DANA POINT – A drone video that caught three gray whales mating in the fog off the Headlands has gone viral on social media.

The footage was captured by Capt. Frank Brennan Saturday during a featured cruise following the last of a whale lecture series sponsored by Dana Wharf Sportfishing and Whale Watching as part of this year’s Festival of Whales.

“People are really interested in whales now and are more educated on the subject because of all of the recent sightings,” said Donna Kalez, manager of Dana Wharf, adding her video has already gotten more than 130 shares. “All of our lectures were sold out.”

Brennan, on the Ocean Adventure catamaran, spotted the three – two males and a female – in a clear patch of water surrounded by fog about five miles out from the Headlands. The animals were heading north as part of their annual migration to the Bering Sea in Alaska.

While most whales court and mate in the lagoons of Baja earlier in the year, Brennan said, but it’s not uncommon to catch sight of this behavior during the migration. In most cases, mating occurs with at least three animals of different sexes.

“There are usually three whales mating together because of the buoyancy issue,” he said. “Sometimes the two males compete with the female. The female could already be pregnant but still mate on the northbound trip.”

Since mid-November, whale-watch captains such Brennan have caught sight of gray whales in their annual migration from their rich feeding grounds in the Bering Sea to their breeding and birthing grounds in the lagoons off Baja. Gray whale numbers are slightly up from last year, he said.

Brennan spotted his first northbound gray whale on Feb. 7. He has not seen a northbound calf yet.

According the ACS/LA Gray Whale Census done off Point Vicente Interpretive Center in Palos Verdes by founder Alisa Schulman-Janiger, there have been a total of 1,230 southbound gray whales spotted since the group began counting on Dec. 1, 2016. They also counted 68 gray whale calves. They have seen a total of 398 northbound gray whales and one northbound calf, as of March 13.

Contact the writer: 714-796-2254 or eritchie@scng.com or on Twitter:@lagunaini