Skimmer Says... Horseshoe Crabs!

 It’s our favorite time of the year – horseshoe crab season! This month we have a lot of information about these living fossils. Tune in, with Taylor Beck, our Environmental Scientist, to learn all you can about the state marine animal of Delaware, and what your local NERR does during their spawning season. 

To contact the education team about an education program or volunteer event, email us at dnerrprograms@delaware.gov.

You can follow us on Facebook at @DNERR or Instagram at @delawarenerr.

Transcript

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Welcome to Skimmer Says in estuarine podcast hosted by the Delaware National Estuarine Research Reserve. We are your hosts. My name is Laurel. I'm Sadie. And Akshay is not joining us today, but instead we have our next guest co-host, Taylor Beck. Hi, I'm Taylor Beck. I'm an environmental scientist for Delaware Department of Natural Resources and Environmental Control, Delaware coastal programs. So essentially, I conduct research that benefits the state of Delaware and also the Delaware National Estuarine Research Reserve. Awesome, well thanks for joining us today. We're happy to have you here on the couch. Happy to be here. So one of the fun things that Taylor works on that we, Sadie and I, get to work with Taylor on is our horseshoe crab surveys. Taylor's been here for three and a half years. Three and a half years. Time flies. It certainly does. So we're going to get a little bit into the nitty gritty of all things horseshoe crabs today. But before we start on all the details, we're going to have a little game time! Everyone's favorite segment. So today's game will be two truths and a lie. And it's kind of like a test. But don't sweat it. It's easy. You know the information. So, first one, horseshoe crabs have ten eyes. Okay. Second one, horseshoe crabs are real crabs. Okay. And two, three, three and three horseshoe crabs are over 400 million years old. So the first one is true. The second one is a lie, and the third one is true. You got me. Horseshoe crabs have ten eyes. They have two compound eyes. So those are image forming eyes. So that is how they can see you walking on the beach as they come up to spawn. But it is also how they can find food or mates during spawning. The other eight eyes are all along it's body that are just light sensing eyes. So they're simple eyes. The second one that horseshoe crabs are true crabs. They're not true crabs. So when you look at the phylogenetic tree, all of them are animals. True crabs, like a blue crab, are animals just like horseshoe crabs. And they're also all arthropods. But then whenever you break it down further, horseshoe crabs are chelicerates. So they are in the subphylum chelicerata, which has also scorpions and spiders in them. And that is because they have this unique feature called chelicerae. So at the on a spider their chelicerae are those fangs. On a horseshoe crab they are these like two tiny little appendages that help them pinch and grab food and bring it to their mouths. And scorpions have the same feature, whereas true crabs are crustaceans and they do not have that feature. So that separates them, along the evolutionary tree from true crabs like a blue crab. So they are not real crabs, even though they are called crabs. And for those of you who are not watching us on YouTube, maybe you go over for this episode and take a look, because we will definitely add pictures so that people can see. We can. Yes, for sure. We can show that out. And then horseshoe crabs are in a class all to their own as well. They are in class merostomata, which just has the four different species of horseshoe crab in it. So that makes them, I mean, they look visually very unique from other things, and they are classified as such as well. And then the third truth was that they have been around for 400 million years. They are considered living fossils, been around on this Earth for a very, very long time. Well, since we've learned a little bit about the some things about the horseshoe crab, well, we can dive a little deeper about Delaware's species. Yeah, yeah. So Taylor had mentioned four species of horseshoe crabs, but we're only looking at one, correct? Yes. So there is only one species that is native to the American coastline. So the East Coast, so from the Gulf of Mexico all the way up into Maine. That is the Limulus polyphemus, if you're into scientific nomenclature. And they are the largest, of the horseshoe crabs, the other three species are found in like the South Indo-Pacific at different population sizes and ranges within that area. And it's like the tri-spine, the mangrove and the coastal horseshoe crab all throughout Asia have smaller, much smaller populations of those. Yes, they do look similar. It's actually neat to hopefully we'll have some pictures of each of them because especially like the tri-spine has very pokey spines and so there are some like fine, unique features between them. But we do only have the Atlantic horseshoe crab in our Atlantic coast. Yeah. So for the rest of the podcast, we're going to be referring to horseshoe crabs. And we're talking about our species that we survey here. Yes. So, Taylor, I know that you're not from Delaware. Correct. Can you tell us about the first time that you saw a horseshoe crab? So I spent a lot of time