1. Feeding habit: Monopterus albus is an omnivorous fish mainly eating meat, and autumn shade is a good bait. The water temperature in the eel pond should be kept at 15-28 degrees Celsius; Avoid heavy alkaline water and change the water the next day. Otherwise, it is not easy to raise. Monopterus albus generally can't swing food (poor eyesight). It lies at night, hides in the cave during the day and waits for hunting at the mouth of the cave at night. When the temperature and water temperature are high, it often goes out to breathe and hunt during the day. Most of the food intake is nibbling, and the eyesight is not developed. At night, it mainly relies on the developed olfactory folds of the front and rear nostrils to feel the diffusion of weak chemical molecules emitted by bait organisms passing through the water. In the wild, they mainly feed on aquatic insects and its larvae, large zooplankton such as rotifers, but also draught worms, tadpoles, young frogs, snails, mussels and small fish and shrimps, and they are addicted to terrestrial animals. At night, they often swim near the shore and even go ashore for food, preying on earthworms, grasshoppers and moths, and also eating organic debris, filamentous algae and phytoplankton.
Second, the breeding pond: it is best to choose a place that is sheltered from the wind and sunny, and the water source is convenient, so as to change water and drain water. The size of the pond should be determined according to the scale and quantity of aquaculture. Family farming can be 4-5 square meters or more than ten square meters wide. The depth of the feeding pond is1.5m. The inner wall of the pond is coated with a layer of cement. The upper half of the pool should be tilted slightly inward to prevent overflow. Monopterus albus likes to burrow, so the bottom of the pond should be covered with 30-50 cm thick fat mud, and some straw and animal manure should be infiltrated into the mud to increase organic matter, and then stones, broken bricks and other things should be thrown to artificially create the environmental conditions for burrowing. After the pool is paved, a water layer of about 15CM should be maintained above the soil, and a drainage ditch should be set at the level of the water level, and a water inlet should be set at the place opposite the drainage ditch slightly higher than the water level. The water inlet and outlet should be blocked with plastic mesh cloth or barbed wire to prevent escape. You can also use the old septic pits, septic tanks and abandoned biogas digesters in the garden next to the house for transformation and utilization. In order to keep the water quality in the pool fresh and the dissolved oxygen in the water body sufficient, the water should be changed every other day, and the number of water changes should be increased in summer and high temperature season. (Underground or semi-underground feeding ponds should be built in northern and cold areas)
Because eels have the habit of eat small fish, a big fish, they should be kept in separate ponds. Generally, it can be divided into parent eel breeding ponds, fry breeding ponds and adult eel breeding ponds (parent eel breeding ponds can also be merged). During the incubation period of adult eels (April-August), semi-rotten straws such as seeds or pods can be put in the pond for female eels to lay eggs. When they hatch young eels, they can all be caught and fed in another pond. The nursery pond is mainly full of fertilizer and water, and small insects such as Daphnia are cultivated for young eels to eat.
Three, te-yang.cn's aquaculture technology
1 .. Selection and stocking: fry stocking is an important link in eel breeding and production. In order to improve the artificial culture of eel, we should persist in solving the source of fry through multiple channels and adopt scientific culture methods to obtain better yield and better economic benefits.
(1) The source of seeds. It's also a good idea to buy or collect it yourself. In addition, it is also a good method to fish out the fertilized eggs of Monopterus albus and cultivate the larvae of Monopterus albus by artificial incubation.
① One is to buy eel species in the market; Choose strong and harmless eels. It is always in a state of changing water and temporarily raising eel seedlings caught in cages. Monopterus albus damaged by pesticides and those caught by drugs cannot be used for raising seedlings and stocking. The species of Monopterus albus can be generally divided into three types: the first type, with yellowish or orange body color, yellowish brown back, grayish white abdomen, irregular small black spots and fast growth, the largest individual is 70CM long and weighs 65438±0.5kg；; Second, the body color is bluish yellow, and this kind of eel grows generally; The third kind, with gray body color, fine spots and unpleasant appearance. Eel fry should be raised separately. The specification of eel species is preferably about 35 per kilogram, which is too small and has a low survival rate, so it can't be listed that year; The specifications are too large, the weight gain multiple is low, the unit net output is not high, and the economic benefit is low. However, this is not absolute, and market factors should be considered in stocking any kind of eel. If the price of large-scale commercial eels on the market is very high around the Spring Festival, farmers can also consider stocking large-scale eels.
