Underwater acoustic scene analysis: Exploration of appropriate metrics.

Abstract

A recent review of published accounts of acoustic noise exposure and behavioral response found that the reported results were often limited by the lack of supporting information on basic acoustical metrics as well as potentially important contextual variables. [Southall et al., Aquat. Mamm. 33, 411–521(2007)]. Human studies have also shown that simple measures such as sound level are insufficient to represent complex acoustic scenes [Dubois, J. Acoust. Soc. Am. 122, 3011–(2007)]. While source and received levels are frequently reported for underwater studies, other characteristics of the resultant acoustic field are rarely described. Understanding the full spatial, temporal, and spectral nature of the sound field can provide additional quantitative measures useful in elucidating the animals’ response to the incident sound field exposure. The animals’ perception of received acoustic field may also be influenced by the biological meaningfulness of the signal and the experience of the receiver with signals of a given type. Here we provide guidelines for future studies corresponding to three phases: preplanning, field measurements, and postmeasurement analysis, addressing acoustic field metrics as well as the seasonal distribution and baseline behavior of the animals of interest. Examples from selected field measurements will be used to illustrate the salient features.