A virus or toxin was likely responsible for the death of Aurora the beluga whale Vancouver Aquarium staff revealed this morning, although early necropsy results are inconclusive as to a specific cause of death. 

Chief veterinarian Dr. Martin Haulena did say significant liver damage was detected in the 30-year-old female beluga.

"The liver was dramatically compromised, although interestingly enough that did not show up on any blood work that we did on Aurora, and we had blood work done every day," said Haulena.

"The most likely culprit for this is a virus or a toxin given the course of disease and the lack of significant findings in clinical diagnostics [and] early postmortem results," he said.

Beluga Whale Calf 20080812

A two-month-old Qila swims with her mother Aurora at the Vancouver Aquarium in Vancouver, B.C. Both whales died due to similar but unexplained circumstances within 9 days of each other. (Darryl Dick/The Canadian Press)

Aurora died Nov. 25, nine days after the death of her 21-year-old calf, Qila — the first beluga whale conceived and born in captivity at a Canadian aquarium. 

Vancouver Aquarium president Dr. John Nightingale says it appears the deaths are connected.

"We're still seeking clarity as to why the two whales displayed similar symptoms during the very sudden onset of their illnesses," he said.

Haulena says early test result have ruled out bacteria and fungus as a cause of death, and tissue testing continues at numerous locations in Canada and the U.S. 

Possible poisoning?

When asked directly if it was possible the whales could have been poisoned Haulena replied, "Right now we have no obvious sign of mortality ... I will stress that nothing is off the table now."

Nightingale said "police have been contacted," but would not elaborate.

He also said the beluga pool would remain empty until the aquarium could determine how the whales died. The Vancouver Aquarium has six belugas on loan to other marine facilities.

"We will leave no stone unturned," he promised.