Spatial distribution maps of real-time ocean observation platforms and sensors in Japanese waters

Ocean observations are required to provide timely evidence of facts about the ocean in order to evaluate the sustainable management of biodiversity, climate change, fisheries, mineral resources, tourism, and any other anthropogenic activities that support blue economy policymaking. In Japan, this is particularly crucial given that it is an islandic country stretching from north to south, thereby having a diverse coastal environment. Although tremendous efforts towards ocean observations have been made, coordination among sectors is not always sufficient, which prevented availing the comprehensive capacity of ocean observation. In this study, the existing observation platforms and installed sensors, particularly fixed platforms that enable real-time data transmission, were reviewed, and the spatial distribution of them was investigated. It was confirmed that a large number of observation networks cover Japanese waters; however, many of those platforms were used for single purpose, and the spatial coverage was still considerably limited for some sensors, such as salinity, dissolved oxygen, and chlorophyll a. It must be noted that this study intentionally limited the data sources of platforms/sensors to the disclosed data on public reports and/or websites, in order to raise a discussion about information disclosure of observation efforts, conducted by numerous stakeholders. Based on this information, we recommend extending the capacity of ocean observation by utilizing existing platforms rather than constructing new platforms, in order to enhance cost-effectiveness. •The distribution of real-time ocean observation platform and sensors in Japanese waters were visualized.•Observation platforms already cover a large part of Japanese waters.•However, spatial coverage was limited for many of the sensors, except for temperature.•Installing additional sensors on existing platforms appears to be a cost-effective strategy to expand observation capacity.