Rotenone sampling is the most efficient method for assessing the fish assemblage structure and species abundance of low conductivity A mazonian streams. It does, however, cause fish mortality and disturb aquatic ecosystem. The aim of this study was to search for a non‐destructive alternative. The efficiency of electrofishing was compared against complete removal using rotenone. This procedure was repeated in 12 streams dispers...

Fish assemblage indicators developed throughout the world were reviewed and key differences in methodologies depending on ecoregions, basins and contrasting fish fauna summarised. Common elements of existing Indices of Integrity were identified to support the development of a European‐wide fish index. These include, using reference condition, accounting for natural fish assemblage variability, evaluating metric precision and s...

The objective was to develop spatially based (type‐specific) methods to assess the ecological status of European rivers according to the EU Water Framework Directive. Some 15 000 samples from about 8000 sites were pre‐classified within a five‐tiered classification system based on hydromorphological and physico‐chemical pressures. The pre‐classification was used to identify reference conditions and to calibrate the assessment m...

After typological pre‐classification of 398 calibration sites, fish‐based metric models were used to predict the impact of human activities on river quality in European Western Highlands and Western Plains ecoregions. Calibration sites were grouped into six assemblage types and according to their geomorphology; test sites were assigned to their corresponding assemblage type. Five anthropogenic variables were used to describe t...

Mean juvenile fish abundance and fish frequency in a large lowland river during low discharge largely differed among the unvegetated and three morphologically contrasted macrophyte habitats. Single separate models revealed that juvenile fish distribution was largely influenced by trophic variables. With the exception of Leuciscus cephalus , which responded mainly to physical variables (depth and substratum), multiple regressio...