RESEARCH PROJECT OCEAN SOUNDS
VOCAL REPERTOIRE OF KILLER WHALES (Ocrinus orca) AND LONG-FINNED PILOT WHALES (Globicephala melas) IN NORWEGIAN COASTAL WATERS
Killer whales and long-finned pilot whales are highly vocal and rely on a variety of different sounds for underwater communication and navigation. Both species, live in matriocal groups and at least killer whales use group-specific dialects that reflect maternal relatedness, to avoid inbreeding and enhance group cohesion. North Atlantic killer whales live in matrifocal groups and mostly feed on herring and salmon. They use a special form of foraging called carousel feeding, during which they vocalize frequently, perhaps indicating the importance of calls for the coordination of group movements. During the last 16 years human activities around killer whales have been increasing steadily, both by the whale watching and fishery industries. Due to the increase in herring fisheries, killer whales started to feed from discarded fish from fishing boats purse seining for herring. This newly learned foraging behavior was transmitted rapidly and interaction with fishing boats is now common for most killer whale groups. Our goal is to understand the vocal behavior of the whales during different behavioral contexts. We will investigate vocal and airborne behaviors. This includes advanced analysis of the calls’ structure and usage of calls.
Our vocal repertoire catalog of killer whales in Norway includes recordings since 2003 and we collected good recordings from over 17 different groups, which together resulted in 59 call types and 22 sub-call types and 34 different call type combinations.
We have established more comprehensive call repertoire catalogs of different species, which will be used as prerequisite for a long-term study of the vocal behavior in different contexts and in comparisons of different populations. Our results complement photo-ID and genetic studies. They reveal the identity of groups of whales, even under low light conditions such as the Arctic winter.
A comprehensive summary of vocal repertoires of killer whales and long-finned pilot whales can be viewed in the PhD thesis of Dr. Heike Vester