Investigation determines Vancouver Aquarium's beluga whales cause of death

The Vancouver Aquarium says an unknown toxin was the cause of death for two belugas last year.

The aquarium announced the conclusion of a five-month investigation Thursday saying that an investigation also determined the toxin was likely introduced by food, water or through human interference.

The belugas, 21-year-old Qila and her mother, 30-year-old Aurora, died nine days apart last November from what officials said was a mysterious illness.

The aquarium's head veterinarian, Dr. Martin Haulena, said in an interview that the death of the belugas was devastating for staff and the public.

"It's like when you lose a close family member and you go through this classic mourning syndrome," he said, adding that the final results of the investigation have helped bring closure to the incident.

Haulena said the toxin was likely introduced to the whales in the weeks or days leading up to their deaths.

It's not uncommon for a toxin to be difficult or impossible to identify, he said, because it could have been metabolized quickly by the animals, leaving the substance undetectable.

Despite the uncertain result, Haulena said the investigation has helped staff improve the safety of the other mammals in their care.

The facility currently houses three other cetaceans — a false killer whale, a Pacific white-sided dolphin and a harbour porpoise.

Staff were concerned at around the time of the deaths that the other animals were at risk, Haulena said, but several risk factors highlighted in the investigation have since been addressed.

The aquarium said in a statement that is has taken several steps to protect the remaining animals including enhanced food screening, overhauling its water treatment systems and real-time testing of the circulating water.

The aquarium said it is also significantly updating its security to monitor perimeter access and reduce potential threats of human interference.