Integrated hard and soft bottom seafloor substrate map of Rose Atoll, American Samoa combining NOAA Pacific Island Fisheries Science Center Coral Reef Ecosystem Division hard-soft substrate maps with NOAA Center for Coastal Monitoring and Assessment Biogeography Program shallow-water benthic habitat map of American Samoa.

Two hard and soft substrate maps were produced by NOAA Pacific Islands Fisheries Science Center Coral Reef Ecosystem Division, one produced from data collected by the R/V AHI Reson 8101 240 kHz multibeam sonar, and a second using data collected by the NOAA ship Hi'ialakai Simrad em300 30 kHz multibeam sonar, covering deeper water. In both cases, the hard- soft substrate maps were derived using backscatter data, bathymetric variance (at 2 scales) and bathymetric rugosity. Bathymetry and backscatter data were resampled to 5 m grid cell size prior to the classification for shallow water product, and to 40 m grid cell size for the deeper water product. As no seafloor photographs for groundtruthing were available for Rose Atoll, the classification was unsupervised. However, in locations such as French Frigate Shoals, NWHI and Tutuila, American Samoa, where ground truth data were available, the same unsupervised classification method has been found to be a good predictor of substrate type in similar depth ranges and seafloor environments. The shallow-water habitat map produced by NOAA Biogeography Branch was derived by digitally delineating habitat boundaries from georeferenced sonar and orthorectified IKONOS satellite imagery in ArcGIS using the NOAA Habitat Digitizing extension. A first draft map was completed, and areas identified for ground validation. At each ground validation point benthic habitat was characterized by drop camera, free diving or surface observation. A second draft map was produced incorporating the ground validation data.