Bathymetry of the lagoon and hoa of Reao, Tuamotu Archipelago

Bathymetric data were acquired in Reao Atoll, a semi-enclosed atoll lagoon without reef pass but connected to ocean through numerous shallow spillways (known locally as "hoa") along its southern rim. This data was acquired as part of the GAIA (ManaGement strAtegy evaluatIon for small-scale fisheries in Atoll lagoons) project, which evaluates the sustainability of giant clam exploitation within the context of climate change. The lagoon of Reao is composed of three basins with varying depths (the NW basin being the shallowest and the SE basin the deepest). Bathymetric data were acquired from 29/04/2022 to 04/05/2022, within the lagoon with a Multibeam echo sounder IWBMS (NORBIT), and resampled at 5 m spatial resolution. Satellite-derived-bathymetry (SDB) at 10 m spatial resolution was established by coupling this bathymetric data with a Sentinel-2B image captured on 26/09/2020 and using the « Iterative Multi Band Ratio » technique (detailed methodology is described in Quéré et al. 2025). Finally, bathymetric surveys were carried out to characterize the nine most functional hoa of the atoll. One bathymetric survey was carried out in the longitudinal section of each hoa, while one or two surveys were carried out in their cross-sections.