The vocal repertoire of white whales, Delphinapterus leucas, summering in Cunningham Inlet, Northwest Territories

Abstract

The underwater vocalizations of white whales, Delphinapterus leucas, summering at Cunningham Inlet, Northwest Territories, were recorded from mid-July to mid-August 1981 to 1983. A total of 807 tonal calls (whistles) were classified into 16 contour types. The following acoustic parameters were measured for each whistle: minimum, maximum, and mean frequency of the fundamental, contour or shape of the fundamental, duration, and the slope of the frequency changes during the call. Some 436 pulsed calls were classified into three major categories: click series, pulsed tones, and noisy vocalizations. Acoustic parameters measured for each of these calls included pulse repetition rate, range and mean frequency of the call, and duration. Results show that the whistle repertoire of white whales is more varied than has been previously reported. Mean frequencies for the whistle contour types ranged from 2.0 to 5.9 kHz; mean duration ranged from 0.25 to 1.95 s. Although whistles were the most commonly emitted type of vocalization, pulsed tones and noisy vocalizations made up a significant proportion of the white whales' vocal repertoire. The mean pulse repetition rate of pulsed tones ranged from 203.9 to 1289.0 pulses/s. There does not appear to be any between-year variation in the vocal repertoire of these white whales.