We walked all the way to the inlet without a turtle sighting. There was a set of turtle tracks near the campground but unfortunately it was a false crawl. We still had strong turtle vibes and were staying hopeful as we waited at the inlet, hoping that we would get the chance to see one on the way back. After walking a short while, a sea turtle was emerging! We patiently waited as she created her body pit and dug her egg chamber. We witnessed her lay her eggs, cover and then return to the ocean. Her length of the carapace measured in at 97.7cm (38.5 inches) and no pit tag was found. We watched as she made her way back into the ocean and disappeared under the waves. The next morning our dawn patrol team found three new nests and 1 false crawl. The nest we saw during our night walk is marked as nest 130 on our beach. It was below the Spring high tide line so we relocated it. We carefully move her 132 eggs to a safer location. See below for more pictures taken during the dawn patrol.
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We had a beautiful starry night walk to the inlet with enough of a breeze to keep the bugs at bay. It was more of a challenging walk with the incoming high tide but we were still able to make it to Jeremy's inlet. Once there, we waited for a few minutes to hopefully let a turtle come ashore. The inlet is a great place to find fossils and one of our participants was able to find a shark tooth in the dark! There was one turtle that tried to emerge next to the Pavilion stairs but she was unable to find a suitable location. Our night walk group was still able to see her tiny crawl that she left in the sand from her U-turn. Hopefully she was able to find a more suitable place to nest. The following morning we found one new nest and two false crawls. The new nest is marked as 124 on our beach. See below for pictures taken from the patrol this morning! Blog Post By: Karoline, Sea Turtle Intern
Something we often do during dawn patrol is debate relocations. This week, we had several members of the public approach us with questions as we were debating. We don’t take relocations lightly, and oftentimes will be on the fence as to whether or not it is in the nest’s best interest to move it. We always err on the side of caution, which means we will only relocate nests if absolutely necessary. We like to think that in general, the mother knows best, but unfortunately sometimes the nests are just too close to the water to leave in-situ (in its original location). Relocations are a powerful and necessary conservation tool for turtle patrols, but they come with their own risks. The main concern we have when moving eggs is rotation, as rotation of the egg can cause the embryo to detach itself from the shell. It’s up to us to decide if the benefit of moving a nest outweighs the risk of rotation or not. The most common cause for relocations is the nest being “too low”, meaning it is below the high tide line. When a nest is below the high tide line, it is at risk of being washed over by the water too many times. Too many wash overs can suffocate the nest and decrease hatching success. On dawn patrol, the main questions are usually: How many wash overs will this nest go through if it stays where it is, and how many wash overs are too many? Even though our instinct and educated debates are usually very accurate in determining the amount of wash overs a nest will receive, I was wondering if there is any research or perhaps a scientific method that could determine a nest’s wash over risk. And, as it turns out, there is! Researchers at Florida State University have created a model that does exactly that. The model is currently able to predict the amount of harmful wash overs a nest will receive with 83% accuracy. The model combines the beach slope and wave data to calculate harmful wash overs on the beach. With data from calculated wash overs, researchers then created a risk map, which predicted where nests on the beach were most at risk. Creating a new risk map for a nesting beach every year may sound like a lot of work, but researchers have found that the “time-averaged model” was more accurate than the most recent model from the year before. So, just creating one risk map could benefit a nesting beach for multiple years. That is, however, if the beach is not changed by big hurricanes or storms. In that case, a new map would be needed in addition to the average model. With a risk map, we could look at the specific percent risk of harmful wash overs for each nest, giving us more detailed data to use in our dawn patrol debates. Hopefully, the risk map model will become even more accurate and easy to obtain, making it readily available to turtle patrols everywhere! Sources: https://eos.org/articles/predicting-wave-wash-overs-for-sea-turtle-nests https://www.sciencedirect.com/science/article/abs/pii/S0964569118310202?via%3Dihub Following the presentation, it was a short but sweet walk to find a nesting turtle! Our volunteers, Lea and Derek, were already on the beach helping to save some nests which were washing away from the King Tide. Just as we were about to go out on the beach and join Lea and Derek, they reported over the radio, that a turtle was up and was laying eggs! We took the short walk to join them to witness a loggerhead sea turtle laying her eggs! Although the sky was a little cloudy, the