Safe Travels

What does it take to recover a species that was once on the brink of collapse?

In this episode of Safe Travels, we travel to San Diego Bay with researchers from NOAA Fisheries' Southwest Fisheries Science Center for an exclusive behind-the-scenes look at one of the world's most inspiring wildlife recovery stories, the remarkable comeback of the green sea turtle.

Join research biologist Dr. Cali Turner Tomaszewicz, biologist Garrett Lemons, lab technician Anna Cahill, and citizen scientist Tracy Tempest as they capture, examine, tag, and release one of San Diego Bay's resident green sea turtles. Along the way, we explore how decades of science, international conservation, and community involvement have helped reverse one of the greatest wildlife declines of the last century.

You'll discover how researchers monitor turtle populations, use genetics and satellite tracking to understand migration, estimate age through bone science, and investigate the mysterious "lost years" of juvenile sea turtles. The episode also examines the new conservation challenges facing recovering populations, including climate change, warming oceans, vessel strikes, marine debris, and shifting sex ratios caused by rising nesting temperatures.

Most importantly, this episode demonstrates that long-term, science-based conservation works, and that every person has a role to play in protecting our oceans.

In This Episode
  • Field research with NOAA Fisheries in San Diego Bay
  • Capturing and safely handling wild green sea turtles
  • Tagging, blood sampling, genetics, and satellite tracking
  • How scientists estimate turtle age using skeletal growth rings
  • The mystery of the sea turtle "Lost Years"
  • Why most Southern California green turtles originate from Mexico
  • How citizen scientists contribute to sea turtle conservation
  • The impact of climate change on sea turtle populations
  • Boat strikes, marine debris, and other modern threats
  • Why the recovery of the green sea turtle is one of conservation's greatest success stories
  • Simple actions everyone can take to help protect sea turtles
Featured Guests
Dr. Callie Turner Tomasevitz
Research Biologist
NOAA Fisheries – Southwest Fisheries Science Center
Garrett Lemmons
Biologist
NOAA Fisheries – Marine Turtle Ecology & Assessment Program
Anna Cahill
Lab Technician 
Marine Turtle Ecology & Assessment Program
Tracy Tempest
Citizen Scientist & Sea Turtle Conservation Volunteer

Key Topics
  • Green Sea Turtles
  • Marine Conservation
  • NOAA Fisheries
  • Sea Turtle Research
  • Wildlife Biology
  • Ocean Conservation
  • Climate Change
  • Citizen Science
  • Marine Ecology
  • National Oceanic and Atmospheric Administration
  • Wildlife Documentary
  • Environmental Science
If You Enjoyed This Episode:
Please consider subscribing, leaving a review, and sharing this episode with someone who loves wildlife, conservation, or the ocean. Every listen helps us continue telling the stories of the scientists, rangers, and conservationists working to protect our planet.

Creators and Guests

Host
Joey Liberatore

What is Safe Travels?

Safe Travels explores National Parks and wild places through in-depth conversations with the people who know them best - park rangers, scientists, biologists, geologists, archaeologists, and conservationists.

Each episode goes beyond travel tips to uncover the science, history, wildlife, and conservation stories that bring these landscapes to life.

Hosted by Joey Liberatore, Safe Travels Pod turns expert insight into engaging, accessible conversations - helping listeners experience public lands with deeper understanding and appreciation.

Speaker 1:

To me, think they're fascinating. There's there's this dinosaur like quality to them. Right?

Speaker 2:

I think when people think of the ocean, the sea turtle is a perfect like manifestation animal of like what the ocean is to a lot of people. Calmness, beauty, like kind of a safe refuge place and just like enjoying life, man. Turtles enjoy life.

Speaker 3:

They are definitely programmed with some wisdom that is far beyond my understanding.

Speaker 4:

One of the stories I have been most fascinated with has been the recovery of the green sea turtle. And for several months, I've been in touch with doctor Callie Turner Tomasevitz. She is a researcher for the National Oceanic Atmospheric Administration. To better understand green sea turtles and the recovery, Callie invited me to San Diego Bay to join her and the team for a day of research.

Speaker 5:

Doing our spring green sea turtle surveys. We've come out here. We've said we've got a total of three big, long nets in the water out here. They're called tangle nets. There's just kind of a monofilament mesh line that goes about 10 feet down in the water column.

Speaker 5:

And, they can't see it. The turtles can't see it. It's clear line. And so there are so many turtles out here. We keep seeing the heads pop up.

Speaker 5:

It's just a matter of time until they swim through one of the nets, get tangled up, and that's our cue to go over and, pull them out there. This is our fifth day out, I think, of the, spring twenty twenty six season.

Speaker 1:

My name is Callie Turner Tomasevitz. I'm a research biologist here at NOAA Fisheries. I work at the Southwest Fisheries Science Center. And within our, science center here, I work in the marine mammal and turtle division. Specifically, spend most of my time working with the marine turtle ecology and assessment program.

Speaker 1:

And we do a whole bunch of sea turtle research for animals along The US Pacific West Coast. To me, I think they're fascinating. There's there's this dinosaur like quality to them. Right? And as a kid, like most kids, I think I was fascinated with dinosaurs.

Speaker 1:

They were so cool, and you just see them in their face and their eyes, and they are these ancient creatures and again, I mentioned the tail on the male, it's it's a dinosaur tail, there's no getting around it. And you know, you have movies like Finding Nemo and the character Crush that's just, you know, fun and lovable and yeah, they're they're a charismatic ocean animal. There's a lot of them out there and sea turtles just happen to be the one that I kinda fixed on and again, I loved it because I think they're a great communication tool. Right? They kinda hook people's hearts and once you kinda get people invested, they'll listen, they'll pay attention, they'll learn, potentially change their actions and spread the word to other folks, that can positively help not just the turtles, but their full ecosystem and the other animals that might not be as charismatic, you know, a sea slug might not get the love that it deserves, but it still shares the same habitat as the sea turtles.

