Evaluation of a New Hydroacoustic Substrate Classification System for Oyster Reef Mapping in Galveston Bay, Texas

A new hydroacoustic processing software (Visual Habitat) for the assessment and mapping of various substrate types was recently evaluated  using data collected by researchers at Texas Parks and Wildlife Department to quantify and map oyster reefs.  Understanding the distribution of oyster reef habitats is vital in guiding restoration and management efforts.  Obtaining quantifiable data on oyster reef resources is important in establishing a baseline and developing an index for monitoring temporal changes.  The study area is a 5.7 sq km rectangular grid of 10 transects spaced 200 m apart.  Hydroacoustic data collected from the study area were processed and the results were plotted over side scan sonar imagery.  Visual Habitat was compared with two previously existing processing tools; QTC Impact, BioSonics VBT, and a TPWD proprietary SAS method.   The results from Visual Habitat showed high agreement with prior results and resulted in a significant reduction in effort as compared to processing with other software.  In addition to the reduction in effort, Visual Habitat provided data visualization tools in the form of a transect map displaying user-defined color gradients for each data layer. Visual Habitat also provided export of results in KML file format for rapid interpretation via Google Earth.