Occurrence of the nonindigenous clams Rangia cuneata in the macrozoobenthos community in the coastal waters of the Pomeranian Bay (southern Baltic Sea)

This study provides important monitoring of the further expansion of the Atlantic rangia Rangia cuneata, especially migration patterns in the western Baltic Sea. The collected macrozoobenthos samples delivered information on the structure of macrozoobenthos and on the locations of occurrence of living clams in the coastal waters of the Pomeranian Bay. Identification of key environmental factors affecting abundance and biomass structure of macrofaunal assemblages also was carried out. Additionally, granulometric analyses of surface sediments were performed. Dominated species of macrozoobenthos community were typical for the coastal zone of the Pomeranian Bay. Rangia cuneata was identified in three locations, in the depth range of 6.3–12.1 m, in the open Baltic waters on extension of the Świna Strait up to 4 km from it and approximately 21 km east of the Odra estuary. The high abundance of living individuals of Rangia cuneata in the macrozoobenthos community, reaching 5280 ind. m⁻², has never been recorded before in studies on this species in the Baltic coastal waters outside rivers, lagoons and sheltered bays.