#Agricultural Technology Science Competition #Rural low-cost small cage eel farming method
Small cages for eels
Sources and selection of eel seed stocks
(1) Sources of eel fry. In order to save costs and improve the survival rate, the sources of Huangyi seed are mainly from the following two types: first, fishing from natural waters; second, buying directly from nearby markets and buying those farmers who catch themselves to avoid physical injury.
Due to the presence of sexual metastasis, fresh fish with a body length of 53 cm are generally males. The smallest female individual carries only a few dozen eggs, and the largest egg is less than a thousand, so the artificial reproduction of the yellow catfish cannot form an annual reproductive capacity of tens of millions and hundreds of millions of fry like other fish, and the current yellow seed is mainly obtained from the latter two sources. Several methods of harvesting and rearing fresh fish fry are described below.
Eel eggs
(1) Collect fertilized eggs to breed eel seeds. Yellow eels mostly lay their eggs at night or early in the morning after thunderstorms. Broodstock first spit out a large amount of white foam outside their burrows as a nest, and the female lays eggs in the foam, and the number of eggs varies from dozens to three or five hundred, and the eggs are round and large, yellow. Yellow eels generally choose to lay eggs in sheltered burrows with aquatic grasses, grass seedlings and shelter, and the foam nest can be maintained until the eels hatch out of the membrane before disappearing. In the event of a strong wind or current, the egg will sink to the bottom of the water near the mouth of the cave. During the spawning season, small gauze nets can be used to carefully search for and collect piles of fertilized eggs along the edges of rice fields and ditches, and then place fertilized eggs in water basins and buckets for indoor incubation. Change the water 1 to 2 times a day, do not use tap water to prevent chlorine poisoning. After 6 to 7 days, the eel seedlings can be released from the membrane, and after 5 to 7 days of temporary rearing, they can be eaten. Feed cooked egg yolk pulp or zooplankton such as rotifers, twigs, copepods, etc. When it grows to a size of more than 3 cm, it is transferred to the eel seed pond for cultivation.
Eel seed ponds are generally 6 to 10 square meters of cement ponds, the depth of the pool is 50 to 60 cm, the water depth is 20 to 30 cm, the bottom of the pool is covered with a layer of 10 cm thick fertilizer, and each pond is subjected to decomposed pig manure, chicken manure and other organic fertilizers (must be decomposed, or easy to produce diseases. To cultivate natural food creatures, feed water earthworms, fly maggots, terrestrial earthworms, etc., to ensure that the bait is sufficient. It is particularly noteworthy that in the high temperature season, it is necessary to shade the sun to avoid the heat, and pay attention to timely water change and disease prevention, and you can grow an eel species weighing more than 10 grams in that year.
Freshly hatched eel seedlings
(2) Collect eel seedlings to cultivate eel seeds. Newly hatched eel seedlings are generally concentrated in rice fields, ditches and other waters, black clumps, which can also be collected by gauze mesh, and then placed in different eel seed ponds according to individual size and different batches. After the eel seedlings open their mouths to eat, they begin to disperse the activities, at this time, they can be mixed with decomposed pigs and cow dung and a small amount of fertilizer mud and kneaded into small rounds and placed in the seedling pond, forming a small fertile area to cultivate water earthworms, and the small eel seedlings will drill into these fat tuotuo to forage. If the number of eel seedlings is large, it is also necessary to add live bait.
(3) Piling grass to trap eel species. After the rain, some aquatic plants or weeds are piled up and placed in the dark place by the water's edge, and after a few days, when the yellow eel is drilled into the grass pile, the grass pile is covered with a small net made of mesh, and the net is immediately lifted out of the water, and then the weeds are gradually removed, the eels are left in the pocket, and the eels can be caught in the basket.
