For more than two decades, trucks pulled into the seafood-processing houses of the Eastern Shore and the Northern Neck each winter, packed with oysters from Louisiana. Maryland and Virginia shuckers needed product to feed their hungry markets, and the Chesapeake Bay’s famed oyster beds had nothing more to give.

Now, the trucks are going the other way.

Chesapeake Bay oysters have bounced back to such a degree that oyster-processing houses now send their bivalves south for shucking. The wild harvest and the farm-raised crop are on the upswing in both Maryland and Virginia. Meanwhile, oyster production in Louisiana is down by as much as 70 percent, hit by a triple whammy of Hurricane Katrina, the BP Deepwater Horizon Oil Spill and the government’s attempts to dilute chemical pollution with freshwater from other places.

“It is a seismic story. It’s huge,” said Stan Allen, who directs the Aquaculture Genetics and Breeding Technology Center at the Virginia Institute of Marine Science. “It is absolutely a reversal of a paradigm, a sad paradigm, for Virginia, where processors were forced to import Louisiana oysters just to keep their doors open.”

Once, Louisiana supplied most of the oysters consumed in the United States. Immigrants from Croatia and Italy turned the estuarine waters around St. Bernard and Plaquemines parishes into a $300 million industry. By the late 1990s, 60 percent of the nation’s oysters came from the Gulf Coast. Louisiana provided the bulk of that, with the harvest reaching 14 million pounds, according to a Louisiana Sea Grant research paper. No other place in the country came close: Washington state’s harvest was about 8 million pounds, Connecticut’s was 4 million. The Chesapeake Bay wasn’t even on the research paper’s list.

But now, bayou seafood processors are buying Chesapeake oysters for the same reason their counterparts in Maryland and Virginia bought Louisiana product: To stay in business. They have markets, and if they don’t have product for those markets, they will lose the customers to places like New England. Trucking oysters across the country is not economical, but not doing it would be akin to giving up.

Casey Todd owns MeTompkin Bay Oyster Co., a 70-year-old seafood processor on the shores of Tangier Sound in Crisfield. Todd brought in Louisiana oysters for years. He had no choice; without the Gulf oysters, he would lose his customers for good.

Todd began to believe that he would never see the Chesapeake oyster come back. When he was a child, in the 1960s, oyster harvests were counted in the millions of bushels. But disease and overharvesting whacked the populations. By 2003, the public harvest dropped to only 26,000 bushels. But excellent spat sets, favorable weather patterns and more oyster plantings began turning things around; last year, the harvest was 440,000 bushels.

“I’m 60 now, and I didn’t think I’d live long enough to see the oysters come back. I’ve been waiting 30–40 years for this,” Todd said. “I was getting resigned to the fact that they would never come back in my lifetime, but it looks like they might.”

Todd is investing in aquaculture with the hope of lengthening the oyster season. Public harvest in Maryland runs from October until the end of March, while farmed oysters can be tended and sold all year. Since aquaculture became legal in Maryland five years ago, several oyster farmers have turned cultivation into a year-round business, working the public grounds in season and tending to leased beds in the summer, when the price per bushel is nearly twice as much.

Todd said he is comfortable making a substantial investment because he believes the oyster population is recovering.

Don Webster, an aquaculture specialist for Maryland Sea Grant who has been developing farm-raised shellfish programs since the 1970s, said he hopes the return of oysters may soon mean the return of the shucking houses that were attached to processing plants, which shipped oysters all over the country for both the half-shell, white-table restaurant market and grocery stores. Many such operations closed during the dismal harvests of the 1990s and early 2000s.

“I’ve always hoped that we could get into and really rebuild the shucked oyster product,” Webster said. “I think the markets for those products are beyond imagination.”

In Louisiana, there is much less cause for optimism.

Maryland and Virginia each have a public fishery. Maryland’s lasts October through March, and Virginia’s lasts October until February, although oystermen can harvest from the James River until April. Those are the historic “R” months, when people ate oysters. In the spring, wild oysters turn milky as they enter their reproductive phase and are not as desirable.

The states each have aquaculture, where farmers cultivate oysters on leased bottoms — either on shells on the bottom, or in cages or floats. Virginia’s century-old aquaculture industry is robust; Maryland’s is only a few years old, but it’s been growing steadily since the law changed to allow oyster farming in every county in 2009.

Louisiana doesn’t have cage culture. It has a public fishery where oystermen can work grounds that the state helps to maintain. Farmers can also lease grounds from the state, and increasingly, they are leasing oyster grounds from private owners. But a big part of the fishery is the available seed from the public reefs. The state allows oystermen to harvest seed from the public grounds to replenish their leased bottom. That is how many oyster farmers have grown their business.

But since the oil spill on BP’s Deepwater Horizon platform in April 2010, the availability of seed on public reefs has been “non-existent,” said John Tesvich, the chairman of the Louisiana Oyster Task Force and a fourth-generation oysterman.

