Information on the locations for feeding, reproductions, and resting, are essential to effectively protect sea turtle populations and implement conservation efforts. This type of ecological information is critically important for hawksbill turtle conservation in Los Roques Archipelago National Park (LRANP) where turtles have been declining in spite of habitat protection efforts. The goal of this research was to produce a benthic habitat map of LRANP employing in situ visual surveys, remote sensing and geographic information system techniques, and to spatially characterize sea turtle occupancy and patterns of usage by habitat type. Between June and August of 2008, turtle behavior and habitat use were recorded during 159 h of observation, comprising 46 sighting events (n = 20 juveniles, n = 26 female adults). Observed activities were grouped into 4 categories: foraging, resting, swimming, and reproductive behavior. The benthic habitat at each turtle sighting was recorded as one of three categories: coral reef, sand or marine vegetation. Results suggest that the population of turtles within LRANP is comprised primarily of female adults and juvenile individuals and that coral reef is the most important habitat for this species. The most important foraging area in the atoll is a coral patch reef that connects Dos Mosquises Sur and Dos Mosquises Norte. The data in this thesis have been made available in digital and map form to the managers of LRANP for management purposes.

Quantitative photographs of benthic communities at two northern Miami Terrace sites, originally investigated as part of an environmental impact survey in advance of the proposed Calypso pipeline, and two Pourtalès Terrace sites, investigated as part of an exploration of deep-sea coral and sponge ecosystems (DSCEs) within the Pourtalès Terrace Deep-water Coral Habitat Area of Particular Concern (CHAPC), were reanalyzed and compared for similarities and differences. Both terraces are part of an elongated lithified platform that parallels the southeastern Florida coast at depths averaging between 250 and 450 m. Although both sites have similar geological origins and lie under the Florida Current, previous work has suggested that the two terraces support different benthic faunas. Images from 28 phototransects from the two terraces were condensed into two depth bins of 250-300 m and 450-550 m. Distributions of taxa compared among individual sites were depth driven, whereas distributions of taxa between the northern Miami Terrace and Pourtalès Terrace appeared to be driven by geological features, as sites at similar depths had different communities and densities, with the only distinguishing variables being location and geologic features. Results indicate that location is the driving factor contributing to differences in deep-water benthic communities between the two terraces. Depth bin 450-550 m was dominated on the Miami Terrace by hard substrates supporting octocorals (Pseudodrifa nigra, Primnoidae, Keratoisis sp., and Anthomastus sp.), anemones, and sponges (mainly Phakellia sp.) and on the Pourtalès Terrace by hard substrates and coral rubble supporting Paramuricea unid sp. 3, Comatonia cristata, Plumarella sp. 2, and Astrophorina unid. sp. 4. Depth bin 250-300 m on the northern Miami Terrace was dominated by sediment substrates and supported anemones, soft corals and zoanthids, and on the Pourtalès by sediment-veneered hard bottom with Stylaster miniatus, Plumarella unid sp., Hydroida unid sp., and Isididae unid sp. 2. The relationships between depth, location and geomorphology may be useful in designing future benthic mapping projects. In addition, species densities and protection statuses can aid future community assessments between protected habitats and non-protected habitats to measure the effectiveness and management strategies of deep-water marine protected areas. The relationships revealed by this study can be used to support the management of the Miami Terrace, Pourtalès Terrace, and other sites to conserve deep-water coral environments.

The Pourtalès Terrace is a gently curved, narrow triangular platform that parallels the Florida Keys for 213 km running from southern Key Largo to between Key West and the Marquesas Keys. The main Terrace surface begins in 200 m and dips gently to approximately 450 m, where the Pourtalès Escarpment slopes steeply to the deep floor of the southern Straits of Florida. The Terrace platform exhibits a wide variety of Neogene-age geological features, including high-relief ledges, mounds, sinkholes and deep-water biogenic build-ups called bioherms. Previous research revealed dense and diverse benthic assemblages dominated by stylasterid hydrocorals, octocorals and sponges. Many Terrace features also represent popular, long-term fishing targets. Due to concerns about resource sustainability, (National Oceanic and Atmospheric Administration (NOAA) and the South Atlantic Fishery Management Council (SAFMC) included the Terrace in the Comprehensive Ecosystem-Based Amendment 1 (CE-BA 1, June 2010) that protects deep-water Coral Habitat Areas of Particular Concern (CHAPCs) along the southeastern U.S continental margin by prohibiting use of a variety of potentially damaging bottom fishing gear. NOAA also established the East Hump Marine Protected Area (MPA) as a Type II MPA, permanently closed to fishing for and possession of snapper and grouper species. To develop a more robust database on Terrace habitats and resources, a research cruise (September 2011) used ROV Kraken 2 to survey 14 sites both inside and outside the CHAPC and MPA for biological diversity, density, and distribution, with a focus on deep-sea coral and sponge assemblages. The surveys resulted in 58 h of videotape, 2,866 images, and collected 150 specimens of benthic invertebrates. All dive sites were mapped with multibeam sonar. This project used Coral Point Count with Excel extensions (CPCe)©, PRIMER 6.1.10 beta, JMP© statistical software, and Environmental Systems Research Institute (ESRI) ArcMap 10.3 Geographic Information Systems (GIS) to quantitatively analyze transect images and video from the ROV transects. This information was used to characterize dive sites in terms of benthic invertebrate faunal communities, depth, and topography; and compare results relative to protected versus unprotected sites. Of the 14 sites surveyed 10 were analyzed and split into 42 transects of approximately 30 m2 based on five depth and location bin classes. Each site was initially separated into habitat types based on qualitative geomorphologic features for statistical analysis (i.e., mound slope, mound wall, mound top, deep mound, valley, Lophelia mound, sinkhole), using methods established by Reed et al. (2011; 2014). In initial analysis, depth and location were found to be superior to geomorphology as an indicator of what was driving differences in communities among transects. As a result each transect was placed into one of five depth and location bin classes based on depth (m) of each image and location relating to CHAPC/MPA area borders: West 150-300 m (12 transects), North Central 150-250 m (14), Central 250-300 m (8), South 450-500m (5) and South 500-550 m (3). Distinct differences in communities of each depth and location bin class in relation to percent cover and organism density were apparent. Communities vary strongly among bins with some similarities: e.g., West 150-300, North-Central 150-250, and Central 250-300 all included Stylaster miniatus (Stylasteridae): South 450-500 and South 500-550 included Paramuricea sp. 3 among their most dominant species. Also similar species were found within similar depth ranges. Protection status (within CHAPC, CHAPC/MPA, or No Protection) did not affect differences in communities, suggesting protection regulations have not been implemented long enough to show significant differences between protected and unprotected sites. Several new geologic features were found e.g., the southernmost Lophelia pertusa coral mound in U.S. waters. Some important features were described that lie outside of CHAPC/MPA borders, suggesting new borders should be designated. Results showed a strong relationship between depth and location in forming deep-water communities, and that these factors could be used as proxies for creating habitat maps in unmapped areas. These results will also provide managers and scientists with a valuable baseline for assessing benthic invertebrate communities, their changes over time, and the effectiveness of protected areas on the Pourtalès Terrace.