Abstract:

Over the past 5 years the Office of Naval Research (ONR) has maintained a coordinated interdisciplinary research program focused on the auditory capabilities of marine mammals, and the potential impacts man-made noise might have by damaging or obscuring that sensory capability. Auditory studies have included behavioral determinations of thresholds to low-frequency sound, effects of depth (pressure) on auditory function, and temporary threshold shift studies. Anatomical data, auditory-evoked potentials and otoacoustic emissions have been explored with the goal of providing larger sampling of populations and enabling sampling of the larger and rarely encountered species, such as baleen whales. The data collected thus far have further strengthened the view that marine mammal hearing represents the pinnacle of development of auditory sensing. With our own use of underwater acoustic sensing in its infancy, it would be wise to closely monitor those activities which might obscure our window into the ocean environment as well as that of its inhabitants who have led us this far.