In a statement, they said Tilikum had faced serious health issues including a persistent and complicated bacterial lung infection.
His role in trainer Dawn Brancheau's death in 2010 and the documentary "Blackfish" that implied his treatment led to the tragedy sent SeaWorld's business into a spiral.
The male killer whale measuring more than 22 feet and weighing 11,800 pounds, was thought to be about 36-years-old and had been in captivity at the park for 25 years.
As has been documented by "Blackfish" and Outside magazine, Tilikum was captured from the wild off the coast of Iceland in 1983, when he was approximately 2 years old.
Hamilton said he predicted "Tilly" would kill other people following Byrne's death and that the group made recommendations in response to an inquest into the trainer's death, and also advised SeaWorld against putting people in the pool with the whale.
"We have already tested educational orca presentations here and they resonated very positively with our guests, reinforcing that we can be both fun and meaningful in our parks and with our animal exhibits and presentations", the statement said. Whether Tilikum actually killed the man is a mystery, but the man's body was found drowned, mutilated and draped over the whale the next morning. "My heart goes out to our team who cared for him like family", he said. He was not only forced to perform meaningless tricks for food but also manipulated sexually - his sperm was used to produce more baby orcas for SeaWorld to train and sell.
"Tilikum's life was so incredibly tragic". "You have to look at it from the perspective that if these animals weren't in captivity to begin with, would we have cared so much about them as we do now?"
Giants are healthy (minus JPP) heading into playoff game vs. Packers
But the story didn't change 91 days later when the Cowboys traveled to East Rutherford , N.J., for the rematch. The following season the Giants had home field advantage locked up for their season finale with the Vikings.
PETA said SeaWorld had not gone far enough.
"Orca Encounter" will open in Orlando and San Antonio within two years, according to SeaWorld.
SeaWorld San Diego will present its last traditional orca show on Sunday as park officials prepare to debut a new, more educational production later this summer.
Other whales remain at the water park. It was the first killing by an orca at a marine park - in fact, it was the first killing of a human by orcas ever reported, as killer whales have never killed a person in the wild.
"That human experience isn't likely to be replaced", Stafford said.
In 2010 trainer Dawn Brancheau died after being attacked by Tilikum.
However, SeaWorld pledged that its current crop of killer whales would be its last generation of the creatures.