MBES bathymetry data were collected using the ship's own Kongsberg EM 710 and EM 122 multibeam echosounders during the RV SONNE cruise SO309 CoralNewZ (Cold-water Coral Biology & Geology off Aotearoa New Zealand). The primary goal of the cruise was to search for cold-water coral communities and mounds in the EEZ of New Zealand. Hydroacoustic team included Sam Davidson (NIWA), who was funded by the NIWA internal project OCN2503 – NIWA Strategic Voyage Fund. This dataset includes 5 bathymetric grids produced based on the MBES data collected in the EEZ of New Zealand between 2025-01-16 and 2025-02-15. The grids represent 4 working areas: 1) east of Stewart Island; 2) the Graveyard Seamounts (Chatham Rise); 3) central Chatham Rise; 4) Reserve Bank (Chatham Rise); and 5) transits between working areas. Postprocessing of raw .all files was performed by the shipboard hydroacoustic team (Evgenia Bazhenova, Sam Davidson and Alissa Bach) using the QPS Qimera software. Data quality control included 1) verification that the SVP data were applied correctly based on the time and location; 2) blocking outer beams and in-turn data to ensure the best possible quality of the overlapping swaths, 3) manual point cloud cleaning if required. All the grids were additionally cleaned by Yukari Asakura using the MB-System software http://www.mbari.org/products/research-software/mb-system/. Transit data partially have degraded quality due to the bad weather conditions. Depths measured by the MBES are reported in respect to the mean-sea level. Tidal corrections were applied during the data postprocessing, using the predicted tides retrieved from the NIWA tidal model for the working areas (NIWA Tidal Model for New Zealand's EEZ, tides.niwa.co.nz).

These data should not be used for navigational purposes.