The stocking of shrimp fry can be divided into two types according to salinity: seawater culture and fresh water culture. According to latitude, it can be divided into two types: low latitude tropical zone and high latitude temperate zone. In fact, the lofting time of shrimp seedlings is mainly determined by the water temperature. In general, when the water temperature is higher than 22℃, seedlings can be released. However, when the water temperature is higher than 35℃, seedlings should be carefully planted. If the water temperature is high and the water level in the shrimp pond rises, it can also be cultivated. The following information can be used as a reference:
1, Fujian, Guangdong and Guangxi provinces generally raise three shrimps a year, and the order of releasing seedlings is: the end of March or the beginning of April (the first shrimp), the end of June or the beginning of July (the second shrimp), the end of September or the beginning of 10 (the third shrimp needs to be built in a film shed in the later period and sold around the Spring Festival at a high price); -Sea shrimp
2. Generally, four shrimps can be cultivated all year round in Hainan Province. The stocking time is subject to the above "1", and seedlings are released on 1 month. In fact, it is better to try to build a greenhouse in other places in Hainan except Sanya. -Sea shrimp
3. Most prawns are cultured in the surrounding areas of the middle and lower reaches of the Yangtze River. Generally, it can be released from the end of May to mid-July, as far as possible before August. Otherwise, as the temperature drops in the later period of prawn culture, prawns will not grow up without eating, which will affect the market specifications. Of course, seedlings can be released in April if conditions permit, provided that you have a temporary greenhouse for shrimp seedlings, and shrimp seedlings usually stay in a double-layer greenhouse for about 1 month. When the water temperature in the open-air shrimp pond reaches above 22℃, shrimp seedlings can be moved out of the greenhouse, and two kinds of shrimp can also be cultivated. -Freshwater shrimp
4. In the northern area, both seawater shrimp and freshwater shrimp are mostly cultured only once a year. The seedling release time is from June to early July. Of course, it is not absolute. In a small part of the northern coastal areas, two shrimps can also be raised a year by using groundwater or boiler heating equipment, and the seedling release time is similar to that of "3"; -There are both seawater shrimp and freshwater shrimp.
Shrimp is raised in factory, and seedlings can be released at any time all year round. However, it requires high equipment and workshop, large investment and high technical difficulty. Generally, the yield per mu is above 10 thousand Jin. The cost is as high as 20 yuan/kg at low temperature, mainly due to the high cost of temperature rise and water quality regulator.