in the Gulf South, so in Florida, in Louisiana. And the first time I saw a horseshoe crab was probably in an aquarium, which I think is a very similar story for many people that are not from the Mid-Atlantic. And I remember being so very excited every time I saw a dead horseshoe crab carapace wash up on the beaches of like Pensacola, Florida, because it was so rare to see. But then whenever I moved here and started doing the horseshoe crab spawning survey, which let me paint you a picture. Hundreds of thousands of horseshoe crabs coming up on a small, essentially residential beach to spawn, and I was wowed. There were so many more horseshoe crabs than I ever thought were even possible to exist in such a small area, and they were all there to lay eggs and fertilize those eggs. And so it was really, really incredible and special to be a part of. Yeah, I think that's one of the things that we take for granted, like growing up in this area, is that there is this huge phenomenon that's happening in our backyards. And so you go somewhere else, like, I went to school up in Maine and I was like, yeah, the horseshoe crabs. And they're like, yeah, we see five. You've seen one? Yeah. How? Yeah, they do get a lot more than five out there. But having the huge, huge numbers where you're walking down, there's thousands of them on the beach. It's not a typical experience for a lot of people. And I do think that it brings a lot of ecotourism to this area because people come from all over the country and all over the world to see, the horseshoe crabs spawn. And we see that a little bit with our spawning survey participants, too, that they're coming from different parts of the country to participate in that survey with us. Yes. We've even had some international students come down. I believe we had a student who was in school in New York, but he came from China and came down to Delaware to be a part of the horseshoe crab spawning survey. So that just shows how unique and special these organisms are, where they really pull from a very broad audience because it is, it is not something that you can even get to see everywhere. It happens in the highest quantities in Delaware Bay. And boy, is that true. Yeah. So before we go into our horseshoe crab spawning survey, do you mind if I give our listeners a little bit of an overview of what a horseshoe crab looks like? Yes. Okay, so our horseshoe crabs, they are named aptly because they have that horseshoe front to their shell. So they have, they’re big and brown, and they have a rounded front and their legs are underneath of their body. So their shell, when you're looking at it from above, a lot of times it's flat to the surface of the sand. They have eight walking legs, so they're actually using to walk with. And then they have a set of pusher legs, which for the most part the joint structure is the same. But then rather than having claws on the ends of their legs, they have almost what looks like finger like appendages. And they're going to use those to bury in the sand to group their eggs together, and then also to push, they’re named pusher legs. And to scoot across the sand. Yep. So they have that huge front shell. They have what looks like a line on the back, but it's actually a hinge between the front and the back part of their shell. And so they can hinge in the middle and they look like they're wearing a helmet. A lot of, folks will say that it looks almost like a helmet. And, if you flip them over, then what they look like underneath, they have their eight walking legs and their two pusher legs. And in the middle is this circle, oval shape. And it kind of looks hairy. And that is their mouth. So their mouth is in the middle of all of their legs. And then they have those two little chelicerae that Taylor was talking about earlier that are up at the top. And then if we look down towards the bottom, they have book gills, which are named because they're as thin as the pages of a book. And so they're going to flap those in the water. But then there is also a hard piece over top of those book gills called their operculum. And that's going to help protect their sex organs. So then at the end, they also have a tail, or a telson, that comes out. And that is a very special tool for them. They're going to use that to not only rudder or turn in the water when they're swimming, but they're also going to use that to flip themselves upside down when they get stuck on the beach. Which is how many people may have seen them in the past. They’ll flip themselves right side back up. Yeah, yeah, yeah. So that they can scoot along back over to the water. So that is the general picture of a horseshoe crab. But we are going to talk all about why we're looking at our horseshoe crabs. Yes. So, we do this monitoring, this spawning survey that we have sort of teased throughout the episode. So to get into what it actually is, at DNERR, we are a part of a bay wide effort. So Delaware side and New Jersey side of Delaware Bay to get representative samples of how many horseshoe crabs are coming up on the beach during their peak spawning season in May and June. So this standardized survey came out of conservation concern for the species, because of its link to the endangered red knots. So as red knots make their very long journey from south of southern South America all the way to the Arctic, they