Call repertoire and inferred ecotype presence of killer whales (Orcinus orca) recorded in the southeastern Chukchi Sea

• Published in: The Journal of the Acoustical Society of America 2021-10, Vol.150 (4), p.A284-A284
• Main Authors: Madrigal, Brijonnay, Crance, Jessica, Berchok, Catherine, Stimpert, Alison
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/10.0008307

Killer whales occur in the Arctic but few data exist regarding the ecotypes present. Calling behavior differs among ecotypes, which can be distinguished based on pulsed call type, call rate, and bandwidth. Data included in this study were from a passive acoustic recorder deployed 75 km off Point Hope, Alaska, in the southeastern Chukchi Sea (sampling rate 16 kHz, ∼30% duty cycle). A total of 1323 killer whale pulsed calls were detected on 38 of 276 days during the summers (June–August) of 2013–2015. Most calls (n = 804, 61%) were recorded in 2013 with the majority recorded in July (76% of total calls). Calls were manually grouped into six categories: multipart, downsweep, upsweep, modulated, single modulation, and flat. Most detections were flat (n = 485, 37%) or multipart calls (n = 479, 36%), which contained both high and low frequency components. Comparisons with calls reported in the published literature showed similarities with other transient populations in both fundamental frequency contour point distribution and median frequency. This study provides the first comprehensive catalog of transient killer whale calls in this region and reports on previously undescribed calls, providing new insight into transient acoustic behavior and call diversity in the Chukchi Sea.