SAN DIEGO -- It will soon be time to break out the baby booties -- or whatever it is that baby whales wear -- at SeaWorld San Diego.

The park announced Tuesday that its 9-year-old killer whale, Kalia, is pregnant with her first calf.

SeaWorld spokesman Dave Koontz says the baby is due in December.

Koontz says Kalia was artificially and naturally inseminated. Park officials aren't sure which method worked.

They do know the father is Ulises, the park's oldest male killer whale at the age of 30-something.

There have been six successful killer whale births at SeaWorld San Diego since 1988. There have been 31 at all SeaWorld parks since 1985.