stop over in Delaware Bay as sort of like a midpoint to refuel. And one of the best food sources for them are horseshoe crab eggs. They are really high in fat and protein, and these little birds can double their body weight, which is really incredible. In like three days. Can you imagine doing that? They truly just balloon into little fat birds so that they can make it all the way to northern Canada. Yeah, they're on a mission. Yes. So The Red Knot's population was going down. It was noted in this link to horseshoe crab eggs as being an important food source was made. And so we had to start monitoring. And so if the red knots aren't doing well, that probably means the horseshoe crabs aren't doing well. And we need to make them both in greater populations with the efforts that we can that promote sustainability of the species. And I will say, red knots have such a huge range. red knots have such a huge range that there can be things that affect our red knot populations in, you know, southern South America down in Tierra del Fuego or in their breeding grounds in the Arctic. But we at the same time had also noticed horseshoe crabs were that tie and that there was a decrease in our horseshoe crab numbers as well. Correct? Yes. So they were originally used for marine fertilizer. So as they come up in these massive numbers onto the beaches, it seemed like an infinite resource for farmers to use to grind up these horseshoe crabs and use them on their fields. Kind of like manure is used. It's a similar principle. And that practice happened in like the 60s and 70s and sort of ended in the 70s, not because of anything to do with the horseshoe crab, but chemical fertilizers came out and they were much less expensive. So the horseshoe crabs sort of got a break from that. But horseshoe crabs are a longer lived species, and it takes 10 to 12 years for them to reach sexual maturity. So from a population standpoint, that takes a long time to start getting a new cohort of horseshoe crabs that can, you know, essentially recoup that loss over time. And so it was noted in the 90s that this connection between horseshoe crabs and red knots were made. So in order to have a wise and comprehensive plan to hopefully do what we can in the Delaware Bay to promote this endangered species recovery. We can do some monitoring. So the horseshoe crab spawning survey is not a population study. Population studies of horseshoe crabs are going to look at all different ages of horseshoe crabs. And horseshoe crabs only come up on the beach if they are an adult ready to spawn. So we're just looking at the sex ratio of the adults that are coming up on our beach at, I think, 22 beaches on the Delaware and New Jersey side. So that is like the general purpose, and we hope that they are laying lots of eggs for birds to eat. Yeah, horseshoe crabs are definitely playing a numbers game because they're going to lay those. They lay what looks like a clutch of little green peas. They'll use those pusher legs to kind of ball them up into about a little bit bigger than a golf ball, but they'll lay 3 to 4000 eggs at a time. And it's a very, very small percentage. I want to say it's like 1% or less of those horseshoe crabs that are actually going to make it all the way to adulthood, but it's important that we protect the ones that will. Exactly. And it's not to say that those other eggs aren't used in the food web by any means. We have, you know, the eggs that we see on the beach, if you see them sort of scattered out, I think that they sometimes look like Dippin Dots. They do. So, those eggs are not going to be viable. So it's wonderful that birds will eat them and finfish will eat them so that they're still serving a purpose within the ecosystem. The tiny, once they hatch, they, they don't really go through like a larval stage. They just look like the tiniest version of a horseshoe crab, which is pretty cute without a tail. The first the first molt does not have a tail. They just kind of like, flap like that through the water. They, like, flap their gills. And I think they get their tail in the second or third molt. But they're just little guys. They're very, very cute. I'm sure there will be an adorable picture on screen. But they continue to be fish or food for other finfish. And so throughout their life stages, they are providing benefits to other organisms. And then hopefully those few that make it to adulthood can propagate the next generation. Yeah. Well, we've talked a little bit about what they're doing on the land when they're up at our shores. But do we know what they're doing under the water? Like where do they go. Yeah. Where do they go? What are they doing? Yeah. So they spend their they spend their not breeding season in deeper water off on the continental shelf out in the bay. They are only coming up on to the beaches to lay their eggs and spawn. They do not want to be hanging out here when they don't need to be. So they are going to go eat, sleep, be merry, out in some deeper water. Yeah, it's quite dangerous for them to. It's a high risk activity for them to come up onto the beaches to spawn, because these little guys don't have, you know, arms like us where they can push up like they have their telson that can help right themselves if they get flipped over. But essentially, if they are upside down, it's like dead bug. They