How effectively do horizontal and vertical response strategies of long-finned pilot whales reduce sound exposure from naval sonar?

Authored by Patrick J O Miller, Benda-Beckmann Alexander M von, Frans-Peter A Lam, Paul J Wensveen, Michael A Ainslie, Petter H Kvadsheim, Peter L Tyack

Date Published: 2015

DOI: 10.1016/j.marenvres.2015.02.005

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: Other Narrative

Model Code URLs: Model code not found

Abstract

The behaviour of a marine mammal near a noise source can modulate the sound exposure it receives. We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure levels and maximum sound pressure levels (SPLs) by modelling realistic spatiotemporal interactions of a pilot whale with an approaching source. Under the propagation conditions of our model, some response strategies observed in the wild were effective in reducing received levels (e.g. movement perpendicular to the source's line of approach), but others were not (e.g. switching from deep to shallow diving; synchronous surfacing after maximum SPLs). Our study exemplifies how simulations of source-whale interactions guided by detailed observational data can improve our understanding about motivations behind behaviour responses observed in the wild (e.g., reducing sound exposure, prey movement). (C) 2015 Elsevier Ltd. All rights reserved.

Tags

Behavioral-responses Bottle-nosed dolphins Physeter-macrocephalus Offshore wind farm Temporary threshold shift Porpoises phocoena-phocoena Auditory-evoked potentials Globicephala-melas Harbor porpoises Killer whales