Lemon Sharks

Alex Re

Hello, welcome to on wildlife. I'm your host, Alex Ray. On this podcast, we bring the wild to you. We take you on a journey into the life of a different animal every week. And I guarantee you you're gonna come out of here knowing more about your favorite animal than you did before. I think this episode is the perfect way to start off the new year because we have a special guest. Today, I'm interviewing Felicia dilemma, who is a researcher at the Bimini biological Field Station. She studies the personalities of lemon sharks, which is just so cool. So get your scuba gear ready because we're heading to the coastal waters to talk about lemon sharks.

lemon sharks can be found in both the Pacific and the Atlantic Ocean, and they like to live in more shallow waters near coral reefs and mangrove forests. mangrove forests are waters that have aquatic shrubs called mangroves in them. You may be wondering why they're named lemon sharks and it's because of their yellow coloration. These yellow coloration acts as camouflage in the shallow waters against the sand. But they don't need the camouflage to hide from predators. As not many things are trying to eat them. They use this camouflage so that their prey can't see them coming. They also like to live in groups of around 20 tending to group with individuals that are similar in size to them. Adult lemon sharks can get huge, growing to be around 10 feet long, and weighing over 500 pounds. I don't think many ocean creatures want to mess with one of these guys. They can also live for around 30 years with the oldest recorded lemon shark living to be 37 years old. And as I talked about in the white shark episode, sharks have been on earth for over 400 million years, which puts them in the same time as when the first trees appeared on Earth. lemon sharks are carnivores and they eat many different sea creatures including crabs, other fish and race. And they have really good vision and can see clearly under the water. But they're also able to use electrical signals to sense their prey. And we're going to talk more about this in my interview with felici. lemon sharks don't reproduce until they're about 12 years old. And female lemon sharks are actually polyandrous which means that they'll mate with more than one male and they give birth to live young so they don't lay eggs like many fish do. The mothers give birth in the shallow mangrove forests and the pups live in the nursery for multiple years. Unlike the adults, young lemon sharks are susceptible to a lot of different predators. So staying near the nursery is key to their survival. lemon sharks also have some other relationships not involving their own species. They have a mutualistic relationship with another fish called a remora fish. A mutualistic relationship is one where both species benefits remora fish have a suction cup on their head, and that helps them stick to the sharks while they're swimming through the water. In return for a free ride around the ocean. remora fish perform unimportant favor for lemon sharks. lemon sharks will lay down on the ocean floor with their mouths wide open and the remora fish will hang out inside their mouth and eat anything off the teeth of the shark. So the remora fish get a free meal while the lemon shark gets a free dental cleaning. Sometimes the lemon sharks do get a little hungry though, and they end up eating the remora fish. Okay, we're gonna take a break. And when we get back, I'm talking with felici dilemma about her research with juvenile lemon sharks and their personalities. So make sure you stick around.

Time for a trivia question. How many species of insects are there currently in the world? A 1000. b 10,000, c 100,000 or D 1 million? The answer is D. There are over 1 million different insect species in the world. Okay, we're back. Here's my interview with felici Hey, Felicia, how you doing?

Félicie Dhellemmes

I'm doing good. How about yourself? Good.

Alex Re

Well, thank you so much for coming on. I'm really excited to talk about lemon sharks with you.

Félicie Dhellemmes

Yeah, that's my pleasure.

Alex Re

So before we get into lemon sharks, can you just tell me a little bit about yourself?

Félicie Dhellemmes

Yeah, of course. My name is Felicity dilemma. I am a behavioral ecologist. And what that means is that I'm interested in what animals do, why they do it and what happens once they've done it hurt. their environment. And as you've mentioned, I study lemon sharks in the Bahamas.

Alex Re

Awesome. And you are a project leader at the save our seas foundation. And you also do some research at the mini biological Field Station. Could you just talk about these two organizations and what you do there?