can't flip themselves until another wave perhaps crashes into them and helps them, right themselves and so there are many horseshoe crabs that do not survive spawning season, but for their, life history strategy, the spawning strategy still works well for them as a species. And one of the best things that you can do to help horseshoe crabs at this stage is if you're walking out on the beaches during that spawning season and picking them up by the sides of their shell, never by their tail, but by the sides of their shell, and just giving them a flip over. If the tide is pretty far out, you can walk them closer to the water, giving them that flip is going to be doing a huge amount of help and just getting them, getting their gill flaps and their book gills wet again and getting them back out into the water so that they can continue on with their cycle. Because I want to say that getting stuck upside down and letting their gill, their book gills dry out can be one of the deadliest things for them. So just giving them a flip, not a toss, and not holding them by their tail, just giving them a flip and sending them back can do wonders. And if you do this, if you participate in the just flip them campaign, by gently grabbing them by the top of their prosoma That big part of their shell, their helmet, their legs are going to slip and freak out a little. Do not be scared. They can't hurt you. The reason they have lasted this long on planet Earth is because we have very, very strong defense. So they have very hard carapace, their telson is not something to. It's not like a stingray that's going to attack you. They are genuinely survivors because they have strong protection. So they're going to kick their legs. They kind of make skittery noises, but they're not going to, they're going to be appreciative, ultimately, if you bring them back to water. Yeah. Like you mentioned something that is a question that I get a lot when I go out on programs is, well, is their tail going to hurt you? And it doesn't have a stinger. It doesn't have barbs. There's no, venom to be injected into you. It's just there to help them flip over. A lot of times they're not even that sharp, if they have them at all, because sometimes they can suffer injuries that can impact their telson. Or if you hold them by their telson and a lot of times they can break off and they will have none. So I want to say that the scariest part, I feel like for a lot of people is that creepy legs, the creepy legs, the creepy legs. I was going to say the tail. People don't like the tail, but the creepy legs. I think, can also probably give people some anxiety a little intimidating, but they're not like blue crabs. They don't have that meat in their claws that it's going to like be pinching. Like if you get pinched by an adult blue crab, like there goes your finger, right? But if you get pinched by a horseshoe crab, it's kind of I call it like it's like holding my hand. Yeah, a little bit like it's going to have a little bit of pressure and hurt, but it's not going to do any sort of long lasting damage. Like a clothespin. Yeah. If you put a clothespin on your finger, that's kind of what it can feel like. Yeah. So, well, do you want to get into telling us a little bit about one of our longest standing volunteer projects? Want to get into the horseshoe crab survey? Yes, I kind of did a very brief overview, but us specifically have been conducting these surveys since 2002. And for three of the over 20 beaches for the Delaware Bay wide survey, which are Kitts Hummock, Ted Harvey Wildlife Conservation Area and North Bowers Beach, and we collect lots of data with hundreds. I mean, I haven't run the numbers, but we must have had more than a thousand volunteers at this point, like unique individuals that have participated. I think that when Sadie ran the numbers, we trained 90 volunteers this year alone, so our trainings are required for participation in the surveys. But overall, since 2002, we have a lot of folks that come back year after year. But it has to be it has to be over a thousand people that have come through to help count the horseshoe crabs. And I think that that's really special. I think it's bringing people again, closer to that, really special phenomena that's happening in their backyards. Absolutely. And so these surveys are special also in that they take place at night. So we go out there 12 nights, that we survey and every beach, part of this survey goes out on the same nights and starts at high tide for whatever that time is on their specific beach. And we just count the horseshoe crabs with a standardized protocol that we teach in our trainings. But it's I can't decide if the new moon nights are my favorite or the full moon nights are my favorite. We go out around those dates because those are the highest high tides, and so it gives us like, the most beach to cover, I guess, whenever the water pulls back. So the horseshoe crabs come up with the tide and leave with the tide, and sometimes you get to see this big, beautiful moon, and sometimes you see shooting stars on a new moon night. So it's really incredible and special. Yeah, there's nothing quite like being out on the beach at midnight and getting to see everything. And every night is so different. You never really know what you're going to see, because it can be. It can be dependent