Underwater Dinosaurs: Tracking the Loggerhead Turtle

Academy herpetologist Wallace J. Nichols is working with fisherman and using the latest technologies to help save threatened loggerhead sea turtles.

Loggerhead turtles have swum our oceans for 100 million years, inspiring folklore, songs, and art from Japan to California. Yet, not much is known about them.

Nichols knows why. Using a satellite tracking system, he has discovered that loggerheads born on Japanese beaches migrate 6,000 miles across the Pacific Ocean to Baja California, where they feast mainly on palm-sized pelagic red crabs (Pleuroncodes planipes). The transoceanic journey may take up to six years to complete.

They remain here until they reach maturity, about ten years, then navigate back to their natal Japanese beaches to mate and nest.

photo: fishermen with loggerhead
Rodrigo Rangel, fisherman, with J Nichols, right, releasing a black turtle (Chelonia mydas ) in Bahia Magdalena in lower western Baja California. Photo credit: Terri Garland Photography/trtletears@aol.com

Using noninvasive "critter cams," Nichols will get an ever clearer picture of loggerhead turtle behavior. To deepen your knowledge of loggerheads and other sea turtles and to track their movements visit Nichols' Web site at www.wildcoast.net.

map of loggerhead migration
Map of loggerhead migration route in the Pacific.

 

 

photo: loggerhead and mackeral
Migrating loggerhead turtles (Caretta caretta) probably navigate using the Earth's magnetic field. This adult is escorted by a school of juvenile jack mackerel.
Photo credit: Mike Johnson /earthwindow.com

But Japan's nesting loggerheads are rapidly declining, as the turtles are vulnerable to fishing all along their range, from the coast of Mexico, to the deep ocean, to their nesting sites in Japan. Plastic bags are another serious threat; they look like jellyfish, a favorite of loggerheads, and tend to accumulate along the same current the turtles follow across the ocean.

Nichols works closely with fisherman, building upon their knowledge and skills to catch, tag, and recapture the turtles, even sometimes turning them into conservationists: two top poachers in Baja recently joined his team.

Photo: loggerhead waiting for release
"Bety," loggerhead turtle, in her holding tank after the satellite transmitter was affixed. Researchers made sure it adhered properly before releasing her. The note on the transmitter is in Japanese and Spanish. Photo credit: Terri Garland Photography/trtletears@aol.com

 

photo: school children from education program
At the research center in Baja California the Wildcoast project conducts sea turtle education programs. Children learn about the five sea turtle species that occur in the region and how to measure them. At this meeting, children named one of the turtles being tracked "Max."
Photo credit: Louise Brooks/ wildcoast.net