It is noon on a clear September day, and we're standing smack-dab in the middle of the Bay of Arcachon, in southwestern France, the lowering tide lapping around the ankles of our rubber boots. The full sweep of Cap Ferret—a fashionable spit of land on the Atlantic coast about 60 miles southwest of Bordeaux—spans the blue horizon, its pine-studded cliffs and shell-pink dunes barnacled with extravagant vacation homes. But out here, about a mile from shore, it's another world. All around us oysters are slowly emerging from the subsiding water, clinging to sapling poles, resting in chain-mail pouches on shin-high iron racks, and lolling in the dark brown silt.

These are some of France's most prized oysters, which grow on some 2,000 acres of fertile oyster parcs, or beds. About 3,000 tons of the mature mollusks and 3 billion seed oysters are harvested from the bay every year. The beds are the private gardens for some 400 small-scale local ostréiculteurs (oystermen), who call themselves, with a Gallic mix of poetry and irony, les paysans de la mer, "the farmers of the sea".

Low tide is the high point of an oysterman's day, and dozens of men and women labor with stooped backs. It's a romantic blend of the bucolic and the nautical. Boats list, dogs splash up and down the mud, seagulls hover like Brueghel crows.

Yves Fauchier, a chest-poking raconteur with a pointed southwestern twang, labors too. Fauchier farms nearly five acres in the bay, and his turf, like that of his colleagues, is clearly demarcated by the gawky sapling poles, which all but disappear at high tide.

He unhooks the rigid metal pouches that confine the mollusks, forcing them to grow in uniform shapes, then turns them over and reattaches them to the racks. "Oysters spend as much time above water as under," he explains. "We turn the pouches to harden the shells, to expose both sides to the air and sun. The harder the shell, the firmer the flesh inside." Fauchier, who learned his trade from his father, also raises oysters in the silt itself—"wild" oysters that are dirtier and harder to purge than their cousins, though some people prefer them.

Fauchier spends the next two hours or so turning his pouches, repairing racks, and shoveling mature silt-buried oysters into crates. Then he loads his boat with a few dozen pouches of oysters. It is a drill he performs once a day—exactly when depends on the tides—in all but the stormiest weather. (Oysters are harvested at between 24 and 30 months of age; Fauchier generally harvests his at 27 months.)

His chores finished, Fauchier dips his leathery hand into a crystalline puddle and scoops out an oyster. "Hungry?" he asks. He pries the mollusk open with a twist of his pocketknife and passes me the bottom half, the oyster spreading, translucent, across the pearly shell. I touch the feathery lip of flesh. It retracts. I tip the oyster into my mouth, crunch once, and swallow. An ocean of salty-sweet juice envelops my tongue. "Oysters are like wine," he proclaims. "They get their flavor from the soil. It's the algae and the silt, the water itself."

We breakfast on a dozen each, then another dozen, as the waters reverse and begin to rise toward our boot tops. In a few hours, these oyster beds will rest under 15 feet of water. When the tide lifts the hull of the boat, we jump on deck and putt-putt toward shore.