Folks in Puerto Peñasco, Sonora, were disappointed this week when 84 eggs laid by an Olive Ridley turtle on a pricey stretch of Sandy Beach all succumbed to the heat.
The outcome was not unexpected, said Paloma Valdivia, environmental education coordinator for CEDO, the Intercultural Center for the Study of Deserts and Oceans, based in the Sonoran beach town also known as Rocky Point.
Puerto Peñasco lies at the northern end of the turtles’ range, and summer is a brutal time for incubation.
“It was really sad that they didn’t hatch, but it’s something quite natural because at the latitude of Puerto Peñasco, we’re at the limit of ranges of nesting areas for the turtles,” Valdivia said.
The turtle laid her eggs beneath the high-rise skyline on Sandy Beach in front of a condo tower called Puerta Privada, where available units are listed from $500,000 to $1.2 million.
“It’s a little bit weird she laid her eggs here, especially in such a tourist area,” Valdivia said.
Valdivia said the month-long turtle-egg watch was a good education for residents about the turtles, which are an endangered species in Mexico.
Residents of Puerta Privada, who spotted the turtle on July 3, helped cordon off the area with a fence of rebar and wire after a horse spooked by fireworks ran through on July 4, said Mary Snyder, director of sales and marketing for the condos.
They strung rope lights to prevent vehicles from running over it in the dark, she said.
Snyder said residents joked that the turtle chose the spot because it is advertised as “exclusive and private.”
Agents of PROFEPA, the Mexican Environmental Protection Agency, watched over the area day and night, she said, bringing coolers and cots and working in shifts.
Turtle nests are often disturbed on populated beaches by vehicles and horses, or dug up by dogs, Valdivia said.
Olive Ridleys are the most populous species of sea turtle, but their numbers declined in recent decades, triggering a total ban on turtle or egg harvesting in Mexico in 1990. Adults, which have an olive-green shell, grow as large as 2.5 feet and 100 pounds.
They come ashore in large numbers to lay their eggs between June and December, with each female laying up to 100 eggs.
A site near Oaxaca annually attracts 120,000 to 200,000 females in a mass-laying event called an arribada.
Of the 84 eggs laid by this turtle, 20 developed into embryos, but none hatched, Valdivia said.
Turtle expert Jeff Seminoff said the eggs might have stood a chance with some strategic monsoon showers.
Historically, solitary turtles laid eggs in the northern coast of the Gulf of California as far as the Colorado delta, he said. The eggs need moist, but not sodden, sand to thrive.
Seminoff heads the Marine Turtle Ecology Program at the Southwest Fisheries Science Center of the National Oceanic and Atmospheric Administration.
He said the Mexican population of Olive Ridleys experienced “huge crashes” in population from the 1960s into the mid-80s.
Their eggs were harvested as a delicacy and their leather was traded overseas. Recovery programs and the 1990 ban led to “a huge recovery of Ridleys,” he said. “They are one of the success stories.”