Sediment Profile Image (SPI) Analysis and Coastal/Marine Ecological Classification Standard (CMECS) Classification Data used to construct benthic habitat maps for FIIS. Sediment profile imagery (SPI) provides an in-situ perspective of the seafloor and associated characteristics. Specifically, the camera takes a profile photograph of the sediment-water interface, which offers information about the biological and environmental attributes of the surface of the seafloor, the substrate just below the seafloor, and the overlying water column. SPI imagery has been used as the basis for or to complement ecological studies for several decades (for further reading, refer to Germano et al., 2011; Solan et al., 2003; Germano et al., 1989). For this study, SPI images were collected to corroborate and complement the acoustic and grab sample data. Images were taken at each grab sample site and also along a series of planned transects designed to cross boundaries identified in the sidescan mosaics. All deployments of the camera were done in triplicate, resulting in six images per site (one deployment of the camera captures two images ten seconds apart). The images were processed and analyzed in Adobe Photoshop CS3. Color and contrast adjustments were applied to enhance the images for detection of features. Geological and biological features were identified and described through expert interpretation of the images, including relative grain size, bedforms, biogenic features, and presence of seagrass and organisms (identified to lowest taxonomic level). Furthermore, consistent settings were applied when taking penetration and apparent redox potential discontinuity (aRPD) measurements. The aRPD value indicates the depth at which the sediment transitions from being oxidized to reduced (Gerwing et al., 2017).