Manitoba government documents suggest polar bear encounters with people have reached record levels on the shores of Hudson Bay, with more of the mammals ending up in a specialized jail in Churchill.
Polar bear activity reports from the past three years show the number of documented cases in Churchill has jumped to 351 last year from 229 in 2013. The number of bears who were tranquillized and housed in the town's holding facility, known as polar bear jail, before being released into the wild almost doubled from 36 in 2013 to 65 last year.
Daryll Hedman, regional wildlife manager for Manitoba Conservation, said last year set a record for the number of polar bears caught within the populated "control zone" of Churchill.
While Manitoba conservation officers have stepped up their patrols recently, Mr. Hedman and other experts say climate change is largely to blame. Canada is home to two-thirds of the world's polar bears, but experts say climate change could make the Hudson Bay population extinct within decades.
Polar bears depend on winter hunting to build up enough fat to carry them through the lean summer months on land when food is scarce. But Arctic waters now don't often freeze up until early December and thaw much earlier in the spring. That leaves polar bears with less time to bulk up on fatty seal meat while on the ice.
Andrew Derocher, one of the country's leading polar bear experts, based at the University of Alberta, said the population is in "grave condition." The population has stabilized at about 800 bears, but few cubs are surviving past the first year, he said.
As they spend more time on land without food, Mr. Derocher said they could venture more and more into populated areas.