Félicie Dhellemmes

Yeah, of course. So I am one of the project leaders at the sea versus foundation in the Bimini biological Field Station. The fill station is, as its name says, it is a fuel station. And what we're doing out there is shark research, show conservation. And the fuel station is trying to educate the future shark scientists. So we receive a lot of students and we teach them about shark research, and hopefully they become shark researcher, researchers themselves. And because Shrek research is very expensive. deceivers Foundation, which is a philanthropist organization, is funding us to do our research and funds Shrike project, shakin read projects all around the world.

Alex Re

That's so cool. And you guys are doing such awesome work. And so do you guys actually have sharks on the premises?

Félicie Dhellemmes

Yeah, at the Bimini biological Field Station, we'll be keeping a couple of lemon sharks and a couple of nurse sharks in captive enclosures, right next to our station directly on the beach. So we can show people show visitors what lemon sharks look like, what the what they do, etc. And then, of course, we don't keep them in captivity for too long. We release them very, very often in the wild so they can live their lives. But we always have sharks on the premises. That's so great.

Alex Re

So like more specifically about your research, you're currently doing research on the behavior of juvenile lemon sharks. So did the sharks have their own personalities?

Félicie Dhellemmes

Yeah, that has been one of my main focus. I study Shrike personality. And what we have found that is that indeed, sharks have their own personalities. And what this means is that, for example, they will be shy, that are consistently more adventurous than others, there are some that are really, really cautious. And they always say, really, really cautious. And you have new good ones out there who are always taking a bit more risks than their than their friends.

Alex Re

That's so interesting, and and how did their personalities impact their survival in the wild?

Félicie Dhellemmes

That's a very good question. And that's actually one of one of the most important question we've had about personality, and when we found out is that personality not only influences survival, but also influences the growth of the shark. So you have to know that I work with juveniles, and they still have a lot of growing to do before they become big and strong. And the most adventurous sharks are always the ones that grow the fastest, but they're also more likely to die. And that's probably because the they take so much risk requires so much resources to grow as fast as possible that they're not as vigilant. And they're more likely to encounter predators. And in the case of juvenile lemon sharks are predators, just a big shark is always a bigger side, and they're more likely to be eaten.

Alex Re

that's really such interesting research that you're doing. I don't think anybody would have thought that they have their own personalities. So what's something that you found in your research that you find that's really interesting, and something a lot of people may not know about lemon sharks?

Félicie Dhellemmes

So what's very interesting is that I've just described to you how more adventurous strike are more likely to die? That's right now Hmm. Well, we found out that it's not always the case. And in a same way, like if you were a very outgoing person, but suddenly you were in danger, you would probably stop being outgoing. Like, if you were, if you were, I don't know, threatened by someone you probably wouldn't be as are going, well, sharks do the same thing. So they're, they're able to adjust their personality, according to how much risk they're in. When there is a lot of predators around the outgoing sharks will stop being outgoing. This is a trigger, there's something that happens that says, Okay, that's it, we no longer no longer take risks. And I think that's really cool, because no one has actually found that in animal personality before in any animals. And I didn't expect that sharks had such a complex personality that they were able to kind of, you know, adjust to, to what the conditions are like, I thought they were gonna be way more simple, but they're actually very complicated beings.

Alex Re

Yeah, absolutely. And they kind of like our learning Learning from their mistakes almost which you don't really think about a shark doing that, right?

Félicie Dhellemmes

Yeah, that's right. So they they kind of they pro Yeah, exactly as you say, they probably just encounter predators. And a few times they're like, okay, there's quite a lot of them right here. So I'm just gonna stop doing what I'm doing. Really cool.

Alex Re

That is really cool. So, we know that lemon sharks are predators. And I've, I've read that they can pick up on electrical signals that other animals get give off. Can you talk a little bit about that?

Félicie Dhellemmes

Yeah, so this is actually a trait that I think every shark has, every shark has. They have these Oregon, that's on their nose, mostly, those are called ampullae of lorenzini. And they look like they look like little dots. They look like little blackheads on the on the news of the Shrike. And those include Reverend Zinnia, are filled with gel, and they're in Oregon that allows them to pick up electrical signal, as you said, and now Do you know what really emits a lot of electrical signals,

Alex Re

I would love to know.

