Reservoir sediment releases bring benefits of mitigating sedimentation and restoring river consecutive sediment transportation. But high concentrated sediment flow and water quality change may cause adverse effects on fish. For the purpose of analyzing influences of different concentrated suspended sediments on Yellow River Carp (Cyprinus carpio), 7 laboratory experiments were carried out with carp exposed in water containing suspended sediment, which was extracted from the Huayuankou section of the Yellow River during sediment flushing period of the 128 km upstream Xiaolangdi Reservoir in 2011. With sediment concentration ranging from 16 to 182 kg/m~3, dissolved oxygen and mortality were recorded during experiment process. Consequently, influences of sediment concentration, dissolved oxygen and exposure duration on mortality were analyzed. It was discovered that most deaths occurred either in thebeginning 2 hours or about 10 hours later, the former probably due to drastic fall of dissolved oxygen concentration and the later caused by long term high concentrated sediment. With sediment concentration below 60 kg/m~3, it was observed that dissolved oxygen concentration changed gently comparatively, and mortality mainly related to exposure duration. While, survival rates and durationdecreased gradually with the increasing of suspended sediment concentration. Drastic fall of dissolved oxygen concentration was detected when sediment concentration exceeding 90 kg/m~3, which resulted in reaching 100% mortality in the first hour. The relationship between survival time and sediment concentration for different mortal rates is plotted. Findings and discussed principles in this article could give considerable support to the sustainable management of reservoir sediment releases.
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