Key Technical Points for Intensive Management of Oriental River Prawn in Autumn and Winter

Currently, it is the key season for stocking oriental river prawn in autumn and winter. Doing a good job in substrate, seed stock, bait, and water quality control, and effectively preventing disease and surfacing, are the top priorities for increasing production and income of oriental river prawn by the end of the year. Below, the relevant techniques for intensive culture of oriental river prawn are discussed from five aspects, for the reference of the majority of farmers.

1. Do a good job in basic construction of the prawn pond. Seize the work of drying the pond, clearing the pond, eliminating pests, and sunning the pond before stocking, and change the practice of only raising without sunning the pond. This is because after one year of culture, a large amount of bacteria is produced in the pond, and the increase of sludge in the pond easily causes oxygen deficiency and surfacing of prawns. Wide and large pond embankments should be renovated, and thin embankments should be raised and widened. The suitable pond area is 8 mu to 10 mu, with a water depth of 1.2 m to 1.5 m, and there must be a certain area of prawn beach, with a prawn collection trench in the middle, and a matching inlet and drainage system. The pond bottom should be disinfected by broadcasting 60 kg to 70 kg of quicklime per mu over the whole pond, and exposed to sunlight for 15 days to 20 days. 2. Fertilize in a timely manner. Fertilization is mainly to cultivate the early-stage water quality, so that after the prawn seedlings are stocked they can have suitable and appropriate amounts of opening zooplankton. Mainly apply fermented organic fertilizer, 150 kg to 250 kg per mu. In addition, it is advocated to apply chicken manure granular fertilizer. The principle is that this fertilizer has been treated by high-temperature disinfection, is not likely to pollute the water environment after application, and chicken manure contains potassium fertilizer elements, which is beneficial to the growth of the prawn shell. The suitable fertilization time is 4 days to 5 days before releasing the prawns. For old ponds, apply 10 kg to 15 kg per mu; for new ponds, 15 kg to 20 kg, broadcast over the whole pond. If the water quality is still clear and thin after stocking, an additional 5 kg to 7.5 kg can be applied to make the pond water fertile, lively, tender, and refreshing, and prevent the appearance of moss and blue-green algae. 3. Reasonable stocking. The autumn stocking time for oriental river prawn is from late July to early August. For prawn seedlings, choose wild prawn seedlings cultivated in Taihu Lake. The principle is that wild prawns have strong disease resistance, uniform size, and a high marketable rate. The stocking size is 1.5 cm to 1.8 cm, and the stocking density per mu is 60,000 to 80,000 tail. After 10 days to 15 days of stocking, polyculture with 800 to 1,000 tail of silver carp and bighead carp summer fry, and 800 to 1,000 tail of bream. 4. Feeding and water quality management. Stocking of prawn seedlings should be chosen on sunny days. When entering the pond, if there is suitable and appropriate amount of red worms in the pond, no bait needs to be fed for 1 day to 2 days; after the red worms are eaten up, then feed the bait. For bait, choose high-quality special feed for oriental river prawn, such as Dajiang brand feed. In the first 15 days to 20 days, feed crushed feed; in the middle period, use No. 1 feed; in the later period, use No. 2 feed, and add small animal-based trash fish. For a yield of 100 kg of autumn prawns per mu, 150 kg of pellet feed is needed, 50 kg of trash fish or 750 kg of snails, the feed coefficient is 1.8 to 2, and the feed cost is 500 yuan to 600 yuan. 5. Do a good job in disease prevention, prevention of surfacing, and other management work. After 15 days to 30 days of stocking of oriental river prawn seedlings, choose sunny days to apply 4 kg to 5 kg of quicklime per mu. If bacterial prawn disease is found, chlorine dioxide or “strong chlorine essence” can be applied, generally 200 g per mu. One third of the aquatic plants in the pond should be retained. If moss appears, fertilizer can be added; if green sand blue-green algae appears, silver carp and bighead carp, which are fertilizing fish, can be added. One 3,000-watt aerator can be used for every 6 mu to 7 mu. Twenty days after stocking, turn on the machine for 1 hour to 2 hours at noon every day, and turn it on in the middle of the night and early morning on cloudy and rainy days, to ensure good work in preventing surfacing. The water inlet should use double-layer nets (60 mesh and 80 mesh) to strictly filter wild trash fish.