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Benthic Habitat Characterization of the West Florida Shelf Using High Resolution Multibeam Sonar and Towed Underwater Video


New benthic habitat maps of the Florida Middle Grounds, Madison-Swanson, and Steamboat Lumps marine protected areas are of sufficient detail to represent the complex and heterogeneous bottom types found on the West Florida Shelf. Without these maps, habitat characterization is difficult, thereby making it difficult to estimate benthic fish distributions. The primary goal of this study is to integrate high-resolution multibeam bathymetry and backscatter data with recently collected towed underwater video from the University of South Florida's (USF) Camera Based Assessment Survey System (CBASS) to create a detailed benthic habitat map of the Florida Middle Grounds, Madison-Swanson, and Steamboat Lumps Marine Protected Areas using Geographic Information Systems (GIS) software. Areas mapped by USF (300 kHz) and USGS (100 kHz) multibeam include ∼1190 sq km within the Florida Middle Grounds, ∼370 sq km within the Madison Swanson, and ∼370 sq km within the Steamboat Lumps Areas. ∼130 km of CBASS video data were collected in the Florida Middle Grounds during June 2013. ∼70 km of video were also collected in the Madison-Swanson area, and additional video collection is scheduled in both the Madison-Swanson and Steamboat Lumps areas in October 2013. Simrad EK-60 digital split-beam water-column and bathymetry data were collected concurrently during each video cruise. A real-time navigation method was developed during these cruises by feeding GPS data into the ArcGIS software that displays the high-resolution multibeam bathymetry and backscatter data. This method proved useful for real-time cruise planning and was also invaluable in anticipating rapid changes in depth to avoid potential CBASS collisions with the seafloor. Correlations between bathymetry and backscatter data, depth, slope, and visually observed bottom type will be assessed using ESRI ArcGIS Spatial Analyst software. These correlations will be used to interpret other areas of similar remote-sensing characteristics. These predictive interpretations will be tested during subsequent CBASS transects. The secondary goal of this study is to utilize the correlations found to create a bottom-type interpretation scheme for high-resolution multibeam sonar bathymetry and backscatter appropriate for the West Florida Shelf. This potential interpretation scheme will be used to create benthic habitat maps of the West Florida Shelf, and may perhaps be useful over similar carbonate platforms and latitudes.