长江上游合江江段鱼类早期资源与向家坝水库生态调度效果初步研究

合江江段是长江上游干流保持河流生境、适宜喜流水性鱼类栖息的重要江段.为了掌握合江江段鱼类早期资源动态,分析向家坝水库生态调度的效果,于2020年向家坝水库生态调度前后,开展了鱼类早期资源逐日监测.研究期间,共采集到鱼类早期资源5目10科38种(属),其中仔鱼29种(属)、鱼卵19种(属),包括特有鱼类6种.广适应性和喜...

Study on Fish Resources of the Early Life History Stages and the Effects of Ecological Regulation of the Xiangjiaba Reservoir at the Hejiang Section in the Upper Reaches of the Yangtze River

The Hejiang section in the mainstem of the upper Yangtze River locates downstream of the Xiangjiaba Reservoir.It maintains free-flow riverine habitat and provides critical refuges for rheophilic fishes.In this study,ichthyoplanktons were investigated daily during May and June 2020,including an ecological regulation period of the Xiangjiaba Reservoir during May 24 to May 28.Our major objectives were to evaluate the importance of this river section for fish reproduction,specifically for rheophilic and endemic species,and the efficiency of ecological regulation of the reservoir.Total of 38 fish species (genus) belonging to 5 orders and 10 families were identified,including 6 endemic species.Average density (±SD) of larval fish was (89.06±78.55) ind./1 000 m³;larval fish was identified 29 species,including 17 eurytopic species and 11 rheophilic species,and was dominated by eurytopic species,e.g., Neosalanx taihuensis and Rhinogobius spp.Average density (±SD) of fish egg was (19.89±20.58) ind./1 000 m³;and fish egg was dominated by rheophilic species,e.g.,Rhinogobio typus and Coreius heterodon.The density increases of larvae and fish eggs were basically synchronized with the flow regulation of the reservoir.Nine larval species and 7 species of fish eggs,including 2 endemic species,were collected during the flow regulation period.These results demonstrated that the Hejiang section provide important spawning grounds and nurseries for rheophilic species,including several endemic species,and flow regulation of the Xiangjiaba Reservoir enhanced spawning of several rheophilic and endemic species.