When does Jiangnan grass carp open its mouth?

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 into rivers and lakes. Sexually mature individuals lay eggs in rivers, reservoirs and other flowing water. After spawning, the broodstock and juvenile fish enter tributaries and river lakes, usually in flooded shallow grasslands and flooded areas. As well as the ancillary water bodies of main branches and tributaries (lakes, rivers, harbors and other water and grass areas) for feeding and fattening. 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.

High-definition picture of grass carp (3) 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 stage III development stage throughout the winter (December to February); in March to April, the water temperature rises to about 15°C, and the ovaries in the ovaries 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"; but 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 water, there is a "floating row" phenomenon of trembling on the back and belly. After the eggs are fertilized, the egg membrane absorbs water and swells, and the egg diameter can reach about 5 mm. It floats with the water and develops best at about 20°C. The fry will hatch in about 30 to 40 hours.

Cathedral carp photography (3) Grass carp grows rapidly. In terms of the entire growth process, the fastest growth in body length is at the 1st to 2nd age, and the fastest weight growth is at the 2nd to 3rd age. 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 40 kg.

Cow carp grows quickly and is large, with the largest individual reaching 40 kilograms. The meat is tender and delicious. Each 100 grams of edible portion contains 15.5 to 26.6 grams of protein, 1.4 to 8.9 grams of fat, 83 to 187 kcal of calories, 18 to 160 mg of calcium, 30 to 312 mg of phosphorus, 0.7 to 9.3 mg of iron, and 0.03 mg of thiamine. Riboflavin 0.17 mg, niacin 2.2 mg. Grass carp has simple feeding habits, a wide range of food sources, rapid growth and high yield, so it is often used as the main stocking target 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 green grass is put into the grass carp. The feed left in the water and the waste excreted by grass carp can be fermented and decomposed to provide a suitable environment for bacterial reproduction, thereby cultivating plankton, bacteria and plankton. The organisms can also be used 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.

It usually opens its mouth at the end of February, but it actually feeds all year round.