What are the key technical points for autumn fingerling management?

Pond clearing. Transfer the fingerlings into a pond that has been cleared and disinfected for rearing. If water source and pond rotation are difficult, all fingerlings can be transferred out for temporary holding, then the original pond disinfected with 75 kg to 100 kg of quicklime per mu, and the water quality fertilized by conventional methods; once the lime's potency has dissipated, transfer the fingerlings back.

Separate rearing. Adjust and separate the fingerlings according to different sizes so that the fingerlings stocked in the same pond are of uniform size. Large fingerlings have a big appetite and strong food-grabbing ability; if small fingerlings are stocked in the same pond, the small fish will decline in condition because they cannot get enough feed. Fingerlings over 16 cm can be stocked in adult fish ponds for polyculture, while on the small side need to be reared in dedicated ponds.

Sparse stocking. In autumn, fingerlings should be stocked sparsely at a reasonable density according to conditions such as water surface area and depth, to promote fingerling growth and increase the overwintering survival rate. Generally, for a pond 1.5 m deep, stock 4000 to 6000 fingerlings of 7 cm to 8 cm per mu, and by the end of the year they can reach a body length of 13 cm to 17 cm.

Feeding. In autumn the temperature is stable, the water temperature varies little between day and night, and the fingerlings have a large food intake and grow rapidly, so feed supply must be guaranteed. For fingerling ponds mainly stocked with herbivorous fish and mixed with silver carp and bighead carp, green feed should be the main feed with an appropriate amount of concentrate; feed 1.5 kg to 2.5 kg of small duckweed per 10,000 grass carp fingerlings per day. Feed green feed first, then concentrate, to prevent grass carp from competing for food with other fish. Feeding must ensure quality, a fixed amount, fixed times and fixed locations. Fingerling ponds polycultured with silver carp and bighead carp must be fertilized regularly, once every 10 to 15 days, applying 70 kg to 90 kg of fermented human and livestock manure per mu, and keeping the pond water transparency at 30 cm to 35 cm. For fingerling ponds mainly stocked with silver carp and bighead carp and mixed with grass carp, fertilization should be the main method and feeding supplementary; besides applying base fertilizer, apply topdressing once every 5 to 10 days, with 80 kg to 100 kg of decomposed human and livestock manure per mu. At the same time, feed 2 kg to 4 kg of concentrate per 10,000 fingerlings per day; for the mixed grass carp, feed 60 kg to 90 kg of green feed per 10,000 grass carp before feeding the concentrate.

Pond patrols. During fingerling rearing, patrol the pond every day to observe the fish's feeding and living conditions, and add or change new water once a week. Clean the feeding ground frequently, promptly remove leftover residue and bait, and every half month sprinkle the area around the feeding ground with 0.5 kg of bleaching powder mixed with water for disinfection. Feed medicated bait regularly, preferably twice a month, each time for 3 consecutive days.