The Multi-Regional Marine Economy Input-Output Table (MMRIO) serves as a powerful analytical tool for analysing the interdependence between maritime and terrestrial economies, and assessing supply chain environmental emissions. It provides a data foundation for the sustainable development of marine economies in bay areas. Despite the increasing importance of China's bay areas in both the national-level and global-level, existing MMRIO databases do not represent these bay areas adequately. They lack critical details with high spatiotemporal resolution and fail to capture heterogeneity among cities. To address this gap, our research has firstly developed the Bay-MMRIO at the bay area scale. This database covers the years 2012, 2015, and 2017, encompassing 55 sectors (13 marine sectors and 42 non-marine sectors) and is applicable to the bay areas in China. We provide a detailed description of the database development methodology. The Bay-EMMRIO database aims to incorporate more official and publicly available data from national statistical agencies, enhancing accuracy through a multi-source data fusion approach. Finally, we utilize the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as a case study, analyzing the impact of GBA’s marine economic development on the national economy's production activities along the supply chain. This demonstrates the application of Bay-MMRIO.

China; Bay Area; City level; Multi-regional input-output; Marine economy