② The second is to catch wild Monopterus albus seedlings directly from the wild. There are also two ways to collect wild eel fry: Method 1: Rising temperature in spring is the best season to catch eel species, and the habit of eel foraging at night can be used to catch them in other seasons. The best ways to catch seedlings are cage catching and hand catching. Eel cages can be used to catch in rice fields and shallow ditches every summer, especially in hot days or after thunderstorms, when eels come out for activities, there are more at night than during the day. Put it in the ditch in the field at night or after a thunderstorm, and you can catch eels in a few hours. When catching eels in eel cages, we should pay attention to two points: first, it is best to use earthworms as bait, and take eels once a night in each cage; Second, when the eel cage is put into the water, the tail of the cage must be slightly exposed to the water, so that the eel can breathe the air in the cage, otherwise it will suffocate or suffer from hypoxia. Take back the eel cage at dawn, sell the large eel fry, and keep the small one as an eel species. The larvae of Monopterus albus caught by this method are healthy and harmless, and the survival rate is high. Method 2: Light the lamp at night, patrol along the ridge and ditch, and find the eel that comes out for food, and catch it with eel traps or bare hands. Try not to damage the body of Monopterus albus when fishing. The captured eel fry should be released immediately.
(3) Semi-artificial propagation and seedling raising. That is, the fertilized eggs of Monopterus albus are caught in the wild and artificially hatched; Or self-reproduction.
Breeding habit of Monopterus albus: simulate the natural spawning environment in the wild and let it breed naturally in the breeding pool. Monopterus albus has a peculiar sex reversal phenomenon, and it is female from embryonic stage to sexual maturity. The sex of Monopterus albus can be judged by its body length: those whose body length is less than 20~35CM are all females; After laying eggs, the ovary gradually becomes the testis (the body length is about 22CM and it begins to reverse). The body length is 36~48CM elbow, partially inverted, and the number of male and female individuals is almost equal; Most individuals who grow to more than 53 cm are male.
Monopterus albus is mature at the age of two, and the individual with a total length of about 20CM can reach sexual maturity, and the number of pregnant eggs is about 200~400; Individuals with a total length of about 50CM have about 500~ 1000 eggs. The breeding period of Monopterus albus is relatively long, with May-August as the spawning period and June-August as the spawning peak period (the spawning peak period of Monopterus albus starts in the middle and late May and ends in the early June, but the spawning time and peak period are related to the water level change of Monopterus albus habitat. In case of dry year, its spawning and peak period will be postponed until the water level rises. Individuals who lay eggs are mainly in the early stage, and the weight of individuals who lay eggs in early August is less than 50g). Monopterus albus often lays eggs near its caves or in emergent plants and rocks. The cave structure is complex, which can be divided into front hole, back hole and bifurcation hole, with 3-4 exit holes. The hole is usually opened in a hidden place, and the lower edge of the hole is 2/3 submerged in water. The hole in the center of the paddy field is about 3-4 ㎝ deep from the ground and develops horizontally. The spawning place in the front hole is wide, and the back hole is narrow, and the length of the hole is about 3-5 times of the body length of Monopterus albus. Male and female eels often spit and nest outside the cave before laying eggs. The foam is located above the hole and accumulates into a nest, so the fertilized egg hatches in the foam on the water surface. If the foam is broken, the egg will sink. Eggs are produced in batches. Mature fertilized eggs are golden yellow, with higher specific gravity than water and no stickiness. Eggs are 2-4 mm in diameter and can swell to about 4.5 mm after absorbing water. In the process of laying eggs and hatching, both male and female parents have the habit of protecting eggs, generally until the yolk of eel seedlings disappears. The incubation period of fertilized eggs is long, and it takes about seven or eight days to hatch young fish. The whole length of the young eel just emerging from the membrane is about 13mm. At this time, its pectoral fin is covered with blood vessels. The pectoral fin is an important auxiliary respiratory organ in juvenile fish. When the total length reaches more than 30 mm, the pectoral fin gradually degenerates and finally disappears.
