Blue Whale

Bruce Mate

Latin name: Balaenoptera musculus

We began Argos-tagging blue whales in 1995, primarily off Southern California in mid-summer to early fall, learning about their foraging movements and winter migrations into Mexico and as far south as 8 degrees north (500 miles offshore) at an upwelling known as the Costa Rica Dome. This productive area allows blue whales to continue feeding during the winter breeding and calving season, which is contrary to most baleen whales which usually fast during their reproductive season in areas with low productivity. The summer and fall foraging of blue whales has included areas as far north of the Gulf of Alaska and as far west as Hawaii. Our recent studies have included periods of low productivity in the feeding area from warm water blobs and a deep El Niño that resulted in many animals being emaciated early in the foraging season and demonstrating a more limited foraging range. Our recent studies focus on the time blue whales spend in naval training activity areas.

Our research has demonstrated that the highest concentration of blue whales in the Eastern North Pacific is in the entrance to the Santa Barbara channel for commercial high-speed shipping that goes into Los Angeles. The population along the Eastern North Pacific may constitute between 25 and 30% of all of the blue whales remaining in the world. This population was never as decimated as the Antarctic pop from which 366,000 were harvested from 1900 to 1950. 

More information


Movements of North Pacific blue whales during the feeding season off southern California and their southern fall migration.
Mate, B.R., B.A. Lagerquist and J. Calambokidis.
Marine Mammal Science 15(4):1246-1257 (1999)


Dive characteristics of satellite-monitored blue whales (Balaenoptera musculus) off the central California coast.
Lagerquist, B.A., K.M. Stafford and B.R. Mate.
Marine Mammal Science 16(2):375-391 (2000)


Blue whale habitat and prey in the California Channel Islands
Paul C. Fiedler, Stephen B. Reilly, Roger P. Hewitt, David Demer, Valerie A. Philbrick, Susan Smith, Wesley Armstrong, Donald A. Croll, Bernie R. Tershy, and Bruce R. Mate.
Deep-Sea Research II 45:1781-1801 (1998)


Persistent Pelagic Habitats in the Baja California to Bering Sea (B2B) Ecoregion.
Peter Etnoyer, David Canny, Bruce Mate, Lance Morgan, and Glen Ellen.
Oceanography 17:90-101 (2004)

Sea-surface temperature gradients across blue whale and sea turtle foraging trajectories off the Baja California Peninsula, Mexico.
Peter Etnoyer, David Canny, Bruce R. Mate, Lance E. Morgan, Joel G. Ortega-Ortiz, and Wallace J. Nichols.
Deep-Sea Research II 53:340–358 (2006)

Other literature cited:

Branch, T.A. 2008. Current status of Antarctic blue whales based on Bayesian modeling. Unpublished report SC/60/SH7 to the Scientific Committee of the International Whaling Commission.

NOAA Stock Assessment Report, 2007. Blue Whale (Balaenoptera musculus): Eastern North Pacific Stock.