Do Sea Turtles Stop and Ask for Directions?
Monastersky, Richard, Science News
Sea turtles navigating the Pacific Ocean follow the same narrow routes from year to year, as if they were migrating along thin ribbons of highway stretched out across the open ocean. This discovery, made by attaching satellite transmitters to leatherback turtles, may help scientists devise more effective strategies for preserving the dwindling populations of leatherbacks and other endangered turtles.
"Our perceptions are that the oceans are a vast, almost infinite resource. But the turtles are showing us that the resources are clustered along narrow, tight bands," says Stephen J. Morreale of Cornell University. Morreale and his colleagues identified the migratory routes by tracking eight female leatherbacks after they left their nesting site on the west coast of Costa Rica. The scientists describe their findings in the Nov. 28 Nature.
Each year from 1992 through 1995, Morreale's group studied two turtles for up to 3 months. All eight followed similar, in some cases identical, courses toward the Galapagos Islands. Even turtles traveling 3 years apart maintained the same route.
The migration path appears to go beyond the Galapagos for a distance of at least 2,700 kilometers, according to the longest-lived transmitter, which lasted 87 days.
Propelled by the dire situation of sea turtles around the world, researchers have redoubled their efforts to collect data on the behavior and biology of these holdovers from the days of the dinosaurs. Almost all of the information gleaned so far has concerned females engaged in laying eggs, because that is the only time that scientists can easily observe turtles, says Morreale. …