title: Types, distribution, and seasonal occurrence of sounds attributed to Bryde's whales (Balaenoptera edeni) recorded in the eastern tropical Pacific, 1999-2001.
abstract: Vocalizations resembling known Bryde's whale sounds were recorded on autonomous hydrophones at seven sites in the eastern tropical Pacific. Five short (<3 s) low-frequency (<80 Hz) "phrase" types were observed. "Swept alternating tonal" phrases included a 37-Hz tone and often a 25-16-Hz downswept tone, while "nonswept alternating tonal" phrases had a predominant tone at 29 Hz and often additional tones at 16 and 47 Hz. Alternating tonal phrases were found in 79% of the total hours in which phrases were detected, and occurred primarily at the eastern hydrophone sites. "Burst-tonal" phrases included tones that were often preceded by a wideband burst of noise. The "low burst-tonal" phrase contained tones at 19 and 30 Hz, and was detected at five of the hydrophone sites. The "high burst-tonal" phrase included a 42-Hz tone and was observed only on the northwestern hydrophones. A single "harmonic tone" phrase type was observed that included a fundamental tone at 26 Hz and at least two harmonics; this phrase was observed exclusively at the eastern hydrophone stations. This opportunistic survey has shown that acoustics is an effective means of studying this poorly understood, pelagic balaenopterid.
authors.affiliation: Cooperative Institute for Marine Resources Studies, Oregon State University, and NOAA Pacific Marine Environmental Laboratory, 2030 SE Marine Science Drive, Newport, Oregon 97365, USA. sara.heimlich@oregonstate.edu
authors.forename: Sara L
authors.initials: SL
authors.lastname: Heimlich
authors.forename: a David K
authors.initials: aD
authors.lastname: Mellinger
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Nieukirk
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Fox
mesh_terms: D000162:Acoustics; D000818:Animals; D050616:Balaenoptera / Q000502:physiology*; D010140:Pacific Ocean; D012621:Seasons; D012623:Seawater; D013018:Sound Spectrography; D014828:Vocalization, Animal / Q000502:physiology*