基于水声学探测的杨房沟水电站坝下鱼类集群分布特征研究OA

In this investigation,the river section below the dam of Yangfanggou hydropower station on the middle stem of Yalong River was selected for study and we explored the distribution of fish clusters and analyzed the relationship of cluster distribution to flow velocity and water depth.Our objective was to provide support for selecting the inlet location of the fish passage facility.From July 18 to September 24 of 2023,a fish resource survey,and the flow velocity,water depth and other environmental parameters were measured from 200 to 1 000 m below the dam using a fish finder(Simrad EK80)and an acoustic Doppler profiler current meter(ADCP).Gill nets and fyke nets were deployed simultaneously with the fish resource surveys to verify the reliability of hydroacoustic surveys.A total of 11 fish species from 8 genera,2 families and 2 orders were detected in the hydroacoustic survey,primarily Schizothoracinae spe-cies.The body length of fish in the studied river section ranged from 6.14 cm to 23.99 cm,dominated by medium and small sized fishes and similar to the results obtained using the traditional fishery survey method using gill and fyke nets.Fish aggregated mainly in three horizontal zones,in the physical barrier area upstream of the tailrace tunnel,the bank opposite the tailwater outlet,and the right bank 130 m up-stream of Yangfanggou bridge.The flow velocity range of the aggregation areas was 0.6－1.3 m/s.Verti-cally,fish were distributed mainly in the upper and middle water layers,i.e.,0.84－10.00 m below the sur-face.We concluded that fish in the reach downstream of the dam prefer relatively deep,low flow velocity water with a stable flow direction.