Hidden Reefs in the Polish Marine Areas: Implications for Conservation Measures and Maritime Spatial Planning

Hard-bottom habitats are among the most structurally complex ecosystems in temperate shelf seas. Identification of reef habitats is fundamental for biodiversity conservation and ecosystem-based marine spatial planning. We used high-resolution seabed mapping combined with field surveys, including benthic sampling, to identify previously undocumented reefs in the Polish part of the Baltic Sea. The newly detected habitat exhibited characteristic hard-substrate morphology and supported diverse benthic assemblages, indicating ecological relevance disproportionate to its spatial extent. The presence of characteristic reef-associated taxa, high biodiversity, and significant natural value of both macrozoobenthic and macroalgal communities were noted. The data presented here not only enrich the existing knowledge on marine habitats but also contribute to the development of more effective environmental conservation strategies for marine ecosystems under international protection. The findings will have direct implications for marine spatial planning and highlight the need to integrate updated habitat data into decision-making processes.