(4) Cage fishing likes species. Yellow eel cages, also known as eel cages, are cylindrical devices for catching fresh fish woven from bamboo grates or made of plastic, which are sold in the bazaar and can also be prepared by themselves. The yellow eel cage is 60 to 80 cm long and 10 to 15 cm in diameter, and there are mouths at both ends of the cage, one end is the inlet, the other end is the cover, and the inlet is equipped with a flared whisker, making the yellow eel easy to enter and difficult to exit. Yellow eel cages can also be imported at both ends, with the cage body in the middle. According to the daily life habits of eels, select lakes, ponds, ditches and other waters with yellow eel activities to release cages, and put a little poultry offal, eggshells, mussel meat, earthworms and other baits in the cage in advance, and also catch some fireflies in them and put them in bear fish cages, so that the cage hunting effect is better. The yellow eel cage is arranged along the water with the access of the yellow eel at 7 to 8 o'clock in the evening, near the roots of the trees near the water, the edge of the stone, the culvert and the place where there is aquatic grass. When placed, the rear end of the cage should be exposed to the water, accounting for about 1/4 of the yellow cage, to prevent the eel from suffocating due to lack of oxygen. Then cover the surface of the yellow eel cage with some aquatic weeds, so that the eels will enter the cage at night to feed around, and the next morning at 4 to 6 o'clock to close the cage, you can catch a lot of yellow cymbals, generally a yellow cage can catch a few tails to dozens of tails a night. The large individual yellow eel is sold, and the small individual is used as an eel species. The eel species caught by this method are in good health and have a high survival rate. (5) Catch with your bare hands at night with a lighting lamp, patrol along the edge of fields and ditches, find fresh fish that come out to feed, catch them with eel clips (this method is not advocated) or catch them with bare hands. Individuals used as eel species should not be damaged when captured.
Both caged and bare-handed individuals must be domesticated over a period of time before they can be used as eel species. After the catch of eel species is strictly selected, it is kept in separate ponds, and the specifications of eels stocked in the same pond are the same to prevent large fish from eating small fish. When domesticating, it can be placed in a container containing a small amount of water for temporary breeding, change the water once a day, change the water 2 to 3 times a day when it is hot, and then put it into the eel pond after the temperament of the carp species is stable.
Piles of eel seedlings
(2) Seed selection Selecting good eel seeds is crucial to yellow eel culture. At present, there is no supply of large-scale propagation of yellow eel seedlings, and eel species still rely mainly on natural wild resources. Taking the Yangtze River Basin as an example, there are three main varieties of yellow fresh.
Dark yellow-spotted eel
(1) Dark yellow eel. Slender body, round body, body shape standard, dark yellow body color, accompanied by brown-black large markings, dark yellow large spot strong adaptability, fast production speed, large individual, better fresh meat quality, breeding effect better weight multiplier up to 5 to 6 times.
Pale yellow fine spotted eel
(2) Light yellow fine spotted eel. The body shape is also more standard, the body color is light yellow, the brownish black markings on the body are more fine, the ability to adapt to the environment is stronger, and it is easy to raise, but its growth rate is not as good as that of the dark yellow eel. The weight gain multiple can reach 3 to 4 times.
Blue-gray eel
(3) Blue-gray eel. The body color is bluish gray, and there are also fine brown-black markings on the body, its ability to adapt to the environment is relatively weak, the growth rate is slower, and the weight gain multiple of the small size of the eel is only 1 to 2 times.
When choosing an eel species, consider the seasonal season. It is best to choose the yellow eel seed with no injury, strong mobility, strong physique, relatively neat size, yellow color and large spots, and the body color is blue and yellow and has not been temporarily raised for a long time in May to June and August to September of each year, the water temperature and outdoor temperature are generally 20 to 28 °C, and the survival rate of yellow eel seedlings at this time is high. Do not buy seeds in hot summers and harsh winters. As much as possible, individuals caught through eel cages are acquired, and medicinal eels, hook-fishing eels, electric eels, sick eels and injured eels cannot be used as eel breeds. In order to ensure the quality of the purchased eel species, the deep-water pressurization method can be used when purchasing eels, and the survival of the fittest can select eel species. When purchasing, it is found that most of the yellow eels in the water are tilted over, the body color is red, and the paralysis is weak, so do not buy. Hook-fished yellow eels have internal injuries in the throat or damage to the body surface, are prone to water mold disease, do not eat, have a low survival rate, and cannot be used as a seed. Whitish, dull, and thin individuals cannot be used as eel species.
Eel seeds should be purchased as close as possible to avoid long-distance transportation, and people are accustomed to loading with containers such as buckets, bamboo baskets, baskets and so on. The basket is covered with a non-toxic plastic film at the bottom, and a small amount of fresh aquatic grass and 6 to 10 loach are added. When the temperature is high or the time exceeds 1 hour, add an appropriate amount of amoxicillin, oxytetracycline or ginger water to the transport water body to prevent yellow eels from intertwining with each other.
