How Do Chinese Mitten Crabs Overwinter? Overwintering Management Methods and Precautions

September 23rd is the day when fishing for Yangcheng Lake Chinese mitten crabs opens. Apart from those ready for market, the ones that do not reach the required size need to overwinter. So do you know how Chinese mitten crabs overwinter? How are they farmed?

1. How do Chinese mitten crabs overwinter?

Chinese mitten crabs overwinter by hibernating, but in winter they still eat as usual. Moreover, when hibernating, Chinese mitten crabs shut down many organs and hardly move except to forage, which reduces energy consumption and allows them to overwinter safely.

2. How are overwintering Chinese mitten crabs raised?

1. Farming pond

The overwintering pond for Yangcheng Lake Chinese mitten crabs should be an earthen pond, not a cement or brick pond. In the earthen pond, there should also be small mounds of earth rising above the water surface to provide conditions for Yangcheng Lake Chinese mitten crabs to dig holes and burrow, so that they can use the burrows to resist the cold. Second, the overwintering pond for Yangcheng Lake Chinese mitten crabs should have the water level raised appropriately, so as to achieve deep-water overwintering.

2. Water temperature

Generally, the water depth in the pond should reach 1-1.5 m, and the pond water should be kept from freezing as much as possible. Some areas in the north have severe cold and very low temperatures; where conditions permit, plastic greenhouses can be used to help Yangcheng Lake Chinese mitten crabs overwinter safely. An appropriate amount of table salt is added to the overwintering pond to lower the freezing point and meet the physiological needs of Yangcheng Lake Chinese mitten crabs. The salinity should preferably not exceed 0.3%.

3. Feeding

In the earlier stage of feeding, the bait should be mainly plant-based food, such as soaked or cooked wheat grains, soybeans, sweet potatoes, vegetables, etc. The daily bait amount should account for about 5%-8% of the crab weight, fed once each in the morning and afternoon. Feed at 10 a.m.-11 a.m., with the feed accounting for 3 parts, and feed at 4 p.m.-5 p.m., accounting for 7 parts. In the later stage of feeding, the animal protein content in the food should be appropriately increased, and small trash fish and shrimp, snail and mussel meat, compound feed, etc. can be fed in appropriate amounts.

4. Management

More aquatic plants should be placed in the overwintering pond. At the same time, some firewood and grass should be spread on the pond embankment to block wind and snow, so that snowmelt cannot flow directly into the pond. In addition, disease prevention and control for overwintering Yangcheng Lake Chinese mitten crabs should also be done well.