Commercial shrimpers out for the first season since BP’s disastrous spill indicated their catch was plentiful and free of oil, despite a report by scientists that much of the crude remains below the surface of the Gulf.

Fishermen spent much of the summer mopping up oil but got back to work as the fall shrimping season in Louisiana’s coastal waters opened Monday amid anxiety over whether the catch will be tainted by crude and whether anyone will buy it even if it is clean.

“We’re not seeing any oil where I’m at. No tar balls, nothing,” said Brian Amos, a 53-year-old shrimper who trawled in his 28-foot skiff, The Rolling Thunder, in a bay near Empire.

It was a step toward normalcy for many coastal towns that have been in limbo in the nearly four months since the spill shut down fishing, an economic linchpin for dock owners, restaurants and many other businesses along the Louisiana coast. Louisiana ranks first in the nation in shrimp, blue crab, crawfish and oysters, and the state’s seafood industry overall generates an estimated $2.4 billion a year.

Also Monday, five Georgia scientists who reviewed government data said that instead of only 26 percent of the oil remaining in the Gulf, as a federal report said earlier this month, it’s actually closer to 80 percent.

“Where has all the oil gone? It hasn’t gone anywhere. It still lurks in the deep,” said University of Georgia marine scientist Chuck Hopkinson. He headed the quick independent look by the Georgia Sea Grant program at the estimates the White House released.

White House energy adviser Carol Browner said on morning news shows earlier this month: “More than three-quarters of the oil is gone. The vast majority of the oil is gone.”

The Georgia team said it is a misinterpretation of data to claim that oil that is dissolved or dispersed is gone.

“The bottom line is most of it is still out there,” Hopkinson told The Associated Press. “There’s nothing in the report to substantiate the 26 percent.”

Amos and his fellow shrimpers were working in Louisiana’s state-controlled waters, which extend three miles from shore. Shrimpers who ply those waters lost most of their spring season — which runs from mid-May to early July — because of the spill. The fall shrimping season runs from mid-August to December.

Shrimping is also open in state-controlled waters off Mississippi, Alabama, Florida and Texas. Federal waters, which are open nearly year-round for boats to trawl for bigger shrimp, remain closed to shrimping off Louisiana, Mississippi and Alabama, though some spots could open within days, depending on the results of extensive tests.

Laboratory tests on seafood from the Gulf have shown little hazard from oil, and a test is being developed for the chemicals used to disperse the crude, though there is no evidence they build up in seafood. Still, shrimpers are worried that the public won’t want what they catch.

“I feel that we have had a bad rap on the perception of our product,” said Andrew Blanchard, who waited Monday for shrimp boats to arrive at his processing plant in Chauvin. Fewer arrived than normal, five versus the usual 20 on a normal opening day, but he said that was because most boats are still doing cleanup work for BP, not because of any problem with the shrimp.

Also Monday:

— Retired Coast Guard Adm. Thad Allen, who is overseeing the oil-spill crisis for the government, said it will take at least a week to permanently plug the well with mud and cement once he gives the go-ahead for the “bottom kill.” He said he is not sure when that will happen, because scientists are working on ways to perform the kill without further damaging the well.

— The Obama administration announced it is requiring environmental reviews for all new deep-water oil drilling, ending the kind of exemptions that allowed BP to drill its ill-fated well with little scrutiny.

— BP said it will give federal and state health organizations $52 million to help people dealing with stress and anxiety because of the spill, which erupted after the offshore drilling rig Deepwater Horizon exploded April 20, killing 11 workers. The oil finally stopped flowing in mid-July after BP put a temporary cap on the blown-out well.

Shrimp prices spiked soon after the rig explosion, fueled by fears that it would soon be unavailable. But then, despite state and federal assurances that the seafood reaching the market was safe, demand dropped and prices crashed a month ago.

Things were precarious in the industry even before the spill. For the past decade, shrimpers along the Gulf Coast have had to contend with hurricanes, high fuel prices and a flood of imported shrimp.

Louisiana’s shrimp harvest was valued at $240 million in 2000, but that dropped to about $133 million last year. The number of shrimp licenses issued by the state plummeted from about 44,000 in 1986 to 14,000 last year.