Compared with other marine mammals, 40-year-old Kina has lived a particularly winding and high-profile life.

She went from the open ocean off Japan, to a Hong Kong amusement park, to a classified U.S. Navy program, to a Hawaii research lab. Along the way, studies using the false killer whale — a dark-gray member of the dolphin family with a big, round beak — led to major discoveries on whale hearing and helped develop modern military sonar .

"The work that (researchers) have done over the years is quite valuable, and certainly groundbreaking," said Robin Baird, a marine biologist with the nonprofit Cascadia Research Collective, a scientific and education group based in Olympia, Washington.

Now, Kina is again making waves, this time with her latest move to an Oahu marine park. Animal-rights activists say the 13-foot-long (4-meter), toothy mammal and her captive companions deserve peaceful retirements but are instead being traumatized as tourist attractions confined to concrete tanks.

But Kina's handlers maintain she is in excellent care, receiving the best food, veterinary attention and stimulation, all while continuing to contribute to important science. And park officials say she won't take part in any acrobatic shows like other dolphins in their care.

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Kina's journey started in the wild over 30 years ago, when she was captured during a Japanese dolphin hunt. She is believed to be the last living animal in the U.S. from that now-widely condemned fishery. The fishermen sold her to a Hong Kong amusement park, where the U.S. Navy acquired her in 1987.

For the next six years, the Navy used Kina for classified research on sonar, the use of sound to communicate, maneuver and detect objects underwater. It kept her at a Marine base on Oahu's Kaneohe Bay, the largest sheltered body of water in the main Hawaiian Islands.

When that program ended, Kina went to a University of Hawaii lab on Coconut Island, also in Kaneohe Bay, where her science career continued for over 20 years. She took part in echolocation studies that could someday lessen the impacts of man-made ocean noise on marine wildlife. Cetaceans — dolphins, whales and porpoises — use sound waves and echoes to hunt and navigate.

But the university was spending nearly $1 million a year to care for Kina in an ocean pen. So in 2015, amid serious funding problems, the school was forced to auction off Kina and her two dolphin companions.

Sea Life Park , a family attraction just outside Honolulu, put in the highest bid, and the trio has been living there, backstage, ever since.

Animal-rights activists blasted the move as inhumane. Many pushed for a measure that was introduced in the 2017 state Legislature that urged the end to local breeding programs and a phase-out of captivity. The measure failed but could be revisited next year.

Activists also recently led an online "#JusticeForKina" campaign to express their concerns about her confinement at the park, which they say causes physical and psychological distress.

It's "disrespectful to the animal after she gave us so much," said Natalie Parra, co-founder of the Hawaii-based activist group Keiko Conservation .

But Jeff Pawloski, Kina's trainer at the Navy lab 30 years ago and now Sea Life Park's curator, said the campaign has led to a lot of misinformation.

For instance, the park boasts daily dolphin shows and allows visitors — those willing to pay a premium price — the chance to swim with the animals. But Pawloski says that won't happen with Kina. Instead, he hopes his old "friend" will help educate the public about how her research aids wild animals.

"Kina's done some phenomenal things over her career, and we intend to keep that going on as long as possible," Pawloski said.

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The park agreed to let scientists continue to work with Kina at her new home. One study will look at how she uses echolocation to find fishing hooks and other entanglement hazards — a major threat to wild marine mammals.

The findings could lead to fishing gear that is more "visible" to dolphins and whales, said Paul Nachtigall, founder of the University of Hawaii's Marine Mammal Research Program , where Kina lived before moving to the park. And Sea Life Park, he says, where Kina was reunited with her longtime trainer, is the best possible place for his "old whale."

"You want her with the person who has cared for her most of her life, who knows her best, and is in a situation with very good care."

Still, many animal activists contend Kina belongs not in a tank but in an ocean sanctuary environment closer to her life in the wild. No such facilities exist, though at least two groups — a nonprofit called The Whale Sanctuary Project and the National Aquarium in Baltimore — are working to create the first two. Scientists agree most captive whales would die if released into the open ocean with no human care.

"I honestly don't think that any knowledge you can give out in a captive facility would justify keeping the animals in the conditions that they're in," Parra said. They live their lives "stripped of all their physical, psychological, social needs just for our entertainment."

Sea Life Park gave The Associated Press access to Kina, where she spends her days in three interconnected, partially shaded pools with her longtime dolphin cohorts. The enclosure is larger than the one she was kept in at the university.

The false killer whale will go on public display later this year after being moved to an even bigger pool with more animals, park officials say. Sea Life Park also holds sea lions, sea turtles, sharks and reef fish. It has a habitat for endangered Hawaiian monk seals and a rehabilitation program for injured seabirds.

Nachtigall thinks the best way to research and care for animals like Kina is to have a paying public.

"The only places left that keep marine mammals where research can be done are public display facilities like Sea Life Park," he said.

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