Source level and calling depth distributions of migrating bowhead whale calls in the shallow Beaufort Sea

TitleSource level and calling depth distributions of migrating bowhead whale calls in the shallow Beaufort Sea
Publication TypeJournal Article
Year of Publication2016
AuthorsThode A.M, Blackwell S.B, Seger K.D, Conrad A.S, Kim K.H, Macrander A.M
JournalJournal of the Acoustical Society of America
Volume140
Pagination4288-4297
Date Published2016/12
Type of ArticleArticle
ISBN Number0001-4966
Accession NumberWOS:000390347900034
Keywordsbalaena-mysticetus; sounds
Abstract

Automated and manual acoustic localizations of migrating bowhead whales were used to estimate source level and calling depth distributions of their frequency-modulated-modulated calls over seven years between 2008 and 2014. Whale positions were initially triangulated using directional autonomous seafloor acoustic recorders, deployed between 25 and 55m water depth near Kaktovik, Alaska, during the fall westward migration. Calling depths were estimated by minimizing the "discrepancy" between source level estimates from at least three recorders detecting the same call. Applying a detailed waveguide propagation model to the data yielded broadband source levels of 161 +/- 9 dB re 1 mu Pa-2 s at 1m (SEL) for calls received between 20 and 170Hz. Applying a simpler 15 log(10)(R) power-law propagation model yielded SEL source levels of 158 +/- 10dB. The most probable calling depths lay between 22 and 30m: optimal depths for long-range acoustic signal transmission in this particular environment. (C) 2016 Acoustical Society of America.

DOI10.1121/1.4968853
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