The Missing Biography: Where Do Baby Turtles Go During Their 'Lost Years'?

The life of a sea turtle begins as it hatches within the buried sand and instinctively sprints into the water amidst a gauntlet of predators. But many survive... then vanishes, their movements secretly held by the vast ocean.

Depending on the species, a sea turtle spends 1-15 years in the open sea, the so-called ‘lost years’ — the period that ensues after the turtles break free from their eggs to reach the open ocean until the time they come back as large juveniles to their feeding grounds near coastlines. Scientists find it critical to understand this because it serves as the foundation of sea turtle populations. Sea turtles live long lives so understanding this missing part of their ‘biography’ and the threats they may encounter is important to inform conservation efforts and guide policies.

According to Katherine Mansfield, who has studied turtles for more than 20 years, the challenge in completing the turtles’ biographies is that it’s just difficult to survey an entire ocean.

But they did it.

Figure from Mansfield et al. (2014)

She and her team of researchers from the University of Central Florida fit 17 newborn loggerheads with tiny satellite tags. It took them a long time to perfect this. What they realized is that turtle’s shells are made of keratin (as our fingernails are). So what they did is seek a collaborator’s manicurist, and, with her brilliant idea, they were able to fit the satellite tags using an acrylic base coat that seals the shell from peeling. The tags lasted for more than 7 months.

These efforts produced a map which clearly shows the movements of loggerheads for 27 to 220 days.

What Mansfield found out is that the basic overall pattern of movement of loggerheads coincides with previous knowledge, but there were significant nuances in the path each individual turtle takes. 

For instance, contrary to common knowledge that turtles go straight and fast to the North Atlantic Gyre (and they’re mostly right), it turns out they took their time running in local circles, even taking them away from the gyre to the Sargasso Sea.

Sargassum, a type of brown algae, is a favorable habitat for baby turtles since it provides shelter against predators. It's also a haven for the cold-blooded turtles because the warmer waters of the seaweed-filled surface allow them to grow faster and reach sexual maturity earlier.   

Unraveling clues where baby turtles go during their 'lost years' and have it mapped out has been a feat for Mansfield and her team. There are more questions though. So after 5 years, she and a large team of researchers  took it a notch higher.

They developed a computer model that predicts where sea turtle hatchlings go after they leave Florida's shores.

That's for our next blog.

Stay tuned.

Keen to learn more about these fascinating turtles? You can learn more HERE.

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Mansfield, K. L., Wyneken, J., Porter, W. P., & Luo, J. (2014). First satellite tracks of neonate sea turtles redefine the ‘lost years’ oceanic niche. Proceedings of the Royal Society B: Biological Sciences, 281(1781), 20133039.

Putman, N. F., Seney, E. E., Verley, P., Shaver, D. J., López‐Castro, M. C., Cook, M., ... & Peña, L. J. (2019). Predicted distributions and abundances of the sea turtle ‘lost years’ in the western North Atlantic Ocean. Ecography 42:1-12.

Science Daily (2019 Dec 23). Where do baby sea turtles go? New research technique may provide answers. Retrieved from http://bit.ly/37Mpcls

Yong, Ed. (2014 Mar 4). Where do Baby Turtles Go During Their Lost Years? Retrieved from https://on.natgeo.com/2uM5K9I