Do a good winter defense to keep fish safe for the winter

In cold, cold winters, fish ponds are often over-frozen due to water surface, causing fish to be frozen, starved, or suffocated. To do a good job of defense against cold damage in winter and make the fish safe for the winter can lay a good foundation for the winter fish growth, stocking in the spring and raising the morning market, so that the benefits of fish farming can be greatly improved. Many years of practice have proved that the following are the main measures for the prevention of cold damage to fish:

Deep water protection against cold

Choose a pond with a leeward sun and a depth of more than 2 meters to make the fish safely winter. At the same time, wintering pool water can not be in a static state for a long time. Usually, every 20 days to 30 days, some of the pool water is exchanged, and the total pool water is replaced by 1/4 to 1/5 each time to prevent pool water pollution. Conditions can also make use of hot spring water, underground deep well water and other natural environmental conditions for wintering.

Wall hole cold damage

By setting the cold wind wall, avoid cold holes to prevent cold damage. The specific method is to build a windshield with a height of 2 meters or more with straw or mud on the north side of the fish culture pond, and to form a slanting-shaped earth wall on both sides of the east and west sides to reduce the north wind. A drainage ditch should be built around the pond to prevent the pool of stagnant water from flowing into the pool and reduce the pool water temperature. The wall of the north wind wall can be excavated from the bottom 40 centimeters from the bottom of the pool to 2 to 2 meters in depth and 0.8 meters in diameter. The wall of the cave can be bricked or buried with ceramic tubes. When the cold wave strikes, fish can hide in the shelter. Avoid the cold. Practice has proved that this method is cold-proof, low-cost, and effective.

Greenhouse cold damage

On the basis of setting up wind walls and cold-proof holes, it is better to build plastic film cold-proof greenhouses. The method is to use a bamboo or wood material on the pond to build a “human” shaped roof along the edge of the pond. The distance from the ground to the roof is about 2.5 meters. Cover the plastic film with two layers and connect it with the poolside to form a sealed cover. Earth seals the film. Winter pond area is generally 40 square meters to 100 square meters, water depth is more than 2 meters, cement pool, earthen pond can be, stocking density can be determined with the water temperature, water quality and water, generally every cubic meter of water can be placed 15 to 25 broodstock, Or 300 species with 10 cm or less; in better conditions, 30 to 40 broodstock can be placed per cubic meter of water, 400 to 500 fish species; the flow pool can refer to the high-density stocking rate of water culture, which can make The pool dissolved oxygen was maintained at 2 mg/l. In the evening or on rainy days, thick straw curtains can be used to cover the temperature in the sheds. On sunny days, drapes and other coverings should be opened to increase the temperature in the solar energy. When the water temperature is too high, it should be ventilated and replaced with some new water.

Heating and cold damage

1 Steam warming: Hold the stove next to the wintering pond, boil the water with a wok, and let the steam from the special bamboo tube on the lid into the overwintering pool through the connected hose to increase the temperature of the pool water.

2 Infrared lamp heating: In the wintering pond covered with plastic film greenhouses, one 250-watt infrared light bulb is installed on every 35 square meters of water, 30 centimeters from the water surface, and a thick paper with water absorption is fixed at about 60 cm above the bulb. Or other absorbent materials to prevent condensation of water vapour on the film falls into the bulb, causing the bulb to burst or misfire. Turn off the lights when the water temperature rises to 20°C. Infrared lamps have a large amount of heat, fast heating, low power consumption, simple installation, sterilization, and prevention of fish diseases such as hydromycosis.

Add material to prevent damage

During the winter season, the feeding of bait should not be neglected, especially the feeding of high protein concentrates. Increasing feeds containing protein-rich concentrates can improve cold resistance and prevent wintering fish from deteriorating. When preparing, attention should be paid to nutrition, especially amino acid balance, vitamins and trace elements. Generally, the protein content of feed during wintering of general fish should be about 25%, and the feed protein content of tilapia can be lower at about 20%, but the energy content should be higher, and can be fine, bran, bean cake, malt, etc. , and often mix and feed some green lentils, fresh leaves. The soft-shelled turtle is mainly bred through intensive cultivation to improve its own resilience. Before and after winter, turtles need to be supplemented with nutrients. First, they should strengthen their energy and protein supplements. The fat content can be increased to 3% to 5%, and as much as possible to feed some fresh feed, and targeted vitamin supplements and calcium, phosphorus and so on. In winter, the lack of sunlight is likely to cause calcium deficiency. In order to increase yolk deposition, more phosphorus is needed. During the wintering season, the soft-shelled turtle needs more B vitamins, vitamin A, vitamin D, vitamin E, and choline than the normal feeding period, so it should be increased in appropriate amounts. All fish to feed the fine material must also do "three set", that is, quality, timing, and quantitative.

Oxygen protection against cold

If the ice is too thick on the river surface, the oxygen in the water under the ice will cause the fish to suffocate and die. At this time, it is necessary to immediately sweep snow, break ice, change water in time, start aeration machinery, and regularly use microbial preparations to improve water quality. In particular, some of the “old water” ponds, oysters and squid, are also susceptible to diseases such as anchoring head lice in the absence of oxygen. Therefore, they must also timely apply insecticides to prevent and cure diseases in order to achieve cold damage. The disease is the same as prevention and treatment.

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