By Sharon Bernstein

SACRAMENTO Calif. (Reuters) - A killer whale at SeaWorld is pregnant, the San Diego theme park said Tuesday, a development welcomed by the company but decried by animal rights activists trying to outlaw the breeding of captive orcas and "Shamu" shows that feature them doing tricks.

The news of the pregnancy comes weeks after California lawmakers effectively killed a closely watched bill that would have banned SeaWorld from continuing its breeding program and from using killer whales to perform tricks at its California park.

"The calf's birth is expected in December," said spokesman Dave Koontz. Killer whales have a 17 1/2 month gestation period.

The baby would be the sixth at SeaWorld's San Diego park, and the 32nd at parks owned by the company since 1985, Koontz said. It would be the first calf borne by Kalia, a 9 1/2-year-old killer whale born at the park and still living with her own mother Kasatka.

Animal rights activists, some of whom have speculated for months that Kalia might be pregnant, were outraged at the announcement, saying that the mother-to-be is too young to have been impregnated.

"SeaWorld routinely breeds its females too young," said Naomi Rose, an orca biologist who has been active in trying to ban the breeding program and the shows. "In the wild, killer whale females don’t have their first calf until they are around 12 to 14 years of age."

SeaWorld's orca breeding and entertainment programs have come under close scrutiny in recent months following the release of the documentary "Blackfish," which tells the story of an orca that killed a trainer at the company's park in Orlando, Florida, in 2010.

The movie quotes former SeaWorld trainers who say that orcas, which have highly evolved social structures and use sophisticated calls to communicate, do not thrive in captivity and can become dangerous.

SeaWorld has responded angrily to the film, calling it animal rights propaganda and saying its contention that orcas do not fare well under its care are false.

Koontz said the breeding program enriches the lives of the whales "by allowing them to experience, interact with and help raise another member of their pod." Kalia, he said, was artificially inseminated but also had relations with a male whale, Ulises.

The company also pointed to the research it does on marine mammals, and the rescue efforts it has mounted to save whales and other animals who are injured or harmed at sea.


(Reporting by Sharon Bernstein; Editing by Ken Wills)