The mammal named Hana died at the Vancouver Aquarium on Sunday night, just days after surgery for a gastrointestinal disorder.
Aquarium head veterinarian Dr. Martin Haulena said the procedure last Thursday on the 21-year-old dolphin had never been successfully completed before.
"When she survived it, we had a glimmer of hope that aggressive post-operative treatment and her own strength might just pull her through," Haulena said in a news release.
"Hana has been a huge part of our life at the Vancouver Aquarium and will be greatly missed by our team, as well as visitors who came to love and learn from her."
Haulena said he assembled a world-class team of veterinarians, who were flown in from across the continent for the surgery. They brought in the best radiologist, anesthetist and surgeon in the field, and a team of animal husbandry staff who tended to her in waist-deep water around-the clock.
"I can tell you that we did absolutely everything we could to save her," he said.
"This is not the news I hoped to be updating you with."
Hana suddenly became ill on May 18, avoiding food and trainers. Doctors found fluid in her abdominal cavity and diagnosed gastrointestinal distension and inflammation.
Haulena said a commonplace germ may be to blame, and that the sickness occurs in animals everywhere — both in captivity and in the wild.
In a life-saving bid, the team performed the first-ever bowel surgery while the dolphin was under general anesthesia. They knew the procedure was high-risk.
Hana showed signs of improvement on Saturday, but on Sunday her condition took a turn, Haulena said.
"Although we knew it was a miracle that she made it through the surgery and that her recovery was a long shot, her loss still comes as a devastating blow," added Clint Wright, the aquarium's general manager.
Hana had lived at the aquarium since 2005. She was acquired from the Enoshima Aquarium in Japan, where she'd been cared for after suffering injuries in a fishing net off the country's east coast two years earlier.
It was decided then that she would never be able to be released because her injuries wouldn't allow her to survive in the wild.
The aquarium said Hana was visited by more than 10 million people over her time in Vancouver.
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