Speaker 1:

And so if the sea turtles are doing good, people are protecting their habitats, then a whole bunch of other animals and plants and full ecosystems also will reap the benefits of that.

Speaker 5:

The last net is out of the water at 11:14. I believe that was net two.

Speaker 2:

The team has caught as many as 12 turtles in a single day. The day I spent on the San Diego Bay, the conditions were a bit windy and gloomy, which allowed for just one turtle capture.

Speaker 4:

So now that we're back to shore with the turtle, what kind of research or work goes on?

Speaker 5:

Yeah. So we've been monitoring this population here in San Diego since 1990. So a long time. And every time we're out here and catch a turtle, it's kind of the basic workup that we do on it. So we're going to tag them, weigh them, measure them, take photographs that are useful to track changes over time.

Speaker 5:

We also use it for photo identification. And then, sometimes we do have satellite tags and a video born underwater camera that we'll put on too. I think we're hoping to put one of those out today. It's called a cat's camera. Really cool way to see what the turtles are doing under the water, what they're eating, get some neat clues into social behavior, things like that.

Speaker 5:

And overall, we're looking at big questions as far as habitat use, movement, abundance is a big one, how many turtles are here in South in the San Diego Bay. A lot of my research in particular also focuses on the demography of the turtles out here. So what's the size and age class kind of distributions? How many adult turtles, juvenile turtles? How fast are those turtles growing?

Speaker 5:

How fast is population the growing. Those are some of the basics questions that we're looking at today.

Speaker 4:

You had to pull this big big Big boulder? How was it getting her out of the water?

Speaker 2:

She was a big girl. She was a little testy finding out skip, but once we got control of her flippers, yeah. She was big probably over I estimated over three hundred pounds. It took me and Jeff all our coordinated strength to get her in. I'm gonna guess three hundred and twenty three pounds on that girl.

Speaker 4:

Is this one of the

Speaker 2:

biggest ones you've caught this season? Yeah. Definitely one of biggest ones we caught this season. You know, we used to capture a lot of lot of them about this size, but not rare for this area. But, yeah, definitely one bigger ones this season.

Speaker 2:

Yeah. We'll get a weight on her and see. Think I I must say over three twenty. So

Speaker 4:

Garrett Lemmons is another biologist and key fixture within the NOAA Marine Mammal and Turtle Division.

Speaker 2:

My name is Garrett. I work for the National Marine Fisheries Service as a biologist as part of the National Oceanic and Atmospheric Administration. I currently work in the marine turtle ecology assessment program here at the Southwest Fishery Science Center in Loyola, California. I've always, you know, loved the ocean, loved being in it. I've been in ocean since I can remember as a kid, you know, surfing, just enjoying the beach.

Speaker 2:

But I my love for marine biology and my passion really was Ignite, I'd say, I was studying abroad during my undergraduate in Costa Rica. And I'm starting to take some tropical marine biology courses, tropical ecology courses, and working with a professor at University of Costa Rica and really starting to understand, marine conservation and, ocean conservation. And really starting to understand and get exposure to the, you know, the problem with overfishing in our oceans and just all the the conservation programs that plague or problems that plague our oceans and the work people are doing to, you know, overcome obstacles that are threatening a lot of the systems and species on our planet.

Speaker 4:

Once they transport the turtle to land, one of their first tasks is to weigh it. And as you can imagine, weighing a 250 plus pound turtle isn't the easiest task.

Speaker 2:

Sea turtles are heavy and they're they're they're very hydrodynamically shaped but they're they're not a convenient shape to work with either especially when you're trying to tie them. So we have a tripod system and like I said these animals get up to 300 over 400. That's a big animal to weigh. We have a tripod system with a pulley and an electronic scale that we attach them to but the attachment is the tricky part. So we have two methods.

Speaker 2:

There's two methods. We have a big transfer sheet that's usually used for medical transport of humans with like these big nylon sodden handles that we can either wrap the whole turtle in, that's usually the best bed for a larger animal or we have a rope and there's a certain way to like make the rope even swing around its its front flippers and its head underneath, flip it over his carabass tie it under his back flippers and tie a central knot around the middle. But you have to be experienced in that. Sometimes the rope does always work. The turtle carabass can slip.

Speaker 2:

The turtle is really huge sometimes we don't have the rope long enough to do that so it's either the bag knot bag rope method knot and we everyone lifts and we let attach onto the scale or we I tie a rope, I tie a central knot and we lift it up and clip it and then we all sit there and kinda brace it in case it does the scale or the pulley does slip so we're there to catch it and we just get a quick measurement as it's floating in the air. And, yeah, that's kind of a fun thing we all do. We tell take bets and see who's closest to the weight.

Speaker 5:

Are we free?

Speaker 4:

Frank, one twenty eight. Solid.

Speaker 5:

Alright. Grab the top and lower.

Speaker 2:

Disappointing. What's

Speaker 4:

your reaction to one twenty?

Speaker 2:

Disappointed. I think the scale's wrong.

Speaker 4:

She's a big girl though. That's what? Almost Garrett's three prediction of three hundred and twenty three pounds was slightly off. Her official weight was one hundred and twenty eight kilograms, which converts to two hundred and eighty two pounds. After they weighed the turtle, they began to collect blood and skin samples from her.

