Spotters for the ACS-LA Gray Whale Census and Behavior Project saw five orcas harass and chase a gray whale about a half-mile off the nearby Palos Verdes Peninsula on Wednesday.
The ACS-LA volunteers watched the action from the while others observed from nearby boats, including the Redondo Beach-based .
Alisa Schulman-Janiger, who runs the project, told Pete Thomas Outdoors that one adult and four younger killer whales were involved in the confrontation.
In a message to a Patch reporter, she said that spotters had been tracking the gray whale for some time when the orcas appeared.
"They were approaching each other at 'normal' speed, on a course that looked like they would intersect," Schulman-Janiger wrote. "When they met, there were a few minutes (no more than five) of splashing, with the gray whale sticking its head up and half of flukes and/or pectoral fins. Then they separated, with the orcas continuing on their original course."
The gray whale then slowly headed for a nearby kelp zone, she said. "It rolled and fluked and milled there before moving on south past our viewing spot."
The researcher said the whale did not appear to be injured.
Diane Alps, who works as the programs coordinator for the Cabrillo Marine Aquarium in San Pedro, wrote on Facebook that after the orcas moved on from harassing the gray whales, the group killed a sea lion and joined up with five other orcas.
An "adult gray whale is a pretty tough battle for killer whales," Alps wrote in a comment on her Facebook post. "Usually, they prefer small calves [and] pinnipeds."
The group, which has been spotted over the past week in Southern California, were seen in El Segundo later Wednesday.
Orcas, commonly known as "killer whales," actually belong to the family Delphinidae and are the largest dolphins. The giant mammals can swim up to 30 mph and eat up to 5 percent of their body weight—about 500 pounds, on average—every day.
Transient orcas are more often seen off Monterey, but lately they’ve been spotted more frequently off Southern California.
Coming up next on Hermosa Beach Patch—we'll have video of orcas putting on a show.