What are the technical measures for autumn fingerling rearing

Autumn water temperatures generally range between 20 and 30°C, which is a good time for fish growth. If autumn is not used promptly to rear fingerlings into plump, strong, large-sized fingerlings, then when the cold winter arrives, most fingerlings will die because of weak constitution, and the average survival rate is often less than 60%. Therefore, strengthening autumn fingerling rearing is the top priority for farmers. The specific rearing measures are:

Disinfect and clear the pond, then transfer to a new pond. In the original pond used for rearing fingerlings, after several months of culture in spring and summer, water quality gradually deteriorates, dissolved oxygen and food organisms decrease, and pathogenic factors greatly increase, affecting fingerling growth. Especially small-sized fingerlings have weak food-grabbing ability, and their growth is inhibited even more. Grass carp fingerlings grown in this environment are also more prone to disease. Therefore, those with the conditions should transfer the fingerlings to a new pond for intensive rearing. In places where water sources are difficult, the water from the original fish pond can be used, and after pulling the net several times to transfer out all the fingerlings, 40 to 50 kg of quicklime per mu is used for disinfection; after cultivating water quality by conventional methods, the fingerlings are stocked.

Classify by size, and match reasonably. Fingerlings of different sizes should be stocked in separate ponds, and different species should be reasonably matched. For example, if silver carp and bighead carp are the main species, 30% grass carp fingerlings can be added; if grass carp and crucian carp are the main species, about 30% silver carp and bighead carp fingerlings can be added. The suitable ratio of silver carp to bighead carp is 5:1. If the bighead carp fingerlings are small in size, the ratio can be even lower. If it is a pond specifically for rearing these three kinds of fish, the density should not be too high, and the total weight of fingerlings per mu should be controlled at 100 to 150 kg.

Strengthen feeding and fertilization. For fish ponds mainly containing silver carp and bighead carp, fertilization should be the main method, supplemented by concentrated feed. Generally, 5 to 10 kg of chemical fertilizer per mu is applied each week (the suitable ratio of nitrogen, phosphorus, and potassium content is 1:1:0.5), or about 50 kg of human and livestock manure is applied, dissolved in water and sprinkled evenly, to cultivate food organisms in the water. For fish ponds mainly containing grass carp, feeding should be strengthened. For every 10,000 fingerlings, about 5 kg of concentrated feed is fed daily, together with some duckweed and tender fresh grasses. Feeding can be done once in the morning and once in the afternoon, and new water should be injected regularly to keep the water quality fresh, promote fingerling growth and fattening, and facilitate safe overwintering.