Comparison of blue and fin whale behavior and group characteristics in the Southern California Bight (SCB) 2008-2012

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Baseline undisturbed behavior and social patterns of blue (Balaenoptera musculus) and fin whales (B. physalus) are not well described and are needed to identify and understand potential effects of anthropogenic activities in the SCB. In 2008-2012, 72,467 km of aerial line transect and focal-follow effort was conducted in the SCB. Initially observed location, group size, behavior state, heading, and minimum and maximum inter-individual dispersal distance were recorded. Focal groups were circled for 10-60+ minutes and videotaped from outside the plane’s sound cone to avoid disturbance. A total of 122 fin whale sightings (208 individuals) and 65 blue whale sightings (104 individuals) were made. Behavior, occurrence and distribution were related to season, location, bathymetry, and time of day. Blue whales were seen only from summer-fall and concentrated primarily close to shore (