The Night Shift
Graduate Student UNC - Department of Biology
When summer rolls around, most people begin to look forward to lounging at the pool, trips to the lake or the beach, and fireworks on July 4th. But while you’re sipping piña coladas poolside, I’m keeping the schedule of a vampire. Every summer I become nocturnal, meaning my sleeping hours become reversed: I stay up until the early hours of dawn and sleep from sunrise until 3 in the afternoon. It sounds crazy, right? However, if you’re researching sea turtles, it’s a little bit of a must. In most of the U.S. April through October mark loggerhead sea turtle nesting season. Female sea turtles nest at night, and when it comes time for the nests to hatch, well, they also hatch at night.
My first seasonal nocturnal schedule was the summer before my senior year of college; I worked on a research project sampling and identifying nesting loggerhead turtles in the Florida Panhandle. The project was a long-term turtle monitoring project through the University of Florida and USGS, and was run in part by my undergraduate research advisor Dr. Ray Carthy. Because the project was based through UF, I was able to collect data for my undergraduate research thesis during that summer as well. Along with myself, there were six other researchers working on the turtle monitoring project, and we all lived in a tiny beach house, the Fish Inn. The Fish Inn was a typical field research house – designed for work and not for play. All of the windows in the bedrooms had tinfoil taped over them, as a way of blocking out the light, since we slept during the day, and there were about four beds crammed into each room. The house had two refrigerators to accommodate all of us, and there was always sand on the floor so many feet constantly trampling between the house and the beach. Outside the house, the driveway was filled with multiple ATVs and a huge pick-up truck. In order to find sea turtles on the beach for sampling we would drive ATVs up and down the beach all night.
The main goal of the project was tagging every nesting sea turtle. Tagging simply means identifying individual sea turtles. Each turtle is given a specific identification number, by applying two types of tags. One tag is a small electronic chip inserted under the skin, called a PIT tag, and is similar to the ones put in pets. The second tags are metal tags with a unique letter and number code engraved into them, these are applied to the front flippers of the turtles, and look like cattle ear tags. When these tagged turtles then return in future years to nest, they can be reidentified by the presence of their tags. These types of studies are officially called tag-recapture studies, because the animals are ‘tagged’, to identify individuals, and then ‘recaptured’ when they return to the beaches to nest in the future. These types of studies provide essential information about sea turtle population numbers, the number of nests a turtle lays in a season, the geographic locations where the turtle lays those nests, and how frequently turtles return to nest. For instance, tagging studies showed us that in one nesting season sea turtles lay as many as 5-7 nests. This information was crucial in informing conservation practices, as it indicates that simply counting nest numbers doesn’t provide an accurate assessment of the status of the breeding population.
When tagging the turtles, often other types of data, such as turtle length, or skin samples, are often collected in concert with the tagging process. Skin samples are taken as a means of genetic sampling, and are used to determine which nesting populations are genetically distinct, or in other words, from different lineages. This can then inform which regions of coastline should be considered separately for conservation practices. For instance, the turtles nesting in North Carolina and South Carolina are a genetically distinct population compared to the turtles nesting in South Florida and are considered a different management unit in terms of conservation measures.
Until that summer, I had yet to observe a sea turtle laying her eggs. I’ll never forget the first nesting turtle I saw. When we came across the turtle, she had already crawled out of the water, most of the way up the beach. We spotted the turtle’s tracks across the sand in the red ATV headlights, and then we slowly crawled up the sand behind her, to observe and then tag her. When we reached the turtle we found her making a body pit – this is when the turtle settles down in the sand, throwing sand away from the area. Then she began digging her egg chamber with her rear flippers. She scooped the sand out with one rear flipper, and then flicked some more sand away with the opposite one. This motion was then repeated on alternating sides until she dug a suitably deep egg chamber. When she finished digging, she pulled both rear flippers out of the egg chamber, paused and then her rear flippers began to flex upwards in tandem. Three or four flexes later, perfectly round, white eggs began to drop into the nest. We waited patiently for the turtle to lay 5-6 eggs, at which point she entered a sort of trance, and was largely oblivious to everything else going on around her. Because of this all tagging and sampling is conducted when turtles enter their egg-laying trance.
We measured both her carapace, or shell, length and width. Then we applied the PIT tag, the electronic microchip, in her shoulder, and the metal flipper tags to her two front flippers. We also took a skin biopsy, which is a small sample of skin, for genetics. When the turtle finished laying her eggs she started to cover up her nest. To do this, she starts by using her rear flippers to scoop sand back onto the nest, and then pats it down. Once she did a preliminary covering of the eggs she began to fling sand over the nest by wildly swinging her front flippers back and forth. We watched her finish the covering process and then continued driving down the beach looking for more turtles.
Since that first turtle, I have seen hundreds nesting, but it never ceases to be an amazing process to watch. That summer flew by – I spent my nights tagging turtles and my afternoons gathering data for my undergraduate research project. I was absolutely certain by the end of the summer that researching sea turtles was the career path for me. I set my sights on continuing to pursue it, and would go on to spend two more summers tagging turtles. One summer was spent tagging loggerhead turtles again with Mote Marine Laboratory in Sarasota, Florida, and another summer was spent tagging leatherback turtles in Juno Beach, Florida with the Loggerhead Marinelife Center.
Despite the fact that turtle research means keeping the hours of a vampire when everyone else is enjoying the sun, I knew with absolute certainty after that first summer, that no matter how many sea turtles I watched nest in the future, or how many nests I saw emerge, I would always find it to be an incredible experience to witness.
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Ph. D Candidate at UNC