NRU Sea Turtle Genetics Project

We have been quietly working on turtle IDs from the 2023 season. Now that the first wave of 2024 nests are hatchling, we are starting to assign these to mothers as resources are available. Huge thanks to donations from Sea Turtle Patrol Hilton Head Island and the Jekyll Island Foundation to allow us to process these 2024 samples. There are many regulars back, but also some surprises in this first batch of data.

Female CC004836 nested on St. Catherines Island, GA and Hilton Head in 2012 but hadn't been detected since. We had written her off as likely being at the end of her reproductive life at the beginning of the genetics project, but she reappeared on Hilton Head this year.

Female CC003897 laid a single clutch on Cape Hatteras, North Carolina in 2010, the first year of NRU-scale sampling. She also went undetected since, until she decided to test out the sand on Jekyll Island this year! We suspect she has been spending some quality time in Florida.

These turtles underscore the importance of long-term datasets for understanding survival and population dynamics in this long-lived species.

Sticking with Kemp's theme a bit longer...

Some portion of the Kemp's ridley juveniles spend a portion of their lives in the Atlantic Ocean. The proportion of Kemp's post-hatchlings that remain within the Gulf of Mexico versus traverse the Florida Straits and enter the Atlantic likely varies each year depending on the Loop Current and other surface current dynamics in the Gulf. Decades ago, there was debate about whether these Atlantic turtles were "lost to the population." This female demonstrates that Kemp's ridley turtles growing up in nursery habitats on the Atlantic coast can and do return to nest in the Gulf of Mexico.

A sea turtle with a special connection to South Carolina was recently confirmed to be alive – and nesting – in Mexico! 🐢 🇲🇽

SCDNR biologists have tagged many sea turtles over the decades, but it's not often that we see those animals again. That's why staff were so excited to hear from University of Alabama professor Dr. Thane Wibbels about a tagged Kemp's ridley sea turtle detected on a nesting beach in Mexico.

Boaters found this small, female turtle injured with a propeller wound near Edisto Island in 2017. SCDNR staff and volunteers responded and transported her to the South Carolina Aquarium, where she became known as 'Coral' and recuperated for nearly a year before returning to the ocean.

Kemp's ridleys are the world's most endangered sea turtle species and are the only sea turtle to nest during the daytime in large groups. Young Kemp's ridleys forage in South Carolina waters throughout the year, but the vast majority of them nest along the Gulf Coast. Coral's re-appearance underscores recent SCDNR research showing the importance of our coast to a sea turtle primarily thought of as a Gulf Coast species.

Coral has now joined the incredibly important ranks of nesting Kemp's ridley mothers – thanks in large part to the tireless work of South Carolina's many sea turtle advocates. 🙌

Photo: Former South Carolina Aquarium veterinarian Dr. Shane Boylan inspects Coral upon intake in 2017 (SCDNR).

The Kemp’s ridley theme continues, but this time with an unexpected twist. As I was calling 2023 data from Ossabaw Island, Georgia last week, I ran across a hybrid sample. The sample was salvaged from a “wild” (undetected) nest that had been depredated by a feral hog well into incubation, so the DNA we retrieved represents the developing embryo that was inside the egg rather than the mom's DNA. Several of the markers that I designed for individual ID in loggerheads have alleles, or length variants, that fall outside of the loggerhead array in other species.

If you look at the picture for marker 24 in black, all the gray vertical bars indicate loggerhead alleles that we have detected in southeastern US loggerheads. For this sample, one peak fell within bin 290. Another peak fell at 252, upstream of the loggerhead variants (note no gray bar in the background for this far left peak). This allele could indicate green turtle or Kemp’s ridley. For marker 73 in green, one peak fell at 381, a loggerhead allele. The other is upstream of the loggerhead array at 316. This indicates Kemp’s ridley. I knew I was dealing with a hybrid involving Kemp’s ridley and loggerhead turtle genetics. However, for other markers that are diagnostic, there were two loggerhead alleles. This told me that I was not dealing with a first-generation hybrid, but a backcross to loggerhead as roughly ¾ of the alleles were loggerhead, and ¼ of the alleles were Kemp’s ridley.

My first thought went to a hybrid female that nests on Wassaw Island and Ossabaw Island. Caretta Research Project first saw her in 2018. We determined that her father was a loggerhead and her mother was a Kemp’s ridley. She mates with loggerhead males, producing ¾ loggerhead, ¼ Kemp’s ridley offspring. I thought this sample might be her offspring, but she last nested in 2022 and wasn’t due back last year. When I analyzed parentage, the sample matched a known loggerhead mom! Therefore, these Kemp’s ridley alleles had to have come from a hybrid male. As far as we know, this is the first known contribution from a loggerhead x Kemp’s ridley male to the next generation. It confirms that the males are fertile just like the females.

