Management experience of overwintering in parent shrimp breeding ponds of cultured crayfish

During the whole period of overwintering, parent shrimp basically do not eat, and consume a lot. Therefore, it is necessary to strengthen feeding before overwintering, strengthen the physique of parent shrimp, reserve necessary nutrients for safe overwintering, and improve the survival rate of overwintering. When the water temperature drops below 10 ℃, the basic parent shrimp cave overwinters and seldom comes out of the hole. At this time, the water level should be properly deepened to ensure that there is water or moisture in the cave, but the water depth should not exceed the mouth of the cave, which is slightly lower than that of the hole, otherwise the parent shrimp will come out of the hole to choose a new place to drill the hole. When the parent shrimp basic human hole, spread a thin layer of plant straw, such as straw, Reed, cattail, etc., along the water edge around the pond, one is to keep warm. The second is to provide a hiding and overwintering place for the young prawns born before parent shrimp overwintering.

When the water level is full, fertilizers should be applied to maintain a certain degree of water quality. Generally, mature organic fertilizer 100kg is applied per mu and piled in the water around the four corners of the pond. The water quality in winter is very easy to clear due to the influence of the weather. According to the actual situation, it is necessary to apply fertilizer when necessary to keep the transparency around 30cm. The purpose is that water and fertilizer are not easy to freeze, and there will be more plankton in the water. Especially in spring, plankton will multiply very quickly. As soon as the larvae get out of the hole, they can easily get nutritious and palatable natural bait, which can improve the survival rate of the larvae. There are two kinds of caves. One is that the entrance of the cave is sealed with pagoda-like soil. This kind of cave is commonly known as "sealing hole". Shrimp will not come out of the hole until spring. The other kind of hole is open, and the shrimp will swim between the bottom of the cave. When the weather is fine and the temperature rises, the shrimp will come out of the hole and move near the mouth of the cave. When the weather is fine and the temperature rises during the winter, it is necessary to properly feed a certain amount of bait near the opening of the open hole at noon for freshwater crayfish coming out of the cave. It is necessary to improve the survival rate of overwintering, and persist in patrolling the pond many times a day. To observe the activities of parent shrimp, ice should be broken in time in cold weather, and all kinds of records should be done at the same time, especially the death, including the number, size and weight of male and female shrimp, which is beneficial to the estimation of feeding and seedling quantity in the future.