Speaker 1:

Tissue samples will typically include skin that we use for a stable isotope analysis and also genetic analysis. Stabilized isotopes are basically chemistry that we can look at that will change depending on the habitat that a turtle is living in and also what food it's eating. So if the turtle was eating primarily eelgrass, it's going to have a different carbon isotope signature for example, than a turtle that's more specialized on red algae or invertebrates. So that's a real neat piece of information we can get just from a teeny tiny skin sample. And then blood is another sample that we'll collect too and can be used for a huge host of things from health to contaminant analysis, genetics and epigenetics, omics in general, has really increased what we can learn from again these really small biological samples.

Speaker 1:

In addition to taking those types of data, you know, size, weight, and tissue samples, we also take the opportunity to tag turtles. So they all get a flipper tag most of the time and then they all will get an internal microchip basically just like we might get for our cats or our dogs, which makes it great for other people who might encounter these turtles in their other locations to be identify it, to be able to identify those turtles.

Speaker 2:

So what's the, the next step? The next plan right now is to take two blood samples, two different tubes. They, do different things. This one's gonna be for stabilized stope analysis and genetics. This one's gonna be from some physiological parameters like, you know, we do a regular blood panel at your doctor with calcium, dissolve oxygen, dissolve carbon, stuff like that.

Speaker 2:

And, yeah, we're gonna hopefully, she looks pretty calm right now. We're gonna collect about 15 milliliters of 15 cc's, excuse me, of blood if we if we can. While

Speaker 4:

collecting data on this individual turtle, the team realized they had captured and interacted with her on several other occasions. First in 2016 in Seal Beach, California, then in 2017 in the San Diego Bay, and now a third time nine years later.

Speaker 2:

After you've seen so many of these animals for so long, you start to actually identify individuals and see one and I actually remember that individual female. She was a lot smaller. We got it by remember from the mark on the back of her carapace that it was the same animal. And actually, Callie just shared information with us today that that animal's first, tagged in Seal Beach refuge. So we're always talking about connectivity between the foraging grounds.

Speaker 2:

The Seal Beach, you might not know is a 100 miles about north of us about it's a different foraging ground and we really don't see overlap between turtles that forge in San Diego Bay Verseal Beach, or other. So the California foraging spots are usually pretty they'll bounce around off the coast and find their foraging in, but I wouldn't say they pre stay they stay site feed all to those spots and this one was actually one of the first ones that was first tagged in Seal Beach, National Wildlife Refuge, came down to San Diego Bay, tagged it '7 2017. We didn't know it at that point that it was from Seal Beach. We just now then, now it's been in San Diego Bay but we we like, who knows how many times it's visited Seal Beach back or it's been staying in San Diego Bay. So I mean, yeah, that's part of like, part of the joy of, like, being able to, you know, experience these long term data sets and doing these long term coverage.

Speaker 2:

You get you kinda get to know the animals. I feel like they're you get to see individuals. You kinda get start to get to know them.

Speaker 1:

We don't have many turtles that we've captured at multiple different locations. It's probably fewer than 10 that have come popped up in these different areas. So that was really cool. So we caught it in 2016. About a year later, 2017, now here in San Diego Bay.

Speaker 1:

And then like you said, nine years later, yesterday, caught it here in San Diego Bay. And when we looked at the size, I think it was around 70 centimeters curved carapace length when we caught it the very first time in 2016. It was about three centimeters bigger the next year when we caught it in San Diego Bay. And when we cut it yesterday, it was almost a full even nine sorry, 100 centimeters long. So a full meter and that makes 30 centimeters of growth over ten years which averages three centimeters for every year, which is a really impressive growth rate for a sea turtle that's that big.

Speaker 1:

We expect more growth when they're juveniles and they're smaller and they need to grow big to sorry, grow fast to get big and have that predator avoidance and stuff. But to see that sustained growth through the nineties and up to a 100 centimeters is really cool, and it really supports what we see for most of these turtles that they get really big, the females anyway, before they start nesting, and they were potentially that turtle is probably easily 20, maybe 30 years old. So clearly, was excited about seeing this turtle looking at that growth and it was in such good shape, know, really robust, healthy. So it's it's apparently seems happy making San Diego Bay its home, so that was really neat to see. Seeing that we have so many turtles and they're still all doing really well is a really good indicator that the South San Diego Bay and the whole bay in general is providing what the turtles need.

Speaker 1:

Right? The temperatures are good. The food availability is clearly supporting all of these turtles too. And again, that longevity. Right?

Speaker 1:

The turtles do stay as year round residents in San Diego Bay, but they do migrate out. We've we have those satellite tags. Again, some of them that will go out of the bay and kinda make forays offshore. We've tracked some of them circling the Channel Islands and then coming back in. They'll often go down to Mexico.

Speaker 1:

We know that that is their their mating and their breeding grounds are in different places down in Mexico. So they'll make those those trips, but it shows us also that they're navigating well enough to go, you know, offshore, down to Mexico or wherever it is, and then come back in and navigate through San Diego Bay, which is obviously a very urban habitat, a lot of shipping, a lot of naval activity. And so it's it's encouraging for us too when we see these turtles that come by and are able to navigate all the gauntlets that, you know, nature and people have thrown their way.

Speaker 4:

As Callie had mentioned, the San Diego Bay is a very urban environment. The turtle we examined during our field day was very healthy but that isn't always the case. In fact, just a few days earlier, the team had captured a turtle that had a severe crack in its shell which presumably was from a boat strike.

Speaker 1:

This is a big part of our research too when we're focused right here and, you know, we have these wild animals that are very big 200, 300 pounds sharing this habitat with us people and who also like to enjoy the ocean. So it's not just our fishing activities, right, we have to take our boats typically to go fishing. And just with these green turtles that do come near to shore, there's a lot of other activities that people do on the water whether it's jet skis and other things like that. They're they're all over the bays around here in Southern California. Mission Bay has a population of, I don't know how many turtles, they are regular spotted, regularly spotted by folks who are out there, and that area is just full of speedboats and jet skis, and you're right.

