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 wi th satellite-monitored radio tags for 3-33 days. Of 42 306 dives made by th e 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, an d 32 min. Five tags measured maximum depths of 29 499 dives during 1220 h a nd 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 equa l to 16 m, but three whales spent most of their time at depths > 48 m durin g some sampling periods. Mean surfacing rates ranged from 18.2 to 47.0/h (m ean = 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 fro m aircraft for 8.5-16.4% of the time (mean = 11.1 +/- 2.4%, n = 8). Three w hales made longer sounding dives and had lower surfacing rates when in grea ter than or equal to 90% ice cover. No consistent diel patterns were found.