Hydroacoustics is a general term for the study and application of sound in water. The term comes from Greek ὕδωρ, water, and ακουστική, acoustics. Hydroacoustics, utilizing sonar technology, is most commonly used for detection, assessment, and monitoring of underwater physical and biological characteristics. Specific Applications * Surveillance Towed Array Sensor System * Fisheries Acoustics * Acoustic Doppler Current Profiler for water speed measurement * Acoustic Camera * Passive Acoustic Monitoring