Shaken, not stirred: blue whales show no acoustic response to earthquake events

Quantifying how animals respond to disturbance events bears relevance for understanding consequences to population health. We investigate whether blue whales respond acoustically to naturally occurring episodic noise by examining calling before and after earthquakes (27 040 calls, 32 earthquakes; 27...

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Bibliographic Details
Published in:Royal Society Open Science
Main Authors: Dawn R. Barlow, Mateo Estrada Jorge, Holger Klinck, Leigh G. Torres
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 2022
Subjects:
Q
Online Access:https://doi.org/10.1098/rsos.220242
https://doaj.org/article/89e57e7848a94132ba63288a04f4a65b
Description
Summary:Quantifying how animals respond to disturbance events bears relevance for understanding consequences to population health. We investigate whether blue whales respond acoustically to naturally occurring episodic noise by examining calling before and after earthquakes (27 040 calls, 32 earthquakes; 27 January–29 June 2016). Two vocalization types were evaluated: New Zealand blue whale song and downswept vocalizations ('D calls'). Blue whales did not alter the number of D calls, D call received level or song intensity following earthquakes (paired t-tests, p > 0.7 for all). Linear models accounting for earthquake strength and proximity revealed significant relationships between change in calling activity surrounding earthquakes and prior calling activity (D calls: R2 = 0.277, p < 0.0001; song: R2 = 0.080, p = 0.028); however, these same relationships were true for ‘null’ periods without earthquakes (D calls: R2 = 0.262, p < 0.0001; song: R2 = 0.149, p = 0.0002), indicating that the pattern is driven by blue whale calling context regardless of earthquake presence. Our findings that blue whales do not respond to episodic natural noise provide context for interpreting documented acoustic responses to anthropogenic noise sources, including shipping traffic and petroleum development, indicating that they potentially evolved tolerance for natural noise sources but not novel noise from anthropogenic origins.