Weiss, J., Miller, J., Rooney, J. J.

Seafloor characterization using multibeam and optical data at French Frigate Shoals, Northwestern Hawaiian Islands

2009

Proceedings of the 11th International Coral Reef Symposium, 7-11 July 2008, Ft. Lauderdale, Florida

Session Number 17

662-666

"Multibeam bathymetry, backscatter, and optical data collected by the NOAA Coral Reef Ecosystem Division (CRED) were used to create maps of seafloor habitats on the bank top at French Frigate Shoals (FFS) in water depths ranging from less than 10-100 m. Supervised classification of backscatter and optical data with user-defined classes results in seafloor maps such as hard (rock, rubble, etc.) and soft (sandy) bottom. However, they suffer from a dependence on the generally limited optical data. Uncertainties in camera sled positioning, limited availability of optical data, and user bias in the supervised class definitions suggest an alternative approach may be necessary. Unsupervised classification of different combinations of bathymetry and backscatter derivatives uses the statistical separability of the data to define unique seafloor types. The optical data are then used to define and evaluate the accuracy of the classes. A variety of methods are being evaluated to characterize benthic habitats and the resulting maps are being used to improve sampling techniques for long-term ecosystem monitoring and to guide groundtruthing operations. Future plans include using these methods to identify coral-rich and species specific environments in the Northwestern Hawaiian Islands (NWHI)."

seafloor characterization; multibeam bathymetry; backscatter; Northwestern Hawaiian Islands