Data on ship locations for a 1-year period (August 2011 – August 2012) from satellite-based Automatic Identification System (AIS) was obtained from the Pacific Islands Ocean Observing System (pacioos.org). Point locations were converted to ship track lines by connecting points with a common ship identification number in chronological order. The line density tool in ArcGIS was used to calculate the density of ship tracks within 100 m raster pixels. The resulting ship traffic layer was used as a proxy for ship-based pollution. To represent the risk of ship groundings and wrecks the footprint of this ship traffic layer was clipped to 9 m depth. Map units are presented as a normalized score from 0 - 1.