* In this working group report only, the term "sonar" is used generically to indicate an acoustic
system. This is in agreement with the original, broad sense of the term (See Glossary). In underwater
acoustics, this is often the practice, as opposed to the general usage in fisheries acoustics
(hydroacoustics). In fisheries acoustics, "sonar" usually refers to horizontal echo ranging with an
active acoustical system. In underwater acousfics, the term would include vertical echo sounders and
passive acoustic systems, as well as horizontal detection and echo ranging systems.