For nearly 20 years, this tiny watermen's village on Hoopers Island has been enlivened each spring by the arrival of several dozen Mexicans - women who bring with them tortillas and tamales, mariachi music and the hands that make the local economy go.

They do the dirty work of Maryland's seafood industry, spending long days picking the premium lump meat out of the blue crab - work that the men who run the seafood processing plants that dot the island say Americans won't do. To hear them tell it, the foreigners have meant the difference between life and death for the generations-old businesses on which the 500 or so year-round residents rely.

But this year, the crab houses could stay closed.

Amid growing demand for temporary guest workers nationwide, only one of Maryland's 21 seafood processing plants was able to get visas to bring the foreigners into the country this year. If Congress does not move quickly to make more available, other processors say they won't open this spring. And the loss of a year's income, several say, means that they probably would shut their businesses for good.

"We just don't have no work force," said Jay L. Newcomb, who employed 30 of the guest workers at the A.E. Phillips & Son Inc. crab house in Fishing Creek last year. "We're going to be out of business if we don't have no pickers."

With Maryland's seafood industry constrained by new state limits on the crab harvest, Newcomb and others say, a season without pickers would devastate not only Hoopers Island but the Eastern Shore. Fishing Creek boatbuilder Phillip L. Jones called the crab houses the "backbone" of the industry, the most important link in a chain that runs from the watermen to the restaurants, from the equipment suppliers to the retail customers.

"They've got to get those workers," Jones said. " Dorchester County will look like a ghost town if they don't."

The H2B visa program allows foreigners to come to the United States for several months to work in a seasonal industry, such as crab picking or landscaping. When the season is over, the workers go home.

In years past, Congress has allowed businesses that were shut out of the visas to bring back employees who worked for them in previous years. Sen. Barbara A. Mikulski, the Maryland Democrat who created the so-called returning worker exemption four years ago, introduced legislation yesterday that would revive it.

"This is about keeping the Maryland seafood industry afloat," she aid.

In the past, the returning worker exemption has won bipartisan support in Congress. But efforts to extend it last year were blocked in both the Senate and the House of Representatives, and opponents have not withdrawn their objections.

Robin Hall says the clock is ticking.

"The whole industry's going to be gone," said Hall, who used 30 guest workers last year at the G.W. Hall & Son picking house. "We need help to save this way of life."

In their inability to get foreign workers this year, the processors of Hoopers Island say they fell victim to a bureaucracy that never gave them a chance.

Congress makes 66,000 H2B visas available nationwide each year, but businesses may not apply until 120 days before the workers will need them. The crab season in Maryland begins April 1, which puts the processors behind an ever-growing number of landscapers, building contractors and others that employ foreign workers.

The application process, which involves the state and federal departments of labor, the U.S. Customs and Immigration Service and the State Department, can take months. This year, only Lindy's Seafood Inc. was able to make it through before the visa cap was reached, according to the other processors. A call to Lindy's, in the Dorchester County town of Woolford, was not returned.

Critics of the H2B visas say the foreigners, who come almost exclusively from developing countries, depress wages for local workers. They say the businesses that use them could find Americans to do the work if they offered better pay.

"Employers are, in effect, using the program simply to have a low-wage work force," said Jack Martin of the Federation for American Immigration Reform in Washington.

On Hoopers Island, a spit of land between the Honga River and the Chesapeake Bay that is a two-hour drive from Baltimore, the processors say that their principal hiring challenges have been the small local population and an inability to coax Americans to relocate here for seasonal jobs.