full moon still provided a lot of light out on the beach. We watched her cover her nest and then return to the ocean, a sight that no participant had yet witnessed! Everyone was overjoyed to see a sea turtle and was shocked by the sheer size of her. The following morning on dawn patrol we only found one new nest and one false crawl, which means we saw the only nest of the night! Our sea turtle intern, Karoline, and our volunteer, Bob, safely relocated this nest to a safer location since it was too low to the tide line. They carefully moved 116 eggs to a newly dug chamber. This nest is now marked as 122 on our beach! See below for pictures taken during the dawn patrol. We had a very eventful night walk on Tuesday! Following our presentation and walking onto the beach, we could see how busy the beach was with beachgoers. I came across one family that had attended our night walk program the week before. They mentioned they saw a group run to an emerging turtle causing her to false crawl. This is why we stress keeping 20-30ft from a nesting turtle to ensure she does not get spooked and continues to nest. Then I got word that a turtle was up and was laying eggs by multiple groups. When I arrived she had just started to cover. Our night walk group got to watch her finish the covering process and then head back into the ocean. She came up at low tide so she had a long and tiring crawl back. A few participants even got to witness when she resurfaced to take a breath of air once back in the ocean. We started our walk back to the WIFI room as we had our turtle sighting of the evening. When I arrived back to the white building, there were tracks leading up the beach. We had another turtle ashore! This time she was digging her egg chamber so we patiently waited until she was laying her eggs. It was a turtley fun night walk! The first turtle we saw is marked as nest 110 on our beach. The second turtle we saw was the first nest we came across this morning, so it is marked as nest 107. Both nests were above the high tide line so no relocation was needed. We found 4 new nests and 1 false crawl in the morning. We also recorded the 2 short U-turn false crawls that we witnessed during our walk. See below for pictures taken from our morning patrol! Blog Post By: Ashlyn, Sea Turtle Intern The anticipation of the morning had been building for weeks. But as the day arrived, there was a buzz of excitement that seemed to rush over the Park, as if being brought in by the morning tide. On Saturday morning, Turtle Fest brought hundreds of individuals to Edisto Beach State Park for food, games, and community building—all based upon a shared passion for the increased education of and conservation efforts towards sea turtles of South Carolina. Here are four outcomes I witnessed as a result of the exciting morning…
We had another successful night walk! We walked only 0.3 of a mile down the beach before we saw an emerging turtle. Some beach walkers came across her and kept a good distance to ensure she continued her crawl. We watched the dark spot on the beach crawl up to the tide line and waited patiently as she started to dig. Once she started to lay we got to get a closer look.
The following morning our turtle patrol had to move the nest because it was below the Spring high tide line. She laid 122 eggs and they were moved to a higher and safer location. The nest is marked as 97 on our beach! We found a total of 6 nests and 5 false crawls today! Bringing our total nest count to 102. We had another successful night walk! During my check to the south end of our beach, I came across a long crawl that went up and into the dunes. This turtle crawled between the jetty and the Pavilion, an area that is not as common for a nest. We patiently waited as she took her time digging that perfect egg chamber to fit all of her eggs! We had the opportunity to witness her laying her eggs, covering them up and then watching her return to the ocean. During her late stages of covering, we scanned her for a PIT tag and took measurements. There was no PIT tag found. Her carapace length from notch to the tip, measured in at 103.1cm. The next morning we found 5 new nests and 1 false crawl! The nest we saw is marked as 89 on our beach! See below for some pictures taken of nest 89 during our dawn patrol. If you would like to adopt this nest, you can visit the Camp Exchange or the Environmental Learning Center! Blog Post By: Chase, Sea Turtle Intern
A lot of the questions we get along our patrols are something along the lines of: "What makes sea turtles so important?" Or, more simply: "Why do they matter?" Surprisingly, we care about our sea turtles for many more reasons than their absolutely adorable babies. Although their cuteness plays a factor in our love, their importance to the world environment is much more motivating. Sea turtles are what's known as a keystone species. This means that the survival of their ecosystem is reliant on their species' survival. In other words, without the keystone species, the environments they occupy would be drastically different, or even cease to exist altogether. The concept of a "keystone" species was bourne from research by Dr. Robert T. Paine. In his research, he removed one species entirely - the ochre starfish - from Tatoosh Island, off of the coast of Washington state. Within a year, biodiversity on the island