Dive characteristics of satellite-monitored blue whales (Balaenoptera musculus) off the central California coast

Dive habits of four Northeast Pacific blue whales (Balaenoptera musculus) w ere studied using satellite-monitored radio tags. Tags summarized dive-dura tion data into eight 3-h periods daily. One tag additionally summarized div e depth and time-at-depth information for these same periods. Tracking peri ods ranged from 0.6 to 12.7 d and provided data for 17 three-hour summary p eriods, representing 2,007 dives (788 of which provided depth information). Total number of dives during a 3-h summary period ranged from 83 to 128. S eventy-two percent of dives were less than or equal to 1 min long. All whal es spent >94% of their time submerged. Average duration of true dives (dive s >1 min) ranged from 4.2 to 7.2 min. Seventy-five percent of depth-monitor ed dives were to less than or equal to 16 m, accounting for 78% of that ani mal's time. Average depth of dives to >16 m was 105 +/- 13 m.