Myles Cockrell shipped at least a hundred boxes of oysters a day from his Heathsville, Va., company before the novel coronavirus began to spread across the United States. Now he sells five at best.

Like many other business owners, Cockrell has hustled to adapt. He has shifted from wholesale to retail, relying on pickup and delivery involving individual customers rather than seafood markets or restaurants. He has avoided layoffs, but he has cut employee hours. He’s still seeding oyster beds and raising the kind of shellfish that diners savor at raw bars from New York City to Florida, but he’s wondering how long his Little Wicomico Oyster can carry on.

“We’re trying to hang in there,” Cockrell said.

It’s much the same across the Washington region for the watermen and seafood processors whose livelihoods depend on the Chesapeake Bay. It also holds true for area farmers, wineries and poultry producers. Pick any part of the supply chain, in almost any branch of agriculture, and the pandemic and government-ordered shutdowns have inflicted damage there.

The region’s dairy farmers, suddenly dealing with a world where schools and restaurants have closed, worry they might have to dump surplus milk, as producers in other states have done. Commercial fishing operations freeze as much of their catch as they can while watching prices sink. Farmers markets — a key outlet for growers and a happy center for weekend socializing — operate under mandatory social distancing regulations.

“Right now everyone’s in survival mode,” said Holly Porter, executive director of the Delmarva Poultry Industry, a nonprofit trade association. Porter said the virus has thinned the workforce at giant poultry plants on the Delmarva Peninsula, such as Tyson and Perdue, and that could reduce output despite consumer demand.

Yet some agricultural producers have found new ways to keep going.

Ian Hertzmark, owner of Migrash Farm in suburban Baltimore, used to sell his custom-milled organic grain to bakeries and restaurants. Now Migrash has shifted to retail sales, selling online directly to homebound customers. Hertzmark said he can barely keep up with the orders.

“It’s literally a 1,500 percent increase in retail sales for us,” Hertzmark said.

At farmers markets, managers have set up hand-washing stations, spaced vendors farther apart and taken on the role of enforcing social distancing guidelines.

“Policing people is something I have never ever thought I would have to do or want to do at a farmers market,” said Diane Bedlin, who manages the Kent Island Farmers Market in Stevensville, Md., where there was a shouting match last week between a shopper who was wearing a mask and another who was not. “People’s nerves are frayed,” Bedlin said. “They are scared.”

This is also the season when business picks up at area wineries. Vineyard tours and special events draw visitors interested in sampling wine and perhaps buying some bottles for home, said Kevin Atticks, executive director of Grow and Fortify, which manages the Maryland Wineries Association.

“The biggest impact is the lack of tourism — the drop to zero in the number of visits, in what would normally be the beginning of the tourism season,” Atticks said. He said vineyards have set up curbside pickup and delivery operations. Some have expanded on wine-of-the-month clubs or other promotions — or started them — to stay alive.

Earlier this year, business at Crow Vineyard and Winery in Kennedyville, Md., looked promising. Judy Crow, its co-owner, said she and her husband had spent more than a decade investing in wine production to diversify and sustain the family farm. In addition to planting soybeans, running a bed-and-breakfast and raising Angus cattle, they tilled about 12 acres of grapes, up from three acres when they set out, and produced 5,000 cases a year.

With sales up as much as 40 percent after a Valentine’s Day promotion, Crow imagined that 2020 might be their most spectacular year ever. Then the pandemic hit, and seemed to erase years of work in a matter of days.

“I feel like we’re at the starting point, [where] we were 12 years ago,” Crow said.

A bright spot: Demand for beef from their farm has increased 30 percent — and that’s enough to make her feel that their business will pull through.

Not everyone has been as fortunate. Ryan and Travis Croxton breathed new life into the oystering operation begun in their family several generations earlier when the cousins launched Rappahannock Oyster, which is based in Topping, Va. Their sales expanded over a decade from about 300 oysters a week to 200,000. They opened seven restaurants — including one in Los Angeles and two in the District, at Union Market and the Wharf — and employed hundreds of people.

In a matter of weeks, they furloughed more than 300 employees, closed the restaurants except for pickup and delivery orders, and watched production return to where it was when they started out. Oysters that have been growing for more than a year into the sort of plump, tasty specimens prized by consumers might have to be dumped. The hardest part has been telling workers they’re being let go so that there might be a company to return to.

“I’m sitting in the chair of my old salesperson and doing all her work, and I’ll probably be here till midnight tonight,” Travis Croxton said. “It’s really humbled me and made me realize what my team actually did.”

Almost every business decision over the past few months has been dictated by a single fact: There was almost no money coming in.

“We’ve lost 98 percent of our business,” Croxton said.

Mike Hutt, executive director of the Virginia Marine Products Board, said the economic toll already has been frightful for the commonwealth’s seafood industry, from the watermen on up. The industry, which ranks third on the East Coast in production and third nationwide, has been reduced by at least 80 percent.

“It’s devastating right now,” Hutt said. “We don’t know who’s gong to be left, who’s going to survive.”