Megapod of orca off Palos Verdes - 12/04/13

PALOS VERDES, CA - A megapod of whales off the Palos Verdes Peninsula stymied researchers for nearly an hour Wednesday afternoon until the mammals were identified as a large group of offshore orcas, according to posts on the American Cetacean Society's Los Angeles Chapter Facebook page.The orcas were spotted at about 2:30 p.m. 5-6 miles off Point Vicente in Rancho Palos Verdes. At first, volunteers with the Gray Whale Census thought they might be migrating humpback whales, but a closer look changed the volunteers' minds.Schulman-Janiger positively identified the type of orca via photographs from a whale-watching boat out of Long Beach's Harbor Breeze Cruises, as well as video from an ABC7 helicopter.The megapod contained at least 30 orcas, Schulman-Janiger wrote.(photo credit: Getty)"They traveled in subgroups spread out over a wide area and moved further offshore, so they were difficult to track," she said. She later added, "There may be over 100 whales spread out over more than 10 miles!"The largest species of dolphin, orcas are commonly known as killer whales. Though transient orcas—also known as Bigg's killer whales—occasionally visit the South Bay, those spotted Wednesday were "shark-eating offshore type killer whales from British Columbia," according to researcher and Gray Whale Census director Alisa Schulman-Janiger. "We last sighted some of this type of orca Jan. 29, 2012."There have been fewer than 80 sightings of offshore orcas recorded in California over the last 30 years, she said.There are approximately 500 orcas in the offshore orca ecotype; through her research, Schulman-Janiger has identified more than "300 of these small orcas with rounded dorsal fins in (California) waters" over the years. "Nearly every time we see them, there are new whales not encountered before!"Though they primarily eat sharks, especially sleeper sharks, the offshore orcas are known to eat opah and halibut.The megapod sighting came only a few days after a group of transient killer whales visited the area. The CA51 family of orcas is well-known to researchers in the area; members of the matriline have been spotted multiple times over the past several years.Gray Whale Census volunteers at Point Vicente also spotted three southbound gray whales, one northbound gray whale, a humpback whale, common dolphins and Risso's dolphins. The annual census tracks the number of gray whales migrating close to the Palos Verdes Peninsula from December through May.Don't forget to like Palos Verdes Patch on Facebook and follow @PVPatch on Twitter!