This year marked the 10th anniversary of recreational side-scan sonar—an inexpensive tool for imaging underwater environments in striking detail. The low cost of equipment, and the ability to process and overlay image data in a geographic information system (GIS) has led to groundbreaking developments in mapping, monitoring, and research of aquatic denizens. Through this original symposium, we convened the early pioneers of low-cost side-scan sonar to showcase the development of new techniques and biological applications. Among the 15 presentations, topics ranged from shallow water to whole river basin surveys, Alligator Gar to freshwater invertebrates, and submerged aquatic vegetation to sturgeon spawning habitat. An ensuing open forum discussion benefitted from the attendance of industry representatives (Lowrance, SonarTRX), and highlighted potential future directions, such as web-based information sharing and automating the classification of sonar imagery. The popularity of the symposium reflected the enthusiasm surrounding the technology and its emerging applications; low-cost side-scan sonar is poised to become an essential tool for investigations in navigable, inland aquatic systems.   — Adam Kaeser, U.S. Fish and Wildlife Service, [email protected] Read the symposium abstracts here.