on things like weather and waves. Right? Absolutely. We survey rain, sunshine, new moon, clear skies, beautiful day. Bugs, everything. But it's lightning and safety concerns. So if there is a major coastal storm and there simply is no beach, we are not going to go out to count because there aren't going to be any horseshoe crabs on the beach. Beach isn't there. And then lightning, of course, because that is highly risky. But otherwise I'm trying to think of, if I have a good horror story, like a bad field trip field day story. But ultimately, I think the worst time I've had out there was it was a very high density night, and there was no wind, so it was quite buggy. And I was the person that was counting the horseshoe crabs and the person that was collecting the data and like writing down my numbers, had the user clipboard to like shoo the gnats out of my face. I think, I think I agree with you. I think the gnats are the worst one. I know that we had very limited fieldwork during Covid that we were allowed to do, so we had special permission to go out and do, a limited number of the horseshoe crab surveys. So Rachael, my boss, was out there and she was my recorder and I was counting, and it was like all of the not so great conditions, it was muggy, like it was so humid. The flies were out, there was no wind, and there had recently been a storm. So there was some of that peat moss that sometimes washes up. So my hands were like covered in dirt. I had my mask on and I had a gnat go into my eye, and I was like, I don't know how I'm going to get this out right now. And it was, it was gross. But we tell these stories with a smile on our face because ultimately it is part of the joy and the fun. If you're into the outdoors, then you probably get it. I think everybody has had a tough day outside. But I've also been out there on nights where we have had a beautiful a beautiful walk on the beach at night, shooting stars. Sometimes we'll see some turtles going through the water, and I think that those are just as special. And rememberable. Or when you have team members that come back and they're like, you were my site captain last year! I was so happy to see you again. We really have a really positive group that comes out and does this with us. Absolutely. And we appreciate all of our volunteers equally. But the privilege that I feel and working and like coordinating these surveys is developing relationships with these volunteers over time too and getting to know them and seeing how I got this job, because I follow the distinct degree path. And, you know, I knew that this was my purpose in life. These volunteers have all kinds of different lives and, you know, interest in all of this. And so for us to share this unique interest and for them to be doing this for some of them, 15 years, 15 seasons that they have been coming out on the beaches, it is not the easiest work to do, but it is special and fun and important. And so to see that dedication is very heartening for me. That, you know, others appreciate this organism and what it does and how it's connected to Delaware history as much as I do. Yeah. So in these surveys, what we're doing is we're going out onto the beaches, as Taylor mentioned, and it's high tide around the new and full moons two days before and the night of and two nights after. And we're taking our quadrants, which is a one by one meter PVC square, and you're counting the number of males and the number of females that are in your quadrants. So how would you say is the best way to tell a male versus a female horseshoe crab? So there are many like context cues that we can use to kind of get like shape an idea in our mind. If you were the counter. So a counter is one of the roles that you can fulfill. One is size. Females tend to be larger than males, the other is position. Males are going to be gathered around the female for the most part. And ultimately what we use in the field is the front of their carapace. So, you can actually feel that a female has a flatter front of her carapace, and the males have an arch to their carapace, and that arch is there so that they can get on top of the female and attach to her. And so males also have these unique their first pedipalps are modified. And so they look like boxing gloves, which gives them a little more grip strength to hold on to the female so that as she lays her eggs, he is ready to release his sperm at the same time. So they sort of pair up in that way, but they're not paired up like long term. They don't have like that kind of mating strategy. They just find the female on stick with her. And there's also satellite male. So it's not just a one on one interaction. There can be one male, 4 or 5 different, or one female, I should say, 4 or 5 different males that are all releasing sperm at the same time. Exactly. And so we kind of have this idea of like, oh, I think that's a male and I'm pretty sure that's a female. And then you do the feel test and ultimately run your fingers over the carapace and then, you know, you count the males first because they're moving and grooving. They're skittering across all of the other males going on, so places to be people to see. That's they are trying to find their own female, their own egg clutch, clutch to fertilize, fertilize. Thank you. And so counting the males is the best idea, because