Culture techniques of freshwater white Pomfret

Pomfret is a valuable large-scale economic fish with the characteristics of good meat quality, large body, fast growth, wide food intake, less disease, hypoxia tolerance and easy fishing. Its introduction and popularization play a positive role in improving the efficiency and improving the culture structure.

Biological characteristics of Freshwater White Pomfret

1. Morphological characteristics: the body of freshwater white Pomfret is similar to that of Pomfret, with egg orchard shape, lateral flattening, small head, head length equal to head height, tail bifurcation, lower leaf slightly longer than upper leaf, fat fin on back, body cover scale, saw-shaped ventral scale from base of pectoral fin to anus, body color is silver gray, pectoral fin, ventral fin, anal fin is red, caudal fin edge is black. The freshwater white Pomfret has black spots on the body surface and disappears when it is an adult, while the adult fish released in the pond is white, silver scale, black tail and red fin match, so it is a very good ornamental fish. It is reported that the largest individual of this fish can reach 20 kilograms in the country of origin.

2. Living habits and eating habits: Pomfret lives in the middle and lower layers of the water, likes to travel in groups, and does not kill each other among ethnic groups. Pomfret has a well-developed digestive system and is an omnivorous fish. it eats not only bait such as small fish, shrimp and benthos, but also plant bait such as grass, vegetables, algae and so on. Under the condition of artificial feeding, wheat bran, rice bran, bean cake and compound bait can be fed.

3. Ecological habits

The suitable temperature range of ①: the growth temperature of Pomfret is 21 ℃ 32 ℃, the optimum temperature is 28 ℃, and the lowest critical temperature is 10 ℃. The normal eating temperature is 16 ℃. It is dormant under 14 ℃ in the middle and lower reaches of the Yangtze River and Huaibei area, lying on the bottom of the pool on its side.

② oxygen tolerance: freshwater Pomfret has a strong tolerance to hypoxia and can live for several hours when dissolved oxygen is 0.5mg / L. the best dissolved oxygen for its growth is 4mur6mg / L.

③ salt tolerance: it could grow normally in 5-10 ‰ salinity waters, and there was no fish disease, and died in 15 ‰ salinity for 16 hours.

④ pH range: PH5.5-7.4, prefer acidic or neutral water.

⑤ capture rate: fresh water from Pomfret gentle, good gregarious, generally the first net capture rate is more than 90%, the two nets can basically be caught.

Tolerance of commonly used ⑥ drugs: freshwater Pomfret was the most sensitive to organophosphorus pesticides and trichlorfon. It died 11 hours after 0.2ppm, 4 hours after 0.5ppm, and immediately at 1pm. Malachite green can also cause poisoning of freshwater Pomfret at the water temperature of 20ml 250.3ppm. 0.135ppm can cause "red head" symptoms. There was no abnormal phenomenon when the fish was soaked with copper sulfate at 10ppm concentration for 25 minutes, and there was no abnormality when the bleach (available chlorine 30%) was 2ppm. At 4ppm, the fish lost balance and died in 100 minutes. There was no abnormality in mercurous nitrate 0.2ppm, and all died within 10 hours at 1 ppm. 0.1ppm has a special effect on the control of melon disease.

Adult Culture of Freshwater White Pomfret

1. The main culture of overwintering fish species: the general weight of overwintering fish species is 15mur20g. The middle and lower reaches of the Yangtze River and Huaibei area are generally released in the first and middle of May, and the fish are caught in mid-late October. The growing period is 5 months, and the average body weight is more than 750g.

2. Mixed culture of overwintering species in adult ponds: the specification of overwintering Pomfret in high-yield adult ponds should be enlarged, 40MUE 50g, 50Mu interculturing 60 fish per mu, without increasing feeding, the yield can be increased by 50m / 60kg.

3. Cage culture: fresh water white Pomfret has dense scales, is not suitable for injury, has strong disease resistance, likes to gather together, and likes to eat artificial bait, so it is suitable for cage culture.

① cage requirements: fresh water white Pomfret upper and lower jaw has sharp teeth, in order to prevent it from biting through the cage, generally use single-layer steel wire mesh structure. The specification is 4 × 4 × 2 or 4 × 6 × 2, with large 3cm mesh and many uncovered nets. When the cage is set, the lid is 0.5m higher than the water surface.

② fish stocking: overwintering fish are put into the box in the middle of May, the specification is 15g-20g / tail, and the single culture density is generally 150ind / square meter.

③ feed requirements: artificial feed, egg self-quality content of 25Mel 28%.

④ feeding method: two days after entering the box, the fish are domesticated and fed four times a day when the water temperature is above 25 ℃. Be patient with bait, observe while sprinkling, and swim away with most of the fish when they are full. The best growing period is June, July and August, and the protein content and feeding amount should be increased.

⑤ daily management: daily management should achieve "three precautions": disease prevention, escape prevention, theft prevention. The water body of the cage should be pollution-free, disease-free, and the water quality should be fresh. When the fish species enter the box, wash them with 3% salt water for 20 minutes, and hang the basket with bleach after entering the box; clean the cage regularly and check the cage to prevent damage and escape fish; send someone to take care of it and keep daily records.