The stonewort Chara connivens was rediscovered in the Vistula Lagoon in 2011, almost 35 years after its last record. In 2012, the species was recorded for the first time in the Szczecin Lagoon. Chara connivens occurred at shallow (0.5-1.2 m) sandy-muddy and muddy bottoms of small embayments. In the Vistula Lagoon, the stonewort was represented by single small specimens, while in the Szczecin Lagoon, it formed dense and extensive patches.

A set of classification methods was developed for the Polish coastal and transitional waters regarding the biological quality elements -phytoplankton, macrophytes and macroinvertebrates as required by the EU Water Framework Directive. Mean summer chlorophyll-a and total summer biomass of phytoplankton were proposed as indicators in the * Corresponding author e-mail: Elzbieta. Lysiak-Pastuszak@imgw.pl phytoplankton assessment. Macrophytes were assessed by the Macrophyte Quality Assessment Index, including biomass and percent bottom coverage of the selected taxa. Macroinvertebrate assessment was based on a biotic index comprising abundance, dominance structure, taxonomical richness and species sensitivity/tolerance to eutrophication. A preliminary assessment of the ecological status revealed that the coastal and transitional waters failed to reach a 'good' ecological status.