A 19-year-old Hawaiian monk seal, who’s had a troubled past in the wild but has been exemplary while in captivity, is settling into his new home at Sea Life Park Hawaii.

Kekoa, who was known as KE18 while a research subject, was introduced to his new surroundings Thursday, an open-air pool surrounded by rock structures. On Saturday morning, staff at the Makapuu park and a few dozen visitors held a blessing to introduce Kekoa to the public.

David Schofield, the Marine Mammal Health and Stranding Response Program coordinator for the National Oceanic and Atmospheric Administration, welcomed back the monk seal during the blessing.

“We’re commemorating the return of an old friend back to Hawaii,” Schofield said.

The male seal, considered about middle-aged, was in quarantine for a month at Sea Life Park after being brought to Hawaii from California, where he had participated in physiological studies for about a decade.

Schofield said researchers have learned more about critically endangered Hawaiian monk seals after studying Kekoa’s auditory biology and metabolism.

“It’s been a perfect opportunity to capitalize on him being with us to gain new insights into science that can benefit the wild population,” Schofield said.

Only about 1,400 Hawaiian monk seals remain in the wild, with roughly 1,100 of them located in the Northwestern Hawaiian Islands and 300 in the main Hawaiian Islands. The seals are protected under federal and state laws.

Kekoa was born at Kure Atoll, and as he got older he displayed aggressive behavior toward pups, which is normal for males. Most monk seals outgrow the behavior, but in Kekoa’s case the aggression intensified, and in 2011 he killed two pups and attacked seven others.

NOAA had decided to euthanize Kekoa to protect other monk seals, but crews couldn’t find him at first. The delay gave officials enough time to organize a plan to spare the seal and send him to the University of California at Santa Cruz’s Long Marine Laboratory.

The plan included eventually transferring Kekoa to Sea Life Park once the research was finished, and in May the state Department of Agriculture allowed him to be imported back to Hawaii.

While he’s been in captivity, he’s been a “very calm, very gentle and very mellow animal,” said Beau Richter, a veterinary assistant at the park who worked with Kekoa in California.

“There’s no seals around here, so you can’t rehearse that behavior,” Richter said. “That’s kind of a common thing I’ve seen with animals that may have challenges out in the ocean. If they come work with people, some of those challenges, depending on the context, tend to go away.”

Richter held a public feeding for Kekoa after the blessing without incident. The monk seal, who never appeared distressed, performed a few tasks in and around the pool and was rewarded with fish.

Beth Doescher, Sea Life Park’s staff veterinarian, said Kekoa is in good health and that staff is working to get him used to his new home. He’s the only monk seal at the park right now — there are only a handful in captivity worldwide — but the species isn’t particularly social even in the wild.

“They get together for breeding and things like that, but they don’t cluster together to sleep,” Doescher said. “And if we have more than one in an exhibit they’ll kind of go their separate ways. So it’s not necessarily an unusual situation for them to be alone, and probably for some of them it’d be preferred.”