Alaska has long allowed authorities and hunters to kill bears and wolves on national wildlife refuges as part of what it called an “intensive predator management” program. Approved methods included shooting wolves and their pups in dens, using bait to hunt bears, killing mother bears with their cubs – and one made famous by former Alaska governor Sarah Palin: gunning down wildlife from helicopters.

That’s now about to change. In defiance of several Alaska officials, the U.S. Fish and Wildlife Service approved regulations that ban nearly all predator hunting on national wildlife refuges that is not approved by the federal government and “based on sound science and in response to a conservation concern.” The new regs specifically prohibit hunting bear cubs as well as bear hunting using traps, snares or helicopters, among other methods.

Alaska’s predator hunting has been a flash point in a growing battle between state and federal officials over who has authority over federal lands. Alaska officials, who criticized the ban as federal overreach, say their program increases moose and caribou populations that attract hunters and serve as a food source for rural Alaskans. But in a column for the Huffington Post on Wednesday, Fish and Wildlife Director Dan Ashe denounced it as unethical and based on flawed science about predator-prey relationships.

“Over the past several years, the Alaska Board of Game has unleashed a withering attack on bears and wolves that is wholly at odds with America’s long tradition of ethical, sportsmanlike, fair-chase hunting,” Ashe wrote. “We have a long history of cooperative management with the states, including Alaska, and we have deep respect and admiration for our state agency professional colleagues. But there comes a time when the U.S. Fish & Wildlife Service must stand up for the … principles that underpin our work and say ‘no.'”

The new rule, which takes effect in early September, will protect a lot of predators on a vast amount of land. National wildlife refuges in Alaska cover 73 million acres, or about 114 square miles, and include the 20 million-acre National Arctic Wildlife Refuge. The regulations exempt subsistence hunting.

Fish and Wildlife often goes along with state rules for hunting on national wildlife refuges. But it has shown increasing frustration with Alaska’s liberalization of predator hunting, which wildlife advocacy organizations say is unusually cruel. In its announcement, Fish and Wildlife cited “public interest and concern” about the bear and wolf killings and said the regulations simply “clarify” federal domain over the refuges.

“Every moose or caribou killed by a wolf or bear is one less hunting license fee paid to the state,” said Wayne Pacelle, the president and CEO of the Humane Society of the United States, which praised the new regulations. “But there’s a booming ecotourism business in Alaska, and people go to these parks and refuges because they want to see the animals. When you shoot them … you diminish the numbers of animals and the experiences of people who trek to Alaska to have the thrill of a lifetime.”

Pacelle noted that some members of Congress are seeking to prevent similar federal government rule-making.