Status of global seafloor mapping effort and priority areas for future mapping

Yakufu Niyazi^1*Elin A. Thomas¹Nicolas Pucino^2,3Denise J.B. Swanborn¹Heather A. Stewart^1,4Alan J. Jamieson¹

• ¹Minderoo-UWA Deep-Sea Research Centre, School of Biological Sciences and Oceans Institute, University of Western Australia, Perth, Australia
• ²Fenner School of Environment and Society, Australian National University, Canberra, Australian Capital Territory, Australia
• ³Environment, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, Australian Capital Territory, Australia
• ⁴Kelpie Geoscience Ltd., Edinburgh, United Kingdom

Several global and regional initiatives exist to increase the proportion of seafloor mapped by direct measurements, brought together through international collaborations, of which the Nippon Foundation-GEBCO Seabed 2030 Project is perhaps the most well-known. Nearly halfway into the United Nations Decade of Ocean Science for Sustainable Development, we used publicly available bathymetric and type-identifier datasets from the General Bathymetric Chart of the Oceans (GEBCO) to systematically evaluate progress in the global seafloor mapping effort between 2019 and 2024. We explore each major ocean basin and sea, exclusive economic zones (EEZs), and different depth zones. Proportionally, the North Atlantic (NAO) and North Pacific (NPO) have the highest mapping coverage, with over a third of each ocean mapped by the end of 2024. The Southern Ocean (SO), South China and Eastern Archipelagic Seas (SC&EAS), South Pacific Ocean (SPO), and Indian Ocean (IO) each approach 30% mapped by 2024. When considering mapping coverage by depth zones, approximately one-quarter of shallow areas (0-200 m) and the abyssal zone (3000-6000 m) have been mapped, comprising 6.3% and 68.4% of the global mapped seafloor area, respectively. Nearly 40% of seafloor in the upper (200-1000 m) and lower (1000-3000 m) bathyal zones has been mapped, corresponding to 5.6% and 17.7% of the global total mapped area. Although, the hadal zone (>6000 m) makes up only 1.0% of the global seafloor, it has is highest (55.6%) proportional mapping coverage, comprising up to 2.0% of global mapping effort. Mapping progress is strongly influenced by EEZ size, economic status and the presence of offshore resources. This study reveals the uneven mapping efforts worldwide and more focus should be given to the two polar oceans, IO, and Southern Hemisphere, as well as the EEZs of African and Asian states, to reach the average global coverage. With the current average rate of new map generation of ∼3.2% of total seafloor area annually, we predict that the global seafloor could be mapped in 20 years. Analysis of the seafloor mapping efforts in different depth zones of ocean basins, EEZs, and ABNJ provide future priority areas of exploration for the Seabed 2030 initiative.