ABSTRACT Research on the relationship between phytoplankton abundance and chlorophyll-a concentration was conducted in December 2020 in Tanjung Kudu Lake and Parit Lake, Tambang District. The aims of this study was to determine the relationship between phytoplankton abundance and chlorophyll-a concentration. There were 3 Station, namely Station 1 (inlet), Station 2 (middle of the lake), and St…