The living habits and nutritional value of eel (grows in the sea and grows in fresh water)

Anguilla japonica belongs to the order Anguilla, family Anguillaidae, and genus Anguilla. Also known as Japanese eel, commonly known as: white eel, blue eel, wind eel, eel. English name: Common eel.

The body is slender and snake-shaped, with a maximum length of 1.3 meters. The front end is cylindrical, gradually flattening from the back of the anus, the tail is small, and the head is long and pointed. The snout is blunt and slightly flat; the mouth is large and terminal; the upper and lower jaws and the vomer have pointed teeth; the lips are thick and fleshy; the anterior nares are near the end of the snout and are short tubular, and the posterior nares are located in front of the eyes and are not tubular; The eyes are medium in size; the gill openings are small, located under the base of the pectoral fins, separated from the left and right. The lateral lines are well developed and complete, and the scales are thin and long, hidden in the epidermis. The dorsal fin is low and long, and its starting point is closer to the anus than to the gill opening; the distance between the starting points of the dorsal fin and anal fin is shorter than the head length, but longer than half the head length. There is no pelvic fin, the anal fin is low and long, connected to the caudal fin, the caudal fin is short and rounded. The back of the body is gray-black, the abdomen is gray-white or light yellow, and there are no spots.

The eel is a migratory fish that originates in the sea. It travels up rivers to fresh water to grow up, and then returns to the sea to lay eggs. Every spring, large numbers of young eels (also known as white eels and eel threads) enter river estuaries from the sea. Male eels usually grow up in the mouths of rivers; while female eels travel upstream into river trunks, tributaries and lakes connected to rivers, and some even travel thousands of kilometers to reach various water bodies in the upper reaches of rivers. They grow and develop in rivers and lakes. They often hide during the day and emerge at night. They like running water, low light, and live in caves. They have a strong ability to trace water and their ability to escape is also very strong. Individuals that have reached sexual maturity descend into rivers in large numbers in autumn, swim to river mouths to meet male eels, and then continue swimming to the ocean for reproduction. It is speculated that its spawning ground is south of 30 degrees north latitude and near the southeast of Taiwan, China. The water depth is 400-500 meters, the water temperature is 16-17°C, and the salt content is more than 30‰. One spawning time, one female Eels can lay 7-10 million eggs at a time. The eggs are small, about 1 mm in diameter, buoyant, and can hatch within 10 days. After hatching, the larvae gradually rise to the surface of the water, and are later drifted by sea currents to the coasts of China, North Korea, and Japan. At this time, the larvae are about 1 year old. They turn into white seedlings near the shore in winter and spring, and turn into black as the pigment increases. Seedling. There are white seedlings at the beginning of upstreaming, and in the later stage of upstreaming, there are mainly black seedlings, mixed with a small amount of white seedlings. The gonads of eels cannot develop well in fresh water, let alone reproduce in fresh water. The gonad development of female eels is only completed after they migrate down the river and into the sea. In late autumn (between August and September), a large number of female eels descend into the river and into the sea when they are close to sexual maturity, and they accompany the male eels growing in the estuary to the open sea to reproduce.

Eels often hunt at night. Their food includes small fish, crabs, shrimps, crustaceans and aquatic insects. They also eat decaying animal carcasses. Some individuals have even found detritus of higher plants in their food. The feeding intensity and growth rate increase with the increase of water temperature, and are generally highest in spring and summer. The feeding intensity of pond-raised eels decreases in midsummer. When the water temperature is lower than 15°C or higher than 30°C, appetite decreases and growth slows down; feeding stops below 10°C. In winter, they dive into the mud and hibernate. Eels can breathe through their skin and sometimes leave the water. As long as their skin remains moist, they will not die.

Eels are distributed in the Yellow River, Yangtze River, Minjiang River, Hanjiang River and Pearl River basins, as well as in Hainan Island, Taiwan and Northeast China.

The eel meat is tender and delicious, especially rich in fat. The content of vitamin A in the meat and liver is particularly high, and has a very high nutritional value. Each 100 grams of edible portion contains 19.0 grams of protein, 7.8 grams of fat, 146 kcal of calories, 46 mg of calcium, 70 mg of phosphorus, 0.7 mg of iron, 78 international units of vitamin A, 0.06 mg of thiamine, 0.12 mg of riboflavin, Nick Acid 2.4 mg. Jiangsu and Zhejiang areas are classified as top-quality fish; Fujian, Guangdong and Sichuan are regarded as high-grade tonics and are called "water ginseng". The yield is quite high in the four provinces of Jiangsu, Zhejiang, Fujian and Guangzhou. In natural fresh water bodies, the largest individual can grow to weigh 1 kilogram. A considerable amount is exported to Japan and other countries every year. The export price is extremely expensive, and its skin can be made into handicrafts.

The meat, bones, blood, swim bladder, etc. of eels can be used as medicine. Its meat is sweet and flat in nature, and has the effects of nourishing and strengthening, removing wind and killing insects. It is used as medicine to treat physical weakness caused by prolonged tuberculosis, tuberculosis fever, redness and vaginal discharge, rheumatism, bone pain, physical weakness and other symptoms. Li Shizhen believes: "Eels are responsible for all kinds of diseases, and their function is to kill insects and remove wind."

When processing eel, you should be careful because its serum is toxic. Although the toxin can be destroyed by heat or gastric juices, drinking raw eel blood can sometimes cause poisoning. Its main function is to poison the nervous system, cause spasm, heart failure, and cause respiratory arrest and death; it can also cause the coagulation of blood to disappear, causing hemolysis, and damage the kidneys to produce hematuria. Its toxin also has a strong effect on the mucous membrane. If the human mucous membrane is damaged or the fingers are injured, contact with eel blood will cause inflammation, suppuration, and gangrene; at the same time, due to inflammation and infiltration of the lymphatic system, severe tissue edema will occur. To prevent eel blood poisoning, in addition to not eating raw fish and drinking raw eel blood, the oral mucosa, eye mucosa and injured fingers should avoid contact with eel blood to avoid inflammation.

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