Singing fin whales tracked acoustically offshore of Southern California

Fin whales (Balaenoptera physalus) produce a stereotyped low frequency call (15-30 Hz) that can be detected at great range and is considered song when produced in a repeated pattern. These calls, referred to as 20 Hz calls, were localized and animals were tracked using a kilometer-scale array of fou...

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Bibliographic Details
Main Author: Varga, Leah McLean
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: eScholarship, University of California 2016
Subjects:
Online Access:http://www.escholarship.org/uc/item/14q4d8w8
http://n2t.net/ark:/13030/m5p31kv7
Description
Summary:Fin whales (Balaenoptera physalus) produce a stereotyped low frequency call (15-30 Hz) that can be detected at great range and is considered song when produced in a repeated pattern. These calls, referred to as 20 Hz calls, were localized and animals were tracked using a kilometer-scale array of four passive acoustic recorders deployed at approximately 800m depth, northwest of San Clemente Island in the Southern California Bight. A total of 4969 calls were localized over four continuous weeks during late fall of 2007. The average estimated source level for the localized calls was 190.9 ± 7.4 dB peak-to-peak re 1µPa2 at 1m. The majority of the calls in these data were in the form of a doublet song pattern, with average inter-pulse intervals (IPI) 13s and 18s. The tracks were the first to be recorded for singing fin whales transiting alone using passive acoustic monitoring. Acoustic tracking of fin whales provides insight into the ecology and behavior of the species. Estimating call source levels help future predictions of how these whales are impacted by anthropogenic noise. Call source level, along with calling behavior, provide important parameters required for population density estimation. Furthermore, studying fin whale song patterns may aid in distinguishing different subpopulations.