The history of marine mammal bioacoustics at the Navy Marine Mammal Program

The United States Navy Marine Mammal Program (MMP) has been in existence for over 50 years. Following its inception, the program quickly became involved in the study of marine mammal sensory systems and bioacoustics. Early studies included the pioneering work of C. Scott Johnson in obtaining the first behavioral audiogram in a dolphin and Sam Ridgway’s electrophysiological studies of dolphin hearing and sound production. Marine mammal bioacoustic studies grew substantially in the decades following the MMP’s inception, and included numerous investigations into odontocete biosonar, pinniped and odontocete hearing (using both behavioral and physiological methods), and the impact of human-made sound on the hearing, behavior, and physiology of marine mammals. The MMP’s bioacoustic research has significantly contributed to the Navy’s environmental stewardship mandate (i.e. to predict and mitigate the impact of Navy activities on marine mammals), the development of bio-inspired sonar systems, and the ability to assess the hearing capabilities of marine mammals in the wild, under human care, and in stranded or rehabilitation scenarios. The MMP continues its bioacoustic studies today with investments focused on bottlenose dolphin and sea lion bioacoustics, but with expansion to the passive acoustic monitoring of wild marine mammals.