Point Reyes Light - December 5, 2002

Tropical sea turtle visits Tomales Bay

By Chez Shadman

An olive ridley sea turtle, thousands of miles north of its normal territory for this time of year, showed up on Shell Beach I in Inverness for 40 minutes Thanksgiving Day.

Equally extraordinary, biologist Reuven Walder from the Forest Knolls-based Turtle Island Restoration Network happened on the beach with his family when the 2.5-foot turtle crawled out of Tomales Bay. Luckily Walder had his camera along.

"We were sitting on the beach when we saw its head poke out of the water only 30 feet offshore," Walder told The Light afterward.

While it is normal for an olive ridley turtle to travel alone for thousands of miles, it is an unusual to spot one in Northern California.

Should be in tropics

"The olive ridley sea turtle is normally found in warmer waters off the coast of South America this time of year," said Sarah Allen, science advisor to the Point Reyes National Seashore. "We’ve had them on the coast before, but not in Tomales Bay."

The fact that this turtle was spotted in Tomales Bay probably has something to do with warmer water forced north by El Niño conditions in Central and South America.

The turtle disappeared after crawling off Shell Beach, and Walder on Wednesday said it had at least a chance to survive by getting back to warmer waters. However, Steve Brorsen of the Monterey Bay Aquarium was more pessimistic.

"The turtle was probably following a warm current leading to Tomales Bay," Brorsen said. "The current most likely disappeared leaving the turtle cold, stunned, and stressed."

Brorsen and Walder both speculated that the turtle came ashore to get out of Tomales Bay’s cold waters. "Unfortunately, I don’t think the Tomales Bay shore gave the turtle the warmth it was seeking and that could be potentially hazardous for the turtle’s life," Brorsen said.

How El Niño works

Allen and Walder attributed the turtle’s being so far from the tropics to an El Niño event. Winds in the tropics normally blow from the Americas westward to Asia, pushing a swell of water ahead of them and causing sea level in southern Asia to be slightly higher than on the west coast of Central and South America.

Periodically, however, the winds die down and the swell of water sloshes back across the Pacific, bringing a warm current to countries such as Peru and Chile. Once the current reaches the Americas, part of it splits north, carrying warm water and high barometric pressure to the United States.

The olive ridley sea turtle is an endangered species. However, "of the six endangered sea turtle species, olive ridleys, are thought to be the most abundant," the Sea Turtle Restoration Network reported. "They are still endangered because there remain only a few nesting sites worldwide where they congregate in large numbers.

Many of the turtles die when they become ensnared in fishing nets. Also contributing to their decline are egg poachers.

Point Reyes Light Cover | News | Coastal Traveler