Excerpts from Dr. Eva de Lourdes Edwards’ journal: April 20-21 2006: Student field trip to Culebra, Puerto Rico/leatherback turtle

Observing a leatherback

The students are divided into two groups. The first group visits Brava Beach on the first night. The second group visits Resaca Beach the following night. The groups are kept small to minimize the impact on the environment and interference with the turtles’ nesting process.

Reaching Brava Beach in the dark is an athletic undertaking—a 35 to 50 minute walk meandering through mosquito-ridden sea grape trees, mangroves, rocky hills, crevices, wet and muddy spots. Because leatherbacks are sensitive to white light, but do not register red, only red flashlights are used to observe the turtles and surroundings. Cell phones are verboten. On a dark beach, the light of a cell phone can disorient the turtles.

At about 7:30 p.m., already dark on the island, we arrive at the beach entrance and hike single file, to avoid creating excessive footprints in the sand, to the center of a half-moon shaped beach and set up camp. Everyone is paired and given hourly schedules for walking the beach, looking for nesting turtles. Two pairs leave on the hour, each pair moving in opposite directions from the camp. They walk to the end of the beach looking for clues of nesting turtles from the shore to the vegetation line. The major clue to a leatherback’s presence is the tractor-like prints left in the sand as it lumbers up the beach. Carrión-Colón mentions that the leatherback sometimes moves inland to the vegetation, then turns back to select a nesting spot midway between sea and vegetation.

We are instructed to flash twice towards the center if a turtle is found. We are to observe from a distance until the guide and his assisting student arrive. The turtle is not to be disturbed until she starts nesting. Then she goes into a trance-like state as she lays the eggs, and we can all approach her. Those remaining in camp rest and sleep on towels until it is their turn to scout, or a leatherback is sighted.

It is difficult to search for a leatherback in the dark. Even though their carapace length can be between 1.2 m (4 ft) to 2.4 m (8 ft), and weigh between 226 kg (500 lbs) to 907 kg (2,000 lbs), their coloring camouflages well with the sand. On two occasions students confuse large beach rocks and fallen palm fronds with turtles.

The temperature in May in the tropics is very pleasant, but at night with a strong breeze from the east, it feels cold. Students trying to rest and sleep on their towels complain of the coldness. On the other hand, they are thankful that the breeze dissipates the mosquitoes. Most of the students in this group, Jorge Alicea, Sarazel Cardé, Aidylmari Lacroix, Josué Leduc, Carmen Moyet, Wilmarie Pérez, Marline Tolentino, Yarely Torres, Luis Umpierre, and Gladys Vázquez, have never been to Culebra, and those who have, have never visited an isolated beach at night. They marvel at the many stars visible from the beach even though there is a half moon in the horizon and count falling stars to pass the time.

Counting and measuring

The 1:00 a.m. pair heading west discovers the first leatherback and flashes twice towards the center. The leatherback proceeds to dig the nest, about three feet deep, and packs the walls of her nest with her flippers. It takes those in the center camp a good 15 minutes to reach the site.

Students Umpierre and Moyet observe the leatherback in her nesting. That is the reward for finding her. “I held her left flipper and Luis the right one, and we counted the eggs,” says Moyet. There are 98 eggs in total; 68 yolked and 30 smaller yolkless. This particular turtle measures 1.6 m (5.4 ft) long, small in size by leatherback standards. It is estimated that she weights 455 kg (1,000 lbs). She has lacerations on her carapace, possibly due to a shark attack.

Nesting takes between one to two hours. The turtle then covers the nest with sand using her flippers. We step back to avoid getting blasted by the sand. The leatherback proceeds toward the sea, but no longer in trance, perceives us and heads back toward the nest. The group leaves the nest area and she returns to the sea. Students leave a buried pole to identify the location of the site. During the daytime, someone from the Culebra project will return to mark and fence off the nest to protect it from people.

As students observe and measure, they notice what appear to be tears from the leatherback’s eyes. These are secretions of excess salt that occur in and out of the water. While the turtle is in trance, students are allowed to touch her and observe her closely. “It was incredible to see such a special, large and prehistoric creature in front of us,” says Leduc of the experience. “At first I felt fear seeing such an enormous animal, but then I relaxed when I learned that she was harmless,” adds Vázquez.

The data collected by students for the Culebra research project goes to the data bank maintained by the Puerto Rico Department of National Resources’ Division of Wildlife says Miguel García, Ph.D, director of the division. Data such as the number of turtle nests and number of nests in a year are shared with other researchers throughout the world, to assess areas where the numbers have increased or decreased, or where leatherbacks have disappeared altogether. The data collected by the Culebra research project was shared in April at the 26 th Annual Symposium on Sea Turtle Biology and Conservation on the island of Crete, in Greece.

After finishing their research, and all the information on this particular leatherback has been documented for the Culebra project, students leave the beach area around 4:00 a.m. The walk back from the beach seems longer and more arduous than before, but everyone is in high spirits because of the experience.

Proposing solutions

While in Culebra, students also visit Flamenco Beach and Zoni Beach. These beaches have sections for nest sites, cordoned off by fence-like lashed poles. Besides our students, other groups are part of the solution to protect the habitat of the Culebra leatherback turtle.

Our second group of students visits Resaca Beach the following night. They include Zuleyka Agosto, Damaris Báez, Myreliz Díaz, Alexander Rivera, Luis Santos, Shakira Santos, Gary Torres, Ramón Torres, and Ana Vázquez. Cynthia Corujo, academic coordinator of the SSS and Carlos Carrión, another local guide and the son of the first group’s guide, accompany the students in what is an even more difficult hike to reach an isolated nesting beach. Corujo has been in charge of organizing this academic and cultural activity with the Culebra project for the past four years. This second group follows the same process of setting up a center camp and walking the beach in pairs. But they do not spot any leatherbacks that night.

Students discuss why the numbers are dwindling. “We become aware that the majority of the species in danger of extinction are in this situation because of us, due to our ignorance,” says Báez. There is much speculation as to why the numbers of nesting turtles have diminished worldwide. Increased human presence, coastal development with artificial lighting, human waste discharge into aquifers, industrial pollution, and concomitant global warming may contribute to the leatherback’s demise. Environmental protection is part of the solution. Leatherback turtles eat mostly jellyfish. Many have been found dead with a plastic bag in their stomachs, possibly because they confused it with a jellyfish.

Fishing nets are a major culprit in dwindling numbers of leatherbacks because these turtles cannot swim backwards and are unable to extricate themselves from nets. Culebra has fines of up to $100,000 and jail for catching leatherbacks, purposely or accidentally. Students meet with older people from Culebra who tell that in their youth they used to eat the eggs in omelets, though they claim these are not as tasty as other types of turtle eggs. These eating habits are changing with younger generations.

The hatchlings become male or female based on the surrounding temperatures. Sand temperatures above 29.5 º C (85º F) in embryonic stages produce more females, and below 29.5 º C (85º F) more males. Temperatures fluctuate within the nest. As temperatures rise globally, more females than males are hatched, affecting the reproductive cycle of the leatherbacks.

Students become aware that this endangered species is not just a Culebra problem, but a global one. The leatherback may take a full year going up the Gulf Stream, the river within the sea, and another year to return. It touches and it is touched by waters worldwide and affected by people across continents.

Professor Eva de Lourdes Edwards is the Director of the Student Support Services Program at the College of General Studies at the University of Puerto Rico, Río Piedras Campus.

eedwards@uprrp.edu