关键词: 苏州河, 鱼类物种多样性, 群落结构, 指示鱼类

Abstract: In order to evaluate the changes of fish diversity and assemblage structure during the comprehensive restoration of Suzhou River in the past two decades, an investigation on fish resources including 13 sections along the Suzhou River in June (summer) and September (autumn) was carried out. The results showed that a total of 10102 fish samples were collected, comprising 45 species belonging to 8 orders, 15 families and 37 genera. In summer and autumn, there were 36 species of fish in upper reaches, 12 and 15 species in lower reaches. From upstream to downstream, the Shannon-Wiener diversity index (H'), the Margalef species richness index (D) and the Simpson dominance index (C) showed a gradual decrease. Relative Importance Index (IRI) showed that the common dominant species of the upper reaches in summer and autumn was Pseudobrama simoni, and while the lower reaches were Carassius auratus and Misgurnus anguillicaudatus. The abundance-biomass comparison curve (ABC curve ) revealed that the fish assemblage structure of the whole river was unstable, especially the downstream in summer. Cluster Analysis and Non-Metric Multidimensional Ordination, based on species and quantity, indicated that fish assemblage structure can be divided into two groups, I.e. upstream group 1 and downstream group 2. P. simoni, M. anguillicaudatus, C. auratus, Pelteobagrus nitidus and Acheilognathus chankaensis were the main discriminating species causing the differences between two groups. Compared with the 43 species in 2001, and 28 species in 2006, the species of fishes had shown a obvious increase, especially the downstream. This trend of fish migration from upstream to downstream indicated that the water quality difference between the upper reaches and lower reaches was narrowing. The water ecological restoration of the lower reaches is obvious. The paper suggested that the reduction of differences in fish assemblage structure between upstream and downstream, and the appearances of Culter alburnus, Cultrichthys erythropterus, Abbottina rivularis, and Rhinogobius giurinus in lower reaches, those can be used as an ecological sign for the comprehensive restoration effects of Suzhou River.

Key words: Suzhou River, species diversity of fish, assemblage structure, indicative fish