1. Selection of wintering pools. Pro-crabs are generally wintered in outdoor earthen ponds. Over-wintering ponds should be selected where they are sheltered from the wind, sunny, close to water, and where the environment is relatively quiet, east-west, rectangular or square earthen ponds, water depths of more than 1.5 meters, and clay soil or clay is preferred.
2. Water quality regulation. During the winter of holding eggs and crabs, when the water body is frozen, insert a proper amount of grass handles and break ice before the sun rises every morning to clean the snow on the ice. Focus on maintaining a relatively stable water environment, the main water quality indicators are monitored once every two weeks, salinity of about 25 ,, dissolved oxygen more than 5 mg per liter, pH value of 7.8 to 8.7 as well.
Leaked earthen ponds shall be filled with water once every 5 days to 7 days. The amount of water exchanged shall not exceed 30% of the total body of water to maintain the water level above 1.5 meters. When more than 5°C is reached, fresh seawater must be added and replaced regularly.
3. Feed feeding. Choose nutritious fresh live bait, such as sand, fresh fish, malt and so on. After the pro-crabs hold eggs, with the continuous change of water temperature, depending on food intake, the daily feeding amount is generally controlled to be 2% to 10% of the total weight of the pro-crab. No matter how the surface water temperature changes, as long as there is a pro crab activity, it is necessary to feed it properly. Feed it once a day before sunset, put the feed below the water level along the soil pool, check the feeding situation on the second day, remove the residual bait, and adjust the feeding amount. A variety of bait species to alternate feeding. Water temperature above 8 °C to feed fresh bait and with bait.
4. Daily management. Every morning and evening, one or more patrols are performed to observe the activities of the crabs, the feeding conditions, and changes in the water color; check whether the escape prevention facilities are damaged; check the fertilized eggs of the brooding crabs regularly every half a month. Take and adjust management measures to ensure that the egg-bearing crabs have passed the winter.
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