Speaker 1:

We do see a handful of turtles every year that have some sort of trauma that is most likely due to boats. And so, that one turtle that we saw was pretty remarkable, the big break through the back of its shell with those kind of parallel markings through it, that's just kind of a textbook example of what would happen when a turtle's hit by that boat and the motor and propellers kind of going through it. And the fact that that turtle was healing up so well really is a testament to the resiliency of these animals, but also the dangers of living in these kind of very urban areas. And so that's a really hard part for us to see in our research. And so it was a little bit heartening, even though it was really unfortunate to see that turtle was heartening to see that this one was able to survive.

Speaker 1:

Because again, there are so many times where we just see the turtle and it's it's already dead by the time that we have to go respond to it.

Speaker 2:

It's a challenge, you know, these urbanized areas I mean, people gotta live, and we live in cities, but these these animals will settle where, you know, their resources and their resource needs are met. So it's it's a mixed bag. You're happy to see that the animal can recover and is doing fine in the in the South Water of San Diego Bay, but it's also, you know, you don't like seeing these animals being hit by boats or whatever made probable strikes by vessels or human impacts that are causing these injuries. And, you know, it gives us motivation to keep working to, like, help, you know, keep mitigating these plan mitigating these events in the future, trying to create more awareness for users of these water rays and know, hey. Sea turtles are here.

Speaker 2:

You know? Use more caution. Maybe we can prevent these injuries from happening, but it's also good to know that when these injuries do happen, these animals are affected by, you know, urbanized centers that they are they do have somewhat of a protective status, and we do have, like, like, research and monitoring programs that actually enable us to check on these animals and actually see severity and and the, you know, the occurrence and the frequency of these incidents and injuries so we can get a better understanding like how we're mitigating these threats, how these animals are dealing with these threats, and maybe learn to live in a more harmonious way, still in these urbanized systems with these animals. Alright. Here we go.

Speaker 4:

After all the data and research is collected, the best part about the field day is when the team is able to release the turtle back into the bay.

Speaker 2:

It is artificial to take these animals out the environment, sample them. Is more invasive than know, some people would think you should have a hands off approach, maybe observing, do minimal invasive. Once we get them out of the sample here and we put them back in the water to see them release, it's kind of just like that snapshot of like, you know, a a turtle being healthy, doing what it's supposed to do. It's like the turtle, you know, leaving the nesting beach, going return back to the water. And it's like, we know it's not nesting where we're doing our work and we're releasing it manually.

Speaker 2:

But I think it's just that like one snapshot of like what a sea turtle's life should be, you know. Be able to safely enter and leave the oceans, continue their life cycle, and it's just awesome to see these animals that have didn't, you know, evolved to be perfect in the water. See them, you know, use their flippers, you know, scoot along land and then gracefully enter and just see this, like, this creature has been here for millions of years. Can you do this thing? And just to for me to be alive during in that in a small window at the same time is just fascinating.

Speaker 2:

Like, I just feel very fortunate and it's just awesome opportunity and just I think that's why it's appealing to see the animal, you know, transition from where we're based on land in our element, go back to the water where it inhabits both, you know, it can do both so.

Speaker 4:

The day after our field day, I visited the Noah Southwest Fisheries Science Center in La Jolla to further chat with Callie about the team's research, specifically about skeletonology and the early stages of a sea turtle's life known as the lost years.

Speaker 1:

These are some of the humerus bones from dead stranded turtles. So anytime a dead turtle is recovered, we will go do necropsy on them. One of the key samples that we collect for this research in particular are these humerus bones. So it's the upper flipper bone of the turtle. This is actually from a turtle that was recovered in the San Diego Bay.

Speaker 1:

It was found a long time later after it had died, so that's why it's marked mummy on here. But the size of the bones definitely, reflects the size of the turtles. So these are from much smaller turtles, probably under 70 centimeters. They get a little bigger, but they get much bigger than this up to about this big for some of our 90 to to a 100 centimeter turtles. So here's one of the humorous bones that we recovered from a dead stranded turtle actually very near our field site in South San Diego Bay.

Speaker 1:

And you can see all the discarded fishing line that was completely wrapped around it. I've probably seen at least five of these. Some of them on turtles that are still alive. So, you know, this fishing line had wrapped around, had dug all the way through the flipper, through its muscle and everything, down to the bone. And you can see it's almost, what, a full centimeter plus dug into that super thick, super strong bone.

Speaker 1:

Obviously, this turtle did not survive. The fishing line was wrapped into its mouth and in through its its line. So very unfortunate way for the turtle to go and sadly far too common in our kind of urban waterways. Skeletocrinology, again, is the basically the analysis of growth layers within bones. And so for hard shelled sea turtles, so all sea turtle species except for the leatherback, it's the humerus bone right here that we talked about earlier getting wrapped up in that fishing line.

Speaker 1:

But that humerus bone, when you cross section it at a very particular point, has these annual growth rings, think about rings on a tree. And so that's been a technique that has been acknowledged for a very long time that these humerus bones, and that's true for all vertebrates that have these long bones, they have that to some degree or another. And I think, again, some of the sea turtles stuff goes back to, like, the nineteen thirties that we're acknowledging these growth layers. But George Zug was one of the first researchers in the late eighties who kinda documented really well that for these species, this could be a potentially great tool. And so we had talked a minute ago about how some of these turtles do dead strand.

