First, commodity crab management
Icebreaking: The quality of commercial crabs is high, and the temperature after snow is low. It is difficult to culture and manage. By ice-ice or ice-breaking, on the one hand, it can be observed whether there is water shortage and oxygen deficiency in the wintering pond, and on the other hand, some harmful gas in the water body can escape. When the water is deficient in oxygen, it is less than 1.8 mg per liter. In the vicinity of the ice eye, aquatic insects such as scorpionfish and pine mites can be seen to gather, and oxygenation measures are taken in time according to the observed situation.
Aeration: 85% of the oxygen in the water comes from phytoplankton photosynthesis oxygenation, and a small part comes from the incorporation of air and hydration. The ice should be kept clear, and the wintering pond should be sealed with clear ice. If it is frozen into ice, it should be broken and re-frozen to ensure that the ice area accounts for more than 50%. After snow, the snow is cleared in time, and the snow area accounts for more than 80% of the pond area. If the ice is gone or the snow is not timely, it will cause insufficient light under the ice, blocking photosynthesis, and easily cause hypoxia. Mechanical oxygenation, can be continuously started for 2 hours to 3 hours with a 1.5 kW ~ 3.0 kW aerator. In the case of lack of water in the wintering pond and lack of water, use a water pump to circulate water to increase oxygen, and use a gas cylinder or air pump to press air. Add oxygen to the water. Chemical aeration, in the case of an emergency, using a chemical such as Zengyangling to increase oxygen.
Replenishment: Ensure that the water depth of the wintering pond is above 0.8 meters. If it is lower than this, it should be filled with water at any time. The water temperature of the hydration should exceed 4 °C.
Starting catch: 0 ° C or above can be caught in the dry pool, below 0 ° C is not suitable for catching, can enter the crab pool water, such as the day to catch the crab in the dry pool, the crab pool back into the water in the evening.
Second, river crab species management
Water level control, it is necessary to frequently check whether there is leakage in the wintering pond, and the crab pool cannot be in a low water level for a long time. The wintering pond should be kept at a water depth of about 1.5 meters. The river crabs will not be frostbitten and frozen if they are in a deeper water body. Otherwise, the crab, if hidden in a cave or mud, is still exposed to the air and will be frostbitten or frozen. It is found that the water level drops, and water should be added in time. The temperature difference between the inlet water and the water does not exceed 2 °C.
The bait was fed, and the crabs basically stopped eating after the snowstorm. When the ice and snow melt, the amount of crab activity increases, and attention is paid to maintaining fresh water quality. When the water temperature rises to about 5 °C, the animal feed containing high fat and protein, cooked wheat grains, corn, etc. are appropriately increased.
For daily management, special personnel should be used to patrol the pond. The ice-covered pond surface should be broken and frozen in time to minimize the phenomenon of crabs such as boating, fishing, fish and shrimp, etc., to avoid the crabs being shocked and injured and consuming physical strength.
Third, the main points of crab production after the disaster
1. Pond clearing Before the stocking, the pond must be cleaned. After the snow, the pond will also strengthen the pond and remove excess sludge. About 15 days before the stocking of crabs, the pool is thoroughly cleaned. There are two methods for dry pool and clear water pool. Generally, the dry method clear pool uses 75 kilograms of quicklime per acre, and the whole pool is splashed after melting. The water-clearing pool is only used when the pool water cannot be mostly discharged. The specific amount can be flexibly controlled according to the depth of the pool water, and it can ensure that the enemy organisms in the water can be killed.
2. Reinforced anti-fighting facilities A strong anti-floating facility shall be built around the cultured river crab pond to prevent the river crab from escaping. The inner wall of the anti-escape facility should be smooth, and the plastic film, iron plate and aluminum plate are commonly used.
3. Aquatic plants have been planted with aquatic plants such as Elodea. To prevent the freezing of water plants, the specific method is to ensure that the water level is higher than that of water plants and that the ice layer is above the water plants.
4. When the temperature of the stocked crabs is below 0 °C or when it is snowing, the crab species cannot be arrested, transported and stocked to prevent frostbite of the crab species. Wait for the weather to pick up, and when the temperature is above 5 °C, carry out the related operations of the crab species.