Echolocation click parameters of short-finned pilot whales (Globicephala macrorhynchus) in the wild

J Acoust Soc Am. 2021 Mar;149(3):1923. doi: 10.1121/10.0003762.

Abstract

Short-finned pilot whales (Globicephala macrorhynchus) are large, deep-diving predators with diverse foraging strategies, but little is known about their echolocation. To quantify the source properties of short-finned pilot whale clicks, we made 15 deployments off the coast of Tenerife of a deep-water hydrophone array consisting of seven autonomous time-synced hydrophone recorders (SoundTraps), enabling acoustic localization and quantification of click source parameters. Of 8185 recorded pilot whale clicks, 47 were classified as being recorded on-axis, with a mean peak-to-peak source level (SL) of 181 ± 7 dB re 1 μPa, a centroid frequency of 40 ± 4 kHz, and a duration of 57 ± 23 μs. A fit to a piston model yielded an estimated half-power (-3 dB) beam width of 13.7° [95% confidence interval (CI) 13.2°-14.5°] and a mean directivity index (DI) of 22.6 dB (95% CI 22.5-22.9 dB). These measured SLs and DIs are surprisingly low for a deep-diving toothed whale, suggesting we sampled the short-finned pilot whales in a context with little need for operating a long-range biosonar. The substantial spectral overlap with beaked whale clicks emitted in similar deep-water habitats implies that pilot whale clicks may constitute a common source of false detections in beaked whale passive acoustic monitoring efforts.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acoustics
  • Animals
  • Echolocation*
  • Fin Whale*
  • Sound Spectrography
  • Vocalization, Animal
  • Whales
  • Whales, Pilot*