Key points of daily management techniques for polyculture of river crab and freshwater shrimp

Water quality management

Based on the living habits of shrimp and crabs, which require clear and light water quality for growth, new water should be added frequently. In the early stage, add new water once every 15 to 20 days. During the peak feeding and rapid growth season, add or exchange water 2 to 3 times per week, or even once every evening. Note that water should not be flushed when shrimp and crabs are concentrated in molting, otherwise it may cause adverse effects on molting shrimp and crabs.

Turning on the aerator at the appropriate time

Generally speaking, turn it on at noon on sunny days and in the middle of the night during continuous rainy days. When the weather is hot, the operating time is long; when the weather is cool, the operating time is short. At noon the operating time is short; in the middle of the night the operating time is long (when turned on in the middle of the night, it must not be stopped until after sunrise in the morning). If signs of floating head are found, turn it on as early as possible.

Management during the molting period

1. Splashing external medication and fertilizing should avoid the relatively concentrated molting period.

2. Grasp the molting pattern and predict the next molting peak.

3. One week before the molting peak, change the water and then disinfect; add molting hormone to the feed.

4. During the molting peak, reduce the feeding amount and pay attention to keeping the environment relatively quiet.

Disease prevention and control

During the breeding process, adhere to prevention first, and normally splash quicklime at 10 to 20 grams per cubic meter over the whole pond every 15 to 20 days. At the same time, use biological agents to regulate water quality and improve the water body's ecological environment.

Harvest

Freshwater shrimp can begin to be harvested in the first half of the year, and all are harvested when the pond is dried at the end of the year. Macrobrachium rosenbergii and Penaeus vannamei can adopt the method of partial harvesting and thinning to avoid concentrated marketing, while also reducing the breeding density, which is beneficial to the growth of the shrimp remaining in the pond. River crabs generally begin to be caught and marketed in October.