SOUTH THOMASTON, Maine — It’s not yet 5 a.m., and the landing at the Spruce Head Fishermen’s Co-op is shrouded in predawn fog that obscures the waters beyond. It’s time to go to work, and Virginia Oliver and her son Max approach the dock in the dark in a 30-foot lobster boat.

They tie up under the stark, mist-speckled glare from an overhead light. Bait is brought aboard, equipment adjusted, and Max peers into the gloom as he eases the boat into Penobscot Bay.

In the world of Maine lobstering, it’s a scene that is repeated countless times up and down the state’s rugged coast. But here’s the difference: No other boat has a 101-year-old lobsterwoman aboard, and a fully working one at that.

“I grew up with this,’’ said Virginia Oliver, a Rockland woman who began lobstering when she was 8, just before the Great Depression. “It’s not hard work for me. It might be for somebody else, but not me.’’

Oliver moved deliberately but confidently about the boat, which is named Virginia, for her. She smiled and laughed readily, walked with only a slight stoop, and bent to her work with no-nonsense attention to detail and not a word of complaint.

The fog began to burn off shortly before 7 a.m., and the Olivers pointed out landmarks that have been embedded in family lore for well over a century. Fat seals lay perched on seaweed-covered rocks. Max pointed out a “sweet spot’’ for lobstering among the many small, rocky islands.

His mother came to work this day with a bit of makeup on her face, her blue eyes and a pair of small earrings twinkling in the hazy dawn.

“I try not to wear the dangling ones because I’m afraid they’ll catch,’’ she said with a laugh.

Virginia Oliver has been working these waters since she first accompanied her lobsterman father as a young girl. After raising four children, she returned to the bay with her husband, who died 15 years ago. Since then, she has continued to venture from shore, three mornings a week, to a saltwater world as familiar as the street where she was born and still lives.

“When I first started, there weren’t any women but me,’’ Oliver said, dressed in olive-green overalls, a blue sweatshirt, and high boots. “My husband and I used to go out in all kinds of weather. There aren’t as many lobsters today, though. They’re way overfished, like everything else.’’

Oliver’s job is to measure the lobsters, using pliers to place tight bands around the claws of the keepers, tossing the undersized overboard, and stuffing small pogies into bait bags.

Naturally right-handed, Oliver has worked the pliers with her left hand since she broke her right wrist several years ago. Despite the change, her hand movements seem remarkably supple and strong.

“You know, you do what you have to do,’’ she said. “We used to have to haul by hand. No work, I think, is as it used to be.’’

Oliver is meticulous when she measures, tossing back lobsters that are only a hair shorter than the 3¼-inch legal minimum from the eye socket to the rear of the body shell. She also can’t keep egg-bearing or reproductive females, a state requirement that helps bolster the lobster stock.

And the lobsters they do keep can be a little testy.

“That one won’t quit,’’ Oliver said with a smile, reaching gingerly for a feisty claw-snapper that wasn’t about to go quietly into a tank of seawater.

Max Oliver, 78, does double duty as helmsman and hauler, emptying every trap that a hydraulic wheel pulls from the water. Between mother and son, they have choreographed an intricate ballet of demanding, physical work that’s conducted quietly and efficiently.

Max chuckled over his mother’s stamina and work ethic.

“It’s pretty damn good, that’s what I call it,’’ he said, maneuvering the boat in low water past pine-studded islands.

“She might give me hell once in a while, though,’’ he added with a laugh. “She’s the boss.’’

Virginia Oliver is the oldest licensed lobsterer in Maine and possibly on the planet. But in her eyes, it’s simply what she does. Her world has changed in once-unimaginable ways since 1920, but in other ways it’s hardly changed at all.

She lives one house down from the home where she was born. Her son lives across the street and checks in regularly on her. When he does, she sometimes gives him chores to do.

“I have Max take down the curtains, and I wash them,’’ Oliver said. “I don’t like TV because there’s nothing on it. I like to cook, so I do that. And I like to read Danielle Steel books.’’

She also drinks from a coffee mug that bears the words, “Making the world a better place since 1920.’’

Her son drives her to the boat during lobster season, which for the Olivers stretches from the end of May to the beginning of November. They rise about 3 a.m., go to bed at 10 p.m., and look mildly amused when asked how they manage it.

Oliver said she doesn’t nap when the lobstering is done for the day. There’s shopping to do; there are errands and trips to the post office.

“I find plenty of housework, too. I don’t like to do it, but I have to do it,’’ she said. “I don’t walk around the wharves the way I used to, but I still drive — a GMC four-wheel-drive truck. As you can tell, I’m pretty independent.’’

Her three sons and one daughter range in age from 76 to 82. One of them, 79-year-old Bill, waited at the Spruce Head Co-op this recent morning as he prepared to go lobstering in a separate boat. His mother’s work habits seem to run in the family.

“Someone asked me, why don’t you retire? I said, ‘I can’t. My mother would break my neck,’ ’’ Bill Oliver recalled with a laugh. “I’ve always been pretty active and hard-working, and I can’t see sitting around doing nothing. You keep moving, and I think you’re a lot better off.’’

After five hours on the water, after the last trap had been hauled, Oliver took the wheel as the family headed back to Spruce Head. Their catch of squirming lobsters was landed, put into a crate, and placed into the seawater until a truck would begin their journey to a no-frills lobster shack or fancy seafood restaurant.

A warm greeting awaited her at the dock.

“You’re looking well! I’m glad to see you around and about,’’ said Tom Armbrecht, business manager of the co-op, as he stood beside the boat.

Shortly afterward, fisherman Geno Holmes leaned on a truck and watched in awe as Oliver walked up a steep gangway to shore.

“I’m 50 years old, and I want to retire,’’ Holmes said, shaking his head. “It’s incredible. To be able to get on a boat at her age, it’s crazy.’’

For her part, Virginia Oliver said she has no intention of retiring. When asked how long she would continue lobstering, Oliver didn’t miss a beat.

“Until I die,’’ she said. “And I don’t know when that will be.’’

MacQuarrie can be reached at brian.macquarrie@globe.com.