Dive and surfacing characteristics of bowhead whales (Balaena mysticetus) in the Beaufort and Chukchi seas

We received data from eight bowhead whales (Balaena mysticetus) equipped with satellite-monitored radio tags for 3-33 days. Of 42 306 dives made by the eight whales during 1695 h, 9573 were sounding dives (> 1 min duration). The mean duration of sounding dives for individuals varied from 6.9 to 14.1 min (mean = 10.4 +/- 2.4 min, n = 8). Five whales made dives greater than or equal to 61 min; the longest dives for the other three lasted 56, 45, and 32 min. Five tags measured maximum depths of 29 499 dives during 1220 h and time at depth during 1228 h. All five whales dived > 100 m; the deepest dive was 352 m. Whales spent most of their time at depths less than or equal to 16 m, but three whales spent most of their time at depths > 48 m during some sampling periods. Mean surfacing rates ranged from 18.2 to 47.0/h (mean = 26.2 +/- 9.0/h, n = 8). Tags were exposed to air for 4.0-7.3% of the time (mean = 5.5 +/- 0.95%, n = 8), and whales were potentially visible from aircraft for 8.5-16.4% of the time (mean = 11.1 +/- 2.4%, n = 8). Three whales made longer sounding dives and had lower surfacing rates when in greater than or equal to 90% ice cover. No consistent diel patterns were found.