Study on ecology and meteorology experiment of eriocheir sinensis breeding

Abstract:

River crab faming is impacted a lot by water ecological factors. In order to research the effect of water ecological factors and meteorological factors to the growth of crabs, a breeding observation sites is established where water temperature, PH value, dissolved oxygen and other water projects and river ecological factors are observed, including crab growth and condition monitoring such as crab shelling time, length, weight, disease and other items. Observations statistical analysis of 2011 year shows that: 1) the crab growth process is non-uniform, the difference of the growth rates is rather big in different stages, and two relatively fast growth periods which are late June to mid-July and late August to mid-September in 2011 are observed;2)Before mid-May, both male and female crabs grow slowly , and the difference between individuals and sex is very small; After the late of May ,the difference between individuals and sex increases gradually; In late July, the mean variance of quality increases gradually among male crabs , while relatively stable among female crabs, which indicates that the growth is relatively even between the female crabs individuals; 3) the river crabs grow with the increase of weight and shape as well as the degree of fullness and robust. The degree of robust and fullness among male crabs is generally larger than the female crabs when it closes to the mature stage;4）The water temperature diurnal variation curve of each layer is close to the positive spin curve in Observation point 4, and the amplitude decreases with the increasing of water depth the daily variation of dissolved oxygen value is mainly relevant with the altitude of the sun, the higher the altitude of the sun during the day, the stronger the light will be ;5)the growth of river crab is highly relevant with the water temperature and dissolved oxygen .Water temperature is too low or too high，which is not conducive to the crab’s growth, and low dissolved oxygen concentration is a direct threat to aquatic life, but the greater concentration of dissolved oxygen is not necessary the best, which is proved that the dissolved oxygen concentration between the 5.0 ~ 7.0 mg/L is the best for the growth crab.