Another year of turtles

Happy New Year, NERRds! With the new year comes new intentions and goals along with reflections of the past. While we shiver from this wet, cold weather (winter? In Florida??), huddled in our offices, we are thinking about the year we just completed (and how much warmer it was).

cold

Last year brought us new projects, like our Sentinel Site, several major hurricanes, and one more year of long-term monitoring data (whoop!). We are kicking off the new year with a guest post from a fellow GTM NERRd, Scott Eastman, where he provides a recap of our long-term sea turtle nest monitoring at the GTM this past year. He serves not only as the Stewardship Coordinator of the GTM Research Reserve, but also as the Manager of the Northeast Florida Aquatic Preserve (and is a scientific superhero, in this NERRds’ opinion).


The story of this nesting season was the impact that Hurricane Irma had on our beaches.

This year we documented a total of 196 loggerhead (Caretta caretta) nests and 17 green turtle (Chelonia mydas) nests, for a total of 213 nests documented throughout the 2017 nesting season. False crawls, or non-nesting emergences, are often good indicators for the general beach conditions. If conditions are not suitable for nesting either due to light pollution, obstacles, etc., nesting females will often return to the ocean without nesting, resulting in a false crawl. This season we documented 101 loggerhead and 6 green turtle false crawls, for a total of 107 false crawls.

 

We often look at beach success, or nesting success, as a metric for the condition of the beach. We define beach success as the proportion of nests laid to the total number of crawls on a beach. Mathematically, this is the number of nests laid, divided by the sum of nests laid plus false crawls [ beach success = nests laid / (nests laid + false crawls) ].

equation

This season we documented a lower number of false crawls than previous seasons, with a nesting success = 66.56%. For comparison, in 2016 we documented a high number of false crawls, with 208 nests and 266 false crawls resulting in a nesting success of only 43.88%, whereas in 2015 we had documented 185 nests and 83 false crawls, for a nesting success of 69.03%.

Irma satellite image
Satellite image of Hurricane Irma over Puerto Rico.

Hurricane Irma occurred late in the nesting season, thus many of the nests had already emerged prior to the storm. Before Hurricane Irma, we had documented a total of 211 nests and there were 43 nests, around 20%, still on the beaches when the Hurricane approached our coast. Surveys were initiated several days after the conditions had improved. During these surveys we were only able to locate one nest that was still on the beach, although that nest had been severely inundated and was ultimately considered a loss. To our surprise, we also had two sea turtles nest right after the storm, although these nests were unsuccessful as well.

Overall, we estimate that 20% of our nests from the 2017 nesting season were lost due to Hurricane Irma.

2017 infographic

 

Eastman_S
Scott Eastman, Stewardship Coordinator, GTMNERR

Scott Eastman is an Interdisciplinary Ecology MS student in the School of Natural Resources and the Environment at the University of Florida. He is a member of the University of Florida, Archie Carr Center for Sea Turtle Research, a Center of Excellence, dedicated to seeking innovative solutions for sea turtle conservation through research and education. He is also the Executive Director of Eastman Environmental, a non-profit, 501 (c)3 organization dedicated to protecting, restoring and conserving coastal and marine habitats through research, education and community involvement initiatives. Additionally, he is a contractor with The Ocean Conservancy working to identify stressors for the development of spatially-based cumulative impact score across the Gulf of Mexico for loggerhead and Kemp’s ridley sea turtle species.

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