Shawn Makepeace

Master’s Thesis

Citation: Makepeace, S. (2008) Structural changes in dolphin tonal vocalizations in a changing soundscape: A field study. Unpublished Master’s Thesis


The ocean is a naturally noisy environment.  Until recently, understanding of the effects of ambient noise on cetacean vocalizations has been limited.  Cetaceans have to cope with not only naturally occurring noise such as wind, waves, precipitation, ice, biological and seismic activity, but also with man-made noise as well.  Varying noise levels can have deleterious effects on a dolphin’s ability to communicate.  This study focused on a population of wild Indo-Pacific bottlenose dolphins (Tursiops aduncus) residing around Mikura Island, Japan.  This population is exposed to a wide variety of soundscapes including anthropogenic noise from watercraft.  A manually operated mobile video/acoustical array was used to collect the vocalizations from the population.  Based on spectral and kepstral analysis were used.