It took only 2 minutes and 56 net seconds for Virginia's Deborah Pratt to shuck 24 oysters, easily beating the other five finalists to win the women's title in the U.S. National Oyster Shucking Championships. This day, however, at the St. Mary's County Fairgrounds earlier this month, her strong hands and quick knife would not be enough to beat her male counterpart for the overall crown.

Few can. Scott Stiles of San Antonio is the defending national grand champion. His best time: 2 minutes and 21 seconds. He'll represent the United States for the second year in a row at the world oyster opening championships in Galway, Ireland, next September.

Oyster shucking is serious business. And the pros who compete in these events do so with all the bravado of seasoned athletes: Shaking out the kinks from their shoulders, they pump up the cheering crowds and raise their hands above the worktables and buckets of oysters. They are poised with a singular focus, ready to wield their blades at the blast of the starting horn.

But speed, measured to the hundredth of a second, is only part of the calculation. Each tray of shucked oysters must pass careful inspection. Judges look for bits of shell; traces of mud; mangled, uneven cuts; and how much of the briny oyster liquor has spilled from the shell. Each infraction adds costly penalties to the final tally.

After all, the point of cracking open an oyster is to enjoy the succulent, sea-kissed morsel inside.

Each autumn, local festivals, restaurants and oyster bars kick off the season, celebrating not only the oysters, but also the oystermen and communities built around the harvest. Shucking competitions have always been part of the celebration.

Virginia's official oyster festival, to be held the first weekend in November in the Tidewater town of Urbanna, Va., invites visitors to catch the old-fashioned parade and wander through the local shops and restaurants eating oysters to their heart's content. No surprise, then, that Urbanna is also home to Pratt, the newly crowned women's champion shucker.

The Atlantic coast has a rich history and attraction to the mollusk. In the early 1800s, oysters constituted a major industry in many coastal towns and supported thousands of family-owned businesses, brokers, vendors, restaurants and railroads.

In fact, large oyster beds once thrived in and around Jamaica Bay and New York Harbor. Overfishing and pollution ended that. By the 1880s, what had been a plentiful and inexpensive source of protein for poorer working folks became a delicacy for the well-heeled.

The Chesapeake region was thought to be immune. First, bay oysters reproduce faster than those in colder waters, and the area is so vast it was thought to be sheltered from the industrial pollutions that plagued the big city bays.

But as the demand for oysters led to massive commercial dredging operations to harvest them, many oyster beds were destroyed. The Chesapeake Bay once yielded up to 2 million bushels of oysters per year. Today, that number is 40,000 to 60,000 bushels.

Oysters flourish in coastal estuaries where fresh waters meet the salt waters of the sea -- the brackish waters are an environment rich with algae and other waterborne nutrients. One healthy oyster can filter more than a gallon of water an hour. The once-flourishing oyster ecosystem filtered the entire Chesapeake Bay in just four days, leaving the water pristine and clean.

Today, the higher concentration of bacteria and plankton means oysters lack the delicate flavor they once had.

It also means caution should be taken to assure raw oysters are purchased from a reputable quality source.

The oyster season in the mid-Atlantic region runs from mid-September through the end of April -- the months containing the letter R. And there is some truth to the old tale about not eating oysters in the months of May, June, July and August.

Oysters can be eaten in the summer, provided they are fresh and have been kept safely chilled. However, oysters breed when the waters are warm, so harvesting an already-fragile species at that time of year only further depletes future supplies. And, between the warmer water and the extra activity breeding, summer oysters are not as plump or tender as in the R months, and they tend to be briny.

The summer does something else as well. With less fresh water pouring into the estuaries and higher temperatures and more evaporation, the risk from contaminated waters increases.

Autumn is the season for oysters. The best way to sample the variety, whether from local waters or from around the world, is freshly shucked and served on the half-shell.

Russell Cronkhite is a chef and cookbook author who last wrote for Food about mustard.

The Urbanna Oyster Festival will be held Nov. 4 and 5. For more information, go to www.urbannaoysterfestival.com.

Deborah Pratt of Urbanna, Va., the champion women's oyster shucker, shares the fruit of her labors at last year's festival in Leonardtown.