dropped to half. With the ochre starfish in the environment, the beach contained 15 different species. Without it, 7 species disappeared entirely. What happened on Tatoosh Island? Dr. Paine's research quickly revealed how important the ochre starfish was to the island ecosystem. Without it, mussels and barnacles rapidly populated the shores, killing off a majority of the prey species on the island, as well as all but one species of algae. It turned out that the ochre starfish single-handedly (single-armedly?) controlled only the barnacles and the mussels' populations. By doing so, they also controlled the space available in their habitat, as well as the populations of all types of prey and plant life forms. One species of starfish is able to protect the entire ecosystem from collapsing - earning it the "keystone" title. Keystone species define an entire ecosystem through complex webs of chain reactions. The disappearance of one animal causes more and more of them to disappear, until eventually, the ecosystem is totally different than it started. Sea turtles provide a much similar ecological role, on a much larger scale. Sea turtles munch on seagrass beds, promoting the grasses' health, providing a shelter for fish all over the planet, and preventing seagrasses from overwhelming other plants' resources. At the same time, they also keep prey animals like jellyfish at bay, many of which feast primarily on fish eggs. No sea turtles means no fish, because the fish never hatch. Even more so, sea turtles also provide a food source for many animals both on land and in the water - sharks, birds, crabs, and more all rely on various parts of the sea turtle's life cycle as part of their diet. Being a keystone species is a big deal. Sea turtles are our friends not just because we share an island, but because our oceans rely on them. We need sea turtles just as much as they need us. With a severe thunderstorm watch for our area, we were worried we would have to cancel our program. We continued on with the presentation part of our program and then rechecked the various weather apps to try to determine what the storms were doing. We waited for 15 minutes under shelter as the lightning continued to get further and further away. I did a check to the south end of our beach to search for any turtle activity. At one point, I thought I saw a shadow up ahead but it happened to be an old knocked down sandcastle. While crouching, I lost my phone out of my pocket! I tried not to stress too much about it as the walk must go on! And thankfully one participant in our group located my phone! After we started our walk down the beach, I came across turtle tracks. However, I saw both the incoming and the outgoing set of tracks. This turtle did not successfully nest and had just left a short while ago. We continued down the beach when another bright flash lit up the dark night. Another cell of the storm had popped up a bit closer, so we turned around and ended our walk. The following morning only three false crawls were seen! So even if we would have been able to continue the walk, no nesting turtle would have been witnessed. The one false crawl had an abandoned egg chamber, so she tried but must have hit some tough shells. I have included a few photos taken from this morning. Thank you to our night walk group for their positivity and understanding when we had to cut our walk short! The call for a stormy evening led to a smaller night walk group than usual. Only one group attended the program as the weather had turned wild. Thankfully by the time the presentation ended, the lightning had moved far offshore and we were just left with a light drizzle. We continued our walk in the rain in the hopes of seeing a nesting turtle. Unfortunately no turtles were seen on our walk. The following morning we found three new nests (nest 78, 79 and 80) and one false crawl. See below for pictures taken from the morning patrol. We had a very eventful night walk on June 10th! As soon as I went out onto the beach, following the presentation, I could hear movement over shells. We had a turtle heading back to the water after false crawling. We got to witness her return to the ocean, with the hopes she would return to nest successfully! Then another short walk down and there was another turtle ashore. Some wonderful campers had seen her come ashore and kept their light off and kept a distance as to not spook her. However, she could not find that perfect spot to nest, so she ended up returning to the ocean without laying her eggs. Walking just past the campground, another incoming track was spotted but no outgoing track, which meant the turtle was still ashore! She was laying her eggs so we got to witness her lay, cover and return to the ocean. This carapace measured in at 98.4cm and no PIT tag was found. As we were watching the turtle nest, another turtle started to emerge behind our group! She did not crawl too far before deciding this place was already taken! Luckily she did not expend too much energy and would have tried a different spot to nest. The following morning, our interns Chase and Ashlyn, along with our volunteers, Lea and Derek, found 6 new nests and 5 false crawls. The turtle we watched nest is nest 74 on our beach! See below for more pictures taken from the morning patrol! We had a very fun and successful first night walk of the season! After