A multidisciplinary monitoring framework to support sustainable management of an offshore artificial reef in the Mediterranean Sea

Comprehensive habitat mapping of artificial reefs requires integrated monitoring strategies that combine physical, environmental, and biological information across multiple spatial and temporal scales. Here, we present a multimethod monitoring framework designed to achieve a near-complete ecological characterization of an offshore artificial reef in the central-western Adriatic Sea (Italy). The framework developed within the ADRIREEF project integrates low-impact methodologies such as structural mapping, oceanographic monitoring, fish and benthic communities, visual census, and mussel population assessment. This integrated approach enables the simultaneous evaluation of reef structural integrity, hydrodynamic and trophic conditions, and the distribution, composition, and stability of key biological components. More than 20 years after deployment, the artificial reef maintains its structural configuration and supports well-oxygenated waters, diversified benthic assemblages, and stable fish populations primarily associated with complex reef modules. Habitat complexity, elevation from the seabed, and surface orientation of the artificial modules emerged as key drivers of benthic coverage and fish assemblage structure, while mussel populations showed high recruitment potential but a low proportion of commercial-sized individuals, suggesting unregulated exploitation. This study demonstrates that a multimethod monitoring approach enables accurate habitat mapping of artificial reefs, linking structural features to ecological function and ecosystem services. The proposed framework represents a transferable tool to support ecosystem-based management and the sustainable use of artificial reefs in the Mediterranean and comparable coastal environments.