For the past few summers, numerous surfers in Santa Cruz, Calif., have been victims of a crime at sea: boardjacking. The culprit is a female sea otter, who accosts the wave riders, seizing and even damaging their surfboards in the process.

After a weekend in which the otter’s behavior seemed to grow more aggressive, wildlife officials in the area said on Monday they have decided to put a stop to these acts of otter larceny.

“Due to the increasing public safety risk, a team from C.D.F.W. and the Monterey Bay Aquarium trained in the capture and handling of sea otters has been deployed to attempt to capture and rehome her,” a spokesperson for the California Department of Fish and Wildlife said in a statement.

Local officials call the animal Otter 841. The 5-year-old female is well known, for both her bold behavior and her ability to hang 10. And she has a tragic back story, with officials now forced to take steps that illustrate the ways human desire to get close to wild animals can cost the animals their freedom, or worse, their lives.

California sea otters, also known as southern sea otters, are an endangered species found only along California’s central coast. Hundreds of thousands of these otters once roamed the state’s coastal waters, helping to keep the kelp forests healthy as they consumed sea urchins. But when colonists moved in on the West Coast, the species was hunted to near-extinction until a ban was put in place in 1911.

Today, around 3,000 remain, many in areas frequented by kayakers, surfers and paddle boarders.

Despite these close quarters, interactions between sea otters and humans remain rare. The animals have an innate fear of humans and usually go to great lengths to avoid us, said Tim Tinker, an ecologist at the University of California, Santa Cruz who has spent decades studying the marine mammals. A sea otter approaching a human “isn’t normal,” he said, adding “but just because it’s not normal doesn’t mean it never happens.”

Otters have been known to approach humans during hormonal surges that coincide with a pregnancy, or as a result of being fed or repeatedly approached by people. That is likely what occurred with otter 841’s mother.

She was orphaned and raised in captivity. But after she was released into the wild, humans started offering her squid and she quickly became habituated. She was removed again when she started climbing aboard kayaks in search of handouts, ending up at the Marine Wildlife Veterinary Care and Research Center in Santa Cruz, where researchers quickly realized she was pregnant. It was while back in captivity that she gave birth to 841.

The pup was raised by her mother until she was weaned, then moved to the Monterey Bay Aquarium. To bolster her chances for success upon release, 841’s caretakers took measures to prevent the otter from forming positive associations with humans, including wearing masks and ponchos that obscured their appearance when they were around her.

Yet 841 quickly lost her fear of humans, though local experts cannot explain precisely why.

“After one year of being in the wild without issue, we started receiving reports of her interactions with surfers, kayakers and paddle boarders,” Jessica Fujii, sea otter program manager at the Monterey Bay Aquarium, said. “We do not know why this started. We have no evidence that she was fed. But it has persisted in the summers for the last couple of years.”

Otter 841 was first observed climbing aboard water craft in Santa Cruz in 2021. At first, the behavior was a rarity, but over time the otter grew more bold. This past weekend, the otter was observed stealing surfboards on three separate occasions.

On Monday, Joon Lee, 40, a software engineer, was surfing at Steamer Lane, a popular surf spot in Santa Cruz, when 841 approached his board.

“I tried to paddle away but I wasn’t able to get far before it bit off my leash,” he said.

Mr. Lee abandoned his board and watched in horror as the otter climbed atop it and proceeded to rip chunks out of it with her powerful jaws.

“I tried to get it off by flipping the board over and pushing it away, but it was so fixated on my surfboard for whatever reason, it just kept attacking,” he said.

While Mr. Lee immediately recognized the danger he was in, not everyone in the water is so aware. Last month, Noah Wormhoudt, 16, was catching some waves with a friend off Cowell’s Beach in Santa Cruz when 841 swam up.

“I started paddling away trying to avoid it but it kept getting closer and closer. I jumped off my board and then it jumped onto my board,” he recalled. “It seemed friendly, so we got comfortable with it. It was a pretty cool experience.”

Caught up in the excitement of the moment, Mr. Wormhoudt said he “wasn’t really like thinking about how it could bite my finger off.”

The young surfer watched from the water while the otter stayed atop his board as the swell rolled in. “The otter was shredding, caught a couple of nice waves,” Mr. Wormhoudt said.

Such situations are extremely dangerous, said Gena Bentall, director and senior scientist with Sea Otter Savvy, an organization that works to reduce human-caused disturbances to sea otters and promote responsible wildlife viewing. “Otters have sharp teeth and jaws strong enough to crush clams,” she said.

Contact with humans is also dangerous for the otters. If a human should be bitten, the state has no choice but to euthanize the otter. And with so few sea otters left, the loss of even one individual is a hindrance to the species’ recovery.

If the authorities succeed in capturing 841, she will return to the Monterey Bay Aquarium before being transferred to a different one, where she will live out her days. Her captors have their work cut out for them. Multiple attempts to capture her have been made, none successful.

“She’s been quite talented at evading us,” Ms. Fujii said.

Until the otter can be captured, the California Department of Fish and Wildlife is asking surfers to avoid her at all costs.

Experts also had a message for people who share their close encounters with a sea otter on social media.

“Reporting these interactions to the appropriate personnel, and not sharing them on social media — where it can be misinterpreted as a fun, positive interaction where that may not be the case — is really important,” Ms. Fujii said. “I know that’s hard to do. It gets lots of likes and attention, but in the long run, it can be detrimental to the animal.”