our 30-minute presentation on the loggerhead sea turtle, we proceeded to walk the beach in anticipation of seeing a nesting adult. We walked half a mile down the beach and a turtle was already ashore digging her egg chamber. We patiently waited until she was at a safe stage to view her. We then got to get a closer look and even see the eggs drop! The following morning we found her nest and moved it to a safer location as she laid her nest below the Spring high tide line. There were 114 eggs to move! This nest is now marked as nest 69 on our beach! In 45-60 days the hatchlings will emerge and make their way to the ocean! **If you are out on the beach on your own, please give her 20ft, to avoid any disturbance and the risk of causing her to false crawl. However, if you come on one of our night walks, you have the opportunity of getting a closer look as we are permitted to do so! Blog Post By: Karoline, Sea Turtle Intern
One thing I love about public engagement is that oftentimes you get a question from someone that really makes you think. This week at our first “practice” night walk, we had a question about the temperature-dependent sex determination of sea turtle eggs. Fellow intern Ashlyn and I knew the answer to the question, but I realized I only know the answer to the question, not the reasoning behind it. Public engagement teaches you that there’s always more to learn! To start off, temperature-dependent sex determination or TSD is when the sex of the offspring depends on the temperatures the offspring experiences during development in the egg. TSD is a type of environmental sex determination, and only happens in reptiles and some fish (most vertebrates use chromosomal sex determination systems). The sex of the egg is determined during a specific time during incubation known as the thermosensitive period or TSP. In sea turtles, we use the saying “Hot chicks, cool dudes”. This means that the eggs will be male if they incubate at a temperature below 81.86 Fahrenheit, and they will be female if they incubate at a temperature above 87.8 Fahrenheit. Eggs in a fluctuating temperature zone between these two will be a mix of male and female. The original question asked was: Because the temperature determines the sex of the egg, would an entire nest be all one sex, or can there be a mix of males and females in one nest. Our answer was: it depends! For example, if the entire nest is at a temperature above 87.8, the nest would be all females. But, if the bottom of a nest is cooler than the top, the bottom eggs could be males and the top eggs could be females! This question was a great starting point for me to dive in deeper about TSD. After researching the facts of TSD, I started to wonder about the effects of climate change on the sex ratio of sea turtles. With temperatures rising, will we have more females, leading to less genetic diversity? After some research, I found that I was not the only one with this concern. It is possible that sea turtles won’t be able to adapt to increasing temperatures fast enough, and we could end up with only female sea turtles, leading to extinction. However, some animal species have already started to change their behavior by nesting earlier in the year in order to preserve the sex ratio! It is believed that increasing temperatures might also start to affect the nest choice of the turtles, meaning that they will choose a nest site that stays cooler. So, maybe the turtles can overcome hot temperatures! Another more positive outlook on temperature effects is that maybe within a certain range, maybe having more females will help sea turtles increase their population size :) . On a less positive note, the interaction between TSD and climate change is fascinating, but the current problem with increasing temperatures has nothing to do with the sex ratio of sea turtles. Right now, a large percentage of eggs/hatchlings are dying due to heat stress. The immediate temperature threat we are seeing is nests getting cooked, not the sex ratio. In some places with high temperatures, turtle researchers (and turtle patrols!) are finding new ways to keep the nests cool to avoid heat stress, such as adding shade. I think that’s pretty cool! Sources: https://oceanservice.noaa.gov/facts/temperature-dependent.html#:~:text=Most%20turtles%20are%20subject%20to%20temperature%2Ddependent%20sex%20determination.&text=Research%20shows%20that%20if%20a,the%20hatchlings%20will%20be%20female. https://oceana.org/blog/rising-temperatures-are-cooking-baby-sea-turtles-their-nests-8 https://onlinelibrary.wiley.com/doi/10.1002/bies.202000146 https://en.wikipedia.org/wiki/Temperature-dependent_sex_determination Blog Post By: Ashlyn, Sea Turtle Intern
