Sportsmen and ranchers, who wield considerable political clout in the region, point to growing bear-human conflicts as grizzlies expand their territories in search of food.
Environmentalists argue grizzlies' recovery could falter if they are forced to contend with new pressures posed by hunting of the species outside the park.
They caution that grizzlies already face a decline in a key food source, whitebark pine nuts, due to climate change. Conservation groups and Native American tribes are opposed to the plan.
"A lot of grizzlies will be killed; it's a step back for grizzly recovery," said Bonnie Rice, a Yellowstone expert for the Sierra Club.
Fish and Wildlife has received over 63,000 public submissions on the de-listing plan, far more than typically received for a regulatory proposal, though a spokeswoman said the breakdown between of pro and con was unknown. Supporters of de-listing said prudent bear management requires a levelling off of the population.
- Reuters, AAP