The application of the abundance/biomass comparison method on riverine fish assemblages: limits of use in lotic systems

Fish assemblages have been widely used as ecological indicators for assessing the level of environmental degradation and ecosystem health. Environmental disturbances affect the aquatic community structure in terms of abundance and biomass. Therefore, we tested the utility of abundance/biomass comparison (ABC) method, originally developed for marine ecosystems, to detect the anthropogenic disturbance in lotic systems using fish community data. Electrofishing was conducted in the period between 2003 and 2011 at 35 sites along the Southern Morava River basin. The results indicated that species richness strongly influences the utility of ABC method to detect the anthropogenic disturbance in lotic systems. The Warwick (W) statistic showed the positive correlation and the expected direction of response with some factors defining environmental quality, applying it on the samples with greater species richness. This approach has significant power for detecting environmental quality disturbance but may be limited due to effects of habitat variability in riverine environments.