6/3/2014 2:45:09 PM
Why Look for Polar Bears in Viscount Melville Sound?
By Dr. Andrew Derocher
The world's polar bears are divided into 19 distinct populations for management purposes. Twelve of these populations are located in Canada.
The divisions are based on movement data and genetics from polar bears in the area, and each population is managed as a separate unit with regard to size estimates, hunting quotas, etc. Polar bear movement data is obtained from satellite collars, while genetic information comes from the saliva and hair samples that researchers collect from bears in the surveyed area.
When we're studying a polar bear population, mark-recapture data helps us estimate its size and determine its composition (i.e., sex, age,reproduction, and immigration/emigration).
Canada recommends that each of its 12 populations be surveyed every 15 years to obtain an accurate picture of its status. But challenging logistics and funding constraints can make it difficult to do this exactly, and so the last inventory of the Viscount Melville Sound polar bears took place more than 20 years ago.
Recently, however, circumstances came together favorably, allowing for a new population census study of these bears. And that's why we're here now, at Polar Bear Cabin on the north end of Banks Island.
The satellite collars that we put on the adult polar bear females encountered in Viscount Melville Sound will transmit their signals for up to two years before being released, giving us data on their movements and denning areas. In addition, we are collecting small tissue samples from every bear we come across, which help us learn more about their health status and pollution levels.
Earlier studies of the Viscount Melville Sound polar bears revealed high levels of PCBs and mercury, two pollutants that could potentially affect the population's reproduction and survival rates—yet another reason why a follow-up study like this is so important.