Here is a brief timeline of SeaWorld-related incidents:

Sept. 30, 1987: Chris Barlow of Sea World San Diego was rammed in the stomach by a whale during a show. He was hospitalized but survived.

Nov. 21, 1987: John Sillick fractured his vertebrae, femur and pelvis while riding Corky the whale at Sea World San Diego when he was crushed between two whales during a show.

June 12, 1999: Kasatka, a dominant female whale, began acting strangely during a show, grabbed Peters' leg and attempted to throw him out of the pool at Sea World San Diego. Peters was able to get out of the pool.

July 27, 2004: Ky, a killer whale at SeaWorld San Antonio, repeatedly slammed trainer Steve Aibel underwater during a show. Aibel, who was uninjured, had trained Ky for 10 years.

Nov. 29, 2006: Kenneth Peters, Sea World San Diego's most experienced trainer, was dragged to the bottom of a 36-foot-deep pool by a 7,000-pound killer whale named Kasatka during a show at Shamu Stadium. Peters escaped with puncture wounds and a broken foot after he calmed the whale by stroking it.

Sources: Los Angeles Times, The Associated Press, Sentinel research