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Introduction to Yellow Rice Eel Farming

Introduction

It is not related to the order Anguilliformes, but is closely related to the order Perciformes. It is found in tropical freshwater or brackish waters. It is about 20.70 cm (8.28 inches) long, scaleless or with very small scales, with low dorsal and anal fins that are continuous around the tail end, and gills that usually have only one external gill opening in the throat. Some species have very small gills themselves, and breathe by breathing oxygen through the mucous membrane of the throat or intestine. It is a valuable edible fish in the East, often kept in ponds or rice fields. Yellow eel (Monopterus alba): scaleless, can stand upright in shallow water with the front half of the body, and breathe with its mouth to the surface of the water, storing air in the mouth and throat, so the throat appears swollen. It is widely distributed in southeastern Asia, a common freshwater edible fish, and is found everywhere except the northwestern plateau. It lives in ponds, streams, rice fields, etc., and often lurks in mud holes or cracks in rocks. It comes out at night to look for food. The reproductive situation is rather special. They are female when young, and turn into males after reproducing once. This phenomenon of female-male transformation is called sex reversal.

Morphological characteristics

The body is slender and snake-shaped, with a round front and flat back, and a thin and pointed tail. The head is long and round. The mouth is large and terminal, with a slightly protruding upper jaw and well-developed lips. There are fine teeth on the upper and lower jaws and the mouth bones. The eyes are small and covered with a thin skin. The left and right gill openings are fused into one on the ventral side, forming a "V" shape. The gill membrane is connected to the gill septum. There is usually lubricating fluid on the body surface to facilitate escape, and there are no scales. There are no pectoral fins and pelvic fins; the dorsal and anal fins are degenerate, leaving only skin folds, without soft spines, and are all connected to the tail fin. When alive, the body is mostly yellowish brown, slightly yellow or orange-yellow, with dark gray spots, and a few eels are white, commonly known as "white eels".

Living habits

Yellow eel is a tropical and warm temperate fish. It is a bottom-dwelling fish with strong adaptability. It can survive in rivers, lakes, ditches and rice fields. During the day, it likes to burrow in humus-rich mud or live in burrows in rock crevices near water on the embankment. It rarely moves during the day and comes out of its burrows to look for food at night. Its gills are not well developed, but it uses the inner wall of its mouth and throat as an auxiliary organ for breathing, and can breathe air directly; eels can survive when the oxygen content in the water is very poor. After leaving the water, as long as the skin is kept moist, it will not die within a few days. Yellow eel is an omnivorous fish that feeds on various small animals. It is greedy and eats most vigorously in summer. It can go without food for a long time in cold seasons without dying.

The reproductive season of the yellow eel is about June to August. In its individual development, it has the characteristics of sex reversal, that is, it is female from the embryonic stage to the first sexual maturity (that is, the gonads of individuals with a body length of less than 35 cm are all ovaries); after spawning, the ovaries gradually become testes; when the body length is 36-48 cm, the sex is partially reversed, and the male and female individuals are almost equal; those that grow to more than 53 cm are mostly testes. When the young fish can only grow to 20 cm, the female fish will reach maturity after 2 winters, with a body length of at least 34 cm. The largest individual can reach 70 cm and weigh 1.5 kg. The yellow eel lays eggs near the entrance of its burrow. Before spawning, it spits out foam from its mouth to form a nest. The fertilized eggs develop on the water surface in the foam with the help of the buoyancy of the foam. Both male and female fish have the habit of protecting the nest.

The eel's body is cylindrical, suitable for cave life, which is very helpful for entering and exiting the cave and reducing friction. It is really a bit of a "hermit" temperament, with no special attacking skills and no powerful defensive weapons. Its only skill is "36 strategies, escape is the best strategy". It has neither pectoral fins nor pelvic fins, and even its dorsal and anal fins have degenerated to the point where only a few skin folds are left, and its scales have disappeared to the point where they are difficult to see with the naked eye. However, its body can secrete very slippery mucus, and if you are not careful, it can slip away from your hands. The main functions of the mucus on the eel's body are: preventing bacteria and germs from infecting the body and reducing diseases; preventing parasitic animals and plants from entangling it, which is beneficial for its growth; and its slippery surface is conducive to its unimpeded passage in the mud.

When the eel embryo develops to the first sexual maturity, it is female, but when it begins the second sexual maturity, it becomes male again. This means that the yellow eel is both a mother and a father in its life. This process of yin and yang transformation is called sex reversal in biology. Most fish breathe with gills, but eels are unique. Their gills have degenerated, and they directly absorb air through the tiny blood vessels on the surface of the throat. Therefore, if we want to keep the eel fresh, we must keep it moist and store it in a cool place.

distributed

Distributed in southeastern Asia, this fish is found in all waters of China except the western plateau. It is also found in western Korea, southern Japan, the Philippines, Java and Myanmar.

Yellow eel is widely distributed in lakes, rivers, reservoirs, ponds, ditches and other water bodies across the country. Except for the Northwest Plateau, it has been recorded in all regions, especially the Pearl River Basin and the Yangtze River Basin, which are rich in yellow eel. Yellow eel is mainly distributed in Thailand, Indonesia, the Philippines and other places abroad. It is also produced in India, Japan and North Korea.

Soilless eel farming is easy to manage and has high yield

The factory breeding of yellow eel changes the traditional soil and outdoor static water breeding to soilless and indoor and outdoor flowing water breeding, which is convenient to manage, high in yield and good in benefits. Its production technical indicators are: 2-2.5 kg of eel fry with a specification of 25-40 grams are placed per 1 square meter, and the eel fry are fed with complete compound feed. After 4-5 months of breeding, the production cost is 15-20 yuan/kg based on the current raw material cost. The technical points are as follows: Choose a place with clean water source to build a pond. The breeding pond is divided into outdoor and indoor types, with an area of ​​2-20 square meters per pond, a depth of 0.5 meters, and the pond is smoothed with cement. The pond embankment is built with a width of 0.5 cm and equipped with a water reservoir. The breeding pond is required to be freely irrigated and drained, and aquatic plants are planted in the pond to cover 70% of the pond surface. Select high-quality eel fry and release them at 2-2.kg/square meter. It is best to choose artificially propagated eel fry, and disinfect the fish body before release. Injured and weak fry cannot be used. Feeding complete compound feed Before entering the pond, the eel fry must be domesticated first, and then fed with compound feed. The finished feed must be modulated before feeding, that is, 25% of fresh fish paste is added to the finished feed to make noodle-shaped bait with a diameter of 3-4 mm. The feeding amount is 1%-2% of the body weight of the yellow eel. Yellow eels have feeding inertia. When they become accustomed to a certain bait, do not change it casually, otherwise it will seriously affect the growth of the yellow eel. Strengthen daily management and keep the water flowing for 10 hours a day. At the same time, pay attention to sewage discharge, rodent prevention, and flood prevention. Pay attention to the regular application of anthelmintics and fungicides in the disease prevention and treatment pool, and remove dead and sick eels. If wild yellow eel seedlings are used, because the infection rate of the thorny head is very high, deworming should be carried out before stocking. "Wanlong No. 1" or "Wan No. 3" drugs can be used for deworming.