Stanford Study Looks at Leatherbacks' 'Lost Years'
March 12, 2012
Stanford University marine biologist George Shillinger and his colleagues at the Monterey-based Center for Ocean Solutions have found evidence indicating that ocean currents off the Pacific coasts of Central America and Mexico may play a vital role in keeping endangered leatherback turtle hatchlings safe.
The odds are against Pacific leatherbacks from the very start, even before they crawl from their shells. Beach-prowling predators raid their nesting grounds or wait to pounce on these fragile newborns during their perilous trek to the shore. Many never make it to the water, but the lives of those that do remain shrouded in mystery until their return 10 years later to the beaches of their birth, where they mate and make nests of their own.
So little is known about this 10-year period that biologists call them “the lost years.” But in order to combat the critical decline of this elusive species, we need more information about this aquatic-life stage. Biologists estimate that on average, only 1 in 1,000 Pacific leatherback turtles survive to nest. It is increasingly likely that human activities, such as pollution or fishing nets, may play a major role in the species decline.
"The turtles are on edge. They're being slammed at every turn," Shillinger says. "It's useful to find out what happens to the turtles when they leave the beach, and if there are factors that help them survive."
Thanks to the efforts of Shillinger and Ocean Solutions, an important clue has been found. Stanford’s Tagging of Pacific Pelagics project has discovered that “recurrent mesoscale eddies,” or underwater currents, may act as so-called “hatchling highways,” dispersing and hastening young leatherbacks to deeper waters and away from predators that tend to lurk in the shallows.
The project’s findings were recently been published in several scientific newsletters and magazines such as the Stanford University Press, Science Magazine, and the Proceedings of the Royal Society B. Shillinger and his colleagues are advocating that these underwater super-eddies be protected under more stringent conservation policies, in the hopes of preserving the migratory Pacific leatherback.
“Once we put all of this together, we might start to really understand the life history of these turtles from emergence to adulthood," Shillinger says. "And that information helps us develop conservation strategies that link leatherback nesting beaches, hatchling highways and nursery habitats with migration corridors and foraging hotspots for juvenile and adult turtles across the Pacific."
(Hatchling photo, above, by NOAA)