On Thursday, SeaWorld released a statement which reads:

"In light of the incident at SeaWorld Orlando Wednesday, SeaWorld San Diego has decided to cancel its "Believe" Shamu show for Thursday, Feb. 25. Park officials will determine at a later time whether the Shamu show will be performed on Friday."

With Friday's cancellation confirmed, park officials said they would continue to discuss the fate of any Saturday shows.

Officials at SeaWorld in Orlando are scheduled to hold a news conference Friday to discuss the attack.

A SeaWorld spokesman said Wednesday that it was typical to have a "dry show or no show" following an emergency.

Dan Brown, general manager of SeaWorld Orlando, characterized Wednesday's death as a "drowning."

Witnesses told Orlando-area television stations that Dawn Brancheau, 40, had just introduced the 12,000-pound whale when it came out of the water and grabbed her by the waist and shook her violently.

The whale, Tilikum, who has been in Orlando since 1992 and was involved in the July 1999 death of a man who sneaked into the park after closing and got into the 50-degree water with the orca. An autopsy listed hypothermia as the cause of his death.

Nineteen years ago, Tilikum was one of three orcas blamed for killing a trainer who fell into their pool in British Columbia, according to The San Diego Union-Tribune.

Chuck Tompkins, head of animal training at all SeaWorld parks, confirmed that because of Tilikum's past, trainers were not supposed to get into the water with him, the Union-Tribune reported.

In 2006, Ken Peters, a trainer at SeaWorld San Diego was attacked by a killer whale during a show, suffering injuries when an orca named Kasatka grabbed his foot and twice took him to the bottom of a 36-foot-deep tank.

Animal rights activists have long argued that killer whales should not be kept by theme parks, away from their natural environment, in part because they are naturally aggressive.

"I am sure the trainers will say they are well taken care of, but you can't meet the behavioral needs of these large marine animals in a marine park," Bryan Pease, a San Diego lawyer and chairman of the board for the Animal Protection and Rescue League, told the Union-Tribune.