Every spring, scientists take a census of the polar bears in the Southern Beaufort Sea using a capture-recapture technique. The study helps scientists determine what's happening with this population—and to share this information with the world.
The Southern Beaufort Sea population is one of the best-studied in the world. Such long-term studies are important because they:
Data from this population, for example, helped lead to the U.S. decision to list the polar bear as a threatened species.
How Fat is That Bear? The scientists collect data on:
Size and health of the population
Number of bears in each age and sex class
Movement patterns of the bears and how they're responding to declining sea ice
Alarm Bells. In 2006, scientists reported clear signs of stress in the Southern Beaufort Sea polar bears compared with 20 years ago, including:
A drop in the survival rate of cubs
Lower body weight and smaller skull sizes in adult male polar bears
The Western Hudson Bay population showed the same signs of stress before its numbers crashed, dropping from about 1200 bears in 1987 to about 950 bears in 2004.
Chukchi SeaDramatic sea ice changes are taking place in the Chukchi Sea. But because these polar bears freely roam from the U.S. to Russia and back, scientists weren't able to obtain a complete picture of how the population was faring until recently. A new U.S.-Russia management treaty now allows scientists on both sides to cross borders. Research on the U.S
The Chukchi Sea effort is led by the U.S. Fish & Wildlife Service (FWS) in collaboration with the U.S. Geological Survey (USGS). Right now we know little about the status and health of the Chukchi Sea bears, but the capture study will:
Provide a window into reproductive success, survival rates, and population size Determine if these bears are showing the same signs of stress as the Southern Beaufort Sea populationAnswer basic questions such as what bears are eating and how much time they're spending in the waterThe knowledge gained will help policy-makers with environmental planning, including managing oil and gas activity.
A Satellite Collar
Scientists in the field place satellite collars on a select number of bears every spring. The technology lets research teams follow polar bears across the Arctic from the comfort of a warm office hundreds of miles away. Especially in winter, we have no other practical means of learning about polar bears during 24 hours of darkness, when arctic blizzards howl and temperatures plunge.
The collars allow scientists to:
Track movements and habitat use
Determine hunting patterns
Measure the total distance…