Ecological Significance and Bioindicator Potential of Macroinvertebrate Communities in Open Sea Longline Aquaculture Systems

This study evaluates the structure, diversity, and ecological roles of macroinvertebrate communities associated with Mytilus galloprovincialis cultivated in offshore longline systems in the Black Sea. Monthly samplings conducted between September 2023 and August 2024 identified 20 taxa comprising a total of 99,719 individuals. The community structure was primarily dominated by Jassa marmorata (71.3%) and Stenothoe monoculoides (27.8%). Seasonal analyses revealed that individual abundance peaked in autumn, while species richness was highest during the summer months. Redundancy Analysis indicated that pH (41%) and salinity (34.5%) were the most influential environmental variables shaping species distribution. Additionally, diversity indices (Shannon, Simpson, and Pielou) reflected spatial heterogeneity in habitat quality across stations. The findings underscore the dual ecological and economic significance of mussel aquaculture systems, which serve not only as productive environments but also as biodiversity-supporting habitats. The dominance of opportunistic amphipods, sensitivity of species to environmental gradients, and strong diversity metrics observed at certain stations provide evidence that these artificial structures function as bioengineered reefs. This highlights the bioindicator potential of macroinvertebrate communities and supports the integration of sustainable aquaculture practices into broader ecosystem-based management frameworks.