Today 2 million sterile, native oysters shall go forth into the Yecomico River and not multiply -- spawning new hope for the Chesapeake Bay's ailing oyster industry.
Because they waste no energy on procreation, these native oysters should grow faster and better tolerate the diseases that have ravaged the bay's oyster population, researchers say. And that, they add, could eliminate the need for cultivating Asian oysters, an alien variety whose long-range impact on the bay's ecosystem is unknown.
"Fun as it is, reproduction takes a lot of effort," said Tommy Leggett, who helped develop the hardier variety at a Chesapeake Bay Foundation research facility in Anne Arundel County. "If all an oyster has to do is eat and grow, it's going to be fat and happy."
Overfishing and parasites have decimated the eastern oyster population in the bay in the past century, leaving barely one percent of what was found in the 17th century. In recent years, scientists, watermen and politicians have suggested introducing the Chinese oyster, Crassostrea ariakensis, which grows quickly and is disease tolerant. Some are experimenting with sterile Asian oysters to minimize any unexpected ecological harm.
Of course, sterile oysters of any variety are not a means for restocking the bay. But Leggett and others hope that a thriving native population, though sterile, will prop up the ailing oyster industry while providing researchers some clues to how these creatures resist disease.
A.J. Erskine, aquaculture manager at Bevans Oyster Company in Kinsale, Va., said his company views the project with "guarded optimism."
"With oyster restoration, we're talking ecological restoration or economic restoration," he said. "Those two [approaches] are coming together in a project like this one, which is unique."
Leggett's experiment was born in 2000, while he worked on field trials comparing growth rates and disease tolerance in sterile Asian and native oysters.
Called triploids because they carry three chromosomes instead of the usual two, making them sterile, the sterile native oysters proved themselves more tolerant of disease and grew more quickly than their more virile native counterparts.
Though the Asian oysters grew fastest, maturing to market size in six to eight months, compared with 12 to 14 months for native sterile oysters, Leggett said the natives have a market shelf life up to four times longer, a plus for growers selling to raw bars as far away as Boston.
Leggett, a former waterman with a master's degree in marine science from the Virginia Institute of Marine Science, collaborated with the institute and Bevans on a proposal to the National Oceanic and Atmospheric Administration for a $26,000 grant for researching the production and marketability of the sterile native species.
From Bayford Sea Farms in Willis Wharf, on Virginia's Eastern Shore, he bought two sandwich-bag-size pouches containing 40 million "eyed larvae" -- or baby oysters just reaching the stage at which they latch onto something to grow.
He drove them to the bay foundation's Discovery Village in Shadyside, where the larvae were released into two caged tanks, each containing 200 bushels of oyster shells.
Now, after a month, 2 million of the larvae have grown into oysters as big as a pinky fingernail. Today, they will be driven on a flatbed truck to Bevans, where they'll be transplanted onto the bottom of the Yecomico.
Leggett said he hopes the oysters will reach market size in 18 months. Once they're sold, he and the oyster company can calculate whether the venture makes economic sense.
Researchers see another ecological benefit to cultivating native oysters. Though they are bred to be sterile, about one-half of one percent of triploids retain their virility. That could be a problem with Asian oysters, an alien species whose interaction with native creatures is being studied.
"With native oysters we don't care if we have reproduction, but we are concerned if we have nonnative oysters out there reproducing," Leggett said.