Sea World parks are importing three killer whales from Canada to augment their captive breeding program and reinforce a corps of performing animals.
Two of the massive mammals were blamed for drowning a trainer at Sealand of the Pacific in Victoria, British Columbia, in 1991.
Officials said the whales were unaccustomed to having a trainer in the water near them.
Sea World received permission from the National Marine Fisheries Service last week to import the whales: two adult females and a male calf.
One female and her calf may be added to the five killer whales at the park in Orlando, said Brad Andrews, vice president for zoological operations.
The other likely will go to the Sea World park in San Antonio, Texas. Sea World, owned by Anheuser-Busch, also operates marine parks in Ohio and California.
"It's a tremendous addition," Andrews said Tuesday, noting that the new whales "add to the gene pool."
Six of the 14 whales now in Sea World parks were born in captivity. But Sea World has only two males of breeding age, and all the captive-born calves are female.
The male calf may make a nice complement to those young females, Andrews said.
The company did not disclose the purchase price, but the animals it had in 1990 were valued at about $1.5-million each.
The Canadian park decided to close its killer whale display after trainer Keltie Byrne drowned inside the animals' pool in front of park visitors.
Ms. Byrne fell into the pool and was dragged under by the two female whales and their mate, Tillikum, who was moved to Orlando in January because he was considered a threat to the calf.
"I don't think they were malicious," Andrews said of the adult whales. "I think the animals were unfamiliar with having people around in the water."
Unlike Sealand, Sea World trainers have contact with whales during performances.
Andrews said Sea World trainers will approach the additions with the same caution they would use with untrained animals.
Eventually, Andrews said, Sea World and other marine parks may build up a self-sustaining captive population of killer whales by exchanging animals to prevent inbreeding. Successful breeding reduces the need for capture of the animals in the wild, a controversial procedure.
Animal protection groups had opposed the transfer when it was proposed earlier this year.
"There are serious questions about the viability of keeping killer whales in captivity," said Paula Jewell, who tracks marine mammal issues for the Humane Society of the United States, "and here they are allowing Sea World to import more of them."
But she said her group and others realized that with Sealand closing, the whales needed to be moved to another marine park.