This dataset contains a GeoTIFF with .75x.75 meter cell size representing the backscatter or intensity of sound returned from the seafloor in "El Seco" east of Vieques Island, Puerto Rico. This intensity surface was derived from data collected in March and April 2009. Acoustic backscatter mosaics are an important piece of information when characterizing surficial seafloor features and delineating benthic habitats. NOAA's NOS/NCCOS/CCMA Biogeography Branch, in collaboration with NOAA vessel Nancy Foster and territory, federal, and private sector partners, acquired multibeam data around Vieques Island from 3/26/09 to 4/2/09. Data was acquired with a hull-mounted Kongsberg Simrad EM 1002 multibeam echosounder (95 kHz) for water depths greater than 75 meters, and with a moon pool flange-mounted Reson 7125 multibeam echosounder (dual frequecy, 200/400 kHz) for water depths of less than 75 meters. The backscatter component of the multibeam data were geometrically and radiometrically corrected using Fledermaus Geocoder Toolbox (FMGT) software. The project was conducted to meet IHO Order 1 and 2 accuracy standards, dependent on the project area and depth. All users should individually evaluate the suitability of this data according to their own needs and standards.