As waters warm, California could see an uptick in orca sightings

Whale-watching tour boat operators across Southern California have reported an unusually large increase in orca sightings over recent weeks, which some experts say might be a sign of a shifting ocean environment along the Pacific coast. 

Multiple pods of two different species of orca — the eastern tropical pacific killer whale and the transient killer whale, aka Bigg’s killer whale — have been spotted at a much higher frequency than usual this past month, said Sara Lesser, education supervisor for the Aquarium of the Pacific’s whale-watching program. Lesser told SFGATE that she herself spotted a pod of eastern tropical pacific orcas earlier this month. 

“On the first day that they were spotted up here, I got to hang out with them, which was incredible,” Lesser said. “They’re huge, beautiful animals. They’re inquisitive and curious, so they’ll come right up to the boat and go under it.” 

Native to Mexico and Central America, eastern tropical pacific orcas come to California occasionally but typically stay in warmer waters. This year, however, the orcas have been frequenting areas from San Diego to as far north as Malibu, according to Dr. Alissa Deming, director of clinical medicine at the Pacific Marine Mammal Center. 

“It’s not completely out of the ordinary to see them, but they don’t frequent us regularly,” Deming told SFGATE. “It seems they’ve been sticking around for longer than they have in the short bursts of trips where they’ve been documented in the past.” 

Harbor Breeze, the whale-watching operator that partners with the Aquarium of the Pacific, has logged a whopping 61 orca sightings this year — up from zero in 2022 and only four in 2021. Before that, Harbor Breeze hadn’t logged any orca sightings since 2019, when 16 were spotted. Numbers comparable to this year’s haven’t been logged since 2018.

Harbor Breeze has been operating whale-watching tours in the waters near Long Beach and Orange County for nearly two decades, allowing passengers aboard its long catamaran boats to view hundreds of whales per year. These tours usually spot humpback, blue, gray and fin whales, so this year’s upsurge in orca sightings has been a treat for passengers and experts alike — though the cause of their presence might be more somber. 

The orcas’ unusual behavior this year could be due in part to warmer ocean waters, Deming said. She added that effects of climate change, like an ongoing marine heat wave and a developing El Niño system, have water temperatures at an unusual high for this time of year. 

“In conditions like this, the ocean essentially has a fever, and that might change marine mammal behavior,” Deming said. These changes could include shifts in migration behavior, meaning orca sightings off the California coast could become more common as waters continue to warm.

The behavior and survival of marine mammals are impacted greatly by even minute changes in marine environment, according to an assessment conducted by the National Oceanic and Atmospheric Administration. In terms of marine mammals in California, this has resulted in abnormalities like whale sharks, which are usually found in tropical oceans, being spotted in San Diego, along with large numbers of sea lions starving as their prey moves farther offshore, Deming said. 

“I think we will be seeing shifts in migratory patterns and population impacts. That’s why it’s important to do baseline population monitoring, so that with these warming ocean trends we can better understand how it’s impacting animals,” Deming said. 

Lesser and other experts agree that this year’s influx of orca sightings might also be related to California’s large population of common dolphins, a staple food source for the whales. 

“We have that year-round; these common dolphins don’t have a major migration. So the orcas might be getting wise to the fact that we have a high volume of dolphins, and that their prey is here, so this is a good stopping place because there’s snacks,” Lesser said.

Whatever the cause is of their increased presence, Lesser said the orcas’ extended stay in California this season has been a sight to behold. 

“It’s just an amazing thing to see,” she said.