Main Article Content
A population of Macoma balthica was studied in the Polish coastal zone (up to 3 Nautical miles) of the Baltic Sea within the Pomeranian Bay and in the open coast of Polish Middle Pomerania. Abundance, wet biomass, and the frequency of Macoma were determined in the coastal waters, including estuaries of the Odra River (Swina and Dziwna canals), Wieprza, Slupia, Lupawa, and Leba rivers. The frequency (F) of Macoma in the coastal zone of the Pomeranian Bay was 77.4%, whereas in the open coast of the Middle Pomerania it was lower and amounted to 39.8%. The abundance of Macoma, in the coastal zone surveyed, ranged from 0 to 304 specimens per m-2 of the bottom (x= 46.2 spec. m–2). Wet biomass of this bivalve ranged from 0 to 99.2 gww m-2 (x = 17.6 gww m-2). Apparently M. balthica has found better conditions for living and development in the Pomeranian Bay compared to the Middle Pomerania coast. The abundance of this mollusc in the bay was 4.5-fold higher than in the open coast and the wet weight was 2.5-fold higher, respectively. M. balthica plays an important role in the monitoring of benthos of the Baltic Sea, constitutes a distinct food base of animals (fish, birds), and takes part in the process of purification of waters of the coast stretch studied (biofiltration, biosedimentation).
Key words: Polish coastal zone of Baltic, estuary, Macoma balthica, abundance and biomass