First, water quality analysis and breeding
In the aquaculture process, we generally conduct simple water quality analysis on a regular basis, and qualified entities can establish their own laboratories. The pH value of water, the hardness of water, the content of ammonia and nitrogen in water body, the content of heavy metal ions such as mercury, lead, and copper in the water body all affect the breeding effect. In particular, most fish prefer to live in a neutral and alkaline environment. , Ammonia content in a small water environment.
Second, aquaculture water management and regulation
In the aquaculture production process, with good water sources and good water quality, we must also pay attention to the regulation of water, and the management and regulation of aquaculture water is an important content. This problem can be summed up in the following three aspects.
Water level adjustment In the aquaculture process, we need to timely adjust the water level according to different seasons and different growth stages of the fish. After the beginning of spring each year, the water level is lowered to raise the water temperature rapidly so that fish can be eaten as soon as possible. In the process of summer seedling cultivation, the summer flower cultivation before the â€œinch pieceâ€ should keep the depth of the pool water at about 50cm, and then gradually grow with the fish. Deepen the water level to increase the survival rate of seedlings and accelerate the growth rate. Before the advent of winter, deepen irrigation ponds to make the pool water reach the highest water level to maintain the higher water temperature of the bottom layer of the pond. In our Jianghuai area, the bottom water temperature of the 2 meters deep pond It can reach around 10Â°C, not only can increase the survival rate of fishes in winter, but also can carry out winter fishing at fishing grounds.
Water temperature regulation Each fish has a certain temperature range, and water temperature detection is often performed and some adjustment methods are adopted to make the fish reach the optimal growth state. There are two ways to adjust the water temperature: first, artificially increase water adjustment, and timely add new water so that the temperature of the pond water reaches the optimal temperature of 28-30Â°C. This is particularly important in the open-air breeding of soft-shelled turtles; It is the adjustment of the ecological water temperature, and the proper cultivation of some aquatic plants.
Water Quality Regulation Water quality regulation is an important aspect of water management. It is summarized in the following four points:
(1) Add new water at a proper time. Normally, new water is added every two weeks, each time about 30 centimeters of water is injected, and it is better to use aquaculture in a place where conditions permit.
(2) Scientifically use oxygenation machinery. Generally, a 3kW aerator is installed for every 2,000 square feet, and the oxygen is turned on at a proper time.
(3) Use quicklime to improve water quality. Each kilogram of lime water 25 kilograms of water after Quanchiposa, once a month.
(4) Apply fertilizer timely. During the cultivation process, due to fish defecation, bait, residue and other factors, the ammonia and nitrogen content of the pond are easily increased, and the fertilization amount is generally about 7 kg of dihydrogen phosphate per acre, so as to reduce the ammonia nitrogen concentration in the water and achieve fertilization. And regulate the dual effect of water quality.
Third, water and aquaculture species
When high-density cultivation is conducted, the combination of different water layers and different varieties can be considered; we must pay attention to the constraints of water temperature when breeding tropical fish (such as freshwater whitefish, tilapia) and cold-water fish (such as rainbow trout). factor.
Fourth, water and fish disease prevention
The occurrence of fish disease is a comprehensive factor, but it has the closest relationship with water-related factors. We mainly pay attention to the following three points:
(1) Adhere to the swimming pool once in the morning and evening, and thoroughly clean up the debris and dead fish in the pond in order to maintain the cleanliness of the pond.
(2) Before the seedlings are planted, 250kg of quicklime per acre is used to thoroughly disinfect the ponds.
(3) Regularly use 25g of lime or bleaching powder (containing 25% of available chlorine) per acre to disinfect the pool water and kill the parasite with 0.7g/m3 of trichlorfon.
(4) The intensive culture of ponds is easy for eutrophication, so that the algae can multiply and form â€œbloomâ€, and 0.7 g/m3 of copper sulfate can be used for Quanchiposa.
V. Stress response of water and fish
When the temperature of the fish's living environment changes too much, stress reactions are likely to occur, resulting in colds or frostbite. The temperature difference between the general fry release ponds should not exceed 2Â°C, and the temperature difference when the adult fish transfer to the pond should not exceed 5Â°C.
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