Happy World Sea Turtle Day!
To celebrate, I thought I’d tell you a bit more about what I do as a sea turtle biologist.
Today I am in the lab, working up small (half the size of a pencil eraser), skin and scute samples from hawksbill sea turtles I sampled last summer. Scutes are what make up the “soccer ball pattern” on a hard-shelled turtle’s back (dorsal) shell.
One of the beautiful hawksbills I sampled last year in Nicaragua is pictured here:
My PhD dissertation research is trying to understand where in the water hawksbill sea turtles are eating, and where they grow up. My research focuses on the eastern Pacific population of hawksbills, which includes hawksbills that live and nest from Mexico to Peru along the Pacific coast of Latin America. Specifically, I conduct my research in El Salvador and Nicaragua, where the two primary nesting beaches are for this population, one in each country. The population that I study is unique in that the female sea turtles prefer to nest in mangrove estuaries, rather than on open coast beaches – like all other sea turtles (as far as we know). This population wasn’t discovered to be nesting in mangroves until 2007! However, we don’t know much about the time spent in these estuaries outside of nesting. This is what I am trying to figure out!
Okay, so what do I actually do?
I am both a social scientist and a natural scientist, and I use methods from both fields to help us better understand where in the water these sea turtles are living. I feel lucky to get to work with the amazing people who live near my study sites of Bahia de Jiquilisco, El Salvador and Estero Padre Ramos, Nicaragua. My work would not be possible without their help and support. I am also thankful to collaborate with the amazing non-profits ICAPO and FFI.
Interviews identified where we should be able to find turtles.
I started my fieldwork by conducting interactive interviews with local fisherman in El Salvador and Nicaragua. These fisherman shared their expert knowledge on where I could find hawksbills within their local estuary, and also why they thought I could find turtles in certain places. This identified where we should be able to find the turtles.
In-water capture showed where we could find turtles at a moment in time.
I then returned to the field a few months later, and went out on the boat with some of these fisherman to look for hawksbills in the spots they indicated. When we found hawksbills, we safely captured them (we are all specially trained to do so, please do not attempt to touch or capture a wild turtle), and took the small skin and scute samples that I am currently analyzing. The capture trips taught us where we could find the turtles at a moment in time.
Stable isotope analysis shows where the turtles have been for the past few months (skin) and years (scute).
I am now working in the lab to analyze the skin and scute samples that we took for stable isotope analysis. Stable isotope analysis is based on, “you are what you eat”. The food we eat and the water we drink all has its own environmental fingerprint, when we eat or drink it, our body incorporates that fingerprint into our own tissue – like our fingernails and our hair. For sea turtles, this is incorporated into their skin and into their shell. Their shells are made of keratin, similar to our fingernails. In the lab, we can conduct analyses, called “stable isotope analysis” to extract this environmental fingerprint from the sea turtle tissues and then match that environmental fingerprint to that of the original environment it is from.
Another way to think of this is like a memory match game, when we analyze the sea turtle for the environmental fingerprint we are turning over our first card, then we look for the signature of the environments that matches that we found in the turtle. When they are matched, we can then identify where the sea turtle has been eating! Skin tissue holds the fingerprint for about 3 months, and the scutes can hold multiple years of eating history, so stable isotope analysis can tell us where the turtle has been living over time.
Why is this important?
For the turtles:
Hawksbill sea turtles are critically endangered, which means they are at very high risk of becoming extinct in the wild. In the population I study, it is estimated that there are only 500 nesting females left in the whole population (from Mexico – Peru). To better conserve these turtles, it is important we understand where they are in the water. Understanding where they are in the water helps us better protect those areas, but also gives us insight into how they grow up, what they eat, and what threats they are facing.
Sea turtles travel through different habitats, and because they do, they are also indicators of the health of those habitats, and can help us understand the health of ecosystems that can be difficult to study – like the open ocean. Oceans are important for humans for many reasons (this short National Geographic Video gives a great overview), one of which is that oceans provide food and jobs for many people around the world, we depend on healthy oceans. Understanding where sea turtles are in the water can help us monitor the health of those habitats.
How can you help?
One of the simplest ways you can help is by reducing your use of single-use plastics, as sea turtles, as well as many other terrestrial and aquatic animals, accidentally eat our trash – yuck!
Here are ways you can have a positive impact on sea turtles!
- Refuse single-use plastics, opt for reusable canvas shopping bags and reusable mesh produce bags (all machine washable!)
- Switch out your single-use plastic bottles for a reusable water bottle. They come in all colors, shapes, sizes and some are even insulated to keep your water cold all day!
- Say no to plastic straws, if you really love straws, opt for reusable and dishwasher safe stainless steel ones!
- Don’t purchase items made from sea turtle shell, they can be found at markets in other countries – but they are illegal. You can learn more about being a smart traveler here: http://www.tooraretowear.org/
My goal as a scientist is to get people excited about nature, about science, to revel in the awesomeness of nature with others, to help people connect to nature. I always aim to share the science that I do transparently, as well as the incredible science my colleagues conduct. I hope to show that anyone can be a scientist – we come from all walks of life. And I hope to inspire young girls who are excited about school, and about science, that being nerdy is awesome, it is something to be proud of!
I love to give talks to schools, zoos & aquariums and other facilites, and can do so in person or via video conferencing. I have given talks from pre-K all the way through college classes. If you are a teacher that I can be a resource for, or you know of one, please feel free to contact me!
Thank you for reading!
Happy World Sea Turtle Day!