The Department of Commerce said it had found that, with the exception of one Chinese producer, the crustaceans were being sold in the United States at "less than fair value."

In a "final determination," it set punitive anti-dumping duties in a range of 27.89 to 112.81 percent for Chinese imports and 4.13 to 25.76 percent for Vietnamese imports, depending on the company.

One step remains, however, before the tariffs are confirmed.

The quasi-judicial US International Trade Commission must meet about January 12 next year to decide whether the shrimp imports threaten US industry and, if so, to issue the final anti-dumping order.

In the meantime, importers must pay estimated duties in the form of a bond pending the final decision.

US shrimp farmers, who had pressed US President George W. Bush's administration to protect the industry, celebrated.

"The United States is the most open market for shrimp in the world, but we cannot let Chinese and Vietnamese shrimpers violate the rules of free trade to get ahead of their competition," said Southern Shrimp Alliance president Eddie Gordon.

"Dumping is cheating and we thank the Department of Commerce for offsetting this illegal practice and leveling the playing field for US shrimp fishermen, farmers, processors, and all fairly trading countries."

Gordon said shrimp imports had increased more than 71 percent from 2000 to 2003, far beyond the increase in US demand.

"Desperate to unload their product, Vietnam, China, and four other countries have dumped shrimp into the United States, causing import prices to plummet 42 percent in the from 2000 to 2003," he said.

The Southern Shrimp Alliance, grouping warmwater wild shrimp fishery industries from eight southern US states, said its members employed 70,000 people, while processing shrimp imports only accounted for 3,500 jobs.

Imports account for nearly 90 percent of the shrimp -- the number one seafood -- consumed in the United States.

But importers contend that the US industry, which relies on catching shrimp in the wild, simply cannot compete with the low-cost, farm-raised shrimp shipped from the countries targeted in the dumping case.

The shrimp consumers, represented by the Shrimp Task Force, vowed to battle the tariffs.

"The Shrimp Task Force will continue to fight this unfair and ill-advised food tax, which will hit American families and American businesses that count on access to high-quality, imported shrimp right in their pocketbooks," said Shrimp Task Force chairman Wally Stevens.