One of only two dolphins the Vancouver Aquarium holds in captivity passed away over the weekend.
According to a blog post at the Vancouver Aquarium's website, the animal, named Hana, was recently diagnosed with gastrointestinal distension and inflammation. Surgery was performed by a team of specialists the evening of May 21. That operation was initially considered a success but Hana died shortly after on Sunday, May 24.
"With her condition worsening...the team decided to perform the first-ever enterotomy (bowel surgery) on a Pacific white-sided dolphin under general anesthesia," the blog post reads. "Because cetaceans live in water and are conscious breathers, surgical procedures are high-risk and extremely rare."
The post goes on to quote the aquarium's long-time head veterinarian, Dr. Martin Haulena.
“The surgery had never been successfully completed before,” he said. “When she survived it, we had a glimmer of hope that aggressive post-operative treatment and her own strength might just pull her through. Since the late-night surgery took place Thursday, the marine mammal care team and other volunteers nursed her around the clock, walking with her in waist deep water, supporting her, providing familiar encouraging words and close gentle contact. Although there were signs of improvement on Saturday morning, on Sunday, some of her physiological parameters started to worsen. She passed away peacefully Sunday evening surrounded by a team that had been caring for her daily over the course of ten years.
“I can tell you that we did absolutely everything we could to save her," Haulena continued, "including bringing in the best radiologist, anesthetist and surgeon in the field to provide treatment, and we had an incredible team of animal husbandry staff with her in waist-deep water around-the-clock."
Hana is the second cetacean owned by the Vancouver Aquarium to die in 2015. On February 19, a beluga whale named Nanuq died while on loan to a SeaWorld facility in Orlando, Florida.
Speaking to reporters this morning (May 25), Haulena said the exact cause of Hana's death was still being determined. But he noted the death was related to the animal's gastrointestinal problem.
“The cause is most likely a spontaneous event,” Haulena said.
He added that through a post-mortem examination, it was discovered that food was not properly passing from the small intestine to the large intestine. “That opening was unusually narrow,” he explained. “That would certainly predispose to the rest of the events.”
Hana arrived at the Vancouver Aquarium in 2003 after she was rescued from a fishing net off the coast of Japan. The deceased dolphin was believed to be approximately 21 years old.
Asked by a reporter how that age compared to the lifespan of dolphins living in the open ocean, Haulena responded: “We don’t know their longevity very well in the wild.”
According to the National Oceanic and Atmospheric Administration, Pacific white-sided dolphins can live for more than 40 years. One study often cited by SeaWorld found members of a bottlenose dolphin population living off the coast of Florida seldom survived for longer than 20 years.
In February 2014, the Georgia Straight ran an in-depth feature about the Vancouver Aquarium. That article includes interviews with several marine biologists who said there is evidence that cetaceans kept in captivity do not live as long as their counterparts in the wild.
The beluga that died in February while on loan to SeaWorld was named Nanuq. It was estimated to be 31 or 32 years old. According to National Geographic, the average lifespan of a beluga in the wild is 35 to 50 years.
A July 2014 park board report shows the Vancouver Aquarium owns one dolphin (two including Hana). It also owns eight beluga whales (nine including Nanuq). Two of those belugas are kept in Vancouver, four are housed at Sea World facilities in the United States (Nanuq was a fifth), and two are on loan to the Georgia Aquarium in Atlanta.