Sea Life Park Hawaii announced today the death of Kina, the false killer whale that had been a beloved part of its family since 2015. She was about 44 years old.

“We are all so saddened at the sudden passing of Kina,” said Valerie King, general manager of Sea Life Park, in a news release. “She was an ambassador for her kind, not only through her interactions with the community in our educational programs, but in shedding new light on ways to protect the hearing of marine animals and possibly prevent fishing line entanglements — a particular threat for an endangered species of pseudorca right here in Hawaii’s waters. She has made an indelible impact on all who knew her, and will continue to help the future of pseudorcas around the world.”

Sea Life Park said Kina participated in breakthrough research on cetacean sonar and hearing capabilities at a U.S. Navy program as well as at the Hawaii Institute of Marine Biology until 2015.

The park said her involvement in research on marine mammal hearing also led to findings that were later used to set legislative guidelines for man-made sounds in the ocean. Her amazing echolocation abilities also helped researchers further understand why cetaceans can become entangled in lines and nets, and may one day inform ways to prevent it.

Kina’s transfer to Sea Life Park was controversial, and criticized by activists who oppose keeping dolphins and whales in captivity in marine parks.

Kina was captured during a Japanese dolphin drive decades ago, according to the Associated Press, and was sold by a fishery to a Hong Kong amusement park before the U.S. Navy acquired her.

She was transferred to the park accompanied by her long-time Atlantic bottlenose dolphin companions, Boris and BJ.

Sea Life Park said she interacted with schoolchildren in educational programs and continued to provide insights to the academic community that would help to create a safer marine environment for her counterparts in the wild.