I, life habits
1, food
Grass carp is a typical herbivorous fish, in the natural state of the adult fish to eat water plants. The types of food they like to eat are bitter grass, black algae, duckweed and so on. In artificial feeding conditions, feeding all kinds of favorite water grass, terrestrial grass and all kinds of concentrate feed. From the early stage of fry cultivation, young fish eat rotifers and other small protozoa, to the summer flowering stage to eat large zooplankton such as branches and horns, and to eat duckweed, Lady's Slipper, and tender water and land grasses. All growth stages like to eat artificial concentrate feed. 2, growth
Grass carp is a fast-growing large economic fish. 2-3 years of age the fastest growth. In the pool culture conditions group growth rate 1 age fish generally 50-60g, 2 age up to 500-750g, 3 age 2-3kg, so the grass carp breeding cycle for 2.5-3 years. Sexual maturity 4-5 years, 5 years after the age of growth rate slowed down significantly. 1-3 age of male and female individuals, growth rate is similar. 4 years after the age of the female body growth rate faster than the male body. 3, reproduction
Grass carp belongs to the big river fish. Under natural conditions, there are spawning grounds in the main streams of China's major rivers. Parent fish can swim to the spawning grounds to spawn and reproduce during the spawning season, but not under artificial pond conditions.
The age of sexual maturity and individual size of grass carp are closely related to latitude (heat). In South China, the age of sexual maturity is 3-4 years old, weighing about 14kg; in Central China, the age of sexual maturity is 4-5 years old, weighing about 5kg; in Northeast China, the age of sexual maturity is 6-7 years old, weighing about 6kg. In addition, sexual maturity is also related to nutritional conditions, and differences in age at sexual maturity and body weight can occur depending on nutrition. Males also generally mature 1 year earlier than females, and individuals are smaller than females. Artificial reproduction 1, parent fish selection
Selection of qualified parents with good germplasm and body quality is one of the basic conditions for artificial reproduction of grass carp. The so-called good germplasm, that is, according to China's "three rivers" (Yangtze River, Pearl River, Heilongjiang) "four big fish" germplasm research, to the Yangtze River's germplasm is the best, so the choice of the Yangtze River original species of grass carp is more ideal. The so-called good physique, that is, the fish body is strong, body color is normal, the scales are complete, no injury, no disease of the individual. Individuals that have not reached sexual maturity, as a reserve parent fish, mature individuals, as the year of production with parent fish. In the selection of parent fish, should also pay attention to the male and female collocation, general male body slightly more than female body. 2, parent fish cultivation
(1) Parent fish cultivation pool. Parental fish cultivation pond area 2/15-4/15hm2 (2-4 acres), water depth 1.5-2.5m. location in the catalytic pool near the convenient drainage, quiet environment. Use quicklime to clear the pond before stocking.
(2) stocking density. Each hectare of pond stocking parent fish about 2250kg. The ratio of male to female is 1:1 or 1:1.25. In order to fully utilize the bait and regulate the water quality, under the premise of the grass parent fish, you can also mix the silver or bighead carp parent fish 50-60 per hectare.
(3) feed. The feed for the grass parent fish is mainly gramineous ryegrass, sudangrass, elephant grass and other artificially planted grasses and terrestrial grasses, as well as aquatic bitter grasses, leafy black algae and so on. The second is a variety of cereals and artificial feed. 3, parental fish catalyzing
(1) catalytic time, water temperature: in the middle and lower reaches of the Yangtze River, catalytic time for the middle and end of May, catalytic water temperature 25 ~ 28 main most suitable.
(2) Parent fish selection: the maturity of the parent fish directly affects the effect of the catalytic effect, the identification criteria for the male fish gently squeezed the abdomen with semen flow, immediately dispersed in contact with the water, the female fish abdominal expansion, fluffy and elastic, abdominal scales are sparse. In order to improve the maturity of the group, in the middle of April, the net can be checked, and the poor maturity, according to the size of the individual and the poor maturity, according to the size of the individual and the maturity of the individual, respectively, the injection of LRH-A3-5 micrograms/tail. 4, estrus and artificial insemination