Use of fish as bio-indicator of the heavy metals pollution in aquatic environment

In this review paper, the role of fish as bio indicators is discussed. No other aquatic organism is suitable for the application of so many different methods which allow the evaluation of the severity of toxic impacts by determining the accumulation of toxicants in tissues, by using histological and haematological approaches or by detecting morphological anomalies. Due to its complex habitat requirements, the fish fauna is a crucial indicator of the ecological integrity of aquatic systems at different scales, from microhabitat to catchment. The fitness of fish species both at the individual level (e.g. growth performance) and at population level (e.g. population structure) is determined by the connectivity of different habitat elements in a broad spatial-temporal context. Thus bio indication using fish represents a good monitoring tool especially with regard to both pollution aspects and to river engineering, e.g. river restoration and management.