Félicie Dhellemmes

So it's not your cell phone, although your cell phone does it. Every time a muscle is activated, it is activated by electrical signals. So if you move, you will be giving off an electrical signal. And now, even if you don't move, you have one muscle that is constantly working until you die. And that's your heart. So sharks are actually listening or sensing hearts of other animals and are able to find them thanks to those employee of lorenzini.

Alex Re

Wow, that's, that's really amazing. And I'm assuming that that's like their main sense, they don't really need to use their eyesight or other senses as much as that electrical signals when they're hunting for prey.

Félicie Dhellemmes

So this electrical signal sense is actually pretty short ranged. And I think, you know, sharks can actually see their mouth. So that's their way of being very precise. I think when they hunt, some sharks are much more visual than others. For example, the great hammerhead sharks have has extremely good vision, really, and the bull shark doesn't. But for sure, they all rely very much on these electrical signals.

Alex Re

Well, that's really cool. So do they have any other interesting adaptations that help them with finding prey or just surviving in the wild? Are you talking about lemon sharks or sharks in general? Either one, if you want to have information about lemon sharks, or just sharks in general is totally fine, too. So I have something cool to say about lemon sharks, actually. So I'm just gonna go with that. Absolutely. Have you heard that if shark stops swimming, they'll die? I've heard that Yes.

Félicie Dhellemmes

Right. So and that is true for many, many sharks. And these, a few reasons for that. The first one is that sharks need oxygen to go through their gills. So the water goes inside their mouth and out through the gills that are on the side of the body. And that's what provides them with oxygen. And if water is coming inside their mouth, then they're not getting any oxygen in the day. The other reason is, because sharks are not buoyant. And what that means is that if they're not swimming, they'll just sink to the bottom. So if they're in certain places, they might sink to 11 kilometers down. And that's not exactly exactly healthy. Now, lemon trees have a couple of adaptation that actually allows them to stop swimming. And the first one is that they are able to buco pump. What that means is that they know how to go air by cold water sorry, by themselves, and so they don't have to be swimming in order to get the oxygen that they that they need. They also have I don't know, if you like I guess if you think about a shark body as a cylinder, they will have fins below their body, right? Those are called the pelvic fins. And then they have an anal fin as well, when the limit check is not so much like a cylinder. It's a tiny, tiny, tiny bit flattened, and the pelvic fins are not exactly pointing down. They're mostly pointing to the side. And what that allows them to do is to just put themselves on the ground then not roll onto their side. They're actually very stable if they're on the ground. So what they do is they don't live in very deep water. They go to the bottom of the ocean and they just take us news, they just chill there. And that allows them to stop swimming and just take their oxygen the way they wanted.

Alex Re

Wow, that's that's a really amazing adaptation that like mostly other sharks don't have which is really interesting.

Félicie Dhellemmes

Yep. Yeah, subjects definitely come to that.

Alex Re

How are lemon sharks important to the ecosystems that they live in?

Félicie Dhellemmes

Well, no one could say is valid for most track species. They're, they're what's called keystone species, because they are usually pretty high on the food chain. They're very big predators. When they grew big lemon track will be three meters, there's not a lot that could eat them and track once it's adult. And so those species are actually regulating every single link of the food chain under them. If you if you imagine that lemon sharks eat fishes, and then that those fishes are eating seaweed, for example, if you remove the lemon shark, no one's eating the fishes anymore. And if there is too much fishes, all of the vegetation disappears. That will be like an example. That's what we call a trophic case cascade, and they kind of are under keystone of those things. Wow. So

Alex Re

they're really important to basically keeping everything stable and intact.

Félicie Dhellemmes

Yeah, the deck keeping everything in balance. Yeah,

Alex Re

absolutely. And so, lemon sharks are close to being a threatened species. So what what are the biggest problems that they're currently facing?