Because the loggerhead mother was known, it was possible to determine which of the loggerhead alleles in this offspring came from the hybrid male. Comparing these to the Wassaw hybrid female, they don’t look like full siblings. However, with only half of his fingerprint, we can’t yet rule out the possibility that they are half-siblings that share the same mother and different loggerhead fathers. We are transitioning to more dead hatchling sampling to try to learn more about the males, so hopefully if this male continues to successfully mate, we will be able to reconstruct his full fingerprint in future years.

Keep your eyes peeled during nest evaluations. If you think you see something that doesn’t quite look like a loggerhead, you might well be right!

2024 seems to be the year for Kemp's ridley turtle nesting in Florida. There have already been 12 confirmed nests with 5 additional potential Kemp's nests. Only one nest reported so far north of Florida, just over the border on Cumberland Island. NRU folks, keep your eyes peeled. This could be a big year for Kemp's!

As the 2024 nesting season marches along, we're still assigning turtle IDs to 2023 samples. Thanks to tremendous support from the North Carolina projects, we've had sufficient resources to analyze all North Carolina samples. We have assigned about 93% of these to known mothers so far, and we're trying to wrap up the last of the remaining unassigned samples soon.

Based on preliminary numbers, North Carolina added 160 new nesting females in 2023, and 28 of these had known mothers in the database. Female CC003341 had the most productive recruitment year, adding 3 new daughters to the 3 she already had. These daughters have nested as far south as Cape Romain National Wildlife Refuge, SC to near the North Carolina/Virginia border.

Three of these daughters are full sisters (nesting ranges and recruitment years indicated in the bright blue boxes and text). Despite likely hatching the same year, there is a 7-year span in age to maturity among them. This is consistent with high variability in age at sexual maturity estimates based on skeletochronology. Where these turtles end up finding their food has a large impact on their growth and the time it takes to reach sexual maturity.

North Carolina is now on the board. This nesting season is getting off to an early and unusual start.

Our collaboration with Caretta Research Project is nearing the 20-year mark. Although genetic sampling of Wassaw females didn't begin until 2005, Caretta Research Project has been physically tagging loggerheads since 1973. This has allowed us to go backwards in time for females that nested long enough to match their physical tags with a genetic tag, adding temporal context to mother-daughter genetic matches.

This can yield interesting stories like Caroline's, a female recently fitted with a satellite tag who has a known mother and sisters in the genetic database. Caroline's mother was tagged on Wassaw in 1996, and she is still actively nesting. Caroline's first nests were in 2020, and her sisters started nesting in 2019 and 2020.

To maintain a stable population, each female must replace herself over the course of her reproductive life. Caroline's mom already accomplished this three times over in a single nesting season!

Georgia usually gets the first loggerhead nest north of Florida each year. South Carolina often follows soon afterward, usually the higher density nesting beaches like Cape Romain National Wildlife Refuge.

Well, this turtle had something different in mind. Congratulations to Garden City, South Carolina for getting the first loggerhead nest north of Florida in 2024. This is probably the same female that "false crawled" earlier in SC and NC. Lower fidelity females nesting in this area often nest across all of Long Bay, from Cape Romain in the south to Cape Fear in the north.

I have had the pleasure of visiting with China Girl a few times over the past two decades. She went undetected for 8 years prior to this sighting, and we were all concerned that she had laid her last eggs long ago. But she is back!

For anyone interested in watching, the webinar talk that I gave for the AZA Sea Turtle SAFE program has been uploaded to their youtube channel:

https://www.youtube.com//featured

Loggerheads may be coming to a beach near you soon!

Thank you to Oak Island Sea Turtle Protection Program for a reminder to double check the North Carolina leatherback turtle genetic data over the past two seasons. Leatherbacks deposit "spacers" in addition to normal eggs. These spacers aren't technically eggs at all, but shelled albumin packets that lack yolks and embryos. There are several hypotheses as to why they do this, but no clear consensus. The good news for us is that these spacers give us an opportunity to collect the mother's DNA.

The nearest core leatherback nesting areas are in central and south Florida. For females that display strong nest site fidelity north of these areas, their eggs often don't develop. This seems to be the case for DC000019 that nested in 2022. None of her eggs showed any sign of development. We think this is likely due to difficulty in finding mates as mating is believed to occur near the nesting beaches.