When selecting species, it is also necessary to pay attention to the selection of yellow eels in areas where geography, natural and climatic conditions are closer to the breeding ground, so as to better adapt to the local breeding environment and avoid the phenomenon of "water and soil dissatisfaction" as farmers say.
(3) Eel breeding selection to put a good four levels. After the stocking of inferior eel species, the incubation period of death is 7 to 15 days, and the highest mortality rate can reach more than 90%. Among the many breeding failures, more than 80% are caused by seed quality problems. Farmers selecting fry, it is best to buy them directly from the hands of eel catchers, and the capture time should not exceed 3 days, or they go to the wild to fish, so that the temporary breeding time is short, the trafficking links are few, the quality is good, and the survival rate is high. Generally, the following 4 links should be done well.
(1) Check the body color. The dark yellow eel is the preferred species for the development of artificial cultivation of yellow eel in mainland China, followed by the light yellow fine spotted eel, which has a large population, is convenient for harvesting, and is also an important source of artificially farmed eel species. The cultivation effect of blue-gray eel is not as good as that of dark yellow eel and light yellow fine spotted eel, and generally do not do artificial breeding.
(2) Check the source of eel seeds. The source of eel species in natural waters is either purchased from the market and harvested by themselves. The main fishing methods of eel species purchased in the market are cage fishing, electric fishing, drug fishing, hook fishing, needle fork and freehand capture, but only caged and freehand caught and in a temporary state of robust and harmless eel species can be purchased. When purchasing seeds, it is necessary to understand in advance what kind of way the eel seeds are captured, and it is best to buy them directly from the collectors to avoid intermediate links.
(3) Check from the selection method. Due to the large number of eel stocking, it is impossible to select them one by one, which is both delayed and easy to cause eel injuries. Here are a few ways to screen eel species.
First, sensory screening. It is to screen based on your own vision and experience. The eel breed is healthy and lively, can look up and struggle strongly when caught by hand, and the eel muscles are tight and are high-quality eel seeds. If the body and tail are twisted, erythema, redness and swelling, and the soft body of the eel is weak when caught by hand, it is inferior eel. High-quality eel species are decently smooth and rich in mucus, sick and poisoned yellow eels, whole body or local mucus shedding or decreasing, hand grasping no smooth feeling or smooth feeling is not strong, or lifting yellow eels, mucus obviously shedding, because once the yellow eel loses the mucus that plays a barrier role, it loses its vitality. For sick eels, they should be treated, and only after recovery can eels be made. For example, the surface of the eel has obvious red blood-clot rot lesions, which is rotten skin disease; the tail is white with flocculent villi, which is water mold disease; the head is generally thin, and even stiff and curly, trembling, which is a parasitic disease in the body. The anus is red, swollen and inflamed, prominent, and is an enteritis disease. Eels with such diseases should be removed when selected.
Second, the flowing water screening method. Fresh fish like to act against the water, with the appropriate force to stir the water in the eel pond in a certain direction, the eel fry swim against the water, free movement, that is normal eel; if it follows the current, unable to swim for the quality of fresh seedlings. If the stocking specifications are small or the number of stocking is not large, you can put the eel seed into a plastic pot, add half a basin of water, and use your hand to spiral in a certain direction to form a whirlpool, the eel species with poor physique are generally in the middle of the vortex, and the eel seed with good physique has a strong ability to reverse the water, on the edge of the pot, remove the eel seed in the middle, and release the eel seed on the edge.
Third, the behavior screening method. It is screened according to the clustering of eels. In the soilless pool, the eels drill into the four corners of the rectangular pool in groups of good quality eel species, and those who swim alone and are weak in activity are inferior eels. Strong ability to escape healthy yellow eel, when grasping the hand feels that the yellow eel body is hard, and has a larger ability to escape; the hand grasp is that, soft and weak, the two ends are sagging for unhealthy yellow eels.
Fourth, the slapping screening method. It is screened according to the characteristics of wild eels that are usually less alarming. When screening, use shallow pots to hold eels, and then tap the edge of the pot, good quality eels will jump out, those who can't jump or don't jump are inferior eels, but the injured and parasitic eels also jump out, so carefully identify and screen.
