Seafloor substrate data available from multiple sources has been modified for the purpose of characterizing the seafloor for the Regional Importance of Manmade Structures as Rockfish Nurseries study. Substrate was classified from multibeam sonar data using a video supervised numerical classification methodology. The overall objective of this study is to begin to integrate region-wide oceanographic, geologic, and biologic data so Bureau of Ocean Energy Management has an ecosystem-level synthesis of the marine environment on which to base management decisions. The initial efforts in applying this synthesis will focus on understanding the regional importance of platform habitat as rockfish nurseries in order to predict consequences of decommissioning oil rigs to essential fish habitat and managed fish species.