The fertilized eggs of Monopterus albus were collected in the field, and then artificially hatched to raise seedlings. Every summer, in some swamps along the lakeshore and in rural ditches and paddy fields, you can often see some foam balls floating on the water, which may be the hatching nest of Monopterus albus. When this phenomenon is found, it should be gently scooped up with a rice spoon or rice spoon in time and put into a basin or bucket filled with fresh water. Then, carefully put the eel eggs into the eel egg hatching nest to hatch. The management of incubation period is the same as that of artificial propagation incubation period.
Self-artificial propagation, incubation and seedling raising: at the end of each year, individuals with strong physique and yellow body color and luster are selected from artificially propagated adult eel seedlings, and they are concentrated in a pool rich in organic soil for wintering, and naturally spawn and breed in April-August (the peak spawning period is May-June) of the following year. When the water temperature in the pond reaches above 65438 05℃, the feeding of these eels should be strengthened. During the breeding period, we should pay close attention to the eggs laid by eels and the eels hatched. After finding the eggs, we can take them out for special incubation. When you find the seedlings, you should also take them out in time and put them in different pools to prevent the big eels from eating the small eels and killing each other. In the culture pond, organic fertilizer such as chicken manure can be used to cultivate plankton, and then eel fry can be put in to make the eel fry grow by eating zooplankton. If zooplankton is insufficient, you can help feed some cooked egg yolk slurry. Once young eels start eating, they can gradually disperse their activities.
In the future, Monopterus albus will be fished around 5438+ 10 every June, and the small Monopterus albus will stay in the pool and let it drill into the mud hole for the winter. At this time, the pool water should be drained to keep the soil moist. In cold places, a layer of straw can be covered on the pool soil to keep warm and prevent freezing. After the warm spring in the second year, the water is put into the pond, and the young eels come out of the hole to feed and become the breeding seedlings in the second year.
(2) The quality of fry. Strong physique, no disease and no injury, can be a seedling. Those scratched with hooks have a low survival rate after stocking, and even if they don't die, their growth is quite slow. So it is generally not suitable. When fishing eel fry, don't hook eel with wire. If you are in the market, you can't buy eel fry fed with saccharin.
(3) fry specifications. Generally speaking, 25g is the best seed size. 40 tails per kilogram is more suitable. The seedlings of this specification are neat, strong in vitality, high in survival rate, fast in weight gain after stocking and high in yield. Eel species are too small, with poor feeding ability and slow weight gain, so they can't make a profit in that year. In the same nursery pond, the specifications of the stocked seedlings should be neat, the size should be as consistent as possible, and the disparity should not be too great. It is best to raise seedlings of different specifications in different ponds to avoid competing for food and killing each other, which will affect growth and survival rate.
(4) There are many varieties of Monopterus albus, among which the strongest are green and yellow, and the yellow and strength on the spine are also excellent. In the development of Monopterus albus breeding production, we should gradually select the superior and discard the inferior, cultivate and use excellent varieties to ensure high yield and good benefit.
2. Stocking time and stocking density. The stocking time should be early, and it is best to stock the first batch of fished or self-bred eel fry in early spring. In early spring and April, Monopterus albus goes out for food. In April, the seedlings can be put into artificial eel ponds. Monopterus albus after wintering can only sustain life. After spring, it needs to eat a lot, with a large appetite and a wide range of eating habits. Therefore, it is necessary to release seedlings as soon as possible to facilitate domestication, start eating early and extend the growth period. Stocking density: It varies with the size of eel pond, the source of bait, the specifications of fry and feeding management. The stocking density of farmed Monopterus albus can be slightly higher, with 50-60 young Monopterus albus weighing 25g per square meter, that is, per square meter 1.5kg. Experienced people can put 80- 100 tails. If the stocking specification is large, the density can be reduced accordingly. On the contrary, it can be increased accordingly. In general, the stocking amount per square meter of family farming is. 1- 1.5 kg, and some loaches can be stocked in the pond. Generally, each kilogram of eel fry can grow into 5 10 kg of adult eel. The growth law of eel is that when the young fish can only grow to 20 cm, the female fish with 2 winter age will reach maturity, with a body length of at least 34 cm. The largest adult eel can reach 70 cm and weigh 1.5 kg. In artificial culture, the optimum water temperature is between15 and 280℃. When the water temperature is 25-33℃, 30 grams of Monopterus albus can gain 30-40 grams per month, but this growth rate can only be maintained for about 5 months. After 5 months, even if the climate is suitable, its appetite will not be strong, because it is already thick and short, and the whole obesity will reach the limit.
