His achievements include determining the characteristics of ambient sea noise from physical, biological and shipping sources for the Australian Indo-Pacific region, based on extensive experiments and modelling. He also developed the first comprehensive theory of sound generation by motion of fluid interfaces such as the sea surface that has been verified by measurement. He established the characteristics of the humpback whale song for Australian stocks, the geographical and temporal variation and differences from northern hemisphere songs. He was an architect and a Principal Investigator of the Humpback Whale Acoustic Research Collaboration (HARC).