The living habits and nutritional value of grass carp (water pioneer)

Grass carp (Ctenopharyngodon idellus) belongs to the genus Ctenopharyngodon idellus, family Cyprinidae, subfamily Ctenopharyngodon. Common names for grass carp include: grass carp, oil grass carp, grass carp, white grass carp, grass carp, grass root (Northeast), mixed carp, etc. English name: Grass carp.

The most famous among my country's important freshwater economic fishes are the world-famous "four major fish" such as grass carp (Ctenopharyngodon idellus), black carp (Mylopharyngodon piceus), silver carp (Hypophthalmictuthys molitrix), and bighead carp (Aristichthys nobilis). Although they are all from my country Grass carp is a unique fish, and grass carp has been transplanted to various parts of the world as a pioneer because of its unique feeding habits and foraging methods.

Its body is long, slightly cylindrical, and its abdomen has no edges. The head is flat and the tail is flat on the sides. The mouth end is curved and unnecessary. There are two rows of hypopharyngeal teeth, the sides are flat and comb-shaped, and the sides of the teeth have transverse grooves. There are no hard spines on the dorsal and anal fins, and the dorsal and pelvic fins face each other. The body is dark brown, the back is grayish-grey with a hint of grass green, and the even fins are slightly yellow.

Grass carp generally likes to live in the middle and lower layers of rivers, lakes and other waters and near shore areas with many aquatic plants. It has the habit of migrating rivers and lakes. Sexually mature individuals lay eggs in rivers and streams. After spawning, the broodstock and juvenile fish enter tributaries and river-connecting lakes, usually in flooded shoal grasslands and flooded areas as well as affiliated water bodies of main branches and tributaries ( Lakes, rivers, harbors and other aquatic and weedy areas) feed and fatten. In winter, they overwinter in the deep water of main streams or lakes. Grass carp has a lively temperament, swims quickly, often looks for food in groups, and is gluttonous. It is a typical herbivorous fish. The fry stage feeds on zooplankton, and the juvenile stage also eats insects, earthworms, algae, duckweed, etc. When the body length reaches about 10 cm or more, it completely feeds on higher aquatic plants, especially grasses. The types of plants that grass carp eats change with the conditions of the food base in their living environment.

The reproductive situation of grass carp is similar to that of several other domestic fish. Under natural conditions, it cannot lay eggs in still water. The spawning sites are generally selected at the confluence of rivers in the main rivers, deep trough waters on one side of the meanders, and river sections that suddenly tighten on both sides as suitable spawning sites. The reproductive season is similar to that of silver carp and slightly earlier than that of black carp and bighead carp. The reproductive period is from April to July, and is more concentrated in May. Generally, when the river water rises early and violently, and the water temperature can be stabilized at around 18°C, grass carp spawning will take place on a large scale. The reproductive habits of grass carp are similar to those of other domestic fish. The ovaries of grass carp that have reached maturity overwinter in the third stage of development throughout the winter (December to February); in March and April, the water temperature rises to about 15°C, and the ovaries in the ovaries overwinter. The stage III oocyte quickly develops to stage IV and begins reproductive migration. It completes the development from stage IV to stage V in the process of backmigration. During its backmigration, if it encounters hydrological conditions suitable for spawning, it will stimulate time, the eggs are laid. Usually spawning is carried out in the water layer, and the fish body does not emerge from the water, which is commonly known as "stuffed spawning"; however, when encountering good reproductive ecological conditions, such as a sudden rise in water levels accompanied by thunderstorms, the female and male fish will When chasing in the upper layer of the water, a "floating row" phenomenon occurs with the belly trembling. After the egg is fertilized, the egg membrane expands by absorbing water, and the egg diameter can reach about 5 mm. It floats along the water and develops best at around 20°C. The fry will hatch in about 30-40 hours.

Grass carp grows rapidly. As far as the entire growth process is concerned, the fastest growth period in body length is 1-2 years old, and the fastest weight growth is in 2-3 years old. When 4-year-old fish reach sexual maturity, growth slows down significantly. 1. The body length of winter-age fish is about 340 mm and the weight is about 750 grams; 2. The body length of winter-age fish is about 600 mm and the weight is 3.5 kg; 3. The body length of winter-age fish is about 680 mm and the weight is about 5 kg; 4. The body length of winter-age fish is about 680 mm and the weight is about 5 kg. The body length of the old fish is about 740 mm and the weight is about 7 kg; the body length of the 5-year-old fish is about 780 mm and the weight is about 7.5 kg; the largest individual can reach about 35 kg.

Grass carp grows quickly and is large, with the largest individual reaching 35 kilograms. The meat is tender and delicious. Each 100 grams of edible portion contains 15.5-26.6 grams of protein, 1.4-8.9 grams of fat, 83-187 kcal of calories, 18-160 mg of calcium, 30-312 mg of phosphorus, 0.7-9.3 mg of iron, and 0.03 mg of thiamine. Riboflavin 0.17 mg, niacin 2.2 mg.

Because grass carp has simple feeding habits, a wide range of food sources, rapid growth and high yield, it is often used as the main stocking object in pond culture and lakes, reservoirs and rivers. Since the success of artificial induction of labor and fertilization and hatching technology in 1958, fry and fingerlings have become easy to source and have become the main targets of intensive breeding in my country. Grass carp is also used by fishermen to roam outside for one or two years to open up wasteland and eliminate weeds because of its ability to remove grass in water bodies and along the coast. Grass carp is known as the "pioneer" because of its ability to quickly clear various grass species from water bodies. At the end of the Tang Dynasty in my country, there were records in Guangdong of building ridges on uncultivated fields, irrigating them with rainwater, and stocking grass carp for one or two years to remove weeds and mature the fields. Grass carp is often mixed with silver carp and bighead carp, and grass is put in to feed grass carp. The feed left in the water and the waste excreted by grass carp are used to cultivate plankton and serve as feed for silver carp and bighead carp.

Grass carp is widely distributed in the plain areas from Guangdong to Northeast China except Xinjiang and the Qinghai-Tibet Plateau. Since the successful hatching of artificial insemination in 1958, it has been transplanted to many countries in Asia, Europe, the United States and Africa.

Grass carp meat is sweet, warm, non-toxic, and has the effect of warming the stomach and soothing the heart. People in Guangdong use it to steam with fried dough sticks, eggs, and pepper to benefit the eyes and improve eyesight. Its gallbladder is bitter, cold, and poisonous. Animal experiments show that grass carp gall has obvious antihypertensive effects, expectorant and mild antitussive effects. Folks in Jiangxi use bile to treat sudden deafness and burns caused by water and fire. Although bile can cure diseases, bile is poisonous, and poisoning cases often occur due to swallowing excessive amounts of grass carp gall. The poisoning process mainly involves toxins acting on the digestive system and urinary system, causing gastrointestinal symptoms, liver and kidney failure in a short period of time, often combined with cardiovascular and neurological diseases, causing cerebral edema, toxic shock, and even death. For swallowed There is no specific treatment for grass carp gallbladder poisoning, so it is not suitable to use grass carp gallbladder to treat diseases. If it must be used, it must be used with caution.

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