Happily, the eggs in DC000020's six nests were fertile, so she bucked the trend we typically see north of Florida. Unfortunately, four of her nests fared poorly due to tidal overwash and storm events. But we can keep our fingers crossed that hatchlings from the surviving nests might contribute to a North Carolina leatherback rookery one day.

Texas has received its first Kemp's nest of 2024. We're in the process of analyzing the backlog of FWC rare species nests from the past few years, including the Kemp's ridley's. Stay tuned for future updates.

The first Kemp's ridley sea turtle nest in Texas was laid here at the national seashore — a first-time nesting sea turtle laid 81 eggs! The eggs were collected by trained biological technicians and relocated for protected incubation. When the eggs hatch in 42-56 days, they will be released into the Gulf of Mexico.

If you are out in the park or on another Texas beach this summer and find a nesting sea turtle, please report your sighting to 1-866-TURTLE-5 (1-866-877-8535). Take as many photos as possible at a safe distance of 20 feet away, and mark the tracks left behind by the turtle. Please do not closely approach or disturb the nesting female during this process.

Won't be too long now!

This may not look like much, but it's a sure sign that one of our favorite seasons is right around the corner!

USFWS biologist Jerry Tupacz spotted these mating loggerhead sea turtles in Cape Romain National Wildlife Refuge today. Mating can last several hours and fertilize multiple egg clutches, but females can also mate with more than one male. Over the coming summer, the female (not visible beneath 300-something-pounds of her hulking mate) will crawl ashore to lay numerous nests. Sea turtle nesting season officially begins on May 1.

As always, be sure to report sick, injured or dead sea turtles to our 24-hour hotline at 1-800-922-5431.

If you spot a live, healthy sea turtle (or turtles), we'd love to know about that, too! Please report here: https://survey123.arcgis.com/share/a7c87e03d4b541c38667c0e80193f02c

We want to extend a huge thank you to the Jekyll Island Foundation for a $9,300 donation that will allow up to process Jekyll Island samples from 2023 and 2024.

Female CC006701 turned up in the most recent batch of Jekyll Island samples that we analyzed. 2023 marked her first year nesting on Jekyll but her 5th nesting season since the project began. Most females seem to quickly settle on where they like to nest, but CC006701 apparently likes variety. She has nested on 11 different islands, spanning Cumberland Island, GA through Hunting Island, SC, over the past decade.

I'm battling a bug, so we have postponed the webinar to 1 pm next Thursday to give me time to get my voice back. If you were already registered, you should have received an email acknowledging the date change. I hope everyone will be able to make the new date. Sorry for the curve ball.

I've added turtle IDs for several hundred nests over the past couple of days.

CC001031 was tagged on Jekyll Island in 2010 and has been scarce until she reappeared on Edisto Island in 2023.

CC002044 laid 5 clutches on Hunting Island, SC in 2011, the second year of the NRU-scale project. She reappared in 2023, nesting essentially on top of her 2011 nesting footprint.

I would sure like to where these ladies have been and what they've been up to while they've been away.

I will be speaking about the genetic tagging project as part of AZA's Sea Turtle SAFE webinar series on April 4th at 1 pm. Please register via the QR code or registration link in the flyer.

Caretta Research Project fitted two females with satellite tags during the 2023 nesting season. One of these was Buffett, CC08882, a turtle that has been visiting Wassaw since 2016. Her 2023 Wassaw nesting history is missing a nest around mid-June. Based on her satellite track, she may have laid this clutch on Ossabaw or St. Catherines Island. We will target the nests in this window for processing soon to she if she shows up.

Caretta Research Project was curious if Buffett had any close relatives in the database. She doesn't have a known mom in the database, but she does have a half-sister who started nesting in 2022, right next door on Ossabaw Island.

We want to extend a huge thank you to Caretta Research Project for a recent donation that will allow us to finish data collection for their 2023 samples.

Satellite Tagged Sea Turtle is still enjoying her winter foraging grounds! Adult Loggerheads from the Northern Recovery Unit (NRU) migrate along the Atlantic coast to forage. Some of their favorite foods include Shrimp, Jellyfish, Horseshoe Crabs, Bivalves, and other hard-shelled snails like Whelk and Conch.

To track buffett with us, visit https://bit.ly/48ApieB
To learn more about the Northern Recovery Unit check out NRU Sea Turtle Genetics Project

Shout-out to Savannah Bee Company for promoting our work, and to the Sea Turtle Conservancy for partnering with us to follow !

So far, we have assigned 76 of the 2023 green turtle nests to 32 unique females. Twelve of these were remigrants that we detected as early as 2013, and 20 were new in 2023. Most of the remaining nests look like they belong to new females. We run these a second time to confirm before adding them to the database.

