|Title||Offshore killer whale tracking using multiple hydrophone arrays|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Gassmann M., Henderson E.E, Wiggins SM, Roch M.A, Hildebrand JA|
|Journal||Journal of the Acoustical Society of America|
|Type of Article||Article|
|Keywords||abundance; echolocation clicks; localization; orcinus-orca; pacific; sea; signals; sperm-whales; whistles|
To study delphinid near surface movements and behavior, two L-shaped hydrophone arrays and one vertical hydrophone line array were deployed at shallow depths (<125 m) from the floating instrument platform R/P FLIP, moored northwest of San Clemente Island in the Southern California Bight. A three-dimensional propagation-model based passive acoustic tracking method was developed and used to track a group of five offshore killer whales (Orcinus orca) using their emitted clicks. In addition, killer whale pulsed calls and high-frequency modulated (HFM) signals were localized using other standard techniques. Based on these tracks sound source levels for the killer whales were estimated. The peak to peak source levels for echolocation clicks vary between 170-205 dB re 1 mu Pa @ 1 m, for HFM calls between 185-193 dB re 1 mu Pa @ 1 m, and for pulsed calls between 146-158 dB re 1 mu Pa @ 1 m. (C) 2013 Acoustical Society of America.