title: Comparison of echolocation clicks from geographically sympatric killer whales and long-finned pilot whales (L).
abstract: The source characteristics of biosonar signals from sympatric killer whales and long-finned pilot whales in a Norwegian fjord were compared. A total of 137 pilot whale and more than 2000 killer whale echolocation clicks were recorded using a linear four-hydrophone array. Of these, 20 pilot whale clicks and 28 killer whale clicks were categorized as being recorded on-axis. The clicks of pilot whales had a mean apparent source level of 196 dB re 1 μPa pp and those of killer whales 203 dB re 1 μPa pp. The duration of pilot whale clicks was significantly shorter (23 μs, S.E.=1.3) and the centroid frequency significantly higher (55 kHz, S.E.=2.1) than killer whale clicks (duration: 41 μs, S.E.=2.6; centroid frequency: 32 kHz, S.E.=1.5). The rate of increase in the accumulated energy as a function of time also differed between clicks from the two species. The differences in duration, frequency, and energy distribution may have a potential to allow for the distinction between pilot and killer whale clicks when using automated detection routines for acoustic monitoring.
authors.affiliation: Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark. idaeskesen@hotmail.com
authors.forename: Ida G
authors.initials: IG
authors.lastname: Eskesen
authors.forename: Magnus
authors.initials: M
authors.lastname: Wahlberg
authors.forename: Malene
authors.initials: M
authors.lastname: Simon
authors.forename: Ole Næsbye
authors.initials: ON
authors.lastname: Larsen
mesh_terms: D000818:Animals; D004455:Echolocation; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D009664:Norway; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013045:Species Specificity; D061350:Sympatry; D013997:Time Factors; D014159:Transducers; D014828:Vocalization, Animal; D050685:Whale, Killer / Q000502:physiology*; D050686:Whales, Pilot / Q000502:physiology*