The communication space of humpback whale social sounds in wind-dominated noise

In animal social networks, a large acoustic communication space tends to involve complex networks. Signal masking may reduce this space, leading to detrimental effects on the animal's ability to obtain important social information. Humpback whales use acoustic social sounds (vocal sounds and surface-generated sounds from breaching or fin slapping) for within-and between-group communication. In this study, changes in various sound parameters (e.g., signal-above-noise and frequency content) of received humpback whale social sounds were statistically modeled against the combined effect of increasing wind-dominated noise and distance from the source (whale) to produce masking models. Behavioral data on vocalizing groups were also used to inform these models. The acoustic communication space, in this shallow water (< 50 m) environment, extended to approximately 4 km from the signaler in median wind noise. However, the majority of behavioral interactions occurred within 2 km of the signaler. Surface-generated signals propagated better and likely function to maintain this space in higher wind noise. This study provides a basic wind-noise masking model for social communication signals in humpback whales which can be updated as more information on humpback auditory capabilities, and potential masking effects of anthropogenic noise sources, becomes available. (C) 2018 Acoustical Society of America.