Tilikum, the orca at the center of the 2013 documentary Blackfish, has died on Friday.

SeaWorld Orlando announced on January 6 that the whale was suffering from serious health issues, including a persistent bacterial lung infection. The cause of death has yet to be determined after a veterinarian performs a necropsy.  In March 2016, SeaWorld announced that Tilikum was lethargic and seemed to be deteriorating, but his condition improved.

>WATCH: Dr. John Jett uInterviewed On ‘Blackfish’

Tilikum was SeaWorld’s most prolific male orca, siring 14 calves while he was at SeaWorld Orlando. He arrived at the park about 25 years ago and was noticeable for his size at more than 22 feet and 11,800 pounds.

Tilikum was most famous for the controversy over the ethics of keeping orcas in captivity. Over his approximately 33 years in captivity, he was involved in three human deaths, including the death of a trainer at SeaWorld in 2010. Those interviewed in Blackfish argued that the whale had become psychotic after being torn from his wild pod at a young age and kept in barren, isolated tanks.

SeaWorld Entertainment officials announced in March 2016 that the tourist attraction would end its orca breeding program and theatrical shows involving killer whales. The decision came six years after Brancheau’s death and three years after the release of the documentary, “Blackfish,” which chronicled Tilikum’s life.

“Tilikum had, and will continue to have, a special place in the hearts of the SeaWorld family, as well as the millions of people all over the world that he inspired,” SeaWorld CEO Joel Manby said in a statement. “My heart goes out to our team who cared for him like family.”