Desenvolvimento de um índice piscícola para os rios de Portugal Continental.

Abstract

The Water Framework Directive advocates an assessment of ecological quality of rivers based on hydromorphology and biological elements, including fish fauna. This topic has been poorly developed in Portugal, and the existing approaches are mainly based on expert knowledge and not on sensitivity analysis. This work presents the biological metrics responsive to different types of anthropogenic pressures and the biotic index to assess the ecological status of Portuguese rivers based on ichthyofauna. Sampling took place from 2004 to 2006, during Spring, in 397 sites of the main basins of Portugal. The selection of metrics was based on correlation analysis between metrics and pressure variables. Based on the available data and on the obtained results, the assessment of the ecological status using the fish fauna is feasible in three out of five Groups/Types of Rivers previously identified for this biological group;Group North medium and large drainage area (N2 e N1>100km2), Group South mix (N4, S1>100km2, S2 e S3) and Type South medium and large drainage area (S1>100km2).