Incorporating Particle Motion in Fish Communication and Listening Space Models

Noise from vessel activity is a major contributor to underwater soundscapes throughout many parts of the world. Vessel noise often induces physiological and behavioral changes in marine animals and can mask ecologically important signals, i.e., limit animals’ abilities to detect these signals. Quantitative study of in situ masking in marine environments is often challenged by limited understanding of noise characteristics, sound propagation, and hearing physiology of animals. As a result, studies often make assumptions about model parameters based on limited data. Masking studies in marine environments traditionally use sound pressure, which is detected by mammals and some fishes, to describe in situ acoustic data and animals’ hearing thresholds. Few masking assessments have incorporated particle motion, the back-and-forth vibratory part of sound which is the primary stimulus for fish and invertebrate hearing, limiting application of models to these abundant taxa. In this chapter, models previously employed to estimate masking effects of noise on communication and listening space in aquatic environments are summarized, followed by an example and discussion of how particle motion data can be incorporated into these assessments. Challenges and needs for more accurate estimation of masking experienced by fish and invertebrate taxa are discussed.