The first report on the establishment and spread of the alien clam Rangia cuneata (Mactridae) in the Polish part of the Vistula Lagoon (southern Baltic).
Information on distribution of the bivalve Rangia cuneata in the Polish part of the Vistula Lagoon is presented. The species, first recorded in the Lagoon in 2010, has since rapidly colonized almost the entire basin. The distribution and population structure of the species have been studied in the Polish part of the Lagoon since 2012. Preliminary results on distribution and size structure of the population highlight extensive fluctuations in 2012-2014. A drastic reduction in the abundance following the relatively long winter of 2012/2013 suggests that the winter oxygen deficiency associated with the ice cover could be critical for the population development. Potential effects of the new invasive bivalve on the structure of benthic habitats and macrozoobenthos communities are discussed.