A harbour porpoise that has lived at the Vancouver Aquarium since 2011 has died.

In a statement, the aquarium said staff became concerned on Tuesday after the animal, named Jack, lost interest in food and play. 

It said staff took immediate action after noticing Jack wasn't behaving normally but symptoms "progressed rapidly." The porpoise died just before midnight on Thursday. The aquarium did not release a cause of death.

"Jack will be missed by all, including our members, donors and guests," the aquarium said in a news release.

The aquarium said Jack has lived at the facility since September 2011 when it was discovered by the Marine Mammal Rescue Centre and deemed non-releasable by Fisheries and Oceans Canada. 

It says its experience with Jack provided it with valuable knowledge it used to rehabilitate other cetaceans, like Levi, a young porpoise, who in 2013 became the first cetacean to be successfully rescued, rehabilitated and released by the aquarium.