Speaker 1:

I think that this is one of those, you know, silver linings that comes from a turtle. If it does end up dying, we can still use these bones from those turtles to learn more and protect and understand the turtles that are still alive. So when we get that bone, we take it into the lab, cross section it, decalcify it, make this really thin little paper thin cross section of it, stain it, and put it under a microscope to image, and when we do that, that's where we can identify these growth layers, and they're separated by these lines that we call LAGS, which stands for layers of arrested growth, and we can essentially estimate the age of the turtle by counting the number of growth layers that are there with this, like, correction factor that gets applied, because as turtles grow, the middle of the bone does get reabsorbed. So it's not a perfect record like you would get with a tree, but it ends up giving us a really good estimate of that turtle's age, and there's no other way to age sea turtles right now. We're hoping that we can build these tools, which we have research in progress right now using epigenetics, and so hopefully one day we can use this epigenetic clock to age turtles using just a skin sample or a blood sample.

Speaker 1:

But in the meantime, this is the best that we've got. And so we can estimate not just the age, but also the turtle's body size, which then gives us this growth rate, which is a great way to kind of track and basically estimate the full life cycle of these turtles. And so to your question about the lost years, it's, you know, if we get a turtle and it's been dead stranded and it was say 60 centimeters in size, that bone will typically retain most of its first years of its life. And that fills in that gap, specifically when we combine it with stable isotope analysis, and this was a lot of what my PhD work was on, was trying to develop this technique of how can we combine these two methods to basically recreate this history for multiple years in a row for an individual turtle, which again, there's no way you can do this for a turtle, right? They live in these wide open oceans, they live for a very long time, but when you put these two techniques together, the Skeleto ISO approach, you can start to look at the chemistry of each of those individual bones and when the turtle is off shore during that oceanic phase, those lost years phase, that will have a very different isotopic signature than it will once it settles into a near shore habitat.

Speaker 1:

And so by looking and seeing what age and body size that turtle's chemistry shifts, that's when we can say, you settled into the San Diego Bay when you were about fifty centimeters, about six years old, therefore your last year's stage was about six five to six years long. And that's really helpful for us when we're trying to think about the threats that these turtles might encounter during their lifetime. Right? Are they susceptible to offshore fishing, you know, for four years, five years, fifty years? What is that compared to the time that they're spent exposed to the near shore threats and interactions with people?

Speaker 1:

So from the management point of view, our goal again as a scientist is to provide that really robust science so that management can make decisions that are most efficient to protect these animals, and again also make that we can keep doing the fishing that needs to be done.

Speaker 4:

The green sea turtles that call the San Diego Coast home are largely and almost entirely from Mexico. Callie and other researchers know this because of a biological and genetic concept called a haplotype.

Speaker 1:

And so that's one of the foundational things that happens here at the Southwest Center. Also, members from our team in the marine mammal and turtle division, there's a marine turtle genetics program, and they've done fantastic work. Again, this is using just a small skin sample. They can look at the haplotypes of the turtles that we have here in our foraging area, and what they'll do is, using a vast network of partners from all over the world who have also collected skin samples from nesting beaches, characterize their haplotypes, it basically becomes a matching game at that point. And so if there are unique haplotypes that are only found, say, at the Rivieraos Islands, and we see our turtles here in San Diego Bay with that same unique haplotype or, you know, one of the six unique ones, whatever it is, that tells us, okay, these turtles are most likely from that Riviera's nesting population versus turtles that are, say, in the main mainland.

Speaker 1:

Michoacan is the main state in Mexico where these sea turtles that we find in Southern California anyway are coming to, and that's the nesting beach at Michoacan is kind of one of the index nesting beaches where their populations have just really imploded in the last few years in a really good way, just continue to climb, and again, is a testament to that international protection and conservation, but especially the efforts that have happened on the nesting beach there in Mexico to allow this population to recover. So, anyway, by playing that matching game with the haplotypes, we can start to get an idea of the percentage of turtles, say, in San Diego Bay that are from Michoacan versus Rivieraeros. There's a handful that have been tracked to nesting beaches in Hawaii, or Galapagos, we've got a few of them from there, a couple Costa Rica, but most of the turtles that we find in Southern California are from the Riviera Jarras Islands, and those turtles are kind of classified based on, you know, collaborators' research. Those turtles end up being really big, much bigger than the turtles that nest for whatever, for a variety of reasons. The turtles that nest at Michoacan tend to be smaller body size than those Riviera Jados turtles are, and so that kind of tracks with what we've seen in the field the last few days too when you've been out there with us, right, this turtle that's a 100 centimeters and is still growing, very good chance, I haven't looked at her haplotypes yet, but very good chance that that turtle would have a Riviera hados haplotype just given her body size and her growth that we're seeing.

Speaker 1:

So it ends up being a really nice piece of the puzzle when you can track them back to their origin. And this is done by researchers, sea turtle researchers all over the world and is a really valuable tool. And as genetic technology continues to improve, the refinement gets better and better. So using tools such as microsatellites and other things that are kind of beyond my expertise has been a really fantastic tool to see just take off in the last even five years.

Speaker 4:

Just as Callie had said, thanks to decades of sustained conservation efforts, green sea turtle nesting sites are seeing population surges all across the world. However, these population booms are facing a large threat, and that threat is the rapid change of the Earth's climate.

Speaker 1:

Warming temperatures, both ocean temperatures and air temperatures, is definitely something that researchers of any ectotherm are definitely paying attention to for obvious reasons. So, you know, in the water, changing ocean temperatures is making us pay extra attention to kind of where in the ocean these turtles are found, with the idea being that their distribution just in the open ocean could shift. Right? So if these sea turtles who follow have this kind of like high fidelity to certain temperature bands, if those temperature bands are moving or shifting, then it means that those turtles will follow those temperatures, which is where their food is. And it's important for us as the managers, again, to know when and where those shifts are happening or might potentially happen in the future.

