Whale researchers are celebrating a newborn orca in the waters off San Juan Island in Washington state.

The newest member of a population of endangered killer whales that frequent Puget Sound was observed over the weekend swimming between two adult females, most likely the orca's mom and aunt.

Ken Balcomb with the Center for Whale Research says the orca probably is less than 1 week old. Researchers don't know yet whether it's a boy or a girl.

Balcomb says the new baby is reason to celebrate after two whale deaths this year. But he cautions that orcas are still struggling because of pollution, lack of food and other reasons.

Balcomb says the newborn orca, designated L-120, brings the number of killer whales in the Puget Sound population to 79.