[English Summary]
Species composition of polychaetes and patterns of their distribution on the shelf off the south Sakhalin (up to 48° N.L.) have been studied. From the tidal zone to a depth of 50 m 200 species and sub-species of polychaetes have been found belonging to 41 families and 126 genera (except Spirorbidae). 42 species were not found in the studied region before, 3 species and 3 subspecies of them were described as new, 10 species were found for the first time in the fauna of the USSR.
Neoboccardia gen. n (Spionidae) was described. Data presented deal with systematics, ecology, quantitative distribution of species on the shelf of south Sakhalin and geographic distribution. Sizes of mature eggs for 50 species are given.
130 species have been found off west coast of the island, 160 species in Aniva Bay and 134 species off eastern coast. The whole area is regarded as a part of Japanese low boreal subregion (Pacific boreal region). The role of boreal-arctic species increases from west to east and with increase of depth, cold water species inhabiting shallower in the sea of Okhotsk off Sakhalin coast than in Japan Sea. Polychaetes biomass of the shelf of south-western Sakhalin as a whole is lower than that in Aniva Bay and south-eastern Sakhalin.