Speaker 1:

So that's one big part of sea turtle research and kind of warming temperatures. The other then then you said is the air temperatures and that what you see on the nesting beaches. So again, sea turtles, ectotherms, the sex of the hatchlings that are born are determined by the temperature at which they incubate in the nest. The temperature is called the pivotal temperature, and it's kind of this theoretical temperature where the turtle will either be, if it's over that temperature, so a warmer temperature, the turtle's gonna be a female, and if it's a lower temperature, then the temperature or the sex of that hatchling will be a male. And it's kind of a fantastic evolutionary design when you think about it, right, these turtles are in this big nest, kind of a big basketball shaped, you know, size collection of these eggs, and the turtles on the outside are gonna be exposed to, you know, the rain and the cooler temperatures, and that will typically be the males from that clutch, whereas versus the ones that are in the center are kind of incubated even more by those that are surrounding it, and those tend to be the female.

Speaker 1:

And so it's this great design to get, you know, approximately a fifty fifty mix from of males and females coming out of each nest. However, if the temperatures on the beach are increasing such that that all the nest or most of the nest is above that pivotal temperature, you end up with way more females and way fewer males. And so this is a very active area of research in sea turtle research around the world, is trying to track what are those nests doing, what are those temperatures like, using a lot of different tools, different bio loggers that folks will put into the nest to try to track, you know, if we assume that this pivotal temperature holds and is true for that particular nest, what then would we predict is the male to female ratio coming out of each of these nests. And the results are all over the place, but more and more it's trending that, yes, we're getting this much more feminization happening where there are way more females coming out of each nest and then showing up in the foraging populations. We've been doing the similar research for our foraging turtles here in Southern California.

Speaker 1:

There's a study that came out just over ten years ago, I guess it was in 2014, that developed a new technique to look at the sex of ratio of turtles, and what you basically do is use blood samples, just like we collect in the field, and you're looking at testosterone as the indicator, right? Because there's no genetic XY chromosome in these reptiles. And so you use the testosterone level to assign a turtle that you can't tell just by looking at it based on tail size. So using it especially for those juveniles to determine the male to female ratio. And that study, again, published in 2014, said there were about three females to every one male in this foraging ground.

Speaker 1:

It's now twelve years later, we have that much more samples in the freezer, and so we just finished all the lab work, just a couple weeks ago actually. Looking at that, the data's still pending, we gotta still do a whole bunch of analysis on it, but it's looking like that level has increased even more where it's even a higher number of females to males. And so, again, this is kind of the pattern that researchers throughout the world are starting to see. And then I think, in my opinion, the next big question is how adaptable are these sea turtles? Again, these turtles have been around for millions of years.

Speaker 1:

So it's really an interesting thought exercise and we're kind of seeing it play out in real time, is how do these turtles change? Right? This pivotal temperature we're talking about, how fixed is that? We already know that different locations around the world, typically higher latitude or lower latitude ones, have different pivotal temperatures, so we know there's some flexibility in the species in general. But then thinking about even within a single species, in a single population, at a single location, might that pivotal temperature change over time in response to the continued warming that we see happening?

Speaker 1:

And if that's the case, then, you know, this might be a a self correction that could happen, but who knows how long that will take, if it will occur, and so again, this just goes back to something I've said before already, is that this is why it's important for us to continue to do this long term monitoring to collaborate with partners around the world to really keep an eye on on this and to see what happens in the future.

Speaker 2:

Feminization is a concern just like any other all these other threats or potential threats that the animals face a concern, but it's also, we know these animals are very resilient. I mean, it's not an excuse to, you know, ignore what's going on with changing environments or pollution because, oh, the animals are resilient. You know, we, we see them survive everything. But there is hope though. Like, so why we study and we we, you know, examine these possible things with caution like feminization and, other things that go along with like habitat destruction with changing climates and environments.

Speaker 2:

There's also a little bit that's tempered with little hope and that fuels these efforts because we know these animals are resilient. And if we can give them, you know, a little bit of a break or, you know, at least do our part in mitigating our impact on them, these animals will thrive and will continue to persist because they are. They're they're they're strong, they're they've been here millions of years like I said and so it's it's kinda yeah. It's, there are concerns with with stuff like that but it's also an opportunity, you know, like, hey, these animals can do okay, we know they can if we just give them like little protection and we understand them a little bit, these animals can persist, you know. And it's it's really like I said, these animals persisting now and the ability to even observe that how strong they are and how, like, you know, resilient they are is basically a testament to all the conservation work done that was done for the past decades on this their main nesting beaches like in Mexico.

Speaker 2:

Like, all those people that all that community conservation, all that work, you know, reducing fish interactions, protecting nesting beaches, stopping the egg poaching, all that is the reason why we have these animals come back really in abundance up here because we're we we just monitor pretty much our forging grounds, which is important, but a lot of that work and a lot of that aid to the resiliency was done in past, I guess, you know, those nasty beaches. So it's it is, it's troubling to think about those things, you know, like the feminization of how how changing environment is gonna affect these animals, but we know that, you know, the earth does change. And these and the animals, you know, can individuals don't adapt, populations do, but these populations can adapt. And we know that if with a little bit of our knowledge and understanding, we can make an impact and change, you know, the trajectory of these species by, you know, just doing a little bit and understanding their life history and doing our small part.

Speaker 4:

Anna Cahill is a lab technician with the Marine Turtle Ecology and Assessment Program. She wears many hats within the program but one of the things she's most passionate about is community outreach and working with citizen scientists.

Speaker 3:

I love doing outreach because people in San Diego get really excited to talk about our turtles that we have. A lot of people don't even know that we have sea turtles in San Diego, so to be able to go out to communities that have spent time in the cove or live near San Diego Bay and you tell them that there's 200 turtles in the bay and they go, what? There's no there's no there's not. No way. And you just say, nope.

