Brett Wlock's job is to keep polar bears away from people. If they can't scare nuisance bears away, they capture them, and bring them to what the locals call Polar Bear Jail. To make sure they're not tempted to come back to town again, the bears are given no food, just water, so that they do not grow accustomed to associating food with the town or its human inhabitants.
When their 30-day sentence is up, they're tranquilized and airlifted back out into the tundra.