also, whenever we lay that quadrant down, it's like a snapshot in time. So if the male is in the quadrant, whenever you lay it down, he counts as one male counted. If he walks in 10 seconds later, he doesn't count. So we have the counter do all the counting males first, and then females. Report that information to the recorder. So they're going to be partnered up, and that person is going to write down those numbers in the neatest handwriting possible, because I'm the one who gets to read those numbers and look at the data, you know, after the survey is complete. Yeah. So if you're interested in volunteering with us, we take volunteers every year. We host our trainings in usually February or March, usually around March. If you contact us, the sooner the better. We can add you to our listserv. So you get information about those volunteer opportunities. And, we require training every three years, but we will go ahead and drop the email address of dnerrhscsurvey@delaware.gov so that you can contact us if you're interested in participating with us, because we would love to have you out for a survey. I have gotten friends to come participate. I have got my parents involved and I think the only people that have a bad time are the ones that really just don't like being outside, you know, like, I think that if you're just an indoor kind of person, maybe this isn't for you, but anyone who enjoys interacting with animals or being outside, especially at night on the beach, it's really, really beautiful. I think we can find a way for you to have a nice time. Everyone has fun here. Yes, absolutely. It's it is one of the most popular programs for a reason because it's ultimately fun. Even if you swallow a couple bugs while you're out there, it's just protein. Yeah, yeah, I've had a couple. So Sadie, did you ask our team if they had any questions? I did. So we do have some questions from the coastal section, and I have my paper here. I will say one of my favorite things about this podcast and about our coastal section chat is we all do really different jobs in terms of like, there's regulators and there are scientists that are focusing on much different things. And so I think that when we're like, hey, do you all have any questions? The questions that we get are so good and they don't necessarily know the answers. Yeah. So they're genuinely asking. They're not doing us a favor. They don't know. They're curious. So fun. So our first one is what is the best kind of night to survey? And I think they're asking like, should I go full moon or should I go, new moon? And I think you kind of touched on that a little bit with, if you want to see the moon or if you want to see stars. But what? Laurel, maybe you can answer, like, what's your favorite? Because you've been doing the surveys for a very long time. I love them all. I will say that I like a full moon night because I think it gives me a little bit more light, but I think that my ideal perfect survey night would be full moon, and there is a medium amount of crabs. There is a gentle breeze coming off of the water. Breeze, yes. And it is a balmy 68 degrees. I am going with a new moon night because I like in the time clear skies, new moon night because in the time that we are waiting for the tide to turn, you can sit down on the beach and look at the stars. So I really enjoy starting the night off that way and I would like a busy night. I want to count as many horseshoe crabs as possible, but that's not the point of the survey. The point is to get an accurate representation of the horseshoe crabs on the beach. But I want a busy night where we feel like we are really moving and grooving and again with the light breeze. So the bugs are off and that temperature sounds wonderful. There's nothing like having elbow deep in crabs. Yes, I think I like the medium nights because I'm like, okay, we can keep it moving. And you're not like so overwhelmed because there's so many crabs. But I do like me a busy night, sometimes. I’m a field biologist. I'm like, give me all. Well, I'll count them all. Yes. Okay. This one, what happens if a horseshoe crab loses its tail or telson? It loses its ability to right itself, unfortunately. And this can happen. I think Laurel touched on it a little bit earlier, but this can happen for a variety of reasons with just getting damaged, perhaps by a predator or by, sadly, human beings. I don't know, that that's not how you're not supposed to hold a horseshoe crab by the telson. It's only held together with, like, this little tendon and everything so it can get damaged. Or it could be a molting issue. Just some damage that happened during the molting process and then moving forward, it doesn't have a telson, and so it loses its ability to flip itself, you know, right side up. Or has a crooked one. I've seen some telsons lately that I think we're molting issues. Yes. Most likely. We saw that forked one, too. Oh, that was crazy. Yeah. And I will say that, I know that when you're going out and there's so many horseshoe crabs that have to be flipped, you can't always flip them all. A lot of times Taylor and I will act as the site captain. So, like, we can kind of follow behind the groups and make sure that they're all doing okay, but that they can also like, we can flip some horseshoe crabs behind so we're not skewing the data. And I want to say that