Marine benthic habitat mapping is increasingly recognized as an essential tool in integrating available data to inform marine ecosystem-based management. This study presents the first comprehensive and detailed marine benthic habitat map of Bohai Bay, China, utilizing a classification scheme that incorporates both abiotic and biotic features. A total of 20 distinct marine benthic habitat types were identified, reflecting the spatial distribution of reef biota, semi-terrestrial plants, ecologically and economically important benthic communities, as well as areas impacted by anthropogenic activities. This study underscores the value of habitat mapping in providing a robust scientific basis for decision-making and the sustainable utilization of coastal and marine resources in Bohai Bay.

Introduction: Marine habitat mapping serves as a critical tool for ecosystem-based management and scientific research. This study reviews the environmental characteristics of the Beibu Gulf and proposes a habitat classification system to support spatial ecological analysis and regional planning.Methods: A habitat classification system was developed that integrates biological zones, substrate types, and vegetation, based on multidisciplinary data sources—including bathymetry, optical remote sensing, geomorphology, and biological surveys—combined with GIS techniques to produce detailed habitat maps.Results: A total of 19 habitat types were identified, comprising 8 intertidal, 5 infralittoral, 5 circalittoral, and 1 deep circalittoral habitats. The most dominant habitats were deep circalittoral mud (55%), circalittoral mud (19%), and infralittoral mud (14%), while littoral mangroves, saltmarshes, and seagrass each accounted for less than 1%. Map confidence was generally moderate, with lower accuracy observed at the boundaries between biological zones, and higher confidence in the littoral zones.Discussion: These findings provide a comprehensive and detailed habitat basemap that supports marine monitoring, scientific research, ecological conservation, and regional planning. The study highlights the significant application potential of habitat mapping in coastal and marine management.

Marine spatial planning (MSP) has emerged as a fundamental process for achieving the balanced development of marine ecology, economy, and society. However, increasing conflicts among multiple marine uses, particularly between port development, industrial activities, fisheries, recreation, and ecological protection, highlight the pressing demand for robust and science-based planning tools. In this study, we propose an integrated analytical framework for multi-objective spatial suitability evaluation to optimize MSP. Using the coastal waters of Dalian, China, as a case study, we evaluated the spatial suitability of five key marine activities (ecological protection, mariculture, port construction, wind energy farm development, and coastal tourism) and applied a multi-criteria decision-making approach to inform spatial zoning. The results emphasize the region’s ecological significance as providing critical habitats and migratory corridors for protected and threatened species as well as fishery resources, while also revealing substantial spatial overlaps between conservation priorities and human activities, particularly in nearshore zones. The optimized zoning scheme classifies 22.0% of the coastal waters as Ecological Redline Zones, 32.4% as Ecological Control Zones, and 45.6% as Marine Exploitation Zones. This science-based spatial classification effectively reconciles ecological priorities with development needs, providing a spatially explicit and policy-relevant decision support tool for MSP.