Initially, all green turtle samples are analyzed with the same 16 markers that we use for loggerheads. Some of these don't give us any useful information (beyond species ID) for green turtles, so fully sorting out relationships will require running additional markers. Despite this reduced power, some cases are obvious.

CM000123 and CM000135 appear to be full sisters. Despite sharing about 50% of their genetic make up, likely hatching the same year, and potentially even emerging from the same nest, you can see very different site fidelity patterns for these sisters as they have begun nesting.

All of CM000123's nests from 2021 and 2023 fall within a 7-mile stretch of the northern Outer Banks. CM000135's first recorded nest was on Bald Head Island, but her second nest was very close to her sisters' nests, almost 200 miles to the north. It will be interesting to see how close to one another these females nest in future years.

"Female sea turtles return to where they hatched to lay their eggs."

We often comment that such a statement is an oversimplification. The majority of females do appear to return to a birth region. However, this may not mean the same beach, especially for the species that nest along continental coastlines like loggerhead turtles in the U.S.

Female CC009676's nesting history is an extreme example of not putting all of your eggs in one basket. After initially nesting on Little St. Simons Island, GA and DeBordieu Beach, SC in 2016, this female "vanished." She reappeared in 2023, nesting on Little Cumberland Island, GA prior to traveling over 750 km to the north to lay her very next clutches at Cape Hatteras, NC. This demonstrates the importance of long-term and broad scale data sets.

2024 marks the 20th year of our collaboration with the Little Cumberland Island Sea Turtle Project founded by Dr. Jim Richardson and currently led by Russell Regnery. The idea for genetic tagging using eggs began there with technician Jocelyn Coulter in the summer of 2005. Many thanks to the Little Cumberland Project for a donation to cover processing of the 2023 Little Cumberland samples.

We continue to slowly add turtle IDs for the 2023 samples in the database.

Many thanks to Robert and Abby Morris and their dedicated crew for their hard work surveying Pritchards Island and Little Capers Island. These islands are only accessible via boat. We are also grateful for their recent donation that helped cover the cost of processing the samples from these islands.

Female CC001070 wins the consistency award among the Little Capers females. We just assigned her 36th nest since the project began in 2010. Even though she clearly likes the St. Helena area, note that she has nested on four different project beaches over the years: Hunting Island, Fripp Island, Pritchards Island, and Little Capers Island. This demonstrates the importance of the regional sampling approach for capturing the nesting efforts of even the females with relatively strong site fidelity.

We are slowly catching up with assignments for the 2023 samples. We've assigned about 75% of the North Carolina samples with a couple of batches left to run.

Among these were samples from most green turtle nests, primarily from North Carolina, but also South Carolina and Georgia. Florida shattered previous records with over 76,000 green turtle nests last year. The 130 or so nests from north of Florida don't sound like many by comparison, but they likely represent the early stages of colonizing new nesting sites. Some regulars returned in 2023 (including CM000052, see map), but the majority of females appear to be newcomers to the genetics database.

We hope to analyze these with additional markers to sort out relatedness among them and to compare them with the Florida nesting populations. Although small in number, these nests provide us the rare opportunity to document population expansion in real time.

As 2023 comes to a close, it’s a good time to reflect over the past year. Please join me in congratulating four undergraduate students who graduated this semester. They have served as the nucleus of the sample processing crew for the past two summers. Thank you all for your time in the lab, and I wish you the best with your future endeavors.

Left to right: Katie Runyon (lab alumna who graduated this spring), Kayla Evans (interim lab coordinator who keeps all of us straight), Amaya Kemple, Abigail Cunningham, Aalea Grimes, and Brendan Amman.

For those on or near the Georgia coast, I'll be giving a talk in Brunswick as part of One Hundred Miles Naturalist 101 series on December 7th. I promise to keep the genetic methods talk to a minimum.

This in-person event is free and open to the public. Please register at the link below. I don't believe there will be live remote attendance options, but the talk will be recorded and posted later.

Naturalist 101: Genetic Tools for Sea Turtle Conservation Join us Dec. 7 for Dr. Brian Shamblin's lecture on scientific innovation and conservation, featuring some of our favorite coastal animals.

You are what you eat...

Congratulations to Simona Ceriani for publishing the results from the latest round of her stable isotope analyses. She determined where Northwest Atlantic loggerheads live when they're not at the nesting beach. The Northern Recovery Unit was represented by samples from Bald Head Island, North Carolina, and South Carolina: Hilton Head Island, Kiawah Island, Cape Romain National Wildlife Refuge, and South Island. Several permit holders in St. Johns County, Florida contributed nest samples as well.

