The west Florida shelf (WFS; Gulf of Mexico, USA) is an important area for commercial and recreational fishing, yet much of it remains unmapped and unexplored, hindering effective monitoring of fish stocks. The goals of this study were to map the habitat at an intensively fished area on the WFS known as “The Elbow”, assess the differences in fish communities among different habitat types, and estimate the abundance of each fish taxa within the study area. High-resolution multibeam bathymetric and backscatter data were combined with high-definition (HD) video data collected from a near-bottom towed vehicle to characterize benthic habitat as well as identify and enumerate fishes. Two semi-automated statistical classifiers were implemented for obtaining substrate maps. The supervised classification (random forest) performed significantly better (p = 0.001; α = 0.05) than the unsupervised classification (k-means clustering). Additionally, we found it was important to include predictors at a range of spatial scales. Significant differences were found in the fish community composition among the different habitat types, with both substrate and vertical relief found to be important with rock substrate and higher relief areas generally associated with greater fish density. Our results are consistent with the idea that offshore hard-bottom habitats, particularly those of higher vertical relief, serve as “essential fish habitat”, as these rocky habitats account for just 4% of the study area but 65% of the estimated total fish abundance. However, sand contributes 35% to total fish abundance despite comparably low densities due to its large area, indicating the importance of including these habitats in estimates of abundance as well. This work demonstrates the utility of combining towed underwater video sampling and multibeam echosounder maps for habitat mapping and estimation of fish abundance.

The West Florida Shelf (WFS) is an extremely important area for both commercial and recreational fisheries. However, the lack of habitat maps in this area makes planning fisheries independent monitoring surveys difficult, and hinders the ability to manage and monitor fish stocks and ecosystems over time. As of 2015, only 5% of the WFS had been mapped in high resolution using a multibeam echosounder with little effort expended to infer and verify habitat type. In 2015, The Continental Shelf Characterization, Assessment, and Mapping Project (C-SCAMP) began using a multibeam echosounder and towed underwater video to map benthic habitats and improve our understanding of fish-habitat relationships on the WFS. For this study, high resolution multibeam bathymetry and co-registered backscatter data were collected and processed. A portion of these areas were then “ground-truthed” using towed video transects to assess habitat type and identify fish. Habitat maps were created using a statistical classification model that predicts benthic habitat type based on the acoustic signature. Progress towards a unified habitat map of the West Florida Shelf will be presented including habitat interpretation of multibeam surfaces collected by other groups prior to this project, particularly focusing on those within Marine Protected Areas. Applications of the resultant habitat maps for fisheries management will be demonstrated and discussed.

A combined technology approach, using towed underwater video from the Camera-Based Assessment Survey System (C-BASS) and previously collected multibeam data, was used to characterize two concurrently established Marine Protected Areas (MPAs) located between 60 and 180 m on the West Florida Shelf (WFS): Madison-Swanson and Steamboat Lumps. C-BASS video was used to characterize habitats, identify reef species such as groupers and snappers, and estimate populations and assemblages. Several previously undefined habitat characteristics were identified in C-BASS video imagery in these areas and added to a Coastal and Marine Ecological Classification Standard (CMECS)-based flowchart, developed to suit towed video analysis on the WFS, including high-relief hard bottom, moderate-relief hard bottom, low-relief hard bottom, and covered low-relief hard bottom. In Madison-Swanson, the most commonly observed fishes were Lutjanidae spp., Priacanthidae spp., and Serranidae spp.; similarly, in Steamboat Lumps the most frequently encountered fishes were Lutjanidae spp. and Serranidae spp. Between the two MPAs, Madison-Swanson contained both higher abundance and diversity of fishes in the years observed with towed underwater video. Initial results of multivariate statistical analyses suggest habitat preferences of certain fish species, as well as substantial contributions from widespread sandy habitats to total fish abundance despite higher densities of fish over rocky habitats.

The use of marine offshore benthic habitats by sea turtles is poorly characterized due to the difficulty of obtaining in situ data. Understanding benthic habitat use that is important to the species’ reproduction, foraging, and migrations is critical for guiding management decisions. A towed camera-based assessment survey system (C-BASS) equipped with environmental sensors was used to characterize and assess benthic habitats on the West Florida Shelf (WFS) from 2014 to 2018. During these cruises, sea turtles were opportunistically observed during the surveys, and critical in situ data such as spatiotemporal information, species identification, habitat use, behavior, and environmental data were collected and evaluated. In total, 79 sea turtles were observed during 97 transects of approximately 2700 km of seafloor, which was recorded on 380 h of video. Several sea turtle species were spotted within the WFS, including loggerhead Caretta caretta, Kemp’s ridley Lepidochelys kempii, and green turtles Chelonia mydas. These opportunistic sightings revealed an area of high use on the WFS, an anthropogenic structure known as the Gulfstream natural gas pipeline (GSPL). C-BASS survey results suggest that 2 sea turtle species (C. caretta and L. kempii) utilize this artificial structure primarily as a resting area. We emphasize the importance of combining habitat mapping techniques (towed underwater video and multibeam bathymetry/backscatter) with tracking technology to better understand the fine-scale habitat use of sea turtles.

The Red Grouper Epinephelus morio is an ecologically and economically important Gulf of Mexico reef fish species. The well-documented excavation behavior of this species generates several-meter-wide holes that serve as habitat in otherwise structureless areas. These mesohabitats are notably dense within the Steamboat Lumps (SL) Marine Protected Area (MPA) in the eastern Gulf of Mexico. Previous work in the SL-MPA used high-resolution multibeam bathymetry to analyze changes in hole density and structure (width, height, and slope) between 2006 and 2009. The present study utilizes additional multibeam data collected in 2017 to further these analyses. Overall, the density of holes within the SL-MPA continued to increase, but no definite trend in structural changes could be identified. Additionally, a towed camera was used to directly observe 95 holes, of which 63 had detectable reef fishes. Within the occupied holes, approximately 46% had a Red Grouper or other grouper species (Epinephelidae) present. The most frequently observed species within the occupied holes were invasive lionfish Pterois spp., which were present in 84% of the holes. The increasing density of Red Grouper holes in the SL-MPA indicates that the closure of the area may be resulting in a more robust local population of this species. However, quick colonization of the holes by lionfish has occurred, and additional studies are necessary to determine the impact of this on grouper and other native reef fish populations found within this type of uniquely created habitat.

Measuring seafloor motion in shallow coastal water is challenging due to strong and highly variable oceanographic effects. Such measurements are potentially useful for monitoring near‐shore coastal subsidence, subsidence due to petroleum withdrawal, strain accumulation/release processes in subduction zones and submerged volcanoes, and certain freshwater applications, such as volcano deformation in caldera‐hosted lakes. We have developed a seafloor geodesy system for this environment based on an anchored spar buoy topped by high‐precision GPS. Orientation of the buoy is measured using a digital compass that provides heading, pitch, and roll information. The combined orientation and GPS tracking data are used to recover the three‐dimensional position of the seafloor marker (anchor). A test system has been deployed in Tampa Bay, Florida, for over 1 year and has weathered several major storms without incident. Even in the presence of strong tidal currents which can deflect the top of the buoy several meters from vertical, daily repeatability in the corrected three‐component position estimates for the anchor is 1–2 cm or better.

Early-career scientists aboard the 2016 UNOLS Chief Scientist Training Cruise explored recently reactivated underwater methane seeps in the San Diego Trough.