Grass carp grows rapidly, the fastest growing period of body length is 1 ~ 2 years old, and the fastest growing period of body weight is 2 ~ 3 years old. When the 4th instar fish reached sexual maturity, the growth rate slowed down obviously. In the natural state, 1 winterfish is about 340mm long and weighs about 750g g. Two winter fish are about 600mm long and weigh about 3.5kg, and three winter fish are about 680mm long and weigh about 5kg. Four winter fish are about 740mm long and weigh about 7kg. The five winter fish can reach a body length of about 780mm and weigh about 7.5kg.. ..

High-yield culture and management techniques of intensive culture of grass carp in pond

Breeding conditions

1. Pond conditions: the area is 5 ~ 10 mu, the bottom of the pond is flat, the bottom is loam, the sediment 10 ~ 20 cm, and the water depth is about 2 meters. The ponds are east-west, and each pond is equipped with a 3 kW impeller aerator and a 4-inch water pump.

2. Clean-up and disinfection: under the condition of dry pond (accumulated water is 5 ~ 10 cm), irrigate the whole pond with quicklime 100 kg or bleaching powder 10 kg per mu, and then irrigate the whole pond with warm water to avoid dead corners and completely kill pathogenic bacteria.

3. Water quality: the PH value is 7.5 ~ 8.5, the transparency of the pond water is about 30 cm in the peak season (June ~ September), and the organic oxygen consumption (COD) is18 ~ 20 mg/L. ..

4. Fish species selection: the grass carp species should choose individuals who are golden in color, harmless in appearance, lively and robust, and weigh about 100g/ tail. At the same time, because grass carp hemorrhagic disease and enteritis are easy to infect the larvae of that year, the second-year-old larvae are better in the selection of larvae.

5. Fish stocking

A. stocking time: stocking in spring or autumn. In spring, the water temperature rises to above 12℃, and in autumn, the water temperature is between 15 ~ 12℃.

B. Stocking mode: Stocking mode can be divided into main feeding mode and mixed feeding mode, with main feeding mode as the main mode. Grass carp accounts for 80% ~ 85%, silver carp, bighead carp, snakehead and crucian carp account for 20% ~ 65438 05%.

C stocking specifications and density: when the total length of grass carp stocking specifications is 15 ~ 20 cm, the stocking density per mu should be 1400 ~ 1600. The stocking density of grass carp is 1200 ~ 1400/ mu when the stocking size is 20 ~ 25 cm.

5. Disinfection of fry: Before stocking fry, soak them in 3% ~ 4% salt solution or 20 mg/L potassium permanganate or 20 ~ 30 mg/L multivitamin copper iodine (containing available iodine 1%) for 5 ~ 10 minutes.

6. Fish feed: The feed for intensive culture of grass carp in ponds is mainly compound feed, accounting for 85%, supplemented by green feed, accounting for 15%.

7. Feeding management: Feeding in intensive culture pond is the main work in the feeding management stage, including conventional feed feeding and drug bait feeding. The feeding method adopts artificial domestication and fixed-point feeding, and strictly adheres to qualitative, quantitative, regular and fixed-point feeding. Specific practices are as follows:

A. Conventional feed feeding: pellet feed is the main feed, with protein content of 28-32%, supplemented by turquoise feed. Feed feeding follows the principle of "coarse before fine".