It is a gamble, of sorts, that most Island businesses are forced to take each year.

When seasonal employees shuffle off at the end of each summer to either return home or to college or to explore farflung corners of the world, employers have no guarantee the same workers will return at the start of the busy season next year.

As a result, they must try their luck again the next spring with help wanted signs and newspaper advertisements, and hope that enough qualified applicants will come forward to fill all the open positions. Some employers get lucky, and most of the previous year's employees return. Others, however, are not so lucky, and will struggle all season to find employees, which can hurt business and put a strain on them and the rest of their workers.

In recent years the unpredictable summer employment market has been steadied to a degree by foreign employees - many from countries like Bulgaria, Belarus and Russia - who come to work on the Island through H-2b visas or temporary student visas.

H-2b visas can be acquired by foreign nonprofessionals not working in agriculture, and are available for up to one year. Temporary student visas are generally valid for up to four months.

The odds for employers hoping to beat the fickle summer employment market by hiring foreign workers fell considerably this year because of processing delays at U.S. Labor Department offices in Atlanta, Ga. Although the administration problems delayed the arrival of some workers, all indications are that they have not caused any major disruptions around the Island.

It is difficult to gauge the availability of seasonal workers this summer, and evaluations differ, depending on whom you ask. Some employers report heavy numbers of applicants seeking summer jobs, while others say their employee ranks are thin.

Michael Wallace, owner of Jim's Package store in Oak Bluffs and several other Island businesses, said he saw a healthy number of applicants this year. Most of his positions have been filled, with a waiting list of applicants.

"I haven't had any real problems yet," he said.

But Christopher Dacunto, the owner of Tisbury Taxi, painted a different picture.

"Worst I've seen in 12 years. There's nobody to fill the jobs, nobody to drive the taxis - that's what a lot of drivers are saying," he said.

Mr. Dacunto said the lack of workers was bad for business owners and the Island economy.

"If there's nobody to drive the cabs, then there's no way to make money. Plus there's nobody to pick up the fares," he said.

Marilyn Wortman, personnel director for Edgartown and administrator for the town park and recreational department, said she had a difficult time finding enough lifeguards.

"We just didn't see the same number of applicants this year. It's hard to tell why, really, it seems to differ every year. Probably has something to do with the housing [market]," she said.

Kathe Lattanzio, a longtime restaurant and retail manager on the Island who is now managing the newly opened Sugar Shack restaurant in Oak Bluffs, said the number of applicants was above average, although career professionals are no longer so much in evidence.

"Going back five or ten years ago you would see a lot of career waiters and cooks; people who would work on the Vineyard in the summer, then go somewhere else in the winter, and then come back to the Island the next summer. You see less and less of that each year - now it's mostly younger kids who are just looking to make some money," she said.

Tisbury police chief John Cashin said he was surprised by the low number of applicants for seasonal police officer positions.

"I thought we would get more applications; it seems like coming to live and work on the Vineyard for someone interested in a career in criminal justice would appeal to a lot of people. But I also understand coming here is not the easiest thing in the world - there just aren't a lot of places to live here on the Island, and those that are available aren't cheap," the chief said.

Nancy Gardella, executive director of the Martha's Vineyard Chamber of Commerce, said the number of visits to the chamber's Live/Work MV Web site is up this season. Ms. Gardella also said a steady stream of potential employees have stopped in the chamber offices in Vineyard Haven seeking information.

"We have seen all sorts of people - college students, foreign workers, professionals. Most of the businesses I have talked to report they have been able to fill their positions; but then there are others who are having a problem [filling positions]. It's kind of hit or miss for some employers," Ms. Gardella said.

Tracking the number of seasonal workers from year to year can prove as difficult as predicting the number who may arrive any given summer. The most recent available data from the state department of labor, from 2005, indicates that around 5,000 seasonal workers worked on the Island that summer.

By most accounts, the number of seasonal workers has remained roughly the same over the past three years. However some say there has been a recent trend of undocumented immigrants leaving the Island in large numbers.

The number of undocumented immigrants who work on the Island - most of whom are natives of Brazil - is another great unknown on the Island. While some have estimated there are perhaps 4,000 or more Brazilians who live and work here, census data and other records for the most part prove ineffective at pinpointing their actual population.

Some employers this week speculated that illegal immigrants - fed up with the United States immigration policy which does not allow them to travel home to visit their families - have simply opted to move back to their home country permanently. Some also suggest the falling value of the U.S. dollar in the Brazilian economy may have also slowed an influx of Brazilians moving to the Vineyard to find employment.

One Edgartown business owner, who asked not to be identified, said he has seen fewer new Brazilians applying for jobs in recent years.

"It's economics. The American dollar used to be worth four times more than the Brazilian currency - now it's worth only two times as much. A lot of workers come here and send money home so they can build a home back in Brazil, but now it takes a lot longer to save up that money," he said.

Another Oak Bluffs restaurant owner said three of his employees - natives of Brazil who live here year-round - opted not to return this summer. He said they got better-paying jobs in landscaping.

"I can't blame them for taking the job - it pays better. They've been here for a few years now and they know the language - they're through washing dishes and bussing tables, they're moving up," the restaurant owner said.