Diving behaviour of narwhals (Monodon monoceros) at two coastal localities in the Canadian high Arctic

• Main Authors: Kristin L. Laidre, Mads Peter Heide-jørgensen, Rune Dietz
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: Arctic; Baffin Island; Canada; Nunavut; Somerset Island; Tremblay; Tremblay Sound; Baffin; Creswell Bay; Monodon monoceros; narwhal*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.529.5187; http://staff.washington.edu/klaidre/docs/Laidreetal_2002b.pdf

Abstract: In August 1999 and 2000, four suction-cup-attached time–depth recorders (TDRs) were deployed and re-trieved from narwhals (Monodon monoceros) in Tremblay Sound, Baffin Island, and Creswell Bay, Somerset Island, Nunavut, Canada. The TDRs remained on the whales for between 12 and 33 h and collected 64.5 h of dive data. Mean dive depths ranged from 20.8 m (SD = 14.8 m) to 50.8 m (SD = 43.8 m) and mean dive durations ranged from 3.4 min (SD = 1.6 min) to 4.9 min (SD = 4.5 min). There appeared to be individual differences in dive parameters both within a region and between regions. Three of the whales made short, shallow dives, while another whale made dives twice as deep and twice as long. One whale had maximum dive durations (>20 min) that exceeded predicted aerobic dive limits for narwhals. There was a strong relationship between maximum dive depth and duration for all whales (p < 0.0001). Narwhals spent between 30.3 and 52.9 % of their time at depths <5 m and the range of correction factors for availability bias was 1.9–3.3. Satellite-linked TDRs were simultaneously deployed on the whales at both localities. Dive data collected using the two methods were compared and good agreement between the methods was obtained.