Decades of disease, overharvesting and pollution have decimated the Chesapeake's fabled American oyster, the Crassostrea virginica.

Now, in a drastic attempt to resuscitate the industry, the Virginia Seafood Council is planning to raise nearly 1 million Asian oysters - a non-native species - in the Chesapeake's brackish waters.

The controversial aquaculture experiment - it would begin in June - raises concerns about the long-term effects of deliberately introducing into domestic waters a foreign species, even one held captive in cages and genetically incapable of reproducing.

To some, especially the storied watermen and the few remaining oyster businesses in the area, the Asian oyster, or Crassostrea ariakensis, represents the hope of salvation of the wounded bay, and thus the region's economy and way of life.

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Others, however, are concerned the plan could put the bay - and possibly the whole Eastern Seaboard - at risk. If the oysters manage to escape and reproduce, they could become an invasive species. And because one of the two parasitic diseases crippling the native species likely came from another non-native mollusk that was deliberately released into the Chesapeake two decades ago, many scientists want to proceed with caution.

At the very least, that means waiting for word from a National Academy of Sciences committee that is examining the risks of raising non-native oysters in the Chesapeake Bay. Committee members, along with the U.S. Environmental Protection Agency, the U.S. Fish and Wildlife Service and the U.S. Forest Service, were so alarmed by the seafood industry's aggressive solution that they voiced concerns even before the study's expected completion this summer.

"I admit (reviving native oysters) looks bleak, but whether everything has been done remains to be seen," said geneticist Dennis Hedgecock, chairman of the committee and a professor at the Bodega Marine Laboratory at the University of California-Davis. "The introduction of the Asian oyster seems like another simplistic solution to a complicated issue."

Industry members argue that if studies drag out any longer, they will have no business left to save. Waiting for the report and subsequent baywide discussion would delay commercial trials of the Asian oyster for two more years, according to the Virginia Seafood Council.

Meanwhile, Maryland is expecting a record-low harvest of only 50,000 bushels this year - and Virginia less than half that. Already, 99 percent of the oysters processed in Virginia come from other waters, such as the Gulf of Mexico.

"We feel absolutely desperate," said Francis Porter of the Virginia Seafood Council. "We've been creative, we've had success stories with moving seeds (of native oysters) to another location in the bay. But after two years, they're dying or dead. Shucking houses have closed. We're in dire straits as an industry."

According to the proposal, each of 10 sites around the Chesapeake - eight in the bay and two along the Atlantic Ocean - would receive about 100,000 seeds of the Asian oyster. The animals, placed in either clam cages, bags or a floating raft, would be harvested when they reach market size, estimated to take 9 to 18 months, according to the plan approved by the Virginia Marine Resources Commission and, after initial trepidation, by the state of Maryland.

To prevent the creatures from wreaking ecological havoc, scientists created a modified oyster with three chromosomes, called a triploid, so it cannot reproduce. But the process is not foolproof, and it is possible that normal oysters with two chromosomes - diploids - could be among the triploids.

"Depending on the frequency, they could be juxtaposed close enough to breed," said Stan Allen, director of the Aquaculture Genetics and Breeding Technology Center at the Virginia Institute of Marine Science. "We could determine as close as 1 in 1,000 are accidental tourists."

Moreover, as they age, triploids are capable of reverting to diploids. Oyster growers say they would pluck the oysters out of the water before that happens. But there is always the chance that some of them could be lost or stolen.

Allen says the risk potential is low unless the oysters are in the water for a decade, but some EPA officials worried about the two-year time frame and initially objected to the plan.

In March, federal officials reached an agreement with industry that alleviated some of their concerns, said Mike Fritz, living resources coordinator for the Chesapeake Bay Program, a partnership between states and the EPA. The 15 conditions that must be met before the industry receives an Army Corps of Engineers' permit include requiring that the oysters are pulled from the water no later than June 30, 2004. In addition, any recommendations by the committee must be considered.

"We would have liked for them to have waited (for the study), but we negotiated satisfactory conditions," Fritz said.

Oysters, a food source dating back at least to the Stone Age, start life as free-swimming larvae. In its first two weeks, an oyster develops its shell as it scours the bottom for a hard-surfaced home. Using its own glue, it adheres to a rock or empty shell and waits for tidal currents to bring it plankton for food.

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Virginia's native oysters reach market size in about three years. But the diseases MSX and Dermo ravage the local shellfish after about two years, despite attempts to rebuild reefs and breed disease-resistant oysters.

The Asian oysters, which grow faster and larger but taste similar to Virginia's mollusk, have shown a fondness for the Chesapeake. In earlier trials they were able to fight off the diseases.

In addition to their commercial value, oysters filter sediment, algae and nutrients, something the Chesapeake sorely needs these days. In the late 1800s, when oyster reefs were so abundant they were considered navigational hazards, the hardworking mussels filtered the Chesapeake every three days. Now the water is filtered about once a year.

Though more than 7 million oysters were harvested in the Chesapeake in the early 1900s, the numbers had dropped to 4 million by the 1950s. The disease MSX showed up in the 1980s when entrepreneurs seeking to boost the harvest dumped another Asian oyster - Crassostrea gigas - into the bay, walloping a species already fighting the native disease Dermo, pollution and overharvesting. Recently, seasons of drought have allowed diseases to proliferate and kept the population down.

France, facing a declining oyster population, introduced the Pacific oyster in the 1970s. Since then, France's oyster culture has grown to about 6 million bushels a year, Allen said.

"You have to move forward when you come to dead ends," said Jim Wesson, head of conservation replenishment for the Virginia Marine Resource Commission. "We've done everything people have asked us to do for safety: These are sterile animals in cages. We're trying to be as careful as we can, knowing a clock is ticking. If we wait too long, there will be no reason to do it."

At the family-run Bevans Oyster Company, which supplies seafood wholesalers and restaurants in Chicago, the trial cannot come soon enough. Though the company has expanded its product lines, Ronnie Bevans still longs for the good old days, when he would tell watermen whether or not he needed their oysters, and his own boats were trolling the waters of the Chesapeake.

"We had so many oysters right here," sighed Bevans, who founded the company in 1966 with his wife, Shirley, when he was 18. "I didn't realize I should have been taking pictures of them."