So far in this year’s turtle nesting season, loggerhead turtle momma’s have made their way onto our State Park Beach to nest above the Spring High Tide Line. But how are we able to tell that it is in fact loggerhead turtles crawling up on our beach, and not another sea turtle species? Each species of sea turtles that crawls up on a beach has a unique and identifiable track pattern left on the sand. Loggerhead turtles crawl by alternating their flippers, leaving behind staggered comma or “V”-shaped indentations in the sand. That “V” indentation is also an indicator of the direction of the crawl, with the tip pointing towards the direction the turtle came from. The loggerhead crawl additionally has a wavy and smoothed track center, with no defined tail-drag marks. Kemp’s Ridley Turtles are much smaller in size in comparison to loggerheads, and the same can be said about their crawl patterns. Like loggerheads, they have an alternating comma-shaped flipper indentation left behind with a wavy smooth track center. The best indication that a Kemp’s Ridley left the crawl tracks versus a loggerhead is the smaller, more compact size of the flipper marks. Green Turtles crawl as if using a swimmer’s butterfly-stroke, leaving behind parallel flipper marks on the sand. The track center of the crawl is ridged, and a punctuated tail-drag can often be observed. Leatherback turtles are often easily distinguishable from other species simply due to their massive size (the total track width is around 6 to 7 feet!). Similarly to the Green turtle, the Leatherback uses a parallel flipper motion to move, and a punctuated tail-drag can be observed. It is often joked that if it looks like a tractor drove out of the ocean, you are probably looking at a Leatherback turtle’s tracks! Every morning that we go out we are eager to spot any new or rare (to our beach!) species of sea turtles have crawled up on the beach by looking out for unique track patterns. But until that morning where we find a new crawl, we will continue to be excited for each Loggerhead track we see! Blog Post By: Chase, Sea Turtle Intern If you’re familiar with the Edisto Beach State Park’s exciting Environmental Learning Center, you might be familiar with our two diamondback terrapins, Turnip and Rudy. Diamondback terrapins are a common species of turtle found all across the East Coast of the United States, from San Antonio to Massachusetts Bay. Unfortunately, due to human encounters, their population is now Threatened. Their threatened status, however, does not stop some of them from living wonderful lives full of curiosity - and determination. Terrapin turtles nest in a fairly similar manner to our sea turtles; the mothers come on land in the early months of summer searching for suitably sandy environments to lay their eggs as their sole motherly duty before disappearing into the water to continue their lives. This can be observed on our state park beachfront, where terrapin tracks and even nests can occasionally be found. More surprisingly, though, this behaviour can also be observed on Runway 4L of JFK International Airport in metropolitan New York City. Since as early as 2009, a runway at JFK International Airport has been consistently, annually invaded by a sea of diamondback terrapins seeking to nest in the sandy soil on the other side of the runway. In 2009, around 100 terrapins shut the whole runway down for nearly an hour and a half as crews raced to move the turtles from the runway and into suitable sand. A year later, an even larger turtle army slowly heaved their way across the runway to lay their eggs. And again in 2011, even more turtles than before, again and again until 2013. The massive, ever-growing, yearly turtle invasions forced JFK International Airport to install a 4,000-foot long, 8-inch diameter plastic tube alongside the runway to serve as a barrier to keep the turtles from once again entering the runway. It has not stopped them. The team at JFK International reports a 50% decrease in turtle sightings and removals since the installation of the turtle wall. The native diamondback terrapins still come around every year - albeit in smaller numbers - just a little slower. They cannot climb the wall, but when the high tide rolls in, so do the turtles. These events of mass turtle crawling have since become the focus of a team of wildlife biologists at the airport. Laura Francoeur, the chief wildlife biologist with the New York Port Authority, describes the issue as one of the most challenging issues her team has faced. They are seeking an explanation as to why the turtles keep coming back to the runway, no matter how many times they are removed, relocated, or even (very rarely) struck by planes. Her team has one prevailing hypothesis: a massive decrease in raccoon population in 2008 may have caused many more terrapins than normal to hatch on the runway’s sand that year. This may have led to the large population numbers in recent years, as the young terrapins return to lay on the nesting grounds they were born upon. In contrast, as the raccoon population has bounced back, the terrapin population has decreased dramatically to an alarmingly low level because the raccoons eat 95% of their eggs. Ms. Francoeur’s team must now both protect the turtles from the dangers of the runway and the predation of the raccoons. This lighthearted story of turtle-caused runway inconvenience makes for a fun but perplexing tale. The diamondback terrapins showcase the resilience of nature - the terrapins keep coming back to nest, year after year, no matter how much the humans move them or relocate them. Simultaneously, the turtles need the humans’ protection from the raccoons in order to keep nests safe and continue their population’s growth. Everything plays its part in nature, from the deadly raccoons to the fertile sand to our stalled planes. Finding our balance - that is the key to true sustainability. |
Leah SchwartzentruberSea Turtle Biologist Archives
June 2024
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