Techniques of cage culture of Monopterus albus in ponds and ditches

Ricefield eel is rich in nutrition, delicious meat, nourishing and health care, and is deeply loved by consumers. Raising ricefield eel has the advantages of low investment, short cycle, quick effect and high economic benefit, so it is a good rural sideline. Cage culture of eel by using existing fish ponds and river ditches does not affect the yield of conventional culture, but also can cultivate small-size rice field eel into large-size commercial eel, do not occupy land, save the cost of pond construction and increase the economic benefits of aquaculture. The specific conditions and methods of culture are as follows:

1. Ponds and ditches. The area of ponds and ditches can be 3 to 5 mu, and the average water depth in culture season is more than 1.5m. Fish species are kept in ponds and ditches as usual. The water quality of aquaculture water is good, no pollution, the pH value is about 7.2, the dissolved oxygen is rich and the transparency is high. two。 Cage specifications. The cage is 3m long, 2m wide and 1.5m high. The polyethylene mesh with good texture, dense mesh and tight mesh is adopted. The mesh size depends on the specification of cultivated ricefield eel, which is based on the principle of not escaping the eel and being beneficial to the exchange of water inside and outside the box. 3. Cage setting. There are 40 cages per mu in ponds and 30 cages per mu in river ditches. The distance between cages is about 3m. In the pond, each cage is fixed with 6 bamboo piles. Due to the great change of water level in the river ditch, floating cage is adopted to make the box rise and fall naturally with the change of water level. A week before the rice field eel was released, the newly made cage was soaked in water to attach a biofilm to the surface of the net coat to soften it so as not to get sick from body surface abrasions. Each cage is equipped with 1-2 tables, which are about 5 cm from the surface of the water. 4. Artificial transplantation of aquatic plants. When water peanuts are transplanted in the cage, the coverage accounts for about 80% of the cage area. This can not only purify the water quality, but also provide a hiding place for Monopterus Albus, which is beneficial to the growth. The transplanted water peanuts had better wash the roots and soak 10min in 50g salt water to prevent leeches and other pests from being brought into the box with the grass. 5. Stocking. (1) stocking of fish species. Clear the pond with quicklime before stocking the fish. 120kg quicklime is used in dry ponds per thousand square meters, and fish species are released after the medicine disappears, with an average of 60kg per dry square meter. The fish were soaked in 40g salt water for 15min before entering the pond. (2) Eel species are stocked. The free-range eel species are mainly wild seedlings caught in eel cages from rice fields, ditches and other waters, with an average weight of more than 30g and a large one of more than 100g. The specifications for stocking in each cage are as consistent as possible to prevent each other from eating each other. The eel species required for stocking are lively and robust, disease-free, injury-free, smooth and shiny. The body colors of eels are yellow, green and red. Yellow spotted eel is the best and grows fastest, followed by blue eel. In addition, 1-2kg Misgurnus anguillicaudatus was stocked in each cage, which partly increased oxygen by making use of the upstream and downstream migration habits of Loach. Misgurnus anguillicaudatus and yellow rice do not compete for food, which can not only remove the residual bait of ricefield eel, but also prevent ricefield eel from entangling each other in still water because of its high density, and reduce the occurrence of diseases. The stocking time is mainly after June 15, and the eel should be disinfected with glutaraldehyde and other disinfectants before each stocking. The soaking disinfection time is determined according to the water temperature and the actual tolerance of rice field eel, usually 5-10min. 6. Feeding method. The first thing to do in raising ricefield eel in cage is to domesticate and feed. The newly released ricefield eel should wait 4 days before feeding. At the beginning, the amount of feed should be less, and earthworms should be mixed into the conventional feed used for a long time in the future, such as wheat flour, silkworm pupa powder, small miscellaneous fish, snail meat and so on. Generally, it is better to mix several kinds of feed into strips, and then put them on the table regularly. At first, the feeding time was about 1 hour before sunset, once a day, and twice a day after domestication, that is, an increase at 9:00 The feeding quantity in the morning accounts for about 30% of the whole day, and the specific daily feeding amount is mainly controlled flexibly according to the weather, water temperature, water quality and the activity of ricefield eel. In principle, it is generally eaten about 2 hours after each feeding. 7. Daily feeding and management. First, we should do a good job in feeding. The eel species in each cage had better be released on the same day, no more than 2 days at most, otherwise it will make it difficult to domesticate. After successful domestication, feed according to the "four fixed" principles of quality, quantity, fixed point and timing. Second, special personnel should be responsible for feeding and management. during the main growth period from April to the end of October, the cage should be inspected twice a day in the morning and evening to check whether the net coat is damaged and whether the mesh is blocked. The activity and eating of ricefield eel are often observed, and the depth of the cage in the pond should be adjusted according to the water level after heavy rain. During the flood season, we should pay more attention to prevent the branches and sundries washed by the flood from scratching the cage and causing the eel to escape. Third, it is necessary to regularly remove the dirt in the cage, fish out the dead eel in time, and wash the cage regularly to ensure the exchange of water inside and outside the cage. The dead water peanuts should be fished out in time and replaced with new ones, and the residual bait on the table should be removed in time, so as not to affect the water quality due to decay and deterioration. 8. Disease control. Diseases rarely occur in wild ricefield eel, but in the case of artificial high-density feeding, diseases are easy to occur due to the change of ecological conditions, so it is necessary to do a good job in disease control and carry out the policy of "giving priority to prevention and early treatment of diseases". To prevent eel disease, in addition to selecting good eel species and disinfecting eel during stocking, bleach or chlorine dioxide should be used to hang bags every half a month from May to September, 2 bags per box, 150 grams per bag, and adding "Yukangda" or "florfenicol" to feed, once every half month for 3 days. Once the disease occurs, the right medicine should be prescribed according to the condition. Because the exchange of water in the pond is slow, drugs can be directly used to disinfect the cage water body. However, due to the flow of the water body in the river ditch, when spraying drugs in the cage, it is necessary to surround the cage with plastic film or colored stripe cloth in advance, so that the water body can not be exchanged temporarily, and then disinfect the water body in the box according to the concentration of the medicine. the disinfection time should be controlled flexibly depending on the tolerance of Monopterus Albus.