The Vancouver Aquarium is expected to release more information Monday about what caused the death of its lone surviving beluga whale, just over a week after her daughter suffered the same fate.

Aquarium staff announced the death of 29-year-old Aurora on social media Friday night, just hours after issuing a statement to media that the whale appeared to be recovering.

Veterinarians had been keeping a close eye on their last beluga following the "sudden loss" of Aurora's daughter, 21-year-old Qila, on Nov. 16. In the last nine days, Aurora's health has been a bit of a rollercoaster, outlined in near-daily updates from the aquarium.

The day after Qila died, Aurora seemed to be suffering from similar symptoms, but then started to show signs of recovery. Then again, the aquarium said it was "increasingly concerned" for her health, but Friday said she had started playing and seeking rubs from her trainers, behaviour she hadn't exhibited since Qila's death.

The facility's head veterinarian Martin Haulena said results from Qila's necropsy had arrived late Thursday night, and provided some clues to what may have been ailing the mother-daughter duo. Haulena – who hadn't been home in days, choosing instead to sleep at the aquarium to provide round-the-clock care for Aurora – said the undisclosed evidence helped them develop a new therapeutic strategy for the remaining whale, and she'd showed signs she was getting better.

But in a lengthy statement posted on Facebook Friday night, the aquarium confirmed that Aurora had succumbed to her illness.

"Aurora had been sick for the past two weeks, showing symptoms of abdominal cramping, loss of appetite and lethargy," the statement said.

The whale's care team consulted with veterinary specialists, pathologists, marine biologists and "other experts from around-the-world" to provide treatment and investigate her ailment, but her life could not be saved.

"She slipped away this evening surrounded by the people who loved her, some (of) whom have cared for her since she first arrived in 1990," staff wrote.

"To our team, Aurora was a part of our family and her loss is absolutely heartbreaking. The marine mammal care team working night and day to care for her are our true heroes, even if we lost the battle."

The aquarium said the past two weeks have been "extremely difficult," and that Aurora's death "left a hole in our hearts."

In the statement, staff thanked its team of 1,500 people, and everyone who'd reached out with messages of support and offers to help.

"You're shared countless stories of how Aurora and Qila have impacted you and your family and we're grateful to everyone who has shared those connections with us."

One of those people with a story spoke to CTV News Saturday morning, saying she was "incredibly heartbroken" by the news.

"I've grown up coming to the aquarium. I love the beluga whales. I originally wanted to become a marine biologist," she said.

"The aquarium had a big part in that. So for me, finding out that they had passed away was huge."

Through tears, she said the whales were special to her, and that she loves the aquarium. She said it was hard to hear, and the news was sudden. Now an adult, she and her young children are members of the aquarium, and the whales are now her daughter's favourite exhibit.

She said she wonders if Aurora died of heartbreak, following her daughter's death. As a mother of girls, "I'd be heartbroken," she said.

Another woman said she was "very sorry" to hear the news, but that she'd still continue to support the aquarium.

"We were thinking about all of the people who work here, and we're hoping that they're feeling OK. We're sorry and we're grieving for them," she said.

She said she came to the aquarium as a child, and became a member as an adult so she could take her young son to see the animals.

A boy who was visiting on Saturday said he was "pretty sad" about the deaths.

"I love the belugas… I just liked how, they were really cute."

His mother said she felt the whales are too large to be held in a smaller tank, so that "in a way, it's freed them."

Aurora's history at the aquarium

Aurora was taken from the Western Hudson Bay beluga population, the last acquired by the aquarium before it instituted its policy of only accepting cetaceans born in captivity. She was named after the aurora borealis, and "immediately won hearts and inspired generations of visitors, employees and volunteers with her curious nature and gentle personality," the aquarium said.

The aquarium wrote that her 26 years at the facility allowed staff to teach millions of visitors about her species and belugas' ecosystem in the wild.

She'd also helped with studies into whales' physiology, hearing and communication between mothers and calves. Aurora's daughter, Qila, was the first beluga ever conceived and born in a Canadian aquarium. The whales were both part of studies dating back to 2002.

Aurora had other babies during her time at the aquarium, but her offspring did not survive. One of the babies lived three years, and the other died after only one year. Her daughter Qila also gave birth, but the young whale died at the age of three.

The aquarium was well known for its resident belugas, one of which inspired the Raffi song "Baby Beluga." That whale, Kavna, died at the age of 46 in 2012.

Whales' deaths renew calls for change

Some groups, like the California-based In Defense of Animals, hope the recent deaths will encourage the aquarium to no longer take in whales.

In a statement on its website, the group called the aquarium "a facility whose business is based on exploiting whales and dolphins by keeping them in captivity."

The group encourages the public to sign a petition directed at the Vancouver Park Board and Vancouver Aquarium CEO, asking the aquarium to end all whale and dolphin captivity and move remaining cetaceans to "retirement facilities."

With files from CTV Vancouver's Maria Weisgarber