松花江依兰段鱼类多样性调查分析报告OA

A systematic 10-day fisheries resource survey was conducted in the Yilan reach of the Songhua River from September to October 2025.Using a combination of gill nets and trap nets,a total of 33 standardized samples were collected.The survey recorded 46 fish species belonging to 6 orders,13 families,and 41 genera.Cyprini-formes was the dominant group,accounting for 65.22%of the total species and occupying a predominant position in the fish assemblage.Based on the Index of Relative Importance(IRI)developed by Pinkas,three dominant species were identified:common carp(Cyprinus carpio),silver carp(Hypophthalmichthys molitrix),and topmouth culter(Culter ilishaeformis).Nine common species were also identified:Ussuri catfish(Pseudobagrus ussuriensis),yellow catfish(Pelteobagrus nitidus),spotted steed(Hemibarbus maculatus),Amur ide(Pseudaspius leptocepha-lus),mandarin fish(Siniperca chuatsi),white bream(Xenocypris argentea),northern girder goby(Saurogobio dabryi),pikeperch(Lucioperca lucioperca),and Amur catfish(Silurus asotus).Community diversity analysis re-vealed a Shannon-Wiener diversity index of 2.752,a Pielou evenness index of 0.794,and a Margalef richness in-dex of 4.502,indicating a relatively stable community structure and moderately high diversity.Compared with the multi-site and multi-season survey results by Zhang(2022),the species count in this study was lower than the cu-mulative value of 80 species in the middle reaches of the Songhua River,but the diversity pattern was consistent with the trend observed at the Yilan sampling sites.This study systematically assessed the fish community character-istics and diversity status in the Yilan reach of the Songhua River,providing fundamental data and a scientific basis for fishery resource management,ecological conservation,and sustainable utilization in this river section.