Call discrimination for an unknown pod of killer whales (Orcinus orca) in the Eastern Canadian Arctic

Abstract

Killer whales produce pulsed calls, which are used for communication. Calls are highly stereotyped, and repertoires are unique to individual pods. Discrimination amongst these calls and comparison of call repertoires between pods can help determine population structure in killer whales and can be used to track pod movements. Calls were detected in underwater acoustic recordings from August to September 2017 in the waters near the community of Pond Inlet, Nunavut, Canada. Eight stereotypic call types were identified using whistle contour extraction and network analysis to compare contours. We present a repertoire of killer whale calls recorded. The potential for increased killer whale presence and magnitude of predation on narwhals is a source of concern for management of the population and by Inuit subsistence hunters who rely on narwhals for food and economic benefit. Describing the acoustic repertoire of killer whales seasonally present in the Canadian Arctic may help identify the stock or pod and determine their seasonal movements. Comparisons of this repertoire with killer whale calls from other Atlantic pods has not yet yielded a match. However, the results presented may provide a basis for future comparisons and aid in identifying killer whale ecotypes making seasonal incursions into Arctic waters.