三峡水库变动回水区蓄水期鱼群空间分布及生境特征

Spatial Distribution and Habitat Characteristics of Fish Swarm in Fluctuating Backwater Zone of Three Gorges Reservoir in Impoundment Period

三峡水库蓄水后变动回水区水动力条件和泥沙运动发生了显著变化,鱼类栖息地也受到了不同程度的影响。为了掌握三峡变动回水区朝天门至涪陵河段蓄水期鱼类栖息地现状,研究采用Bisonics DT-X科学回声鱼测仪对朝天门至涪陵河段进行了鱼群空间分布及生境特征监测。结果表明:蓄水期该河段水环境因子空间分布变化不显著,表明水环境因子不是影响该河段鱼群分布的主要原因;水深与流速在该河段变化较大,是影响鱼类栖息的关键因子;监测到8个大型鱼群平均密度为(64.6±13.5)ind/(10^(3) m^(3)),鱼类平均体长为(16.8±4.6)cm,以中小型鱼为主;回水沱、深潭及分汊河道是鱼类喜居河段,是鱼类重要栖息地。研究结果可为三峡水库变动回水区鱼类保护和栖息地修复提供科学依据。

Impoundment in the Three Gorges Reservoir has remarkably changed the hydrodynamic conditions and sediment movement in the fluctuating backwater zone and has affected the fish habitat to varying degrees.The habitat characteristics and distribution of fish swarm in the fluctuating backwater zone of the Three Gorges Reservoir from Chongqing to Fuling was obtained by using the scientific echo sounder Bisonics DT-X.Results revealed no significant spatial distribution of water environmental factors in the study reach,implying that water environmental factors were not the major factors that affect the distribution of fish.Water depth and flow velocity,which varied notably,were key factors affecting fish habitat distribution.The average density of the eight fish swarm was(64.6±13.5)ind/(10^(3) m^(3)),and the fish swarm was dominated by small and medium-sized fish whose average body length was(16.8±4.6)cm.The backwater pool,deep pool and branching channel are fish’s favorite habitat sections.The results provided scientific basis for fish protection and habitat restoration in the fluctuating backwater zone of the Three Gorges Reservoir.