Correction: An earlier version of this article misstated the time frame of the first European navigation of Chesapeake Bay waters. The earliest European explorers reached the area in the 1500s, not the 1700s. Captain John Smith navigated and mapped the bay’s waters in the early 1600s. This version has been corrected.

A modern-day Lazarus story is taking shape in the Chesapeake Bay, a resurrection from the all but dead.

The bay oyster is making a modest comeback, judging from last year’s harvest. The oyster’s habitat is dangerously polluted, its reefs overfished, its numbers decimated by a pair of ravaging diseases — and yet it lives.

Virginia and Maryland officials recently gave welcome news for everyone concerned with the fate of the iconic bivalve, a once abundant and precious resource that helped shape the identities of the states and provided a way of life for watermen.

Virginia harvested only 79,600 bushels of oysters in 2005 but racked up about 236,200 last year, the most since 1989. Maryland had only 26,400 bushels in 2005 but hauled in 121,200 last year.

More than half of Virginia’s increase came from private aquaculture. Officials in both states said the fall stock surveys that assess the population also were promising last year.

Virginia’s oyster population has been in a slow upswing recently because of better management of the fishery, said James A. Wesson, director of conservation and replenishment for the state’s fishery division. But the overall population baywide still represents less than 1 percent of its historic numbers.

“It’s good news,” said Mike Naylor, director of the shellfish program for the Maryland Department of Natural Resources. “But don’t get excited.”

When Virginia Gov. Robert F. McDonnell (R) announced the recovery in a statement last month, his words suggested excitement. Virginia’s oysters are “delicious” and “profitable,” he said, “hitting tables across the nation and the world on the half-shell, fried, steamed, roasted in a stew.”

Maryland Gov. Martin O’Malley (D) noted in his remarks about the same time that the state’s oyster survey showed the highest survival rate since 1985 — 92 percent — a sign that “our continued commitment to renewing this iconic species has begun to pay off,” even though the patient’s health still doesn’t look all that good.

The states have taken different paths in their efforts to save oysters from pollution, harvesting and disease.

Virginia protects oysters with large sanctuaries in public waters such as the Rappahannock River but allows watermen to harvest them on a rotating basis about every two years. The state also strongly encourages private aquaculture, selling plots of riverbed or bay floor to oyster farmers for $1.50 an acre. A total of 93,000 acres of water bottom is leased for farming. Virginia’s aquaculture tradition goes back decades, but large -scale farming is about 10 years old.

Maryland has poured $50 million into its oyster recovery effort over the past 16 years, with little to show for the investment. Now the state forbids oyster harvesting on a quarter of its reefs, protecting them with a fine of up to $25,000 and 15 years in prison. Maryland is only beginning to develop aquaculture. Since state lawmakers passed a law to allow oyster farming in 2009, 30 applications for the practice have been approved, Naylor said.

Both states engage in oyster breeding, submerging adult males and females in warm water to encourage them to mate. This goes on at Maryland’s Horn Point Lab, where eggs are nursed from fertilization to babies, which are called spat.

When the spat are big enough, they are attached to custom-washed shells recovered from waterways across the nation and restaurants where oysters are slurped. Millions of spat clinging to shells have gone from labs to oyster reefs.

Some environmentalists and scientists say none of that is enough. In August, the University of Maryland Center for Environmental Science recommended a drastic step: End the harvest.

The recommendation was based on a study that determined what natural resources officials in the states already knew: The oysters were all but gone, reduced by nearly 100 percent from the hundreds of millions of bushels that existed when European explorers first navigated local waterways in the early 1500s.

Michael J. Wilberg, the study’s chief researcher, said that even a moratorium might not save the oyster.

State naturalists say the problem is more complicated. Even if left alone, oysters would die by the bushel on their reefs. The diseases Dermo and MSX — origin unknown, but possibly from Asia, officials said — kill many about the time they become adults, just before they’re ready to mate.

“The fishery has been a headache for us for 30 years,” said John Bull, a spokesman for Virginia marine resources. “It has almost bordered on a nightmare. The diseases almost wiped out the oyster.”

It is thought that Dermo and MSX became particularly deadly in the 1990s, when the oyster population fell off a cliff. It went from 55,400 bushels in Virginia in 1995 to 17,600 a year later. Maryland’s steep drop started six years after Virginia’s, when the harvest fell from 348,000 bushels in 2001 to 26,400 in 2005.

The diseases are present in both states, but Virginia has more of a problem because the level of salinity in the bay is higher there. They thrive in saline.

Wesson said studies have shown that Virginia oysters appear to be developing a resistance to the diseases. Naylor said there’s no evidence to show that Maryland oysters are doing the same, but officials theorize that high water volume in the past two years has diluted salinity. Drought increases the salinity level, which increases disease.

Virginia officials say their oysters have fared a little better than Maryland’s, but for that they have farmers to thank. Of the 236,000 oyster bushels counted in the latest survey, nearly 137,000 came from private aquaculture.

And farmed oysters look better — clean and plump, perfect for slurping. Farmers grow a triploid oyster, sterilizing them by adding a third chromosome. It robs their desire to procreate in summer, a process that leaves the oysters looking cloudy and nasty.

The fatter, juicier oyster resembled what McDonnell lauded.

“It’s good news, but don’t get excited,” Mark Bryer, director of the Chesapeake Bay Program for the Nature Conservancy, said about the recent recovery. “I wouldn’t overstate it . . . because it’s only been a couple years. We want to see it happen for five, 10, 20 and 50 years. ”