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一、周期性水面的成因与特性周期性水面是指北方干旱或半干旱地区的一些湖泊的水源完全是依靠流域内的自然降水供给.这些湖泊的水量随着降水的多少而起落.由于降水量的不均衡,造成这类水面有着丰水——枯水——再丰水——再枯水……的不规则的周期性循环变化.这种周期多则4～7年,少则1～2年,把达到养鱼条件要求的蓄水期称丰水期,只要能保证一年以上鱼类生长期的,即可及时投放鱼种,可创较好的经济效益.枯水期即是水位大幅度下降,水质浓缩,造成鱼类不能生存,成为渔业生产中的空闲期.由于该期内摄食浮游生物和底栖
First, the periodic water surface causes and characteristics of periodic water refers to the northern arid or semi-arid areas of some of the lake’s water supply is entirely dependent on the natural precipitation within the watershed.The amount of water in these lakes rises and falls with the precipitation due to precipitation Of the imbalanced, resulting in such a surface has abundant water - dry water - then abundant water - then dry ... irregular cycle of cyclical changes in this cycle as many as 4 to 7 years, ranging from 1 ~ 2 years, the conditions of the fish meet the requirements of the storage period known as the wet period, as long as more than one year to ensure that the fish growing season, you can put the fish species in a timely manner, can create better economic benefits. Decline in amplitude, concentration of water, resulting in fish can not survive, becoming an idle period in the production of fisheries. As the period of feeding plankton and benthic