Fifth, the water pressure screening method. Put half a bucket of eel seeds in the fish bucket (yellow eels only account for 1/3 of the volume), fill the water with water and cover the lid, after 10 to 15 minutes, open the lid, observe the activity of the eels in the bucket, floating on the surface of the water, the head protruding from the water surface is poor oxygen tolerance, weak physique, injury and disease of the eel species, to be eliminated, sinking into the bottom of the box to be retained and stocked.
Sixth, brine soaking screening method. With 3% to 5% of the salt water soaked for selection, within 4 to 5 minutes the body injured and sick eel species will jump violently, poor physique of the eel species will be comatose, weak and deformed, these fresh seeds as commercial fish treatment, in the brine normal activity of the eel species for stocking. This method is easy to cause secondary injuries to yellow eels and should not be used frequently.
Seventh, the acupuncture screening method. It is screened according to the characteristics of the eels living in the cave. The eel seed is put into the water body with soil or aquatic weeds, and the fresh species that drill into the cave or aquatic grass in about 2 hours are good eel seeds, do not drill holes or do not drill grass, or drill bits do not drill tails, or drill in and come out again, most of them are bad eel seeds.
Eighth, the feeding screening method. Screening is based on whether the feeding of the eel species is normal or not. Eel species are generally not fed for the first few days after fishing, transportation, etc., and are fed 2% compound feed (3% yellow mealworms, 5% earthworms or 8% ground fresh fish meat) after opening feeding, and when the water temperature is 20 to 28 ° C, if you can eat more than half of the feed within 2 hours, you can be regarded as a good quality eel species.
Finished eel
(4) Check from the transportation method. It is generally transported in wooden or plastic barrels. Below the water temperature of 25 ° C, the barrel with a capacity of 50 kg can be loaded with 25 kg of seed, change the water every 4 hours, the temperature difference between changing the water should not exceed 3 ° C, and often stir from the bottom of the barrel by hand to prevent the weak constitution from being injured at the bottom of the barrel for a long time. The best thing to do is to put about 1 kg of loach in each bucket and avoid entanglement of the yellow eels due to the loach swimming.
(4) 4 square meters of small cage eel culture technology
The 4 square meter small cage with its artificial easy control, small range of yellow eel activities, fast growth, short cycle, high survival rate, less investment, convenient catching, high efficiency, in many parts of the mainland has been widely promoted, representing the development direction of intensive breeding of yellow eel, is the first choice for farmers to get rich and well-off.
(1) Water body requirements. Ponds with cages require sufficient water sources, no pollution, convenient inlet and drainage, an area of 3 to 5 acres, and a water depth of 1.0 to 1.5 meters. The total area of the cage shall not exceed 50% of the area of the pond water.
The cage is now set up
(2) Cage setting The cage size is 2.0 meters × 2.0 meters, the box height is 1.2 meters, and it is made of polyethylene nodular mesh pieces of 0.3 to 0.5 to 1.0 cm. The cages are set up in separate rows, using cement columns with a side length of 25 cm and wires 0.5 cm thick to be fixed in the middle of the pool. The interval between the boxes is 1 to 2 meters, the underwater part is 0.7 meters, and the water part is 0.5 meters. The small cage of 4 square meters increases the yield per unit area, reduces the management cost, and only 1 person can complete the operation of clearing and washing the box on the small fishing boat, which has brought fundamental changes to the management of eel farming.
(3) Preparation before stocking. The cage is watered 5 to 7 days before the eel seed enters the box, and the newly made cage is soaked in water for about 15 days to make the toxicity of the cage disappear, and a layer of biofilm is formed on the box to avoid abrasions of the eel seed. Water peanuts are then stocked in the box, covering about 80% of the cage area, aiming to purify the water quality and provide a hidden shade for huangyi.
(4) Eel seed sources and stocking. Eel species to dark yellow large spotted growth fastest, stocking time selected in the dragon boat festival after the middle and late June, the temperature and water temperature is relatively stable, the most important thing is the weather, if the stocking of eel seeds before and after the 3 days is sunny, the survival rate of eel species will reach more than 80%, to avoid its current stress reaction. The feeding specifications are 10 to 20 grams of tail weight and a density of 20 to 30 tails per square meter, and it is appropriate to note that the larger the ray species, the lower the survival rate. Fresh seed sources are artificial breeding and eel cage capture.
