Oceanography Seminar: An Acoustic Survey of Beaked Whale and Kogia

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Oceanography Seminar: An Acoustic Survey of Beaked Whale and Kogia in the Main Hawaiian Islands Using Drifting Recorders

presented by Jennifer Keating, Sr. Passive Acoustic Associate, Joint Institute for Marine and Atmospheric Research (JIMAR)

During the 2017 Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS), a network of 13 drifting hydrophone recorders was deployed around the main Hawaiian Islands with the goal of improving detection of beaked whales and Kogia. These Drifting Acoustic Spar Buoy Recorders (DASBRs) contained a two-element vertical hydrophone array at 150 m depth, sampling at 288kHz for 2 min of every 10 min. Deployment locations were planned to cover a 50 nmi minimum convex polygon around the main Hawaiian Islands (MHI Stratum). In actuality, DASBRs drifted significantly within the MHI Stratum and up to 200 nmi beyond. Overall the DASBRs collected data on 251 days and over 6,354 km of drifting track. Using the Click Detector Module within PAMGuard (version 2.00.11), 2-min periods of clicking were classified based on peak frequency. We found frequency modulated (FM) pulses characteristic of Longman’s, Cuvier’s, Blainville’s, and Cross Seamount beaked whales (BWC) in over 900 2-min files, spread along the drift track of each DASBR. Additionally, two types of Kogia echolocation clicks were detected with peak frequencies of 116 kHz and 123 kHz. To further improve detections of Kogia echolocation clicks, custom MATLAB subroutines were used to re-analyze the recordings in greater detail resulting in 60 2-min detections. Acoustic detections of beaked whales and Kogia were much more numerous than those from the towed array efforts during HICEAS and will enhance understanding of the distribution of these species in the main Hawaiian Islands.

Jennifer Keating has worked in the field of acoustics for 17 years focusing on various marine mammals, bears, and birds. Currently, focusing on acoustic detection of false killer whales and various species of beaked whales.

Event Sponsor
Dept. of Oceanography, Mānoa Campus

More Information
(808) 956-7633, uhmocean@hawaii.edu, http://www.soest.hawaii.edu/oceanography/seminar.html

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