This cruise was conducted at Pulley Ridge mesophotic reef in the Gulf of Mexico, from August 22 to September 4, 2015, in collaboration with the University of Miami, HBOI-CIOERT, NOAA Fisheries, and the University of North Carolina at Wilmington (UNCW) Undersea Vehicles Program. This is the fourth and final cruise of this grant. The University of Miami ship R/V Walton Smith was used along with the National Marine Sanctuary Foundation Mohawk ROV. In 2015, a total of 21 ROV dives surveyed 25 random blocks (Figure 1), and covered 33.64 km at depths from 54.4 to 110.1 m. A total of 58 hours of ROV video were recorded and 4,771 in situ digital images were taken which included quantitative transect images (4,063), and video frame grabs of general habitat images and species documentation images. Sample collections with the ROV included 10 Porifera, 20 algae, 40 Cnidaria (19 Scleractinia, 15 Octocorallia, 1 Antipatharia), 3 Echinodermata, and 2 geological (rock/sediment) specimens.