3. Feed source. Monopterus albus is a carnivorous omnivorous fish, and its feed can be obtained locally through multiple channels. One is to apply sufficient base fertilizer in the breeding pond. Culture cladocera, copepods, rotifers and benthos; Secondly, a part of crucian carp and shrimp with eggs are stocked in the culture pond to lay eggs and hatch larvae; The third is to raise snails or snails, mussels, etc. Can also be combined with the development of pearl culture, using mussel meat as bait; Fourth, put black lights on the aquaculture pond to trap moths, moths and other insects; The fifth is to use the internal organs of pigs, sheep, geese and ducks; Sixth, breeding (such as "Daping II" earthworm introduced from Japan) or digging earthworms and artificially breeding fly maggots. Seventh, when animal feed is insufficient, plant feed such as rice, flour and melon skin can be fed. The amount of feed is generally 350~500 grams of bait per square meter per day. It accounts for about 6~7% of the body weight of eel, and it can reach 14.3% in summer.
4. Feeding techniques. The feeding of Monopterus albus should adhere to the principle of "four determinations": first, determine the quality, do not feed rancid feed, and ensure that the feed is fresh and does not deteriorate; The second is quantification. The feeding intensity of Monopterus albus is directly related to the water temperature. Usually, the feeding amount is10% of body weight. In August, Monopterus albus has the highest feeding intensity and the fastest growth, and its daily feeding amount can be increased to 8%-10% of body weight. When the temperature reaches about 0℃, feed less or not. Generally, it should be checked 2 hours after feeding. If the bait has been eaten, it means that the amount of bait is insufficient and should be increased appropriately. If you don't eat it within a few hours, it means that the bait is excessive and should be reduced appropriately. Excessive bait will pollute the water quality and cause diseases. The third is timing. According to the living habits of Monopterus albus, it is better to feed it every evening. The fourth is positioning. In order to make Monopterus albus develop the habit of eating at a fixed place, so as to observe the eating situation and clean up the residual materials, a food table should be set up and fed at a fixed place. Eating tables are places where Monopterus albus compete for food. Eating tables should be appropriately dispersed and set up more.
In particular, at present, the fry of Monopterus albus mainly come from wild harvest, which is not suitable for the environment when it is first stocked. Generally, it does not eat artificially fed feed and needs domestication, otherwise it will easily lead to loss of appetite and reproductive failure. The specific domestication and feeding methods are: stocking eel species-don't feed them for a few days, let the food in their stomachs be completely digested, then release the pool water and add fresh water, and feed them at night. When feeding, the eel's favorite earthworms and mussels are chopped, piled into small pieces at the water inlet, and properly fed with water to produce micro-flow. The feeding amount of 1 time is 1%-3% of the body weight of the eel species, and if all of them are eaten in the morning, the feeding amount can be increased to 4%-6%. If you can't finish the feed that day, you should fish out the remaining feed and feed it the next day according to the feeding amount on the day of production. After normal eating, you can mix melon and fruit peels and bean cakes with easy sources in the feed, and at the same time reduce the induced feed. If you eat normally, you can add/ordinary feed every day, and you can feed normally in a few days.
Monopterus albus eats a lot, and its daily food intake can reach 14.3% of its body weight, so it must be fed adequately. You can eat eels smaller than yourself when you are hungry.
At the same time, attention should be paid to prevent ducks, wild animals, cats and rats from entering the pool to catch eels.
5. Prevention and treatment of major diseases
(1) Dermatomycosis: The cause is that the wound is infected with mold due to mutual biting of Monopterus albus or invasion of enemy organisms. Active spores of mold absorb nutrients from the skin of Monopterus albus, grow outward into cotton-wool hyphae, and spread rapidly on the body surface. The sick eel was born with "white hair", lost appetite, and finally died of emaciation.
Prevention and control methods: Before Monopterus albus enters the pond, clean the pond and disinfect it with quicklime. After the onset, fill the pool with a mixture of four ten thousandths of salt and baking soda.
⑵ Capillary nematodiasis: Capillary nematodes parasitize in the intestine of Monopterus albus, destroying the mucosal tissue of the intestinal wall and causing inflammation caused by other bacteria invading the intestinal wall. When the amount of parasites is large, it can directly lead to eel weight loss and death.
