EN
Studies on the Lake Miedwie zooplankton, associated with measurements of water temperature, dissolved oxygen content, and transparency showed the presence of at least 35 rotifer, 10 cladoceran, and 10 copepod species as well as the occurrence of mesotrophic lake indicators: Bythotrephes longimanus, Cyclops scutifer, and Daphnia cristata. The mesotrophic status of the lake is documented also by the structure of the zooplankton community and by the results of the Daphnia magna test for water fertility. All the data demonstrate the improvement in the lakes condition, compared to that in the 1980s. The results obtained attest to the need of biotic parameters to be incorporated into Lake Miedwie monitoring.