What should be noted for fishery production during heavy snow

The rain and snow weather process since January 10 has affected 77.862 million people in 14 provinces (regions, municipalities) including Anhui, Jiangxi, Henan, and Hunan, with 28 deaths caused by the disaster. Ningbo City also began experiencing heavy snowfall starting at 4:00 this morning, with snow accumulation reaching 2.5 cm. Facing the heaviest snow in 50 years nationwide, fishery production in Yinzhou District should pay attention to the following points:

1. Deepen pond water levels as much as possible to prevent fish from being frostbitten due to excessively low water levels. Because when the pond water level drops too much and the pond water is too shallow, water temperature can easily drop suddenly. Therefore, new water should be replenished in a timely manner. On one hand, this can ensure that the pond water body has a suitable water level and water temperature; on the other hand, it can improve water quality and increase dissolved oxygen in the water body. However, when adding new water, be sure not to let the added new water form a double layer and create double ice, as this can easily cause severe oxygen deficiency in the pond under the ice and lead to suffocation.

2. Pay attention to pond freezing, and once freezing is found, break the ice to allow oxygen through. Shorten the freezing period of the water body as much as possible. Before the pond surface freezes, determine whether to inflow or drain water based on the water temperature of the water source and the water temperature of the aquaculture water body, and try to ensure that the aquaculture water body has a relatively high water temperature to delay the time when the water surface freezes.

3. Do not pull nets and harvest too much during heavy snow. If netting is truly necessary, it should be done quickly to reduce damage to the fish. During the overwintering period, fish rarely feed or stop feeding, their activity level decreases significantly, their metabolic level decreases, their growth rate slows, and their disease resistance drops markedly. Excessive netting can easily cause damage to the fish body, and the fish body surface is prone to infection with saprolegniasis.

4. Pay attention to the safety of various fishery facilities. Greenhouse plastic tunnels and ordinary simple management sheds should have snow removed in a timely manner to prevent collapse from excessive snow accumulation. For pond aquaculture, check whether the inflow and drainage channels are unobstructed. For greenhouse soft-shelled turtle and tropical ornamental fish aquaculture, pay attention to the safety of various pipelines to prevent gas, power, and water outages caused by freezing.

5. Increase the number of pond patrols and pay attention to observing the activity of aquaculture aquatic products. During heavy snow, pond patrols should be appropriately increased, and winter protection work should be done well. During the overwintering period, as long as the water level is deep enough (2.5-3 m), the four major Chinese carps can overwinter safely. However, some tropical and subtropical fish, such as freshwater pomfret, Egyptian catfish, and tilapia, will suffer frostbite when the water temperature is below 10°C, and may even die in large numbers from freezing. They should overwinter in greenhouses, tunnels, or by using waste heat from geothermal factories for insulation. Therefore, once abnormal fish activity is found, measures should be taken promptly.