The U.S. National Oceanic and Atmospheric Administration closed 4,213 square miles of the Gulf of Mexico to deep-water trawling for the specialty shrimp royal red.

The closure, covering an L-shaped area of the Gulf east of the mouth of the Mississippi River and south of Mobile Bay, was implemented Wednesday night in reaction to a royal red shrimper finding tar balls in his net Saturday, NOAA said.

Royal red shrimp are caught in depths of 600 feet or more. The royal red fishery is only a small part of the Gulf seafood industry, and NOAA said other shrimp species are not affected by the ban.

The tar balls found in the shrimp net are being analyzed by the U.S. Coast Guard to see if they are from the Deepwater Horizon/BP spill, NOAA said.

At peak output, about 250 shrimp boats trawl for royal reds in the Gulf, NOAA said.

The more common brown, pink and white shrimp are caught in depths of less than 300 feet, often closer to the coast. No tar balls have been reported recently in any of the shallow-water shrimping operations.

"We are taking this situation seriously. This fishery is the only trawl fishery that operates at the depths where the tar balls were found," said Roy Crabtree, assistant NOAA administrator for the agency's Fisheries Service southeast region.

George Crozier, director of the Dauphin Island Sea Lab, said that, without testing that positively proves the shrimp are tainted, NOAA may be acting too quickly by closing the area.

"There is little reason to believe that the shrimp have eaten tar balls and incorporated toxins," Crozier said. "Show me the data."

He said that anyone with doubts about the purity of shrimp should devein them thoroughly with a tool available at most food and fishing stores. The vein in a shrimp, Crozier said, is actually the crustacean's intestine.

He said the worst effect of the ban on Alabama shrimpers is a belief by the public that all Gulf shrimp may be unsafe to eat.

"The biggest problem facing Alabama is the enormous gap between what they think is happening and what is happening," he said.

Speaking to the Press-Register at a community Thanksgiving dinner in Bayou La Batre, Walter Kraver echoed Crozier's sentiments.

Kraver, patriarch of a family that owns multiple seafood-related businesses in Bayou La Batre, said the closure of royal red fishing may have a small economic impact but a large impact on perception.

"When I saw that on the morning news, I said, 'Oh my God, here we go again,'" Kraver said.

He said few if any Bayou shrimpers work the deep water for Royal Reds. Still, he said, he recalled the boat Country Girl on Thursday, even though that crew was shallow-water shrimping. He said he did not want those enforcing the deep-water ban to bother them.

"That's the problem, perception," Kraver said. "The perception is what really hurt us in the seafood industry. The seafood has been tested up one side and down the other. Everything we're getting looks perfect."

Kraver said shrimp processing plants are suffering from the lack of shrimp coming in, with some not getting enough to continue running.

He said that despite reports of a Gulf teeming with seafood after the reopening, the boats that are working are not producing a high-volume catch.

"We thought there would be worlds of shrimp," Kraver said. "We had a couple of good nights, and then it tapered off."

(This report was written by Press-Register Staff Writers Mark R. Kent and Lawrence Specker.)