In a First, Sea Turtles Were Spotted Nesting on the U.S. West Coast. Scientists Say the ‘Super’ El Niño Could Have Brought Them There

Two olive ridley turtles were found laying eggs on beaches in Southern California in September. In the Pacific Ocean, these reptiles normally nest farther south, often in Mexico, Nicaragua, Costa Rica and Panama

Margherita Bassi | Daily Correspondent

September 25, 2026 4:24 p.m.

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This month, Southern California hosted some very special guests—who left behind historic mementos.

On September 16, an olive ridley turtle dug a nest and laid her eggs near Seal Beach in Orange County. It represents the U.S. West Coast’s first known natural sea turtle nesting, according to a social media post by the National Oceanic and Atmospheric Administration (NOAA) Fisheries West Coast. Then, three days later, a sea turtle of the same species was seen doing the same thing close to the Huntington Beach Pier, just a few miles south of the first observation.

“What happened this week—and we’re very excited about—is there’s never been a recorded instance of any sea turtle nesting on a California beach,” Aquarium of the Pacific President and CEO Jeff Flocken tells SFGate’s Olivia Harden. “And we’ve had two confirmed sightings of an olive ridley hauling up onto the beach and nesting—digging a hole.”

“Typically, the most north we know of any olive ridley or any sea turtle that nests are in Mexico, so this is quite a bit farther north for them,” he adds.

The first olive ridley was found by lifeguards, Flocken tells the outlet. Different lifeguards spotted the second turtle at Huntington Beach a few days later, Trevor McDonald, marine safety division chief for the Huntington Beach Fire Department, tells Sara Cardine at the Daily Pilot, published by the Los Angeles Times. Experts initially wondered whether the same turtle graced both locations.

They found clarity after Cali Turner Tomaszewicz, a biologist at NOAA’s Southwest Fisheries Science Center, carried out a photo I.D. analysis, according to another social media post by NOAA Fisheries West Coast. Comparing body shape, numbers and locations of barnacles, and shell scale pattern revealed that the turtles were, indeed, two distinct individuals.

The nesting sites have been fenced off and are being monitored by authorities during their typically 45- to 60-day incubation periods, according to the agency, which urges people to keep their distance to avoid disturbing the eggs. These measures can’t protect the nests from every threat, however.

“The biggest hurdles these developing baby turtles face will be cold temperatures as we get deeper into the fall, and the potential for inundation from the extreme high tides that are common this time of the year,” Jeff Seminoff, a marine ecologist at NOAA’s Southwest Fisheries Science Center, explains in a social media post by the City of Huntington Beach.

Olive ridleys are among the smallest sea turtles on the planet. Adults weigh up to 100 pounds and grow to around 2.5 feet long. They’re also some of the most abundant and widespread sea turtles, primarily inhabiting tropical regions of the Pacific, Indian and Atlantic oceans.

However, compared to their estimated historical numbers, their populations have decreased drastically. Experts suspect that up to ten million of these turtles once swam in the Pacific Ocean. Today, a fraction is left. A popular nesting beach in southern Mexico hosts an estimated 450,000 nesting females, while two beaches on Costa Rica’s Pacific coast host around 600,000.

So, why did the two turtle mothers pick California for their nesting sites?

That’s the “million-dollar question,” Justin Viezbicke, California stranding coordinator for NOAA, tells the Guardian’s Lois Beckett. One possible explanation is that a recent hurricane caused the turtles to lose their way. Warmer coastal waters and other effects of the “super” Niño also could have contributed, he adds.

Seminoff agrees that this naturally occurring climate swing, which is predicted to become extremely strong this season, probably played a large role. But that might not be the whole story.

“If we know anything about sea turtles and how they navigate and how they move throughout the oceans, we know that they use multiple cues,” he tells KTLA’s John Ross Ferrara and Chip Yost.

“It’s not just temperature or warm water. They also use an internal compass, sort of an internal GPS in their brain. They’ll respond to wave direction and wavelengths of those prevailing currents. They’ll respond to food availability,” Seminoff notes. “So, it could be a lot of different things.”

Margherita Bassi is a freelance journalist and trilingual storyteller. Her work has appeared in publications including BBC Travel, Discover magazine, Live Science, Atlas Obscura and Hidden Compass.