What is the relationship between the farming of the four major Chinese carps and meteorological conditions?
Fish live in water, but they are also closely related to meteorological conditions.
Temperature: fish are ectothermic animals, and the water temperature is their body temperature. The water temperature directly affects their life metabolism. The suitable temperature range is 10 to 33°C, and the optimal temperature is 25 to 30°C. Below 10°C they begin to hibernate. At 10 to 15°C they begin to feed and grow slowly. At 15 to 20°C their appetite increases and they grow faster. At 20 to 30°C they grow fastest. Above 30°C their growth slows again. Therefore, when feeding, pay attention to temperature changes. Temperature is also related to the dissolved oxygen content in the water.
Temperature is closely related to the induced spawning, egg laying, egg hatching, fry growth and transportation of Chinese carps. At a water temperature of 18 to 30°C, with consecutive sunny days for induced spawning, the amount of eggs laid, the fertilization rate and the hatching rate are all high. Below 8°C the carps stop feeding. Above 30°C their appetite is poor. Below 16°C the hatching rate is low. Above 31°C the mortality rate is high. At 8 to 10°C the fish move little and consume little oxygen, which is suitable for transportation. Sudden temperature changes make fish prone to death. Especially when stocking fry, pay attention to differences in water temperature.
Light: fish, like other animals, need an adequate supply of oxygen. An important source of oxygen in water is the oxygen released by photosynthesis of phytoplankton in the water. Other organisms and bacteria in the water also consume oxygen when decomposing organic matter. Therefore, severe shading, or long periods of overcast and rainy weather and poor light, will affect the oxygen content in the water and affect fish growth. Without light, the production of aquatic plants is affected, and the food supply for fish also becomes a problem.
Oxygen in the air can also dissolve directly into water, but the amount is not large. When there are wind and waves, oxygen dissolves into the water more than 100 times faster than in still water. When the temperature is high, the dissolved oxygen content decreases, and decomposition is strong, which increases oxygen consumption. Therefore, oxygen deficiency is more likely at high temperatures, causing fish to gasp at the surface. When air pressure is low, the oxygen dissolved in the water also decreases. On overcast days with low air pressure and high temperature, oxygen deficiency is most likely to occur, which deserves attention.