the ones that I always make sure that I flip are the ones that either have no telson or a stubbed telson because I'm like, you're already a leg behind. I'll give you this. Yeah. Even when the water comes in and they're a little more buoyant, they might not be able to successfully flip themselves. So it's not a complete death sentence, but it is definitely a setback. Yeah. This one, if I see a horseshoe crab with a lot of barnacles or shells on its carapace, should I help it by trying to remove them? No, I say leave organisms alone as much as possible. Just as a overall rule. They, so the organisms that are going to attach to a horseshoe crab carapace are going to attach to anything they can. So they're they tend to be like broadcast spawners. So barnacles, for example, oysters, slipper shells, they do broadcast spawning and they just settle on any surface that is acceptable to them. And then the horseshoe crabs just live with them. So we've seen, horseshoe crabs with all kinds of organisms. And I actually have an intern project that is categorizing all of these epibionts. That's what they're called. So attached organisms, epibionts. So I say leave them alone. It's probably more disruptive to scrape them and keep them out of the water for longer than it would be to just let them be. Again, it's it makes them heavier, but it's not a death sentence. We see very heavy horseshoe crabs that are still coming up to spawn year after year. Yeah, some of them have slipper shells. Barnacles. We've seen oysters. We've seen mussels. That one looked like it had a mohawk on it that had like a set of mussels right on the top shell. Sabellaria worms, also bryozoans and even some different types of algae too. So for the most part like a slipper shell here and there, it's not going to be that bad. I want to say, like what Taylor had said of like the ones that are caked. It it's kind of probably similar to the telson where it's a setback, but it's not a death sentence. I think this one can be our last question. How long do horseshoe crabs live? About 25 years, give or take. What is and what is the purpose of the flabellum? I can answer this one. Yeah, I, I don't know how to describe it. It's a sensory organ. Yeah. So it's right up by the base of the pusher legs. And so. Right as the top of the carapace and the bottom, connect at that hinge, you have a little bit of area that allows water in. So the flabellum is at the base of the pusher legs, and it's a sensory organ. And it actually does a water quality check, before the water is reaching into the book gills. It'll test the water quality of the water, which I think is really cool. So they know whether or not they're in good water or not. Yeah. I did not know that. I've actually never heard that. That is awesome. Yeah. Like, I just like it amazes me that really they're as old as dinosaurs, right? We talked about 400 million years old and they haven't really changed. That's right. Yeah. Externally they haven't really changed that much. But even the inside of them is relatively like their digestive system is like a long tube. There's not a ton that is super complex. And when you compare it to us. Right. Yes. It's it's different. But I think that it's cool that it's like, okay, well they've got all of these things going on. They're relatively simple creatures, but then they just have this water quality tester hanging out on the side. That's awesome. They have a couple of things that have just been very, very successful over these 400 million years. So they haven't had they haven't really experienced a ton of selective pressure. They have a very strong carapace that protects them from predators they have, which we haven't talked about yet, but they have blue blood, which is just copper based, but they have, blood that reacts very quickly to pyrogens and bacteria. So they have really strong internal defense as well against disease. And then they have this amazing sensory organ for water quality that can indicate to them where they need to be, the cues to go up to spawn on the beaches and all of that. So they kind of got a lot of things right pretty early on. And if it ain't broke, don't fix it. Yeah, some of my favorite memes are like, when the world is going through another mass extinction and then it's like a horseshoe crab up on the beach. Vibing. Truly. Yeah. So do you have anything else for us, Sadie? Well, I do want to share this really fun fact that Taylor shared with us the other day on how they’re UV fluorescent or they’re fluorescent under UV light, and I know we don't know a whole lot about that, but I think that's really cool because they have all these cool adaptions, but then they just have this one that doesn't really do anything, but it just makes them cool. Yeah. Are they like, bioluminescent? Like it is why the Smithsonian taught me that the other day. And I am very excited to go out and check this out for my little like, blacklight and see, see what I can see out there. Because that's who would have thought. Yeah, that is awesome. Well, I think that that's all that the skimmer has said about horseshoe crabs. If you're interested in volunteering with us, you can contact us and we'd love to have you next year. But in the meantime, thanks for joining us today, Taylor. Thank you for having me. I love horseshoe crabs. Me too. Me too. All right. Bye bye.