Raising two crops of shrimp a year, using resources to improve farming efficiency
Using plastic greenhouses, cultivate early-breeding shrimp fry, and raise the first crop of Macrobrachium rosenbergii (giant river prawn) from May to mid-August, and the second crop of giant river prawn from mid-August to October; or raise giant river prawn from June to September, and raise oriental river prawn from October to May of the following year. In this way, by farming two crops of shrimp a year, the farming water surface and feed resources are fully utilized, greatly improving shrimp farming efficiency.
Giant river prawn (Macrobrachium rosenbergii)
1. Choose the pond well.Shrimp ponds are required to have an area of 8-10 mu, abundant water sources, good water quality, a water depth of more than 2 m, and a slope ratio of 1:2.5. For newly dug ponds, a shrimp-collecting ditch 4-6 m wide should also be dug in the center of the pond bottom to facilitate harvesting; according to the farming scale, build a good high-fill, low-drain water intake and drainage system.
2. Do a good job of cultivating shrimp seed and fry.① Raising two crops of giant river prawn: plastic greenhouses should be built in advance, and early-breeding shrimp fry should be purchased at the end of March and the beginning of April for intensive cultivation, striving to have the shrimp fry reach a size of 3 cm in mid-to-late May, ensuring the needs of the first crop of stocking. At the same time, purchase giant river prawn for the second crop in mid-to-late May and cultivate them in special ponds, so that by mid-August the second-crop giant river prawn seed reaches a size of 3 cm for the second crop of stocking. ② Raise giant river prawn in the first crop and oriental river prawn in the second crop: stock giant river prawn fry in mid-to-late May, cultivate oriental river prawn fry in special ponds, select cultivation ponds in early June, set up several small net cages, and stock berried oriental river prawns, so that by the end of September the oriental river prawn seed reaches a size of 3 cm.
3. Stock reasonably.For two crops of giant river prawn, stock 0.8-1 thousand shrimp seed per mu for the first crop, and 1-1.2 thousand per mu for the second crop. For giant river prawn in the first crop and oriental river prawn in the second crop, stock 20-25 thousand giant river prawn fry per mu in the first crop, or 10-15 thousand shrimp seed, and stock 15-20 thousand oriental river prawn seed per mu in the second crop. Before stocking, the shrimp pond should be well cleaned and disinfected, basic feed should be cultivated, and aquatic plants should be transplanted. Choose a sunny morning for stocking shrimp, and the temperature difference must not be too large.
4. Feed feeding.When raising the two kinds of shrimp, formulated feeds of the giant river prawn and oriental river prawn series can be fed respectively. For raising giant river prawn, in the Taihu Lake area the feed is mainly snail, clam, and mussel meat, supplemented by formulated feed; in other areas, formulated feed is mainly used, supplemented by small fish and small shrimp. Usually at the juvenile shrimp stage, the protein content in the fed feed is greater than 35%, while for adult shrimp it is required to be greater than 32%. The feed fed in the evening accounts for about 70% of the whole day's feeding amount. Feed is put in deep-water areas during the day and in shallow-water areas at night, fed at fixed times, fixed locations, fixed amounts, and fixed quality; the daily feed feeding amount is 5%-10% of the pond shrimp body weight for giant river prawn, and 3%-5% for oriental river prawn.
Oriental river prawn
5. Water quality management.From May to June, at the initial stage of stocking shrimp fry or shrimp seed, keep the pond water depth at 0.8 m; in the high-temperature season from July to September, fill the pond water to the full level; in summer high temperatures and autumn stuffy, hot, rainy weather, according to water quality conditions, replace and add fresh water once every 7-10 days, replacing 1/3 of the water each time. At ordinary times, do a good job of water quality testing and pond patrols.
6. Harvest in good time.For two crops of giant river prawn, the first crop is harvested in early August, and the second crop is harvested in early October. For giant river prawn in the first crop and oriental river prawn in the second crop, starting from mid-August, harvest the large giant river prawns and keep the small ones, bringing them to market in stages and batches; the oriental river prawns are kept until May of the following year to be harvested and brought to market. Where conditions permit, the plastic greenhouse temporary holding method can be used, selecting and keeping part of the commercial shrimp for sale around the Spring Festival.