Abstract

Acoustic technology has been utilized to map seabed characteristics for decades. Originally developed for military operations, the side scan sonar emits acoustic pulses and processes the resultant return intensities to identify bathymetric features on the seafloor. Side scan sonar use has historically been confined to offshore continental shelf waters, but recent technological advances have enabled its use in shallow-water coastal areas. The purpose of this research is to acoustically map benthic habitats in a shallow Mississippi bay system to delineate submerged aquatic vegetation (SAV) and oyster shell complexes relative to bare sand/mud bottoms. An Imagenex Sportscan side scan sonar integrated with SonarWiz.Map mapping software and a WAAS-differentiated global positioning system (GPS) was used to acquire digital acoustic imagery and view those data in real-time via a laptop computer. Relative to most units used for mapping continental shelf features, the Sportscan is small, lightweight and inexpensive, and the integrated system including sonar, mapping software and GPS is cost-efficient at approximately $15,000 USD. Initial results of mapping efforts show excellent detection of SAV and oyster habitats, as well as locations of marine debris and derelict crab traps.

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