Based on long-term data, the structural organization and peculiarities of the dynamics of the coastal fouling community formed by the Black Sea mussel Mytilus galloprovincialis on underwater solid substrates were determined. Material for the work was collected in 2004–2019 within 13 polygons located along the northern coast of the northwestern part of the Black Sea, starting from the mouth of the Dnieper-Bug estuary and ending with the waters of the Suchoy estuary. As a result of the conducted researches regularities of forming of taxonomic, species, size, chorological, trophic, phenotypic and sexual structural organization of the coastal fouling community under the influence of key environmental factors are revealed. The features of life strategies of organisms of the main systematic groups of the community were described. The regularities of the influence of abiotic environmental factors on the development of the fouling community have been established. The nature of the influence of transformed river waters on species diversity and quantitative indicators of fouling community was determined. Biotic links in the fouling community were described. Regularities of long-term, seasonal, monthly and daily dynamics of this community were revealed. The migratory behavior of mass species of the community was described. The restorative potential of the fouling community during succession after catastrophic violations of its structure was determined. The use of indicators of fouling community development for monitoring the coastal zone of the sea was proposed. Of the 65 identified invertebrate species, only 13 were 100 % occurrence. As a result of research, an invasive species of bivalve mollusk Arcuatula senhousia (Benson, 1842), which entered the Black Sea from Southeast Asia at the beginning of the 21st century, was discovered for the first time in Ukrainian waters. This species poses a certain threat to the aboriginal inhabitants due to the fact that its settlements can cover a continuous carpet of mussel settlements, limiting their ability to breathe and feed. It is established that the indicators of species diversity and total biomass of the community are related to the sea water temperature by a complex unimodal dependence, which had a pronounced ecological optimum. It was found that as the level of water exchange between the polygons and the open sea decreased, the diversity of the community increased, and the total number of species decreased. It is noted that as the transformed river waters entering the Black Sea from the mouth of the Dnieper-Bug estuary spread, both the species richness of the community and the biomass of the species included in it increased. It has been established that the biotic links in the fouling community were of a consortium nature. The Black Sea mussel, as a determinant of the community, formed a consortium system in which it was connected with stable biotic links with both consortium species and pelagic inhabitants. At the same time, the mussel showed the characteristic properties of the species of autogenous ecosystem engineer, modifying the environment and creating favorable living conditions for other species. It has been established that over the last 40 years, under the influence of anthropogenic eutrophication, the species composition of the coastal fouling community has almost halved, primarily due to the extinction of stenobiont species. It is noted that the restorative potential of the fouling community during succession after catastrophic violations of its structure depended on degree of destruction of the edificator species population. The recovery period of the community was about six months (in case of preservation of the mussel population) and more than one year (in case of its complete destruction). It was found that the most available parameters of the Black Sea fouling community reflect the state of the environment and can be used for ecological monitoring of the coastal zone of the sea
