STRETCH

For decades, the North Pacific loggerhead sea turtle was a most enigmatic species.

Known in northwestern Mexico as tortuga amarilla or caguama (yellow turtle or caguama), it was found in large numbers in habitats along the coastal Pacific, yet no nesting beaches were known to exist in the region.

It wasn’t until 1987, when a solitary loggerhead bearing Japanese flipper tags wound up in waters off San Diego USA, that the notion of a transpacific migration was ever considered.

With the Mexico-Japan connection confirmed with genetics and more tag returns in the mid-90s, and the story of Adelita—the most famous transpacific loggerhead—in 2000, there was an undeniable loggerhead linkage between the eastern Pacific and Japan—where the turtles are known as Akaumigame.

Equipped with this knowledge, scientists are now deciphering how loggerheads actually pull off such an amazing journey. Where are the migratory routes? Which elements in their environment guide their behavior?

The Current Mission

Over the next four years, our Loggerhead Sea Turtle Research Experiment on the Thermal Corridor Hypothesis (hence our project’s name “STRETCH”) team will release 100 satellite-tag-equipped loggerheads to monitor their movements in relation to oceanographic conditions.

By learning their transpacific tendencies, we will provide vital data for aiding the protection and conservation of this unique endangered species, a responsibility that, because of its migratory habits, is shared by three countries: Japan, USA, and Mexico.

Follow the Satellite Tracking of 25 Loggerhead Sea Turtles

On July 10, 2023, we released 25 juvenile loggerheads into the North Pacific Ocean. Track their movements on the map below! Dates and times are displayed in UTC format.
For each turtle, we have adopted names originating from the regions that share their conservation: Japan, Hawai'i, Mexico, and USA.

The Motivating Study

Our landmark study, Briscoe et al., was conducted in 2021. It demonstrated the value of favorable sea water temperatures and the vast importance of ‘being at the right place at the right time’ for small loggerheads to access the perfect swim-way out of the Central Pacific and into Eastern Pacific waters of North America.

Satellite tracks of 231 juvenile North Pacific loggerhead sea turtles (light gray), including six (various colors) that migrated to the coastal waters of Baja California. The white box represents the area of the hypothesized "Thermal Corridor." Figure from Briscoe et al. 2021

Today, the emerging ‘Thermal Corridor Hypothesis’ sets the stage for our efforts
to use experimental oceanography and satellite tracking of loggerhead turtles strategically placed in Pacific high seas
waters to test the “if”, “where”, and “when” this oceanic gateway opens for eastbound loggerheads.

Loggerhead sea turtles at the Port of Nagoya Public Aquarium (PNPA).
Video credits: Dana Briscoe & Marc Rice

Fifteen of the 30 juvenile loggerhead turtles being raised at PNPA were being fed when we visited them in November. They are growing quickly and look very healthy!