Sea Turtle Ecology

“I Like Tourtles”
by -- April 28th, 2012

On April 25th, after a night of cleaning and packing with full stomachs, we lay fast asleep in our beds when we got a call from Scooby and Rita about a leatherback at Zoni! “She’s almost done,” was the message relayed through the rooms as we rushed to prepare ourselves for the beach. We hopped in the two jeeps, Clifford and Delfin, and rushed to the site. Jen gave us a quick run down of dos and don’ts, explaining things that might deter the turtle or cause her to rush the nesting process. At a jog we made our way down the beach where we found Scooby, Rita and two friends of Abbie’s, watching the leatherback camouflaging her nest. Rita explained that it was best to have as few red lights on as possible and to only shine them above the turtle. She also asked that we whisper to avoid scaring the turtle. One by one, each of us was able to feel the turtle’s flipper and leathery carapace. We were also able to get a closer look at the turtle’s face and see a set of propeller wounds on her left side, proving the resiliency of the sea turtle, but also that humans can have extensive negative impacts on these animals.

Leatherbacks do exist! With a head like a dinosaur...

The nesting process has seven distinct steps: arriving, body pitting, digging, laying of eggs, covering, camouflaging and reorienting to the ocean. Although we were only able to see two of these steps, Wendy and Jen gave us a good overview of the ones we missed. Arriving and digging are exactly that, while body pitting is when the turtle pushes away dry sand to begin the digging process. This is comparable to making a snow angel, since the turtle uses both front and back flippers simultaneously. While laying the eggs, turtles are thought to be in a trance. This is why, despite people around them, leatherbacks are not always frightened away. During laying, researchers also place tags on the rear flippers of leatherbacks. After the clutch is in the nest, the turtle begins to cover her nest with sand. The leatherback then camouflages her nest to help her hatchlings avoid predation. The flipper movement for camouflaging a nest is unique, beginning with pushing lots of sand behind her with her front flippers. After that, she uses her back flippers in sync to push the sand around compacting the sand so that her hatchlings will have plenty of oxygen during incubation. After completing these motions a few times, the turtle turns and repeats the process in a new orientation. Finally, after all her hard work, she must reorient and return to the sea. We watched as the leatherback at first headed to the woods and then made a 180-degree turn toward the ocean. We followed her at a distance until she disappeared into the waves.

Tracks made by the female as she returned to the ocean

Despite increasing numbers of leatherbacks in the Atlantic Ocean, there has been a decreasing trend in the number of nests on Culebra. Carlos and crew think it is possible that Culebra leatherbacks are moving their nests to Fajardo (an area on the northeast coast of the main island of Puerto Rico). By tagging the leatherbacks this season, they hope they can use sightings to see if these same leatherbacks appear on the mainland. Scooby mentioned the biggest problem with this work is that the program doesn’t have anyone monitoring the beaches on the mainland, so there may not be any tags reported. Perhaps they will have researchers monitoring the mainland beaches in a couple of years when this year’s Culebra females return to nest.

Interestingly enough, this leatherback already had a PIT tag, but no flipper tags. Although it appeared the turtle might have previously had a flipper tag, this occasion demonstrates the lack of standardization in sea turtle tagging. Some programs use both types of tags, others only one, or they may use a certain type of PIT tag specific to a certain reader (not all PIT tags can be recognized by one reader, although newer readers are designed to read many types of tags). Other programs may tag only one flipper and others both. The Culebra program and many others, use three tags typically, a PIT tag and two flipper tags. The benefit of using PIT tags and flipper tags (made of either plastic of metal) is to facilitate the recognition of the turtle and the fact that it is tagged by many different people that may interact with the turtle in the future. For example, if a fisherman catches a turtle accidentally he can call it in using a flipper tag, since that is easy to spot and read without an expensive PIT tag reader. At the same time, conservationists use PIT tags because they are internal and often longer lasting, offering another way of identifying the turtle if flipper tags fall off.

One student made a good point at the end of what seemed like a dream come true; it was actually a good thing that the turtle came on our last night in Culebra. Even though it was disappointing not to see a turtle the previous four nights, that night we were all able drive over together and see the nesting leatherback. After putting in so much effort, we all wanted to catch a glimpse of a legendary leatherback, and we felt lucky she chose a beach we could drive to on a night we were all together.

All of us finally got to see a nesting turtle

After getting back to the house with an assortment of new bug bites, which were the last thing on our mind in all the excitement, we fell asleep to catch the first ferry out of Culebra. At around 5 am our morning began a second time, and we quickly ate and packed to meet the ferry to head back to Fajardo. Once we arrived to the mainland we waited for Dr. Robert Mayer, our host in Aguadilla, while having a few snacks and looking back on our time spent in Culebra.

We rode with Robert and luggage caravan from Fajardo to Aguadilla. We stopped for lunch at an outlet mall and had some down time to look around. After taking an ice cream break, we drove for another hour and made it to the hotel we would be staying at for the next two nights. It was raining hard and after a slight delay we braved the rain and settled into our rooms. After about an hour, our quest for dinner began. Santos, one of Robert’s graduate students, also accompanied us. We originally tried for Thai, but after learning there would be a long wait, we headed to another one of Robert’s favorite restaurants in the area. There we had delicious Italian styled dishes and amazing desserts. After dinner, we headed back to the hotel for a relaxing night of catching up on work, blogs, and some much needed sleep.

The colorful outlet where we spent the afternoon

The group at dinner in Aguadilla with Santos

We looked forward to what Robert and his students would present to us about their work with sea turtles and dune restoration in Aguadilla the following day.

©2016 Nicholas School of the Environment at Duke University | Box 90328 | Durham, NC 27708
how to contact us > | login to the site > | site disclaimers >

footer nav stuff