In an effort to sustain commercial and recreational fishing for the next several decades, the United States this year will become the first country to impose catch limits for every species it manages, from Alaskan pollock to Caribbean queen conch.

Although the policy has attracted scant attention outside the community of those who fish in America and the officials who regulate them, it marks an important shift in a pursuit that has helped define the country since its founding.

Unlike most recent environmental policy debates, which have divided neatly along party lines, this one is about a policy that was forged under President George W. Bush and finalized with President Obama’s backing.

“It’s something that’s arguably first in the world,” said Eric Schwaab, the National Oceanic and Atmospheric Administration’s assistant administrator for fisheries. “It’s a huge accomplishment for the country.”

Five years ago, Bush signed a reauthorization of the Magnuson-Stevens Act, which dates to the mid-1970s and governs all fishing in U.S. waters. A bipartisan coalition of lawmakers joined environmental groups, some fishing interests and scientists to insert language in the law requiring each fishery to have annual catch limits in place by the end of 2011 to end overfishing.

Although NOAA didn’t meet the law’s Dec. 31 deadline — it has finalized 40 of the 46 fishery management plans that cover all federally managed stocks — officials said they are confident that they will have annual catch limits in place by the time the 2012 fishing year begins for all species. (The timing varies depending on the fish, with some seasons starting May 1 or later.) Some fish, such as mahi-mahi and the prize game fish wahoo in the southeast Atlantic, will have catch limits for the first time.

Until recently the nation’s regional management councils, which write the rules for the 528 fish stocks under the federal government’s jurisdiction, regularly flouted scientific advice and authorized more fishing than could could be sustained, according to scientists.

Joshua Reichert, managing director of the Pew Environment Group, said the law’s ban on overfishing forced fishery managers to impose limits that some commercial and recreational fishers had resisted for years.

“This simple but enormously powerful provision had eluded lawmakers for years and is probably the most important conservation statute ever enacted into America’s fisheries law,” Reichert said.

And unlike many environmental regulations, which are written and enforced by Washington officials, the fishing limits were established by regional councils representing a mix of local interests.

“Because the final decisions were left on the local level, you have a higher assurance of success,” said James L. Connaughton, who helped prepare the reauthorization bill while chairing the White House Council on Environmental Quality. “If it had been imposed in Washington, we’d still be stuck in 10 years of litigation.”

But the changes have not come without a fight, and an array of critics are seeking to undo them. Some commercial and recreational operators, along with their congressional allies, argue that regulators lack the scientific data to justify the restrictions. And they suggest that the ambitious goals the law prescribes, including a mandate to rebuild any depleted fish stock within a decade, are arbitrary and rigid.

Rep. Frank Pallone Jr. (D-N.J.), who has sponsored legislation with Rep. Walter B. Jones (R-N.C.) to relax some of the new requirements, said his constituents are increasingly concerned that fishing will be curtailed without sufficient justification.

“As more of these limits go into effect, they get more upset,” Pallone said in an interview. “I don’t think it’s fair to put in place a system that’s not scientific and rationally based.”

Counting all the fish in the sea is an imperfect science to begin with, and even federal officials acknowledge that they lack the data they’d like for most species. Because of budget limitations, NOAA conducts stock assessments of commercial species only every few years, using independent trawl surveys, official landing data, ecological data and interviews with operators, among other sources.

Its data on recreational fishing are even spottier. NOAA has created an expanded dockside survey and will use new methodology to analyze the results, but officials say they have not made wide use of this approach before this year. After an annual catch limit is set for a recreational fishery, managers can adopt several measures, such as limiting the season or the size of fish that can be taken, to prevent fishers from exceeding the overall threshold.

Steven D. Gaines, dean of the Bren School of Environmental Science and Management at the University of California at Santa Barbara, said researchers are developing more effective tools to estimate fish populations, by looking at the size of the fish and how fish are faring inside and outside marine reserves. “It’s really transforming the opportunity for us to assess where the fisheries are at the moment and take corrective action early on to correct overfishing,” he said.

Even when NOAA receives fresh data, the agency often comes under fire for finding a population is doing much better or worse than expected.

Just this year, for example, NOAA determined the amount of cod in the Gulf of Maine had declined roughly two-thirds since 2008. Local fishing interests and area lawmakers, including Sen. John F. Kerry (D-Mass.), have assailed the assessment and warned NOAA against setting cod limits too low this year. The current cod catch limit is 12,000 metric tons; because the recent assessment says that only 11,400 metric tons are left, Kerry wrote, it “could require a fishing limit as low as 1,000 metric tons of cod.”

“Are the laws sustaining stocks and also the fishery, or are we just looking at what is biologically reasonable and then decimating small businesses at the same time?” asked Jackie Odell, executive director of the Northeast Seafood Coalition, which represents groundfish vessels operating along the Atlantic Seaboard from Maine to New York.

Fishing interests have also questioned why they need to restrict their take once a stock appears on the rebound. Summer flounder, or fluke, a popular recreational fishing target in the mid-Atlantic, was so overfished that its 1989 population was deemed 88 percent below healthy levels. After a series of efforts to regulate the catch, an assessment in October showed the species had been rebuilt, with an estimated 137 million pounds of mature summer flounder in the region.

But because the assessment showed the fish has not rebounded as much as scientists expected, managers are not raising the catch limit as high as initially planned. This has angered James A. Donofrio, executive director of the Recreational Fishing Alliance.

“We’re only asking for access to stocks that are in good shape anyway,” he said, adding that federal officials have defined the term “overfishing”too aggressively.

“When we don’t see the fish and we can’t catch them, then we know there’s overfishing,” he said.

Environmentalists and many researchers disagree. Brad Sewell, a senior attorney at the Natural Resources Defense Council, an environmental advocacy group, said regulators need to take a precautionary approach because the catch limits aim to achieve the “maximum sustainable yield” without pushing a species to collapse. “You’re fishing right on the edge,” he said.

European Union member states are debating whether to adopt a law mandating the sort of catch limits embraced by the United States.

Stricter limits have helped several species in the Washington region rebound, including mid-Atlantic bluefish, and regional managers took the unprecedented step this past fall of cutting the take of menhaden, a forage fish, for the sake of species that consume it.

Mark Spalding, president of the Ocean Foundation, said that people on both sides of the debate need to acknowledge that the United States is facing the sort of transformational moment in fishing that it did a half-century ago in forestry. Until the mid-1960s, the government allowed loggers unfettered access to public lands, he said.

“We had to have this wrenching, put-the-brakes-on-and-turn-the-truck-around” process, he said, adding that when it comes to setting universal catch limits, “this is a monumental achievement.”