Speaker 3:

Yep. They're out there. Like if you go out there on your kayak or your paddleboard, you'll see heads pop up left and right. You can let them know they're coming from Mexico. They're just you know, you you live in San Diego and there's so many amazing things going on all the time that to to kind of live in San Diego and find out that we also have sea turtles is just like totally mind blowing to some people.

Speaker 3:

And because sea turtles are such a beloved animal in general, it's really exciting to watch people get so passionate about getting boats to slow down nearby or spreading the word that they're sea turtles so people take better care of the environment around San Diego Bay or the cove or letting people know that we have photo ID projects where if you go out into the cove and you take a picture of a turtle, you're directly contributing to really important data. People get super excited and they get right in the water with their camera because they're they're just super psyched to be involved. And I think it's really important that people know that it's very easy to get involved with our local turtle research. So, yeah, it's just it's awesome to get out there and talk to people and see how excited people get.

Speaker 4:

There are many volunteers that support the teams at NOAA and with the Marine Turtle Ecology and Assessment Program. But there's one citizen scientist in particular that stands out and her name is Tracy Tempest.

Speaker 6:

Sea turtles are just mean everything in the sense that conservation and how important they are to our environment and they remind me of one of my best friends and that's how I got into it, seeing them.

Speaker 2:

So Tracy is a a is great example of why citizen science is important. So Tracy became involved in our team over the last, I would say, five years really, pretty much since post COVID a little bit before, and she's just been more and more valuable and useful. Like, she's our she pretty much the eyes our eyes and ears on the water in South Bay because she lives right there and she kayaks there every day and she's our turtle recon. You know? She gives us the info where the turtles at so we can maximize our capture effort, you know, maximize our time out there so we're not wasting resource.

Speaker 2:

We go out there, find where the turtles are, know where to put the nets, and they know it's it's because in water, turtle work, like I said, is very hard to do. So anytime we get a leg up or a little insight on how to capture these animals better or where they're at is really helpful. And Tracy's just been just a great ambassador. She's been a great citizen scientist, and she's been just, like I said, a great community liaison too for the work we do. Because, like, our work too is really based on our our shareholders, our stakeholders, which is the public.

Speaker 2:

You know, public's interested in sea turtles or charismatic species. Public likes sea turtles. The public wants healthy fisheries. Sea turtles and go hand in hand with having a healthy productive fishery and and other protect you know, protecting other essential productive resources. So, Tracy yeah.

Speaker 2:

Tracy's, a great example of how community science can work, how citizen science does work, and how she continues to just keep, like, evolving her role in that, know, doing outreach projects and kind of she's actually a component of her work with us that we don't really talk about too much. She's really communicating our science a lot. In science, there's always this little bit of gap. It can be wider or smaller depending where you're at, where you're trying to communicate and the communication of your science, how to get what you're doing out to the public and have people understand and, like, you know, take interest in what you're actually doing. I think she's a big part of that because sometimes a lot of stuff we do gets a little technical or a little, you know, ecology centric and then we get into our own world here doing what we're doing, but she's a great, conduit to the public.

Speaker 2:

She'll take, you know, she has experience out there capturing, doing the research we do and then she'll go to like local, like elementary schools or local libraries like Coronado or local, like, Cabrillo National Monument, local and give, you know, public presentations along with other staff members to the public and that just that just helps and keeps, you know, helps in their, continued conservation in the future. That's that's a really unsung part of, like, I think ecological conservation now and moving the future is gonna have these citizen scientists who are, like, the bridge to not only assist us in our research but communicate to our our stakeholders and our and the public, like, what we're doing effectively because they are the public. And it's it's kinda like, yeah, they're they're they're the public's, like, citizen scientists into our program and helping us, you know, achieve all the goals and the recovery goals that we're trying to do.

Speaker 1:

We call her the turtle guardian and, you know, all sorts of other wonderful names, but she is so passionate and dedicated. She goes out on her kayak almost every day out on the San Diego Bay, leaves out and is down right by her field side out of Chula Vista near the harbor, and has continued to bring more of her friends and her neighbors and family members and everybody out there on kayaks with her and every time that she's out there, she'll send in one of those sightings reports. And we now have this fantastic distribution. It even guides where we set our nets yesterday when we were in the field because Trace is like, hey, yesterday, this is where we saw three, four turtles. And we go there and sure enough, we'll get turtles in our nets because that's what she's seen.

Speaker 1:

So it's this real time feedback that we get from her because we see her when we're in the field. She comes and joins us and is a critical team member for us too now.

Speaker 6:

It's just unbelievable to be able to have the opportunity to work with these scientists and more importantly to share with them the various sizes that I'm seeing that they don't get to see on the water.

Speaker 4:

The recovery of the green sea turtle is one of the greatest conservation success stories of the modern era. Since the nineteen seventies, global green sea turtle populations have increased by an estimated 28%. Thanks to decades coordinated conservation efforts. Protecting nesting beaches, reducing egg poaching, requiring turtle excluder devices in commercial fisheries, and restoring critical habitat have helped populations rebound across much of their range. In recognition of this remarkable recovery, the International Union for Conservation of Nature reclassified the green sea turtle from endangered to least concern in 2025.

Speaker 4:

While some regional populations still face significant threats from climate change, fisheries bycatch, coastal development, and pollution, the green sea turtles recovery demonstrates that long term science based conservation can reverse decades of decline.

Speaker 2:

That's one of the great conservation success stories. I mean, people tons of people put in decades of work to, you know, change that trajectory of the green turtles at least in the East Pacific and it's it's really nice first to see, you know, the all the efforts and the actual work that was done by people before me, you know, that really pay off and actually see change. That's one of those things when you get into conservation. It's you know, there's a lot of a lot of problems and a lot of challenges facing a lot of systems environments. It's sometimes a lot of doom and gloom, but it's great to actually see a conservation success story so tangible and so directly related to, like, what we do and and the outreach and, like, you know, for species like sea turtle so charismatic, so many people know to have a conservation success story and to show that, you know, effort and dedication and persistence can make a difference is is really motivating.

