The killer whale who swam with her dead calf for 17 days in an apparent act of grieving is a mother again.

Tahlequah, known to researchers as J35, gave birth to a calf last week, according to a news release from the Whale Research Center.

The two orcas were spotted swimming with their pod in the eastern Strait of Juan de Fuca, between Washington state and Vancouver Island, over the weekend, the release said.

Tahlequah made headlines in 2018 when she swam about 1,600 kilometres of ocean with the body of her dead calf. The calf died a few hours after birth, but the mother prevented it from sinking for more than two weeks.

Both Tahlequah and her new calf, named J57, appear healthy, the Whale Research Center said.

"She was still capable of producing a live calf after an approximate eighteen-month gestation! Hooray!" the release said. "Her new calf appeared healthy and precocious, swimming vigorously alongside its mother in its second day of free-swimming life."

Researchers believe the calf was born September 4 because its dorsal fin was upright when it was spotted, a development that occurs about two days after birth because it's folded over in the womb.

With the birth of J57, the endangered Southern Resident orca population is now 73, according to the Whale Research Center.