In the transportation process, every 50 kg of yellow eel should be soaked in 100 grams of vitamin eel life water, long-distance transportation should reduce the number of water changes, it is best not to change water, can improve the survival rate. Before disembarking the box, select the active and robust individuals by the pressurized water method, and then soak in 0.2% to 0.5% of the electrolytic multidimensional for 10 to 20 minutes before entering the box. After the seed is released, the food is stopped for 5 to 7 days, and the first day of the stop period is used to splash the box with eel life, and the next day, the whole pool is sprinkled with chlorine dioxide + 100 blood stop, which can significantly improve the survival rate of eel seeds. Excessive changes in ambient water temperature (±2°C) or long transport times should be avoided.
eel
(5) Feed feeding. After 5 to 7 days of eel seeding, the use of earthworms or water earthworms as open feed can make the eel seed open for feeding earlier. Then the small trash fish, snails, snakes, mussel meat, etc. are mainly domesticated for 3 to 5 days, and after successful domestication, they can be transferred to regular feeding. The main feed is silver carp surimi and eel granule bait (mass ratio 1:1 ~ 2:1) stirring material, appropriate addition of vitamins. The feed coefficient of live fish such as silver carp and small trash fish is 6 to 8, and the feed of compound feed is 1.5 to 2.4. Feeding successfully domesticated yellow eels with pelleted bait soaked in fish blood water increases lures. The amount of feeding is generally 2% to 8% of the body weight of the yellow eel, and the specific daily bait amount is flexibly grasped according to the weather, water temperature, water quality, and the activity of the yellow eel, and it is generally better to feed for about 2 hours. Feeding times are generally carried out about 1 hour before sunset every day. After October, the water temperature gradually lowered, and the bait time of yellow eels was gradually advanced to the afternoon when the temperature was high.
(6) Daily management. Insist on morning and evening inspections. Always carefully check the box for being bitten by water rats, and patch up any loopholes in time. Regularly fish out too many water peanuts in the cage to prevent water splashes from growing out of the box and the phenomenon of escaping eels on rainy days. Pay attention to changes in pond water level, especially in summer when it is raining heavily or high temperature and drought, the cage position should be adjusted in time.
The quality of the water directly affects the feeding, growth and occurrence of diseases of yellow eels. July to August is the best time for yellow eels to feed and grow, with the increase of feeding, excrement increases, especially the breeding of vegetables in the cultured water body is too much, and the water quality is very easy to deteriorate. Depending on the water temperature, weather, feed, feeding conditions, new water is injected or exchanged regularly. The amount of water exchanged at a time is generally 1/3 of the entire aquaculture water body, and the farms with good water source conditions generally change the water once every 2 to 3 days, and add new water away from the breeding cage, so as not to exchange a large amount of water bodies, so that the yellow water has a stress response and affects the growth.
A disease of eels
(7) Disease prevention and control. After the normal feeding of yellow eels, use 100 grams of compound albendazole powder mixed with 30 kilograms of yellow fresh material to feed once, which can completely kill the parasites; after that, every half a month every 50 kilograms of fresh fish with vitamin life 100 grams + stomach powder 100 grams + 2.5% norfloxacin powder 100 grams mixed with 25 kilograms of yellow fresh material feeding for 3 to 5 days. The yellow cattail fed artificial pellets should be fed health powder and fed hepatoprotectine in August to September. During the high temperature season from July to September, when the water temperature exceeds 30 °C, pay attention to adjusting the water temperature, reducing the amount of bait or stopping feeding. Bacillus or E. bacteria are administered every 10 to 15 days to reduce ammonia and nitrogen in the water.
Yellow eel diseases include bacterial diseases (including hemorrhagic disease, enteritis, rotten tail, large head disease, etc.) can be taken internally enrofloxacin powder or with chlorine dioxide 100 blood stop box or whole pool spilled; stress diseases (including grass, whirling, madness, cold, etc.) can be taken internally. Focus on prevention and prescribe the right medicine.
(8) Harvest. After 5 to 6 months of rearing, the eel seed increases by 5 to 10 times, and the smaller the individual, the higher the weight gain. Each cage can produce more than 100 grams of individual commercial eel about 20 kg, the price is 70 ~ 80 yuan / kg, deducting various costs of 30 ~ 40 yuan / kg, the profit of single-port cage is about 800 yuan, the benefit is still quite considerable.