Huge thank you to the Bald Head Island Conservancy - BHI Conservancy sea turtle program, Sea Turtle Patrol Hilton Head Island, Kiawah Sea Turtle Patrol, Cape Romain staff, South Carolina Department of Natural Resources staff, Mickler's Landing Turtle Patrol, Guana Tolomato Matanzas NERR volunteers, Vilano Beach Sea Turtle Patrol, St. Augustine Beach, and Crescent Beach Turtle Patrol for providing samples for this study.

Dr. Ceriani's results reinforce previous stable isotope and satellite telemetry studies in demonstrating the significance of the Mid-Atlantic Bight for the Northern Recovery Unit adult females. The paper is available here:

Monitoring population-level foraging distribution of a marine migratory species from land: strengths and weaknesses of the isotopic approach on the Northwest Atlantic loggerhead turtle aggregation Assessing the linkage between breeding and non-breeding areas has important implications for understanding the fundamental biology of and conserving animal species. This is a challenging task for marine species, and in sea turtles a combination of stable isotope analysis (SIA) and satellite telemetr...

Florida has experienced record green turtle nesting this year with almost 75,000 nests documented in the state! That is a remarkable turnaround given how close Florida green turtles came to being wiped out just a few decades ago. This also demonstrates the value of Endangered Species Act protection and the hard work of many groups in Florida to protect nests, juveniles, and adults.

North Carolina and the Grand Strand of South Carolina are reaping the benefits of these rebounding numbers as green turtles colonize new nesting beaches. Based on mitochondrial DNA (passed down from the mother to her offspring), we think North Carolina estuaries are an important nursery habitat for juvenile Florida green turtles. Maybe some of these females got nostalgic and wanted to come back to visit?

Thanks to generous donations and samples from SCUTE and the North Carolina programs, we will be able to document how many individual females are involved and how they are related to one another. We have a lot of work ahead to catch up with previous years' green turtle samples as well as these new ones.

Great news for sea turtles!

More than 90 green sea turtle nests were laid in North Carolina this season, the most we've ever seen. The previous record was 62 nests in 2019.

To put this in perspective: Twenty years ago, it was a exciting to see 10-15 nests in a single season.

I uploaded turtle IDs for several North Carolina beaches today. Sisters CC003498 and CC008918 are nesting a few islands apart this year. CC003498 has laid 27 clutches of eggs since first identified in 2011. She mostly nests on Figure Eight Island, but her first nest this year was on Wrightsville Beach. CC008918 has laid 10 clutches as far south as Wrightsville Beach and as far north as North Topsail Beach. She seems to prefer the south end of Topsail Island recently.

Despite likely hatching the same year, CC003498 got (at least) a five-year headstart on her sister on the nesting front. Where loggerheads spend their juvenile developmental stages can greatly impact their growth rates, their ultimate size as adults, and the time that it takes for them to reach maturity.

Mama Pritchard is back!

She was rescued while attempting to nest on Pritchards Island in 2008, suffering from old propeller wounds. Thanks to great care at the South Carolina Aquarium, she recovered and was released in time for the 2010 nesting season.

Unfortunately, Pritchards Island was not surveyed in 2010, so we can't say for sure that she nested that year. But she returned in 2013, and 2023 marks her 6th nesting season to appear in the genetics database. Huge thanks to volunteers Abby and Robert Morris and their dedicated Pritchards crew for keeping her story going.

Vessel strikes represent a significant source of injuries and mortality for sea turtles, especially when they are concentrated inshore and nearshore during the nesting season. Sea turtles have to surface periodically to breath, and they often can't react quickly enough to evade fast moving boats. If you're on the water, please be aware of your speed and be on the lookout.

In sea turtles, mitochondrial DNA is passed down from a mother to her offspring. For loggerheads nesting in the southeastern United States, differences in relative frequencies of mitochondrial DNA variation tells us that there are multiple demographically isolated populations, or recovery units. Although female dispersal between these recovery units is rare, it has been documented with tag returns.

Usually, female dispersal is between adjacent recovery units, but sometimes the turtles have more wanderlust and go further afield. Noemi is a loggerhead tagged by Kristen Hart's USGS crew in Gulf Shores, Alabama in 2017. This is nesting habitat for the Northern Gulf of Mexico Recovery Unit.

When I was calling 2023 North Carolina data late last week, I was quite surprised to find Noemi has nested at Cape Lookout National Seashore! This beach is nesting habitat for the Northern Recovery Unit.

Photo by USGS, during permitted activities in Alabama. U.S. FWS permit TE98424-1 and SUP permit 12-006S.