Benthic assemblages of variable density cover three progressively deeper ridges that parallel the Broward County, Florida, coast. An acoustic bottom classification survey using QTCView5 with a 50 kHz transducer showed different acoustic classes on the shallow reef-ridge and the two deeper reef-lines, which both showed the same acoustic signature. Ground-truthing showed that the differences in acoustic signature corresponded to different benthic assemblages: nearshore hardgrounds had low live cover and were dominated by algae covering substrate, the two deeper reef-ridges had the same acoustic signature and similar benthic assemblages (dominated by sponges and gorgonians). The QTCView5 was also able to differentiate between stable sands covered by a thin red algae turf and more mobile sand without turf cover. Acoustic remote-sensing methods can be used to differentiate benthic assemblages, as long as enough differences exist in the growth-form characteristics of the dominant species to provide for a different acoustic roughness.