Félicie Dhellemmes

For lemon Shrike, the biggest problem is the disappearance of their nurseries. So lemon try give birth in the mangroves in the mangroves are a super important habitat for the little babies. That's where they find protection. And that's where they find food. And mangroves are really, really slow at growing. So whenever mangrove forest is being destroyed, that mangrove forest is going to be gone for years and years and years. Unfortunately, a lot of lemon sharks have what we call native Filipina trees. So that means that the female will go and give birth where she's born to her babies. So if she was born in a mangrove and that mangrove has been removed, when she comes back in this domain group, we don't actually know what she's going to do, is she going to find the nearest mangrove is she not going to find anywhere is she just going to put her little babies there, even though there's no mangrove, we don't actually know that. And that's super, super bad, because then it checks take years, maybe 14 years to reach sexual maturity. So when a baby's born, it's 14 years before it can actually reproduce. So it's very important that those baby had very, very good conditions to grow in. And if the mangrove is, is gone, they can't do it.

Alex Re

Yeah, that's and mangroves are really important for a lot of different species and even us, because they help they can help protect us from waves at that coming in that are too strong. Right? And can you talk about, like, what are some issues that are causing these mangroves to to disappear?

Félicie Dhellemmes

So unfortunately, the problem is mostly us humans. And the province that I knew the most about is about the building of resorts and hotels on particularly beautiful places like the Bahamas, where hotels need to be built, and they need to have an access for boats to arrive. So you can't have mangroves everywhere, because then boats Come come. Also, when these mangroves, these mosquitoes and tourists don't like that. So in a lot of cases, the mangroves will be taken away because of tourism. Yeah, which is, which is a real big problem.

Alex Re

Yeah, that's, that's really sad. And is there anything that we can do as average people in order to help lemon sharks and their habitats?

Félicie Dhellemmes

Yeah, I think it's very important to be very mindful of where we're going on holidays. And I know that right now, no one's struggling very much. But probably we'll all be traveling again at some point. And there's some hotel companies that are more mindful or if you want to go for ecotourism in places that include the natural world inside the police, were you saying is is actually really, really important. The other thing that's super important is to actually spread the word that sharks are not these mindless killers and they're, they're actually very important and they're very complicated, complex beings really. So I think those are the two main things we need people to love sharks and we need people to be more mindful of the places where this when they say

Alex Re

yeah, I sharks definitely get a bad rap and they don't deserve it. Because no important

Félicie Dhellemmes

here No, they really don't they this really any problems with sharks, they actually really, really shy animals. In most cases. It's they're fantastic. I hope people will end liking them.

Alex Re

Yeah, me too. They're really amazing animals. So before you go, can you just tell us where we can find information about save our seas Foundation and the Bimini biological Field Station?

Félicie Dhellemmes

Yeah, so you can find information about the mini biological Field Station on Bimini shark lab.com. So that's treating di n i, n i, and then shark and then lab.com. And as for the save our seas on station is save our seas.com. So if you're a young person motivated about science, visit the diminish icloud.com to find out where you can do an internship, and when to try to learn about check research. And if you are a young, sharp enthusiast, and you are looking for funding for your ideas, save rcs.com is where you're supposed to go. And they'll probably provide you with some funding to do your own research, which is awesome.

Alex Re

That's really cool. Well, thank you again, so much for coming on. I learned so much. And I know our viewers are going to love this interview. So thank you. My pleasure. felici is doing some really cool work. And I learned so much from that interview, who knew that sharks could have their own personalities. It really makes you wonder about everything we don't know about the animal kingdom yet. If you enjoyed that interview, and have a newfound love for lemon sharks like I do, you should absolutely check out the Bimini biological Field Station and the save our seas foundation. There are also some other great organizations to check out that help lemon sharks such as marine bio Conservation Society and Oceana. Thank you so much for coming on this adventure with me as we explored the world of the lemon shark. You can find the sources that we use for this podcast and links to organizations that we reference@www.on wildlife.org Don't forget to tune in next Wednesday to learn about a new animal and that's on wildlife. You've been listening to on wildlife with Alex re brought to you every Wednesday.

Transcribed by https://otter.ai