Biological assessment of the Rhine – main stream – 2006 / 2007
During the last years, an extensive biological survey of the Rhine has been carried through.
Due to today’s good quality of Rhine water and the already implemented measures targeted at improving river continuity and at enhancing structural variety the biocoenoses of the Rhine have distinctly recovered: Many species have returned; as far as fish are concerned, the species composition is almost complete. However, concentrations of certain nutrients/substances distinctly increase downstream the longitudinal axis of the Rhine and the number of varied habitats is insufficient, so that many formerly typical species are lacking today, the species number is very low or the presence of these species is restricted to local areas.
After the distinct success concerning the redevelopment of water quality, water bodies should, in future, be designed more nature near and without obstacles obstructing free species migration.