Officials at the Vancouver Aquarium say a young beluga whale died on Friday morning from pneumonia.

Vancouver Aquarium veterinarian Dr. Martin Haulena spent most of Friday with veterinary pathologist Dr. Stephen Raverty at the Ministry of Agriculture Animal Health Centre in Abbotsford, B.C., conducting Tiqa’s necropsy.

"The preliminary results indicate that Tiqa had pneumonia. The underlying cause is not yet known," the Vancouver Aquarium stated in a press release early Friday evening.

"Dr. Haulena is researching potential underlying metabolic disorders, as well as awaiting results of a histopathology, microbiology and toxicology," the release said.

Tiqa the beluga died early Friday morning at approximately 5:45 a.m. PT, according to aquarium staff.

Officials said Tiqa was being monitored for the past ten days because staff noticed her appetite had declined, but was not until Thursday that officials began to suspect she was suffering from an infection.

A man overlooks the beluga tank at the Vancouver Aquarium following the death of Tiqa, a young beluga, on Friday morning. (Emily Elias/CBC)

Staff said they were concerned by her condition on Thursday, but her death was unexpected.

"Vancouver Aquarium staff — particularly its animal care team — and volunteers are deeply saddened by this loss," a statement issued Friday morning said.

Police seek intruder

Vancouver police were dispatched to the aquarium at around the time of Tiqa's death to investigate an early morning break-in.

Aquarium staff first spotted a male intruder in the beluga enclosure around 4:30 a.m. PT.

The unidentified man was scared off moments later by staff, who had the area under 24-hour surveillance, according to aquarium president John Nightingale. He did not get in the water, said staff.

The suspect is described as five-feet ten-inches tall and dark skinned.

Vancouver police Const. Jana McGuinness said the break-in did not appear to be connected to the whale's death.

3rd young beluga to die

Tiqa, who was just over three years old, is the third young beluga to die at the Stanley Park facility. A total of five belugas have been born in captivity at the aquarium.

Tiqa was the first beluga born to a beluga that was born in captivity. John Healey/Vancouver Aquarium

The first calf born at the aquarium was Qila in 1995 to Aurora. She was also the first calf to be conceived and born in a Canadian aquarium. Qila gave birth to her own calf, Tiqa, in 2008, making Tiqa the first calf born to an aquarium-born beluga.

Aurora's second calf, Tuvaq, was born in 2002 but died suddenly in 2005.

Last year pennies and pebbles tossed in the beluga tank caused the death of Nala, another young beluga at the aquarium. Nala was born in June 2009 to Aurora.

Officials from the Vancouver Aquarium said an update and preliminary report on Tiqa's death will be released early next week.