President Obama on Tuesday declared Bristol Bay "a beautiful natural wonder" and designated its salmon-rich waters indefinitely off limits for oil and gas leasing.

Environmentalists say the move provides significant protection not just for the iconic Bristol Bay sockeye salmon, but for crab, herring, halibut and groundfish, including the lucrative pollock fishery. And salmon returning to the Yukon and Kuskokwim rivers pass through the waters that had been considered for drilling.

"Hey, everybody," President Obama said in a videotaped message posted Tuesday on YouTube. "Earlier today I took action to make sure that one of America's greatest natural resources and a massive economic engine not only for Alaska but for America, Bristol Bay, is preserved for future generations."

Some 40 percent of the nation's wild-caught seafood comes from Bristol Bay, and its waters have supported Alaska Native people for centuries, the president said.

"It's something that's too precious for us to just be putting out to the highest bidder," Obama said.

In 2010, Obama temporarily withdrew offshore waters in the northern Aleutians and around Bristol Bay from consideration for oil drilling, but that protection had been set to expire in 2017. Now it's extended with no end date.

Environmentalists say his decision effectively provides permanent protection to Bristol Bay and the waters north of the Aleutian Islands, though they acknowledge another president could reverse course.

The waters at issue stretch over approximately 32.5 million acres in what's called the North Aleutian Basin Planning Area, which includes Bristol Bay.

The government has pingponged over whether to protect the area or allow drilling.

In 1986, the federal government sold oil leases there but lawsuits blocked development. The government in 1995 then bought back the leases. President George W. Bush's administration proposed a new lease sale for 2011 that would have opened 5.6 million acres on the edge of Bristol Bay for drilling. But President Obama withdrew those waters from leasing after the Deepwater Horizon disaster in 2010.

The oil industry has not been pushing publicly for leases in and near Bristol Bay and had no immediate comment on the decision. Royal Dutch Shell had purchased leases in the earlier sale but didn't respond to a request for comment Tuesday.

"Given the lack of interest by industry and the public divide over allowing oil and gas exploration in his area, I am not objecting to this decision at this time," Alaska Sen. Lisa Murkowski said in a written statement. "I think we all recognize that these are some of our state's richest fishing waters." Still, she questioned why the announcement came ahead of the Obama administration's overall plan for offshore leasing.

Interior Secretary Sally Jewell called new Alaska Gov. Bill Walker Tuesday to alert him of the decision.

"The pristine waters of Bristol Bay feed some off the world's most premier fisheries," Walker said in a written statement. He said he looked forward to working with the federal government to develop areas in the state and offshore for oil and gas.

"Bristol Bay, however, is not that place," Walker said.

Two previous presidents used the same section of the Outer Continental Shelf Lands Act of 1953 to protect offshore waters from drilling. President Eisenhower did so around Key Largo in Florida, and President Nixon used his executive power to withdraw waters around the Channel Islands near Santa Barbara in California. Those areas remain protected, according to The Pew Charitable Trusts.

For decades, fishing groups, environmentalists, Alaska Native leaders and others have pushed for Bristol Bay and surrounding waters to be off limits for oil and gas exploration and production. Obama credited those efforts.

Jewell singled out the late Harvey Samuelsen, a commercial fisherman and leader in protecting Bristol Bay.

Son Robin Samuelsen, chairman of the Bristol Bay Economic Development Corp., said he had been approached by oil companies but didn't want his area to end up like Prince William Sound after the Exxon Valdez spill. The economic development corporation is allotted shares of certain fisheries including the Bering Sea pollock fishery for its 17 member villages.

"If there was a lease and there was an oil spill, all that oil would accumulate up in Bristol Bay, and it would be a little sanctuary for holding oil," Samuelsen said.

Tens of millions of sockeye salmon pour into Bristol Bay each summer, but the area at issue also houses valuable nurseries for halibut and crab. And much of the lucrative pollock harvest occurs in the area now declared free from drilling.

"It takes Bristol Bay off the table," said Dorothy Childers, who has been pushing for protection since the 1980s. She's associate director of the Alaska Marine Conservation Council, which works for sustainable fishing and habitat protection. Its 750 members include fishermen and residents of Alaska's coastal communities.

Before, Bristol Bay and nearby waters were vulnerable to lease sales developed every five years for federal offshore waters. The Bureau of Ocean Energy Management currently is working on the 2017-22 lease program, including opportunities for public comment.

"Now the president is saying we are not going to have leasing here in the future," Childers said. "For a future president to undo that would be a very big betrayal."

The wholesale value of the fisheries at stake was about $2.9 billion in 2012, which included all Bering Sea pollock landings, according to the Alaska Marine Conservation Council. It's impossible to separate out the fish caught just in the area that had been considered for leasing, Childers said.

Other groups estimate that the value of the fisheries in the targeted area was about $2 billion.

For sockeye salmon alone, Bristol Bay fishermen earned about $197 million for their catch this year, Childers said.

"We know what we have in Bristol Bay, and we don't want to risk it," Samuelsen said.