One day after a beluga whale died suddenly in at the Vancouver Aquarium, the whale’s mother appears to be showing similar symptoms that preceded the mysterious death.

The aquarium has yet to determine the cause of death for Qila, a 21-year-old whale that died Wednesday morning after losing her appetite and showing unusual behaviour. A necropsy did not pinpoint a clear reason for Qila’s death.

On Thursday, aquarium staff said that Qila’s mother, Aurora, had similarly begun acting strangely with staff and lost her appetite. Both whales have also shown signs of mild inflammation and appeared to have some abdominal discomfort.

"The gang's working really hard. Aurora's our priority right now, and we've got a lot of folks that have put aside a lot of personal time to prioritize her, and Qila before her," said the aquarium's veterinarian, Dr. Martin Haulena.

The aquarium has ordered tests looking for any bacteria and biotoxins in the whales’ tank or food.

The necropsy found an abscess in Qila's lung, but the aquarium says it likely was around for some time. Haulena has suggested it's possible that Qila’s abscess may have suddenly become septic and caused an infection, but that has yet to be conclusively determined.

Without a clear answer, staff caring for Aurora face a challenging task.

"She is undergoing quite a lot of intensive treatment. We're covering as many bases as we can with her given that we don't have a smoking gun," Haulena said. "We have to assume that whatever Qila succumbed to is also what is affecting Aurora, but that might not be the case."

Qila was the very first beluga conceived and born in a Canadian aquarium.