Two mussel settlements are found in the Kievka Bay - at Skaly and Vtoroy Islands. They are formed mainly by Gray mussel Crenomytilus grayanus in druses of 6-230 individuals. Size of their shells is 10-150 mm at Vtoroy Island, with domination of small-sized mollusks < 25 mm, but 14-132 mm at Skaly Island, with the large-sized ones predominance, that reflects more severe environments for mussels in the eastern part of the Bay where Skaly Island is located. Their allometric growth is slower at Skaly Island, too. Besides Gray mussel, 89 other species are presented in the area of the settlements, mainly polychaetes, bivalves, brown algae, ascidia, gastropods, and red algae; 19 of them are common and make a «core» of these benthic assemblages. By their trophic status, they belong to sorters and non-motile sestonophages, with the latter dominating by biomass. Benthic communities in the area of the settlements are formed by 4-37 species, mainly macrozoobenthos. Density of benthic organisms distribution in the assemblages varies in the range 8-1000 ind./m2, their mean biomass is 3235 g/m2 (maximum 7215 g/m2, mainly animals), the average species diversity is 25.7 ± 7.3 species at Skaly Island and 13.9 ± 3.9 species at Vtoroy Island.