Weeks after the White House was warned that a plan to vastly expand a maritime preserve and no-fishing zone in U.S.-controlled Pacific waters would harm the American fishing industry and geopolitically advantage China, the Obama administration has gone ahead anyway—with some concessions to make the environmental medicine, administered by presidential fiat, go down more smoothly.

The concessions did nothing, however, to assuage congressional Republicans led by Rep.Doc Hastings of Washington state, chairman of the House Natural Resources Committee, who accused the administration of taking “secret, unilateral action” to expand the preserve. He warned that “the economic consequences of this decision will be grave, further eroding the U.S. seafood industry and harming the well-being of the U.S. territories.”

The decree that President Obama signed on Thursday boosted the size of the Pacific Remote Islands Marine National Monument, a 77,000-square-mile preserve south and west of Hawaii, to some 490,000 square miles of protected area around a speckling of U.S.-controlled islands—an area that Secretary of State John Kerry, who hailed the move, declared to be “twice the size of Texas.”

(Actually, it’s slightly less: Texas is 268,820 square miles in area.)

The decree essentially bans all commercial fishing and deep-sea mining (which doesn’t exist yet in any case) in the huge tract in perpetuity, though the announcement said there would be some exceptions for “recreational and traditional fishing that is consistent with the conservation goals of the Monument.”

That was significantly less than the roughly 780,000 square mile area initially proposed by the administration and its environment and energy czar, John Podesta, for the expanded preserve—a straightforward extension of a fishing ban to the full extent of the 200-mile, U.S. controlled exclusive economic zone (EEZ) around the islands.

The scaled back area to some extent mollified fishermen and fisheries experts who operate as part of the U.S. government’s own management apparatus in that region, and who were deeply unhappy at the original proposal.

A delegation representing the Western Pacific Regional Fishery Management Council visited Podesta and other administration officials in Washington earlier in September to argue that the proposed expansion, urged on by environmental organizations including the Pew Foundation, was a bad idea

It would, they said, hurt a $100 million a year fishing industry based in Hawaii and give China, which is rapidly expanding its deep-sea fishing fleet, new and unfair opportunities to poach where law-abiding American boats would no longer travel.

The administration evidently listened—in part, perhaps, because the local elected officials in the affected area including Hawaii skew decidedly Democratic and this is a mid-term election year. According to an insider familiar with the process, the wheeling and dealing between the administration, environmental interest groups and fishing and political interests went on into Wednesday, the same day the expansion was announced.

In a subsequent press release, the management council expressed “appreciation” to the administration for taking the “cultural concerns” of fishermen in American Samoa and Hawaii, while noting that the action still took away 65 percent of that population’s traditional fishing rights in 65 percent of the exclusive economic zone.

And the council also noted that “regional experts and industry representatives were not consulted in advance of the initial announcement and only minimally” before the amended version was made official.

To carry out the expansion, the administration used a presidential proclamation power that is associated with the U.S. Antiquities Act, which would normally be used to designate historic locations. The Antiquities Act gambit was also used by the Administration of George W. Bush to create the initial Pacific Monument area.

The fisheries council further noted that Congress has already limited presidential authority to do similar things in Alaska and Wyoming—a tack that House chairman Hill and like-minded congressmen want to extend to include, among other things, consent by state governors when such monuments are proclaimed.

Perhaps significantly, the White House announcement contains almost no mention at all of the threat of commercial fishing to the Pacific area where the expanded monument now extends. It does note that atolls and reefs in the area “are hotspots of biodiversity that harbor uncounted numbers of new and unique marine species”—meaning that they aren’t known to be under threat, either.

It further claims that “the expansion will better protect the habitat of animals with large migration and foraging ranges that stretch throughout the area, including sea turtles, marine mammals, and manta rays”—which are not fished.

The bigger dangers mentioned in the White House announcement are “the impacts of climate change and ocean acidification” which have only hypothetical impact on the area, and in any case are not affected by a commercial fishing ban.

Indeed, the new preserve will have “absolutely no impact” on acid levels in the ocean, says Ray Hilborn, a professor in the School of Aquatic and Fishery Sciences at the University of Washington and a renowned authority on global fish populations.

Nor will it have any impact on the overall accidental “bycatch” of protected or endangered fish species, because the fishing “effort will move somewhere else and do bycatch there.” Moreover, the reefs in the new protected zone are “most unpopulated and not where reefs are heavily plundered,” he says.

The only benefit of the preserve expansion, Hilborn told Fox News, “is for those who believe that closing the ocean is an end in itself.”

George Russell is editor-at-large of Fox News and can be found on Twitter: @GeorgeRussell or on Facebook.com/George Russell