Overwintering management techniques for freshwater pomfret fry and fingerlings after being stocked into ponds

1. Overwintering pond preparation

Area 600-1500 sq m, pond depth 1.5 m; the pond water in the Pukou District area of Nanjing is geothermal spring water, flowing into the pond in a slight current; the inlet pipe is 10 cm, and the mud at the pond bottom is 10 cm thick. After drying the pond and disinfecting it, fill with water. Each pond is equipped with two 3-kilowatt aerators.

2. Stocking of pomfret fry and fingerlings

Stop the water inflow three days before stocking, so that the water temperature of the overwintering pond approaches the pond water temperature, with a temperature difference within 2 degrees Celsius. In the Nanjing area, fry are generally harvested at the end of September and the beginning of October. After the fry are bathed in methylene blue at 0.2 ppm for 10-15 minutes, they are put into the overwintering pond to overwinter. About 180 fish are stocked per cubic meter of water.

3. Feeding

After the pomfret are stocked into the pond, feed them floating feed with a protein content above 30%, feeding 3-4 times per day, with a daily feeding amount of 3-4% of the fish body weight.

4. Daily management

During the overwintering period, the water temperature is controlled at 26-28 degrees Celsius, and the water flow is kept stable. Take samples regularly, check the growth and feeding conditions of the fish, and examine pests and diseases under a microscope. In the later stage of overwintering, as the fish carrying capacity in the pond increases, turn on one aerator, and except when feeding, do not shut it down for 24 hours.

5. Overwintering size control

Freshwater pomfret have a strong feeding ability, and individual growth varies greatly. During overwintering culture, it is advisable to use a small-amount, fixed-point, long-duration feeding method, which avoids excessive size disparity among the pomfret and improves feed utilization. Generally, about 15 kg of overwintered fingerlings can be produced per cubic meter of water.