Department of Biology

Aarhus University Seal / Aarhus Universitets segl

Professor Peter Teglberg Madsen

Using at-sea experiments to study the effects of airguns on the foraging behavior of sperm whales in the Gulf of Mexico

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • P.J.O. Miller, United Kingdom
  • M.P. Johnson, United States
  • Peter Teglberg Madsen
  • N. Biassoni, United States
  • M. Quero, United States
  • P.L. Tyack, United States
  • Department of Biological Sciences, Zoophysiology
Acoustic exposure and behavior of 8 sperm whales were recorded with acoustic and movement-recording tags before, during and after 5 separate 1-2 h controlled sound exposures of industry-provided airgun arrays. None of the 8 whales changed behavioral state (7 foraging, 1 resting) following the start of ramp-up at distances of 7-13 km, or full array exposures at 1-13 km. The most closely approached whale rested throughout exposure but started a foraging dive shortly after the airguns ceased, possibly indicating a delay in foraging during exposure. Using visual tracking and dead-reckoning of tagged animals, we found that their direction-of-movement was random with respect to the airguns, but correlated with their direction-of-movement just prior to the start of exposure, indicating that the tested whales did not show horizontal avoidance of the airguns. Oscillations in pitch generated by swimming movements during foraging dives were on average 6% lower during exposure than during the immediately following post-exposure period, with all 7 foraging whales exhibiting less pitching (p=0.014). Buzz rates, a proxy for attempts to capture prey, were 19% lower during exposure but given natural variation in buzz rates and the small numbers of whales, this effect was not statistically significant (P=0.141). Though additional studies are strongly recommended, these initial results indicate that sperm whales in the highly exposed Gulf of Mexico habitat do not exhibit avoidance reactions to airguns, but suggest they are affected at ranges well beyond those currently regulated due to more subtle effects on their foraging behavior.
Original languageEnglish
JournalDeep-Sea Research Part I: Oceanographic Research Papers
Volume56
Pages (from-to)1168-1181
ISSN0967-0637
DOIs
Publication statusPublished - 2009

See relations at Aarhus University Citationformats

ID: 19223731