Vessel Noise Affects Beaked Whale Behavior: Results of a Dedicated Acoustic Response Study

Abstract

Some beaked whale species are susceptible to the detrimental effects of anthropogenic noise. Most studies have concentrated on the effects of military sonar, but other forms of acoustic disturbance (e.g. shipping noise) may disrupt behavior. An experiment involving the exposure of target whale groups to intense vessel-generated noise tested how these exposures influenced the foraging behavior of Blainville's beaked whales (Mesoplodon densirostris) in the Tongue of the Ocean (Bahamas). A military array of bottom-mounted hydrophones was used to measure the response based upon changes in the spatial and temporal pattern of vocalizations. The archived acoustic data were used to compute metrics of the echolocation-based foraging behavior for 16 targeted groups, 10 groups further away on the range, and 26 nonexposed groups. The duration of foraging bouts was not significantly affected by the exposure. Changes in the hydrophone over which the group was most frequently detected occurred as the animals moved around within a foraging bout, and their number was significantly less the closer the whales were to the sound source. Non-exposed groups also had significantly more changes in the primary hydrophone than exposed groups irrespective of distance. Our results suggested that broadband ship noise caused a significant change in beaked whale behavior up to at least 5.2 kilometers away from the vessel. The observed change could potentially correspond to a restriction in the movement of groups, a period of more directional travel, a reduction in the number of individuals clicking within the group, or a response to changes in prey movement.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 2012
Accession Number
ADA563823

Entities

People

  • David J. Moretti
  • Enrico Pirotta
  • Gordon Hastie
  • Ian Boyd
  • Nancy Di Marzio
  • Nicola J. Quick
  • Peter Tyack
  • Rachael Milor

Organizations

  • Naval Undersea Warfare Center

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Acoustics
  • Animals
  • Broadband
  • Detection
  • Frequency
  • Hydrophones
  • Information Science
  • Mammals
  • Marine Mammals
  • Noise
  • Oceans
  • Odontocetes
  • Ship Noise
  • Sonar
  • Tongue Of The Ocean
  • United States
  • Whales

Fields of Study

  • Environmental science
  • Psychology

Readers

  • Acoustical Oceanography.
  • Marine Mammal Biology
  • Organizational Psychology.