Practical measures against cold in fish and soft-shelled turtle

1. Fishing ponds choose to choose leeward sunny deep water (more than 2 meters) fishing ponds naturally overwinter. The overwintering pool water should not be in a static state for a long time. It is usually 20 to 30 days to replace part of the pool water, and each time the total pool water is changed to prevent water pollution.

two。 On the north side of the fishing pond, a 2-meter-high wind barrier can be built with straw or soil, and the east and west sides can be built into a dustpan shape to reduce the attack of the north wind. When the cold wave strikes, the water temperature will not drop significantly. Drainage ditches should be built around the fishing pond to prevent stagnant water from flowing into the pond and reduce the temperature of the pool water. The north windshield wall 40 cm from the bottom of the pool can dig 1 or 2 cold shelters with a depth of 2 meters and a diameter of 0.8 meters. The walls of the holes can be built with bricks or buried ceramic pipes, and fish can enter the shelter when the cold wave strikes.

3. Build a plastic film cold-proof greenhouse on the basis of setting a wind barrier, build a plastic greenhouse on the fishing pond to keep warm. With bamboo or wood along the edge of the pond to build a "human"-shaped roof, the distance from the ground to the roof is about 2.5 meters, covered with two layers of plastic film, connected with the edge of the pool to form a sealing cover, around which can be sealed with mud. Tilapia overwintering ponds generally have an area of 40 ~ 100 square meters and a water depth of more than 2 meters. Cement ponds and soil ponds can be used. The stocking density can be determined by water temperature, water quality and water quantity. Generally, 15 ~ 25 parent fish can be released per cubic meter of water, or 300 species below 10 centimeters. In the ponds with better conditions, 30 ~ 40 parent fish and 400 ~ 500 fingerlings can be put in each cubic meter of water. The running pond can refer to the high-density stocking capacity of running water culture, which can keep the dissolved oxygen in the pond water at 2 mg / L. The juvenile soft-shelled turtle overwinters outdoors, and its mortality rate can reach 70% to 80% without heat preservation measures. Therefore, if conditions permit, it is best for young turtles to winter in indoor ponds or in open-air ponds with plastic sheds, with a stocking density of about 100 turtles per square meter. if well managed, the overwintering survival rate can reach 80% and 90%.

When overwintering with plastic film greenhouse, thick grass curtains can be used at night or rainy days to maintain the temperature in the greenhouse, while in sunny days, grass curtains and other things should be opened to make use of solar energy to increase temperature. When the air temperature and water temperature are too high, it should be ventilated and filled with some new water. When the cold current invades and the water temperature decreases, the following heating measures can be taken: (1) Steam heating method: add a stove next to the overwintering pool and boil the water with an iron pot, so that the steam from the pot lid on the special bamboo tube enters the overwintering pool through the connected hose to increase the water temperature. (2) Infrared lamp heating method: in the above-mentioned overwintering pool covered with a sealed plastic film greenhouse, a 250 watt infrared light bulb is installed on every 35 square meters of water surface, 30 cm from the water surface, and about 60 cm above the light bulb. fix a piece of thick papery or other water-absorbing material that is easy to dry and absorb water, so as to prevent the water condensed on the film from dripping on the bulb and causing the bulb to burst or misfire. When the water temperature rises to 20 ℃, turn off the lights. The use of infrared heating benefits: infrared lamp heat, rapid warming, less electricity, simple installation, and germicidal effect, can prevent the occurrence of fish mildew.

4. Although the metabolic level of concentrate fish is low during overwintering, it still needs to consume a lot of energy, so feeding is still an indispensable work in the process of overwintering. The main purpose of overwintering is not to gain weight, but to prevent frostbite and death, and to keep the fish in good health. In order to prevent the physical decline of overwintering fish and enhance their resistance to adversity, efforts should be made on the selection of feed. In order to ensure the healthy growth of fish, we should pay attention to the comprehensive and reasonable collocation of nutrition, not to pursue too high protein content and too fast growth rate unilaterally, but to pay more attention to the balance of amino acids and the abundance of vitamins and trace elements. For example, the protein content of the feed used in the overwintering period of tilapia can be lower, about 20%, but the energy content should be higher, and it should be fed mainly with fine bran, wheat bran, bean cake, malt and so on, and often with some green duckweed and fresh vegetable leaves. In order to ensure the soft-shelled turtle to survive the winter safely, the stress resistance of the soft-shelled turtle should be improved by strengthening cultivation. Soft-shelled turtles need to supplement nutrition before and after overwintering. First of all, the supplement of energy and protein should be strengthened, the fat content can be increased by 3% to 5%, and some fresh feed should be fed as much as possible, and then vitamins, calcium and phosphorus should be replenished. Lack of sunlight in winter is prone to lack of calcium, and more phosphorus is needed to increase yolk deposition. The requirement of B vitamins, vitamin A, D, E and choline of soft-shelled turtle during overwintering period is higher than that of normal feeding period, so an appropriate amount of these substances should be increased to improve the cold resistance, disease resistance and prevent poor fat metabolism of soft-shelled turtle.

5. If the water temperature drops suddenly, heating measures should be taken immediately. The cold wave often causes continuous low temperature, overcast and rain, which can easily lead to the deterioration of water quality in fishing ponds and the incidence of pond fish. Some "old water" pond silver carp and bighead carp are susceptible to anchor head disease, etc., in addition to paying attention to changing water, frequently turning on aerating machines and regularly applying microbial agents to improve water quality, it is also necessary to timely apply insecticides and other effective prevention and control to prevent the spread and spread of diseases and insect pests.