Studies were conducted in 2015-2019 in the mussel and oyster farm area. Data were obtained on the species composition of polychaete worms in bottom sediments under the farm, in fouling of farm constructions, and in plankton at the larval stages of development. A total of 48 polychaete species belonging to 25 families were identified. At the same time 23 species were found on the bottom under the farm, 24 species were found in the fouling of mussel collectors and oyster cages, and larvae of 25 species of polychaete worms were found in plankton. In the benthos, Micronephthys longicornis dominated in terms of occurrence and abundance, while in mussel collectors and oyster cages, species of the family Nereididae (Nereis zonata, Platynereis dummelili, Alitta succinea) prevailed. The species composition of polychaete taxacone inhabiting the bottom under the farm and that in the fouling of the farm constructions differed significantly (the Czekanowski-Sorensen index was 0.26). In the benthos under the farm, 66 % of the species were deposit feeders by diet type, carnivores and omnivores were much fewer, whereas filter feeders were represented by only one species. Omnivores species dominated in the fouling (44 %), deposit feeders species were four times fewer, and filter feeders species were three times more than in the benthos. Hydroides dianthus (25 %) and Polydora websteri (67 %) found on and in mussel and oyster shells were highly abundant.