufficient feeding and excessive hunger.

[symptoms] slow activity, no food intake, bluish black body color, emaciation, intestinal congestion, yellow mucus outflow, anal redness and swelling protruding, severe purple.

[treatment] usually 5 kg of allicin or Polygonum polygonum are used to prevent every 100 kg of fish. Every 100 kg eel plus mint 3 kg ~ 4 kg boiled water is sprinkled once / 7 ~ 10 days.

4. Capillary nematodes and echinococcosis

[cause] most of the worms fed with earthworms will occur, which are white and slender worms, which can easily cause enteritis.

[treatment] ① 90% crystal trichlorfon 0, 5ppm~0, 7ppm solution is sprinkled in the whole pool, and sufficient water should be prepared when sprinkling, because the eel is very sensitive to trichlorfon and dies in the whole pool if not used properly, and trichlorfon is prohibited from taking internally. ② was given levamisole 5 g ~ 7, 5 g × 6 days or albendazole in the same amount for every 50 kg eel. ③ copper sulfate + ferrous sulfate (5 ∶ 2) 0 and 7ppm mixture were sprinkled all over the pool to kill parasites.

6. Rotten tail disease: mainly due to insufficient bait, similar remnant food or self-harm, pick up the fish and wash with erythromycin or 1ppm bleach powder.

7. Coma: mainly due to hot weather, high temperature and shallow water, fresh clam meat can be chopped and sprinkled into the pond, or fresh cucurbit melon can be chopped and sprinkled into the pond.

8. Catch a cold: the water temperature is high or low, or suddenly a large number of water changes, resulting in fish dysfunction, death, maintain the water level, reasonable change of water.

9, fever: the main density is high, the weather is hot, the fish secretion is too much in the water, the oxygen consumption, the water quality is not clean, the bait residue or small fish, clam meat does not start to stink. The prevention and treatment methods include A changing water, B sprinkling with 0, 7ppm sulfate ketone or 25 kg water 300000 units of penicillin.

The feed of Monopterus Albus

Generally speaking, Monopterus Albus is mainly animal feed fish, and requires fresh feed, do not eat rotten animal feed. As far as artificial culture is concerned, the feed of Monopterus Albus should be based on animal feed and supplemented by plant feed.

1. Fresh animal feed

This kind of feed mainly includes earthworms, silkworm pupae, fly maggots, snails, clams and small fish and shrimp that Monopterus Albus likes to eat. Earthworms are the most popular feed for Monopterus Albus, with a dry body protein content of 61%, close to fish meal and silkworm pupae. What these feeds have in common is that they are high in protein and rich in nutrition, which are beneficial to the growth and development of Monopterus Albus, and are the main feed for raising eel in cage.

2. Plant feed

Monopterus Albus is mostly forced to eat plant feed. Its digestion is characterized by the effective digestion of animal protein, starch and fat, but almost indigestible to plant protein and cellulose. In large-scale breeding, a certain amount of plant feed is needed. This is because the eel in the artificial culture environment is easier to get food than the individuals in the natural environment, and eat more and eat well. Putting in a certain amount of cellulose-rich plant feed can promote the intestinal peristalsis and improve the feeding intensity of Monopterus Albus. A certain amount of wheat flour (which is also an adhesive), corn meal, bran, bran and soybean dregs are usually added to the formula feed.

3. Artificial compound feed

Feeding artificial compound feed is the trend of raising eel on a large scale. In recent years, experiments have proved that compound feed is suitable for Monopterus Albus culture. In general, the protein content of formula feed is required to be high, generally between 35% and 45%, or even higher. At the same time, it requires a certain degree of palatability. Of course, the proportion of animal feed in formula feed is still large. For example, Yu Jisheng's feed formula 1 of Monopterus Albus from Mingte Fisheries Research Institute of Macheng City in Hubei Province is as follows: fish meal 28%, bean cake powder 10%, earthworm (dried) 20%, cooked soybean meal 30%, blood meal 2%, blood meal 2%, corn gluten 1%, 5% calcium dihydrogen phosphate 3%, binder 5%.

4. Other feeds

According to the habits of Monopterus Albus, animal leftovers can be used as supplementary feed for artificial raising of eel, such as pig, cow lung and other viscera, but the freshness is good and can not be rotting and deteriorating viscera. There are also insects, and some people use black lights at the top of the cage to lure insects to feed the eel. Feed a certain amount of Loach and field snail in the cage, and use certain techniques to make them breed in the cage to become the live bait for eel.