Speaker 2:

And I'm just I hope in the future that whatever was done, you know, all the effort that was done for the green turtle, other successful species like that can continue to be, you know, carried out in the future and be adapted to, you know, overcome future challenges for different species that are still under pressure, facing endangered status.

Speaker 1:

I think it's a good thing. Right? These turtles being delisted, being brought off of that highest concern and having it kinda come down to not be critically endangered is really what we're ultimately working towards. Right? Anybody doing endangered species research, that is the goal, think, to do the research, to implement the actions that can, you know, bring that population back to a safe level.

Speaker 1:

And so I think it's a good thing. Yeah, look at the numbers of turtles that we're here seeing off of our in our waters here off of Southern California. Definitely supports that kind of recommendation. You know, and a lot of science went into looking at those two. Think, yeah, overall, I think it's a really wonderful thing.

Speaker 1:

I think it also introduces new, discussions that is, are being, taking place here in the sea turtle community and other communities really around the world of like, well, what does that mean now that they're here? Are there uses that have been prohibited for a very long time that maybe now should start to be reconsidered? And I think it also warrants a bit of caution to, you know, be like, celebrate this victory, consider implementing changes, you know, as appropriate in certain locations, but also, you know, don't be completely irresponsible. Right? Don't throw out all the hard work that folks have been doing, and continue up with those efforts that are taking place to protect turtles nesting beaches and in their foraging grounds and on the high seas to so that we continue to have this trend of increasing and recovering populations.

Speaker 1:

But it it does introduce conversations that haven't been had before because, you know, in the past hundred years, these sea turtles have not been in the conditions that they are now, and so these are potentially old, old conversations that are coming back, just given this recovery of the numbers. So overall, I think it's a great thing, and I look forward to continuing to do my research with this kind of new era that we're in with sea turtle populations.

Speaker 4:

So how can you help?

Speaker 2:

Different populations face different threats at different parts of their life history, different parts of the world. Right? Different play different populations of different species of turtles are different, you know, extinction status compared to other ones like the green turtle you said is now on the recovery end. I would say though overall because most turtles, most species turtles face these unwanted human interactions, fishery interactions, the open ocean where there's not any kind of like, you know, open ocean international waters, there's no no no country boundary and there's no really laws. Just be really responsible how you consume your seafood, where it's coming from, and knowing the impact of the seafood you eat, where what impact it's having.

Speaker 2:

Because a lot of time, these these turtles, a lot of species of turtle are caught in these incidental fishery interactions through long lines, through, trawl nets, through drift gill nets, and The US has done a lot to mitigate these and put in, like, practice standards to mitigate these and make sure our fisheries are acting but a lot of places around the world don't. So I would say overall to be a person who'd be pick up your trash, don't not treat the ocean that do not litter, not put anything ocean doesn't belong there, try to remove it, anything that in the ocean every time you visit that wasn't that's not supposed to be there And, you know, just be very conscious of where you eat your seafood if you eat seafood, like where it's coming from, the fishing practice practices where they where they catch that seafood and just, you know, how how that industry is affecting the habitat where those turtles come from. And, you know, it's proof each each turtle species and population faces their own threats where they're at. So it's hard to say about on a macro level. And one thing everyone can do is just be really conscientious of where you're getting your seafood and we are part in, you know, the essentially the plastic pollution in the ocean, so

Speaker 1:

The things that I would recommend, number one, just, you know, pay attention if you are out on the water. If you see an area that is marked with, you know, turtles here, go slow zone, definitely do that. If you're out fishing, enjoy it, have fun, but like take care of your gear, throw away the fishing line or the nets when you're done with it kind of thing. Just even if you're in the streets, you don't even have to be at the beach, but right, the the trash in our streets goes down through the watersheds and ends up into the ocean, so keep the streets and things like that clean and it'll keep the pollution out of out of the ocean where the turtles are commonly found with that plastic in their stomach because it ends up into the ocean. And making smart seafood choices, I think that's the other thing and has to be said.

Speaker 1:

I'm here, sitting here at NOAA Fisheries. I love seafood. I think it's wonderful. I encourage people to eat and consume and find all the cool stuff that chefs are doing with seafood in restaurants these days. But there are some seafood that's better than others and so there's great guides that you can use.

Speaker 1:

Again, Fisheries has some really neat stuff that helps you make safe decisions. Monterey Bay Aquarium has a great seafood watch guide that can help you make those those smart decisions too and and those are the kind of things that will protect those oceans out in our waters.

Speaker 4:

As I'm sure you can imagine, there are a lot of people and organizations involved in this research. But for this episode, I'd like to say a special thank you to doctor Callie Turner Tomasiewicz, Garrett Lemmons, Anna Cahill, and Tracy Tempest for participating in this podcast, but also for their amazing work to ensure the long term health of green sea turtles. I hope you feel inspired to join in as it takes all of us to protect our oceans and to ensure the long term health of the species that call our planet home.

Speaker 3:

When I'm watching a turtle kind of crawl its way back into the water after a field day, I'm always wondering, you know, where are you gonna go next? Are you gonna go swim to Mexico now or are you gonna stay in the bay for a couple years? Will we see you next week? Will we see you in ten years? I don't know.

Speaker 3:

What's gonna happen between the next time we see you and right now? It's just amazing what pot like what they could possibly do in the time that it'll take for us to see them again. And I always kinda wonder what they're thinking when when they are going back into the water and what they what they think of the experience that they just had and, how that's gonna affect their next move. Yeah. I'm always kinda thinking about that.