Thursday, June 12, 2014

My First Leatherback and One Nest's Story

The #1 thing on my bucket list is to see a leatherback sea turtle – and today I got to cross that off! I’ve been fortunate enough to receive extensive nesting beach survey training during the past few weeks here on Hutchinson Island – and I have many awesome stories to share from that, but I’m going to start with this one.
The purpose of nesting beach surveys is to get an idea of the number of nests each species is laying each season and how successful those nests are. My past experience with nesting beaches was in North Carolina where the nesting beaches are primarily used by loggerhead sea turtles. In Florida, there are 3 species which are commonly seen: loggerhead, green and leatherback.
When a female leaves the ocean to lay a clutch, she can frequently be scared away by lights, obstacles such as beach furniture or large holes that people dig in the sand, or animals on the beach. When a female comes out to nest but doesn't lay a clutch, it’s called a false crawl. A typical false crawl is a U-turn, but it can be much more complicated than that.

Typical U-turn false crawl - loggerhead female.

You can tell the difference between the species of turtle which laid the nests by the way they crawl as well as the size of the crawl. I’ll show other types of nests in future posts, but here’s what a leatherback track looks like – we saw this out on the beach this morning.

Leatherback crawl, Hutchinson Island, FL.



A unique characteristic of leatherback nesting is something called an “orientation circle,” the turtle does a 360° turn after she’s done laying before she returns to the ocean.

Carrie Keske next to the leatherback orientation circle.

I love leatherbacks because they have very interesting physiology, I’ve actually written a little bit about it in a previous blog here, but this summer is the only time I’ve had the opportunity to see a leatherback because they nest mostly in the tropics, and Florida is in the most northern end of their nesting range (though they travel all over the world).

Unfortunately, sea turtle nests do not always stay intact until it’s time for the hatchlings to emerge and crawl to the ocean. During nesting surveys, we keep track of nests that have been washed over by the tide, depredated, and nested on top of by other sea turtles.
One of the earliest leatherback nests on the beach I’m helping to monitor was laid on April 3, 2014 and it hatched on June 9, 2014. During the survey that morning, we noticed that there were headless hatchlings outside of the nest – a telltale sign of depredation by raccoons.
Early deprated loggerhead nest.
Leatherback hatchling predated upon by raccoons and ghost crabs.

This sight was very sad, of course, particularly since the predators didn’t even eat the entire hatchling, only the heads. What a waste of a life. It’s frustrating to see things like this when you know that every nest is important to the conservation of the species, and leatherbacks are one of the species that needs the most help.
Though I’m becoming a scientist, my love for these creatures as individuals consumes me at times. My heart hurt for this nest. It seemed that all was lost – that all the hatchlings had been eaten and this nesting effort by the mama turtle was for not.
However, as we were surveying the damage to the nest, we noticed something.

Leatherback hatchling crawl.

One little hatchling managed to escape the raccoons and make it to the water.
Sea turtles are survivors. They face so many threats each day – and unfortunately we can’t save them all. Conservation work can be a roller coaster – we lose many battles. This little turtle reminds me that for many turtles, we are winning the war. I still hurt for those babies that we lost – and all the babies we lose to predators each season – but at least one of those little guys made it to the water in the cover of night and got his chance at survival.

Three days after the turtles hatch from their eggs, we perform a “nest excavation” in which we dig out the nest and count the number of hatched eggs, the number of eggs that didn’t hatch, as well as the number of live and dead hatchlings that are inside the nest. Live hatchlings can be left behind when the others leave the nest because they need the momentum of the entire clutch moving in unison to get out of the sand.
The purpose of these excavations is to determine hatching and emerging success of the nests for scientific research as well as rescue and release any live hatchlings that might be left behind. 

Given that the nest had clearly been dug into and most of the hatchlings had been eaten, I wasn’t holding out much hope to see a live hatchling in this excavation. Between the raccoon’s quick, agile fingers and its strong sense of smell, it seemed unlikely that any more could have evaded detection. It was a somewhat somber looking morning, while we were driving up to the nest during the morning survey, it started to rain. Though it was cold and windy, we persevered and the fearless Carrie Keske began to dig up the nest – sorting hatched egg shells, unhatched eggs, etc. into their respective piles to be counted for the data sheet.
To my amazement, we found one little leatherback hatchling that had managed to remain hidden from the predators. Finally, I got to see and touch a turtle that I’ve studied and loved from afar for so many years!
I was so ecstatic to see my first leatherback today!

Check out his little yolk sac - turtles have belly buttons too (sort of)!

After his little photo shoot, we let the hatchling crawl toward the ocean to imprint, and then away he went.


Good luck little leatherback!

Sea turtle conservation is a roller coaster. It is highs and lows – victories and defeats. Maybe most of the hatchlings in this nest were eaten by raccoons – but the track of the hatchling that escaped on its own as well as the hatchling that we rescued during the excavation give me hope that all is not lost for this nest. Luckily, female sea turtles lay many clutches a season – between 8 and 12 – so it’s likely that this female had other more successful nests this year.

Today was a victory - and a victory is a victory, no matter how small.





2 comments:

  1. "Fearless" Carrie Keske...Love it! Love the blog!

    ReplyDelete
  2. Well written! Great description.

    ReplyDelete