Key Technical Points for Winter Management of River Crab Pond Aquaculture

2015 was a relatively warm winter, with daytime temperatures basically staying above 10°C. A warm winter is relatively special for river crabs, as their living habits are greatly affected by temperature. This is mainly because river crabs begin feeding at 10°C and feed normally above 16°C. Therefore, under warm winter conditions, the activity capacity and feeding of river crabs are significantly enhanced. Overwintering is a foundation, and how to let river crabs overwinter healthily and smoothly will directly affect our aquaculture benefits in 2015. This article shares some communication with everyone on the key points of winter management of river crab ponds.

1. Seedling release: After crab seedlings are transported to the pond, differences in water quality, density and other aspects between the seedling pond and the adult crab pond will cause problems such as river crabs coming ashore and other maladaptation. When releasing seedlings, use one set of “Kangjiling” + “Huangjin Duotang” to soak 10,000 seedlings. It can quickly supplement the physique of river crabs and reduce stress-related coming ashore.

2. Feed high-protein feed or small fish once every 5-7 days to ensure the physique of river crabs.

3. Fertilizing water: River crab feeding can be divided into active feeding and passive feeding. Feeding materials belongs to providing bait for active feeding by river crabs. River crabs have a habit of absorbing water, and a large amount of algae and zooplankton will be accidentally taken into their bodies by river crabs, which we call passive feeding. Crabs actively eating feed is what we call active feeding. It is precisely because of this passive feeding that by using “Feishui Wang” + “Huangjin Ye” to quickly fertilize water, while Feishui Wang is rich in amino acids, small peptides and other nutrients that can be directly absorbed by river crabs, it can quickly and directly supplement the physique of river crabs.

4. Disinfection: During transportation, river crabs will inevitably suffer problems such as wear on the tips of their claws. One week after releasing seedlings, after the crab seedlings have properly fed and their physique has recovered, use Chaoiodine at 2 mu*m/bottle for one disinfection to prevent bacterial diseases such as rotten claws that lead to incomplete molting later. 

5. Regular detoxification: For ponds that use pyrethroids, such as Decis, Miechongba, etc. for pond clearing, attention should be paid to regular detoxification even after seedling release, because pyrethroids easily settle into the soil during low-temperature periods, and crabs live at the bottom of the pond. Especially in winter, many crabs like to hide in mud and sand, making chronic poisoning likely. Therefore, it is recommended to do a good job of “four detoxifications”: use Jieduling twice before and after seedling release, once every 7 days. The activated carbon in Jieduling can quickly and durably absorb pyrethroid drug residues, provide an excellent environment for river crab growth, and reduce incomplete molting caused by chronic poisoning during the first molting of river crabs.