Eutrophication and fish biodiversity in Finnish lakes

Summary

Eutrophication due to excessive nutrient loading is a major factor affecting Finnish aquatic ecosystems. In this work we compared the biodiversity of fish in lakes of different trophic status to determine what changes occur under eutrophication. Our work was based on data sets collected using standard multimesh gillnets. In eutrophicated waters cyprinids dominate but we found also that in hypereutrophic lakes even a short-term perturbation, such as oxygen deficiency, may lead to sudden changes in species diversity. In essence, eutrophication has a negative impact on lakes by decreasing their fish biodiversity.

This work is part of the Finnish Biodiversity Research Programme FIBRE (1997–2000).