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

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. 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. 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. 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.