 Northern fur seals spend a great deal of their life at sea and away from the prying eyes of
biologists. For years, researchers have been gaining insights into their lives by attaching data collection devices to the animals themselves. This information has become increasingly important given the continued decline in northern fur seal numbers on St Paul Island, Alaska, the main rookery in the North Pacific.
In the summer of 2009 the Marine Mammal Research Unit sent research teams to two remote islands in the Bering Sea – St Paul and Bogoslof - to equip northern fur seals with a state-of-the-art tag designed to record fine scale movement and orientation. The population on St. Paul Island has been declining for the last half century while a newly established population on Bogoslof Island continues to increase. Researchers want to know whether differences in the at-sea behavior of the fur seals can help explain their opposing population trajectories.
The teams — led by Dr. Brian Battaile — tagged 90 adult female fur seals to record their behavior when they go on foraging trips to the open ocean during the pupping season. The instrument
they used is so sensitive that they were able to record every twist, turn and muscle twitch at 16 times a second. These data can re-create the entire track of the animal from start to finish using three magnetometers (that determine direction from the earth’s magnetic field) and a lot of algebra, geometry, trigonometry and calculus. These data can also distinguish between many different types of behavior that fur seals exhibit while at sea, as we recently discovered with the help of Dr. Kentaro Sakamoto—a visiting professor from Japan.
Animation of fur seals foraging:(Click arrow at bottom to start animation)
This animated movie shows where all of the female fur seals (tagged in 2009) went and some of their behaviors. Changes in the color of the lines represent changes in the behavior of the fur seals (as indicated at the top of the map).The darker and lighter sections of the movie indicate day and night and the time on the bottom is GMT. Researchers are hoping that this new data will give insight into why the two populations are behaving so differently and what might be done about it. Some differences between the two islands are quite obvious as seen in the movie, while others will likely take longer to figure out.
This movie requires the Quicktime plug-in to be viewed. If you do not have it, please download the quicktime plug-in here:
Dr. Brian Battaile (UBC) is a Research Associate at the Marine Mammal Research Unit at U.B.C.
His study is supported by the North Pacific Research Board. (NMFS Research Permit Number 14329.)
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