Sea Turtle Ecology

Wishing for a Leatherback
by -- April 23rd, 2012

On Friday morning, April 20th, we and two more technicians all piled into the two boats from Thursday for a cozy ride to Manglar Bay on the eastern tip of the island of Culebra. There, we snorkeled in the bay while Carlos and the others set up the tangle net so that we could catch more turtles for the saturation tagging project. The visibility in this bay was not the same caliber as Culebrita, but for the area it was a good day. There was plenty of sea grass at the bottom, which we hoped meant lots of green turtles. The group pulled 5 green turtles out in about a half hour, but we had to cut our efforts short because group members on the boat spotted a manatee. Unfortunately, once a manatee is entangled, it will drown almost immediately, so it was important to avoid the encounter of this endangered animal with the net. We also found some eagle rays caught in the net, which we helped free with a little maneuvering of the net. After the net was aboard, most of us made the long snorkel back to the dock across the bay where we tagged the turtles and took similar measurements as the day before.

A green turtle on a lifesaver with exceptionally beautiful counter shading

Green turtles in line for examination

The reason we spent so much time doing in-water surveys of green turtles over the past two days has to do with the reproductive value of foraging juveniles. These juveniles have survived the high mortality of the hatchling stage and have not yet reproduced. Consequently, they have the most potential to reproduce and propagate the population. These tagging efforts also allow researchers to look at the growth rates of recaptured turtles and see if the same turtles come back to the area to forage. Interestingly, Carlos told us that he tagged a dinner-plate sized turtle in Puerto Rico as part of the in-water tagging program, and then said it was recaptured nesting in Panama approximately 16 years later! This means we can approximate how long it takes for turtles to reach maturity and we can see their migratory movements from tag returns.

We all released the green turtles as Mike and Katrina video tapped and took pictures of their rapid getaways.
watch a video here >
Afterwards, we returned to the house for quick showers and a lunch that consisted of chips and salsa, PB &J and fruit. Everyone tried to nap in the afternoon since we knew that we would have a long night of patrolling. We had an early dinner at a bar called El Batey, but it took a little longer than we anticipated for everybody to get their food. We came back to the house and changed into warmer clothes, since Wendy warned us that even though we are in the tropics it can still get cold and windy on the beach at night. We packed our bags with some yummy snacks and caffeinated sodas and split up and got into three jeeps and headed to the three beaches we patrolled: Kristin, Abi, Katrina, Jen, Carla, and Christian went to Brava Beach, Angela, Natalie F., Sasha, Scooby and Wendy went to Resaca and Natalie A., Mike, Alyssa, Alie, and Rita went to Zoni beach.

The group with our turtles for the day

Wendy and Jen releasing a green turtle

A green turtle swimming away after we released it

Resaca beach proved to be a difficult destination. The hike down was tricky with large crabs, large rocks and only a few injuries. The stars were beautiful and we saw several that lit up the entire night sky. Unfortunately, we did not encounter any turtles, but we did learn later that one leatherback nested at Flamenco beach not too far away. We began the evening with camp at one end of the beach, but as the wind died down and the mosquitoes began their attack, we relocated to the middle of the beach. We took half hour rests between walks and waited at the ends of the beach for about 20 minutes. Aside from a few stumbles, the night was uneventful, and we headed back to the house (after making the hike back up and taking a few wrong turns) around 5:15 am.

At Zoni, we paired up and took turns walking half the length of the beach every 25 minutes with an hour break after two shifts of walking. We didn’t see any nesting leatherback turtles that night but it was still an awesome experience; we also saw upwards of 12 shooting stars in the 9 hours that we were on the beach and the Milky Way also become visible after about midnight. Sitting on the beach all night, staring at the stars and noticing that the big dipper changed orientation as the night progressed was such a humbling experience. There were also some blue bioluminescent organisms in the sand that lit up when we stepped on them, which made the walks entertaining. We saw the sun start to peak out over the clouds on the beach before we drove back to the house and slept from 6 am to between 11 and 12 pm.

The sunrise over Zoni beach

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