ESR prepress abstract  -  DOI: https://doi.org/10.3354/esr00881

Behavior of singing fin whales Balaenoptera physalus tracked acoustically offshore of Southern California

Leah M. Varga*, Sean M. Wiggins, John A. Hildebrand

*Email: lvarga226@gmail.com

ABSTRACT: Fin whales Balaenoptera physalus produce stereotyped low frequency calls (15–30 Hz) that can be detected at great ranges and are considered song when produced in a repeated temporal pattern. These calls, referred to as 20 Hz calls, were localized and tracked using a one- kilometer aperture array of 4 passive acoustic recorders at approximately 800 m depth, northwest of San Clemente Island offshore of Southern California for 4 continuous weeks during late fall 2007. A total of 1454 calls were localized over the recording period. The average estimated source sound pressure level was 194.8 ± 0.2 dBpp re 1 µPa2 at 1 m, and 180.9 ± 0.2 dBrms re 1 µPa at 1 m. The majority of these calls were in the form of a doublet song pattern, with average inter-pulse intervals 13 s and 18 s. These tracks are the first to be reported for transiting solitary singing fin whales using passive acoustic monitoring techniques. Acoustic tracking of fin whales provides insight into the ecology and behavior of this endangered species, as well as vocal behaviors, which are important when studying the potential impact from anthropogenic noise. Call source sound pressure 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.