Tilikum, the killer whale involved in the deaths of three people while held in captivity, has died, SeaWorld has confirmed.

Tilikum, estimated to be aged 36, is believed to have died from a bacterial lung infection following years of severe ill health.

Tilikum was the focus of the 2013 documentary Blackfish after he was involved in the deaths of three people, including SeaWorld trainer Dawn Brancaeu, at the Orlando resort.

After the film's release, ticket sales for SeaWorld plummeted, leading to the park announcing it will no longer host its famous killer whale performances after its current generation die.

Gabriela Cowperthwaite, the director of Blackfish, told IBTimes UK: "Tilikum's life was so incredibly tragic. He lived a horrible life, he caused unspeakable pain, so at least his chapter is over. Now we have to turn our attention to retiring the other whales to an ocean sanctuary. Because as it stands, holding whales in concrete tanks is so clearly a model where no one wins."

President and CEO of SeaWorld Joel Manby said: "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. My heart goes out to our team who cared for him like family."

Tilikum and two female orcas submerged a part-time trainer in a pool while in captivity at the now-defunct SeaLand in British Columbia in 1991. He moved to SeaWorld soon after. In 1999, a man managed to sneak into the resort at night and was found the next day dead in Tilikum's breeding tank in the back of Shamu Stadium.

The death of trainer Brancaeu in 2010 shook the world after Tilikum pulled her from a platform by her arm and held her under the water during a live performance.

A SeaWorld spokesperson said: "Tilikum's veterinarians and caretakers delivered various treatment regimens over the course of this illness, which consisted of, among other things, combinations of anti-inflammatories, anti-bacterials, anti-nausea medications, hydration therapy and aerosolised antimicrobial therapy.

"While today is a difficult day for the SeaWorld family, it's important to remember that Tilikum lived a long and enriching life while at SeaWorld and inspired millions of people to care about this amazing species.

"Tilikum's life will always be inextricably connected with the loss of our dear friend and colleague, Dawn Brancheau. While we all experienced profound sadness about that loss, we continued to offer Tilikum the best care possible, each and every day, from the country's leading experts in marine mammals."

A spokesperson for animal rights group Peta added: "Tilikum died without ever again knowing freedom, along with 11 of his children who died prematurely before him and leaving 10 more who will continue to suffer in tiny concrete tanks.

"Peta is calling on SeaWorld to do the right thing and move the remaining orcas to coastal sanctuaries, where they could enjoy a more natural life, and on caring people to shun facilities that enslave animals for our 'entertainment.'"