Bathymetry data based on the multibeam echosounders (MBES) KONGSBERG EM120 and EM1002 was conducted during R/V MARIA S. MERIAN cruise MSM16/3 between 13.10.2010 and 20.11.2010 in the Eastern Atlantic off Mauritania. The expedition aimed at a comprehensive understanding of the complex sedimentary system on the Mauritian Shelf as an atypical tropical eutrophic ecosystem and an archive of palaeoclimatic change in Africa during the Holocene. During the expedition, the chain of Mauritian coral reef mounds was mapped for the first time, carbonate-producing organisms successfully sampled and the flooding history of the Golfe d'Arguin investigated. Hydroacoustic surveys were conducted for a better understanding of the topography, and particularly for the identification of coral mounds and their morphological and structural patterns. In addition to bathymetric mapping, further instruments complemented the research programme, such as the sub-bottom profiler PARASOUND, a fast-rescue boat for shallow water surveys, various sediment sampling and coring devices, a CTD, an aerial dust collector and a remotely operated vehicle (ROV). CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the MSM16/3 expedition, the KONGSBERG EM1002 multibeam ecosounder (MBES) was utilized for high-resolution bathymetric mapping in water depths from 30 to 800m. A semi-circular transducer array with a radius of 45 cm and 160° angular extent transmits a nominal sounding frequency of 95 kHz with a maximum angular coverage sector of 150°. During the reception, 111 beams with widths of 2° by 2.3° are formed. Depending on the reflectivity of the seafloor, the swath width can reach up to 7.4 times the water depth. During the cruise, the angular coverage sector and beam pointing angles were set to vary automatically with depth according to achievable coverage in order to maximize the number of usable beams. The depth of the water column is calculated through the two-way-travel time, beam angle and ray bending due to refraction in the water column by sound speed variations. Combining amplitude (for central beams) and phase (for slant beams) provides accuracy practically independent of the beam-pointing angle. For further information on the system, consult https://www.km.kongsberg.com/. Responsible persons during this cruise / PI: Andre Freiwald (andre.freiwald@senckenberg.de), Till Hanebuth (thanebuth@coastal.edu) & Stephen Schilling Chief Scientist: Hildegard Westphal (hildegard.westphal@zmt-bremen.de) CR: https://www.tib.eu/en/search/id/awi%3Adoi~10.2312%252Fcr_msm16_3/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2010/20100362.htm