Oligochaeta (Annelida, Oligochaeta) in the Curonian Lagoon of the Baltic Sea

The species composition of Oligochaeta (Annelida) has been studied in the Russian part of the Curonian Lagoon. In the contact zone and in the open waters, 40 out of 42 species known to inhabit the Lagoon are detected. Gen. Nais is the most abundant in resident species, being represented by ten different species. In the contact zone on all types of sediment, Limnodrilus hoffmeisteri species dominates, forming, together with the two accompanying species (Tubifex tubifex and Psammoryctides barbatus), the Oligochaeta biomass and the basis of their abundance in the top 5-cm-layer of the sediment. The highest species diversity is detected in silty sediments within macrophyte beds, while the lowest species diversity is in sandy siltstones.