Katherine Martin ’14 and Dr. Ashley Byun research how endangered loggerhead turtles in Brazil navigate to the open sea

Katherine Martin ’14 and  Dr. Ashley Byun research how endangered loggerhead turtles in Brazil navigate to the open sea

by Meredith Guinness

Katherine Martin ’14 has spent much of her senior year at Fairfield University designing and hand-stitching swimsuits — but you’re not likely to find her stretchy lycra creations in Sports Illustrated anytime soon.

That’s because they’re not designed for humans. They’re for tiny loggerhead turtle hatchlings no bigger than the palm of your hand.

Martin and Dr. Ashley Byun, assistant professor of biology, use the ingenious suits — attached to fishing line and glow sticks — to track the navigation patterns of the newly hatched reptiles as they make their way from the shores of Brazil to the open sea.

Previous researchers have shown that the pint-sized carnivores use light reflected off the water to scuttle across the sand from their nests to the surf, but how they navigate to open waters is less certain.

In January 2014, Martin, Dr. Byun, and a team of staffers from the Brazilian marine conservation group Projeto Tamar spent nearly two weeks at night on Brazilian beaches as the eggs in the loggerhead nests so popular with eco-travellers began to stir.
And stir they do.

First off, most nests contain about 100 to 120 eggs. Secondly, once born, the turtles seem hard-wired to get to the shore as quickly as possible.

“They undergo this frenzy state,” said Martin, imitating the frantic paddling motion of the hatchings’ flippers.

“They’re going nuts,” said Dr. Byun with a laugh.

And with good reason: The hatchings face a host of dangers — from fiddler crabs and seagulls to dogs, humans, and the sand buggies that often race up and down the beaches. Though it’s the most abundant turtle in U.S. waters, the loggerhead has been considered threatened since 1978 and is now on the endangered list. Only about one in 1,000 makes it to the mature breeding age of 30 years.

“It’s very important for them to get out right away,” said Dr. Byun.

Because of this frenzy of nocturnal activity, most of the research on how the turtles orient themselves to ultimately reach a protective feeding ground in the Atlantic Ocean has been based on experimental data in laboratories. Martin, a biology major in the College of Arts and Sciences from Thomaston, Conn., and Dr. Byun wanted to take the difficult, but ultimately illuminating step and study the animals in their natural habitat.

“They’re very hard to study once they hit the water because they hatch at night, they’re very small and you can’t use a light to see them because they might react to it and it might affect the way they move,” said Dr. Byun, a specialist in molecular evolution. “We had to come up with something that would track them, but that they couldn’t see and then go try it out.”

And that’s where the suits came in. They decided to use GPS to track the turtles in the water, but they had to be able to keep up with each individual and track it for a certain distance to gather data to study. Before heading for Brazil, Martin and Dr. Byun tested several ways to affix something bright to turtles and came up with a creative solution. The team attached each turtle swimsuit to a two-meter length of fishing line, which was tied to a small microfuge tube commonly found in research labs. They wrapped each tube in black tape, leaving just a thin window through which they could see a little bright glow stick stowed within. The tube would float on the on the surface, where the turtle couldn’t see the glow.

And it worked! For about 10 nights straight, Martin strode the shore, passing suited-up hatchlings to Projeto Tamar team members in kayaks. They would place the tiny turtles in the water and paddle after them with their GPS devices for a good 20 minutes before bringing them back to shore where the turtles could go about their journeys au naturel.

The team gathered data on two turtles at a time from about 8 p.m. until sometimes 2 a.m. “It can be very labor intensive,” said Dr. Byun, who has been teaching and researching in Brazil since 2011.

It is believed the hatchlings might use some combination of wave action and the earth’s magnetism as a guide. The researchers also wondered if the turtles were using sensory cues — such as what they saw — to orient themselves. It was time for another brainstorming session: How could they replicate blindness without injuring the turtles?

Martin and Dr. Byun bought some black latex balloons and cut off the ends to make tiny, waterproof blindfolds. “We could compare a blind turtle in the water with one that could see,” Martin said. “They did move differently, as if they were fine-tuning their direction. We crunched a lot of numbers on that, but we’re still sifting through the data.”

The researchers spent the spring analyzing their results, and Dr. Byun and a new group of students will expand the project by using transmitters in the next nesting season, after she’s applied for external funding. Part of the work thus far was funded by a grant for the Improvement of Post Secondary Education (U.S. Dept. of Education), as well as start-up funds provided by the University.

So why should the average person care about endangered turtles in Brazil? “Overall, you have to look at the ecological ‘big picture,’” said Martin. “If you take away one form of life, it will have ramifications that you can’t even account for. It’s better to know all we can about them.”

Dr. Byun agreed. “We’ve found it to be true over and over again that when you alter an ecosystem, the outcome is often unpredictable and typically disasterous.”

Martin, who won the 2014 Biology Department Award for Academic Excellence, enjoyed the research so much she plans to work in a lab setting for a year before applying to graduate school in 2015. “Evolution, which unites all of biology, is probably the road for me. And with the background I’ve gotten from the start at Fairfield, I’m well-equipped to do it and I already know I love it.”