Control method: Before Monopterus albus enters the pond, clean the pond with quicklime to kill the eggs. After illness, according to the proportion of 5 grams of trichlorfon crystals (purity 90%) per 50kg eel, 1.5kg bean cake powder can be mixed to make granules for feeding. Other nematicides are also acceptable, and the feed should be what you like at ordinary times. )
⑶ Fever disease: The reason is that due to the high-density culture of Monopterus albus, the heat released by mucus secreted on the body surface accumulated in the water and fermented makes the water temperature rise sharply, and the dissolved oxygen decreases, which leads to the anxiety and entanglement of Monopterus albus and leads to a large number of deaths.
Prevention and control methods: a small amount of loach can be mixed in the pool to eat bait, and the loach can swim up and down to prevent the eel from winding. Fresh water should be replaced immediately after the outbreak, or seven ten thousandths of copper sulfate solution should be added immediately, with 50 ml per square meter of eel pond.
(4) Cold disease: The cause is that the water temperature injected with new water is too low, and it can't adapt to it for a while and dies.
Prevention and control methods: Before changing the water in the eel pond with well water or low-temperature spring water, it must pass a certain distance from the ground to raise the water temperature before injecting it into the pond. When the water temperature drops below 120℃ in late autumn and early winter, Monopterus albus begins to enter the cave for wintering. At this time, to drain the pool water, just keep the pool soil moist and cover it with a layer of straw to prevent the pool water from freezing.
Raising Monopterus albus is also one of the special aquaculture, and its economic benefit income is higher than that of fish farming. Therefore, in rural aquaculture, the number of households breeding Monopterus albus has been expanding in recent years, but many farmers breeding Monopterus albus have failed. There are many reasons for this. However, in terms of technical issues, to sum up, there are eight major problems as follows.
① Random purchase of seedlings: Many farmers buy so-called "artificially bred" seedlings or other so-called "high quality" seedlings from other places, which are actually collected wild seedlings. Due to unscientific operations such as temporary breeding and multi-link storage and transportation, the mortality rate of these seedlings is as high as 90%- 100%, so when purchasing seedlings, we must carefully investigate and identify them.
② Variety selection: Monopterus albus has dark yellow big spots, earth red big spots, light yellow small spots and blue-gray small spots. Only by choosing the first two kinds can it grow faster and artificial breeding can achieve ideal economic benefits.
(3) Mixed culture of large and small: mixed culture of the same pond size, eels are weak and even die because they dare not compete for food. When the bait is insufficient, the big eel swallows the small eel, so the big eel grows fast, but the total output of the pond is low.
④ The pool water is too deep: because there is no swim bladder in the eel, it can't float at will, and stay in different water layers to expose the water surface to breathe air. The pool water is too deep, so Monopterus albus often needs to swim to the surface to breathe, which consumes a lot of physical energy and affects normal life and growth. According to the size of Monopterus albus, the depth of the pond should be 10~ 15 cm, and the aquatic plants in the cage should fill the whole cage to provide good habitat and breathing conditions for Monopterus albus.
⑤ Fertilization in eel pond: The water in eel pond is small, and fertilization is easy to destroy the water quality and induce diseases, so "improving the water quality" is not worth the candle.
⑥ Ignore the cultivation of aquatic plants: Aquatic plants can prevent heatstroke, raise eel and purify water. An eel pond without aquatic plants cannot create a good ecological environment, and it is difficult to successfully cultivate eels, or it is difficult to achieve high yield and high efficiency.
⑦ Feeding vegetarian food: Some farmers feed Monopterus albus with vegetarianism such as wheat bran, vegetable cakes, bean dregs, rice and vegetables. Monopterus albus will be swallowed in a small amount when it is seriously hungry and lacks food, but the nutrition can not meet the needs of life activities of Monopterus albus, let alone grow and gain weight, which will lead to emaciation and death of Monopterus albus for a long time. Monopterus albus is a carnivorous fish with fierce benthos, so it should be fed with animal feed or full-price feed.
⑧ Frequent feeding: Because the bait is not guaranteed, farmers often change the bait types for feeding. Monopterus albus feed should have certain stability. If the feed type is changed suddenly, Monopterus albus will be difficult to adapt and refuse to eat, which will affect the normal production and growth.