Abstract:The purpose of this paper was to introduce the conceptual use of the index of biotic integrity (IBI) to the Chinese ecologists, promoting the IBI system suitable for the Chinese inland waters, with particular emphasis on evaluation of shallow lakes in the middle reach of the Yangtze River. According to the characteristics of fish assemblages in lakes in the reach, we modified the IBI originally developed by Karr. An adaptive IBI was obtained, which included 12 metrics: number of total native fish species, n...