Tesvich, who also runs the AmeriPure oyster-processing company in Franklin, LA, said this year the crop has been a “failure,” but it was even worse last year. This year, at least, there are some oysters, but the quality is not what he’s come to expect. (Some unscrupulous packers have put rocks and shells in the sacks to weigh them down; shuckers discover the fraud after they’ve paid.) And the price has doubled, from $25 for a bushel and a half pre-spill to $50 for the same amount today.

The shortage hasn’t given the markets much time to recover from the six months that the oyster fishery was shut down post-spill, or the nearly a year that the processing plants were idle after that.

So, to keep himself in business, Tesvich began importing Chesapeake Bay oysters two years ago. He continues the practice, using farm-raised oysters in the summer and wild-caught ones in the winter.

Tesvich is as shocked as his Bay counterparts about the turnaround; If anyone would have told him a decade ago he would have to import oysters from the Chesapeake he wouldn’t have believed them, he said. But those were the Chesapeake’s 26,000-bushel-a-year days. Now, he needs those Chesapeake oysters to survive.

“Our company cannot guarantee that we will have oysters next month,” he said. “I can’t guarantee that we will have them next week.”

Louisiana has had bad years before. It is losing wetlands at an alarming rate. With the state and the Army Corps of Engineers exercising tight control over the waterways to prevent flooding, oyster farmers have sometimes contended with slugs of freshwater or sediment harming their beds. The freshwater comes from rain and floods, or from water managers’ decisions to divert freshwater into the Gulf and its tributaries to protect New Orleans from high water. Such decisions protect lives and homes, but they destroy oysters, which need a precise mix of fresh and saltwater to survive. Too much freshwater and they don’t grow; too much saltwater and conch parasites, known as “oyster drills,” descend on them.

Vibrio vulnificus has also been a problem; the bacteria flourishes in warm waters, and several illnesses and deaths in the 1990s brought the looming threat, not yet realized, of a summer oyster shutdown.

The oysters had always come back from hard times, Tesvich said. Not so after the BP spill. The Louisiana government decided to pump fresh water into Louisiana’s oyster-rich bays in what many now say was a misguided attempt to flush out the oil. They opened levees to create “diversions,” infusions of massive amounts of freshwater that they hoped would dilute the oil.

The state is embarking on a $25 billion plan to create more diversions, this time for sediment. Engineers will dredge sediment and then pipeline it to restore the wetlands the state has lost. They will also continue with freshwater diversions in an attempt to restore the Mississippi River to the way it was 75 years ago, before man-made engineering developments forever disrupted fishing and habitat.

As just one example, the Mississippi River Gulf Outlet, which opened in the 1960s to connect the Gulf and the New Orleans port, destroyed more than 27,000 acres of wetlands, according to the Restore the Mississippi River Delta, a campaign of a half-dozen environmental organizations.

Scientists, residents and even fishermen support the dredging projects, much of which BP will finance through the various settlements. But Tesvich and his fellow oystermen have railed against the diversions, arguing that the benefit of increased sediment is not worth the cost to the oyster fishery.

The latest diversion debate is just the most recent in a long and turbulent history. About 100 oystermen who worked leased bottom in Breton Sound, southeast of New Orleans, sued the state over past diversions from the 1990s and won $1.3 billion, only to have the Louisiana Supreme Court overturn the verdict in 2004. The Louisiana Supreme Court argued that the diversions were in line with the state’s responsibility to protect, preserve and replenish its natural resources.

“If you want to start a war out here, ask about diversions,” said David Muth, state director for Louisiana’s Coast Campaign at the National Wildlife Federation, which is part of the Restore project.

While hosting a group of journalists on his boat, the Croatian Pride, Tesvich got the news that a federal judge hearing a lawsuit seeking damages for the oil spill had declared BP “grossly negligent.” The finding could mean BP would have to pay as much as $18 billion in Civil Clean Water Act fines.

The courts have already assessed $4 billion in criminal fines from BP, more than half of which will fund coastal restoration projects. Transocean, the company that operated the rig, also pleaded guilty and will pay a $400 million fine, in addition to a $1 billion settlement with the federal government for Clean Water Act violations. Much of that Transocean money will also go to a restoration trust fund.

It could be years before coastal industries see any of the $18 billion, and it will probably be far less than that after all of the legal wrangling.

Still, Tesvich called the news “huge,” and said he hoped it would also signal a turnaround in the way Louisiana managed its chemical industries.

Tesvich’s nephew hopes his uncle is right. Luke Civilich, 22, left college with one year to go on an engineering degree because, he said, the water is in his blood. Raised on stories of the glory days on the waters around Empire and Port Sulphur, he said he could only think of working leases. He outfitted the Croatian Pride and plies the waters every day, even when there are no oysters to catch.

“I hear the stories that my dad and my uncle tell. They seem to me almost like tales, not very realistic,” Civilich said. “I’d like to have a story like that one day.”

Reporter’s Note: This story was made possible through a tour that the Society of Environmental Journalists organized at its 2014 conference in New Orleans. The author wishes to thank Times-Picayune reporters Mark Schleifstein and Benjamin Alexander-Bloch for additional assistance.