Martha Scheffer was working on her family’s Katama Bay oyster farm two weeks ago when she discovered a trove of paternal heirlooms.

She knew them as soon as she saw the shellfish nestled in a cage a colleague pulled up from the water. They were the massive oysters her father, Island aquaculturist and farm founder Roy Scheffer, kept for years as “pets.”

The late Roy Scheffer shows off his beloved pets. — Martha Scheffer

“​​My dad wasn’t really a pet person,” Ms. Scheffer told the Gazette last week, guiding her skiff to the farm through the bay’s scattered buoys. “He never really had dogs or animals, but he definitely had pet oysters.”

The pets are not your run-of-the-mill oysters. These oysters weigh roughly two pounds each, and judging from the growth rings on their shells, are between 7 and 10 years old.

“My assumption... was that [Mr. Scheffer], like any farmer, wanted to see if he could grow something as big as it could get,” she said.

Mr. Scheffer and his partner, Patricia Bergeron, died in a boating accident on New Year’s Day. They were scalloping together when the winter weather took a harsh turn and their boat capsized.

Since then, Ms. Scheffer has taken over the farm. She explained that her father kept his pets together in a special pouch, tucked into one of the hundreds of oyster cages that float year-round beneath the water’s surface. The pets’ cage is unmarked, meaning their rediscovery was a rare surprise.

Ms. Scheffer’s father was on her mind the day she found the oysters, seven months after his death.

“I was just thinking about my dad [when] the pets came up,” she said.

When left alone, oysters can grow quite large. — Ray Ewing

Ms. Scheffer has been oystering for more than 20 years. She spent her first summer on her father’s oyster farm when she was 12. Each summer thereafter, she and her brother, Noah Scheffer, headed out daily to Katama Bay to help him.

“My dad always called it summer camp on the oyster farm,” she said.

Taking over the business meant making oystering her full-time job. She decided to rename it Martha’s Roysters — an ode to the portmanteau under which Mr. Scheffer marketed the farm’s oysters.

The farm is also home to Little Minnow, her brother Noah’s oystering enterprise. The siblings do what they can to help each other out.

“My brother and I, we kind of farm together, which is what we’ve always done,” she said.

Ms. Scheffer’s new responsibilities have made her ponder what she loves most about oystering. For one, there’s the feeling of self-sufficiency — the pride of making a living by nurturing millions of bivalves from seed. There’s also the thrill of working on the water, and the freedom of being one’s own boss.

Martha Scheffer heads out to family farm in Katama Bay. — Ray Ewing

But all of that comes second to cherished family memories.

“A majority of it was being out here with my family and my dad,” she said. “I mean, not a lot of people can be so lucky.”

Tending the farm allows her to tap into the bond she shared with her father. He built just about every piece of it: the raft, the oyster cages, even the skiff used to travel from the farm to the shore.

“Being out here is where I feel closest to him, other than being in his gardens,” she said.

Some days are harder than others, especially when the weather is rough. But her father taught her well, Ms. Scheffer said, and the farm is thriving.

“I don’t think I’m ever leaving the water,” she said. “I’ve tried it a few times, and I always end up back here.”

Ms. Scheffer picked up a mesh bag full of jumbo oysters, ones she collected herself. They are not as mammoth as her father’s pets, but are well on their way. She held one up to her ear and talked into it like a telephone — a favorite joke of his.

These oysters are her pets now, and the first she’ll call her own.