Raising fish species in winter, eight key points to increase yield

Raising fish species in winter, eight key points to increase yield

At present, many fish farmers generally adopt the traditional culture method of "catching fish in spring and winter". Practice has proved that the best way is to "release winter fishing in winter", that is, to release fish species before and after "the Winter Solstice" in the first year, and to put them on the market in the winter of the second year. Practice has proved that the Winter Solstice to the Beginning of Spring is the best time to release fish fingers. due to low water temperature, compact fish scales and weak fish vitality, the fish is not easy to be injured in the process of stocking operation. the survival rate of fish is high after entering the pond. To increase fish production.

To do a good job of releasing fish in winter, we should pay attention to the following key points:

1. Pay attention to clear the pond and disinfect. The pond has a water depth of 10 cm. First, 90 kg of quicklime or 4 kg of bleach containing 30% chlorine is used for every 667 square meters (1 mu), which is adjusted into a paste and evenly sprinkled throughout the pond. Then fill the pond with 12 kg of bleach for every 667 square meters, spread evenly and stir well. Generally, the fish can be released after 7 days.

two。 Pay attention to the fat water in the pond. Base fertilizer was applied after clearing the pond for 5 to 7 days. Generally, 500 kilograms of fermented pig and cow dung or 200 kilograms of human dung are applied in every 667 square meter pond (more can be applied in new ponds or thin ponds), and then injected with water, which is conducive to the growth of phytoplankton and provide natural bait.

3. Pay attention to the appropriate specifications. For the fish species, the length of grass, silver carp and bighead carp should be 15 cm, 13 cm for carp, 10 cm for crucian carp and carp. The selection of fish species should have the same specification and strong physique, which is helpful to improve the survival rate of fish species.

4. Pay attention to the early release. The Winter Solstice around the Spring Festival, or the water temperature is 8: 10 ℃ is the best time to release fish. At this time, the water quality is stable, the fish body is strong, the fish body is not easy to be injured in fishing and transportation, and the mortality and morbidity are low. At the same time, fish species are kept sparsely as early as possible, adapt to the environment early, start eating early and gain weight quickly. When stocking, it is better to choose to carry out at noon on sunny days, but not in frost, rain and snow days where the temperature is too low, so as to prevent frostbite of fish.

5. Pay attention to the disinfection of fish species. The fish should be put into the pond after disinfection. Generally, fish seeds are washed with 3% 5% bleach powder and 8% copper sulfate for 20 minutes, or 5 minutes with 3% 5% salt water for 10 minutes to kill the pathogens on the fish body surface.

6. Pay attention to reasonable mixed culture. According to the water quality, bait and size of fish species in fish culture waters, the reasonable stocking density and quantity were determined. Water and fertilizer, mainly fertilization, combined with bait, should be silver carp and bighead carp; thin water, mainly bait, more green fodder, grass carp. The stocking capacity is about 1000 per 667m2.

7. Pay attention to strengthening management. The pond should be managed by a special person. The water should be changed once every 20 days, and the water should be added 15cm to 20cm each time. The water should be discharged first and then irrigated to adjust the water quality. The weather is suddenly cold and the water level should be deepened to more than 2 meters. For ponds with no replenishment of water for a long time and low oxygen content, ammonium nitrate 5kg / 667 square meters and calcium superphosphate 3kg / 667 square meters are mixed into a small cloth bag and hung underwater, stirring part of the pond bottom with bamboo poles at noon on a sunny day, and then stirring the other part once a month after a period of time. Some pig dung, lees, bean cakes or vegetable cakes should be properly put into the overwintering ponds to improve the water temperature and meet the small food needs of overwintering fish. When the water temperature reaches 7: 8 ℃ in spring, we should apply bait early to cultivate fertile water and promote the fish to grow fast.

8. Pay attention to the prevention and control of fish diseases. During the overwintering period, fish are easy to be infected with water mildew, red skin disease and so on. Water mildew can be sprinkled throughout the pool with a mixture of 4% salt and 4% baking soda, or every 667 square meters, 1 meter deep, with 10 mg / kg bleach powder. Patients with red skin disease were sprinkled with 1 mg / kg bleach in the whole pool on the first day, 0.5 kg of quicklime on the second day, and 1 mg / kg of bleach on the 4th day. Oblique tube disease and filariasis are sprinkled throughout the pool with 0.1 grams of mercurous nitrate and 0.2 grams of chemical water per cubic meter of water, or 0.25 grams of dried chili powder and 0.1 grams of ginger per cubic meter of water. Fish lice are sprinkled with 90% crystal trichlorfon 0.2-0.5 mg / kg.

Stocking fish species in winter

Points for attention

The temperature is low in winter and it is difficult to manage the aquaculture environment, so it is recommended to prevent shallow water. The water in the overwintering pond is shallow, the water temperature changes quickly and the temperature difference is large, which is disadvantageous to the growth of fish. After the water level drops, the fish density increases accordingly, which is easy to cause hypoxia and make the fish stop growing or even die. Therefore, the fish pond should maintain normal water level in winter.

Under normal circumstances, anoxic floodponds mostly occur in the high temperature season in summer and autumn, and are rare in winter. However, under the conditions of fat-water fish ponds, deep pool stagnant fish ponds and cage culture, anoxic dead fish will also occur in winter. In the above-mentioned waters, with the decrease of air temperature, the surface water temperature decreases and the density increases, and the bottom layer is anoxic and oxygen-free water floats, which will cause serious hypoxia in the upper water body. In addition, when the illumination time is short in winter, the photosynthesis of phytoplankton in water weakens and the oxygen production decreases, which will also lead to insufficient dissolved oxygen in aquaculture water. Therefore, it is necessary to take timely measures to increase oxygen in these waters in winter to prevent dead fish from flooding ponds.