Observers of British Columbia's southern resident killer whales say the whale that made international headlines two years ago when she mourned her dead calf for weeks has given birth again.

U.S.-based groups the Pacific Whale Watch Association and the Center for Whale Research each announced the birth of the new calf with media statements on Sunday, while expressing concern that there might not be enough food available for the calf to survive.

The researchers identified the new calf on Saturday, while observing a meeting between the J and L pods of the endangered whales.

Kelley Balcomb-Bartok, spokesperson for the PWWA, said it was an emotional day and a large gathering of the animals.

“A beautiful day, lots of southern residents, and all of a sudden they get into these massive cuddle puddles and lots of social mixing,” he said.

But J35, the orca perhaps best known for spending 17 days in 2018 carrying the body of her dead calf on what the Center for Whale Research dubbed a "Tour of Grief," was keeping her distance from the group, Balcomb-Bartok said.

The observers soon notice the new calf.

“It was exciting because out of nowhere all of sudden you see this little blip,” he said, referring to the baby whale.

Researchers soon determined that the new calf was the offspring of J35, one of two J pod members that had been pregnant.

The baby has been designated J57, and researchers believe it was born on Friday. The birth brings the total population of southern resident killer whales to 73.

Both the Center for Whale Research and the Pacific Whale Watch Association expressed joy at the new addition to the population, but also stressed that the scarcity of Chinook salmon - a critical source of food for the whales - means there is no guarantee the calf will survive.

"We hope this calf is a success story," said the center in its release. "Regrettably, with the whales having so much nutritional stress in recent years, a large percentage of pregnancies fail, and there is about a 40 per cent mortality for young calves."

Marine Mammal zoologist Dr. Anna Hall gave the new calf an even bleaker 50 per cent chance of survival.

“Many times, we don’t know that the young animal has died, we often just see the family with that individual missing,” she said.

It’s not clear if the baby calf is a boy or a girl, but Hall said it is clear the birth was successful and the new calf will have a great family structure.

“At the moment, we have a very robust, very energetic looking little baby," Hall said.

With files from CTV News Vancouver Island's Alanna Kelly