A sea turtle nest excavation. NPS Photo

Editor’s Blog: Sea Turtles Nest Records are Being Shattered – But Why?

This summer, coastal newspapers all around the country boasted headlines of record-breaking sea turtle nests along their local beaches. These headlines were especially prevalent in communities along the shorelines of North Carolina, South Carolina, Georgia, and Florida, which includes are our own home turf of the Outer Banks.

As of the first week of August, (and this number inches up every day), there have been 444 nests recorded along the Cape Hatteras National Seashore, which includes 422 loggerhead turtles, 21 green turtles, and 1 Kemp’s ridley turtle.

This has blown 2016’s previous record of 325 total nests out of the water, and has been a big story as the number has steadily increased all summer long.

The nesting season typically winds down in the latter part of August, so we’re close to the end of a milestone season, but the record number of nests has everyone from scientists to first-time beachgoers asking a primary question – Why?

There’s not a definitive answer, but there are several theories that hold a lot of saltwater.

First, let’s take a look at nesting data for the Cape Hatteras National Seashore over the past 10 years. (Note that the park’s beaches have been monitored since 1987, and prior to the past decade, the fewest number of sea turtle nests was recorded in 1987 at eleven, and there was an annual average of 77.4 sea turtle nests from roughly 2000-2007.)

2009: 104 total nests
2011: 153 total nests
2012: 222 total nests
2013: 246 total nests
2014: 124 total nests
2015: 284 total nests
2016: 325 total nests
2017: 250 total nests
2018: 166 total nests
2019: 432 total nests

See a pattern yet? If not, the following two theories are about to help, and chances are, that they are working hand-in-hand to explain 2019’s Sea Turtle Baby Boom…

Theory No. 1 – This significant increase stems from actions in the 1970s.

On December 28, 1973, the U.S. Congress passed the Endangered Species Act (ESA), recognizing that the natural heritage of the United States was of “esthetic, ecological, educational, recreational, and scientific value to our Nation and its people.” This act was passed due to national concern that many of the country’s living resources would become extinct without protection.

When this occurred, several species of sea turtles were grandfathered into the ESA, while a handful more were added in the years that followed. Because we all love data and statistics so much, here’s the current list of threatened or endangered marine turtles under the National Marine Fisheries Service’s jurisdiction, and the year they were added.

Hawksbill turtle: 1979
Green turtle: 1978
Loggerhead turtle: 1978
Olive ridley turtle: 1978
Kemp’s ridley turtle: 1970*
Leatherback turtle: 1970*
*Listed in 1970 under the precursors to the ESA.

So why did it take upwards of 30 years after the act was passed for species like the loggerhead and green turtle to make big jumps in nesting activity? Because sea turtles need a lot of time to grow up.

According to Tracy A. Ziegler, Chief of Resource Management and Science for the National Parks of Eastern North Carolina, it takes a female sea turtle about 25-30 years to mature, at which point, they can start laying eggs.

“Sea turtles were put on the protection list about 30 years ago, and that’s about the same timeframe for sea turtles to become mature and lay a nest,” said Ziegler. “So this could be one of the first years that there is significant evidence that the Endangered Species Act has worked.”

This is a solid theory, especially considering that numbers are skyrocketing all along the coastline, and not just on our local beaches. Coastal areas south of the Outer Banks in North Carolina, Georgia and South Carolina are all reporting a record 2019, which is a continuation of a trend that has been going strong for a few years.

But wait! There’s more!

Because when you look at the past decade on a local level, there are some deviations. For example, in 2018, the Cape Hatteras National Seashore only had 166 total nests, and there were no major hurricanes or tropical storms in the prime summer months to account for the disparity.

This brings us to theory number two.

Theory No. 2 – 2019 is the height of a long sea turtle breeding season

Per Ziegler, sea turtles don’t typically nest on an annual basis. Instead, they go offshore for 2-3 years, depending on the species, and then return closer to the shoreline to lay eggs during a single summer. So 2019 could be the year in the 2-3 year cycle when many sea turtles are returning to the beaches to breed.

And during this nesting season, female sea turtles have the ability to nest once or perhaps multiple times during the year, which could also increase the numbers, and which is a phenomenon that is coming into clearer focus thanks to DNA-based studies by local and state organizations.

“At this point, we’re not sure if they are nesting once, twice or even three times in the same year,” said Ziegler. “But we are doing DNA work with the North Carolina Wildlife Resources Commission, and are taking DNA from every sea turtle nest in North Carolina that they identify to get answers.”

It may be some time before the DNA data leads to more concrete information about nesting activity and frequency, but the numbers for the past 10 years seem to indicate that nesting activity certainly has a burst every three years or so – and again, this is happening all along the East Coast.

“It’s a big trend for sure,” said Ziegler. “Not only for us, but South Carolina, Florida and Georgia are all experiencing unprecedented sea turtle nesting numbers as well.”  Time will tell if these two theories are valid, especially if sea turtle nesting continues to remain strong in the coming years.

There could be other contributing reasons, of course. A lack of hurricanes during the height of the summer season is certainly helpful, and there are a couple of stray theories that warmer water temperatures may play a role as well. Or who knows – maybe the hundreds of sea turtles that made a trek to our beaches this year simply heard through the grapevine that our islands are a great place to vacation. It has also been an exceptionally busy year with human visitors, after all.

In any case, with Cape Point recently opened to anglers, the summer tourist season still going strong, and sea turtle hatchings now occurring on a near-daily basis, it’s definitely an exciting and active time to be a turtle (or a human) on the Outer Banks.

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