How To Protect The Ocean
SUFB 093: Manta Ray Profiled
Manta Rays are one of the most majestic species in the Ocean; however, it's also the most mysterious. Researchers do not know much about the species, but are finding out new things every year. Listen to this episode so I can introduce you to this wonderful animal.
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Show Notes:
http://www.speakupforblue.com/session93
Welcome to the speaker for Blue Podcast session 93. Today, like I said yesterday, we are going to be profiling one of the most wonderful beautiful majestic species in the ocean, the manta ray in particular the giant oceanic man array. The reason why we're looking at this is because we talked about it yesterday, how we need protect to protect these species and know more about it. So this week, we're going to be focusing on this species. So stay tuned for today's podcast on the giant oceanic manta ray. Welcome to the speaker for Blue Podcast, helping you get involved in ocean conservation. And now here's your host, he just discovered periscope and might be slightly addicted. Andrew Lewin. Hey, everybody. Welcome back to another exciting episode of the speaker for Blue podcast, your voice for the ocean. I am your host, Andrew Lewin, founder, speakupforblue.com, marine ecologist and self-proclaimed ocean panor. And today is species Tuesday. And we're going to be talking about the giant oceanic manta ray. But before we do, I have a couple quick announcements. One, I want to thank the patreon supporters that we have that is Ron and Judy, Dr. Judith, Judith Weiss, as well as Claire and Chris Jeffert. Thank you very much for your support. You can also support the speakupforblue podcast at our patreon site at www.speakupforblue.com/patreon P-A-T-R-E-O-N. You can support us at varying levels of support. It is a monthly support system, so just keep that in mind when you put your amount in. But what you're doing is you're supporting conservation around the world. We focus on gaining an audience in the podcast world, an audience that likes to listen to ocean conservation information, make themselves aware and hopefully inspire them to take action to protect the ocean in their daily life. And we will go through those on tips and tricks on how to do that throughout this podcast. So thank you very much for listening, and let's get to the other announcements. Sorry, I almost forgot, is that we are going to be opening up a YouTube channel. We do have a speakupforblue TV YouTube channel, and one of the playlists will be the speakupforblue podcast. I'm going to be releasing a slew of them all the way up to the most recent episode, which is 93 right now, which is this episode. We're going to be experimenting with different things, but right now it's going to be myself talking to you, so hopefully you'll find that exciting enough. But if you're a YouTube watcher, you can just put it on, put it on in the background while you're doing something else on the computer. Just really, it's another avenue to reach an audience that doesn't normally listen to ocean conservation information and maybe and again, inspire them to take action. So those are the two announcements for today. And you can get to that, you can get to that, I'll put up a YouTube link, but it'll be speakupforblue.com/youtube. So thank you very much for that. I appreciate you guys listening and staying in tune to or staying tuned to our speakupforblue podcast. Let's get back to the show. It is the giant oceanic manoray that we're going to be talking about today. And this manoray, this this species is one that I've really started to get to know over time. And we like we talked about yesterday on Monday's episode, a lot of other people are starting to get to know it and not in a good way. We've seen a reduction in shark finning and the reduction in consuming of shark fin soup in China, due to some great action by some organizations such as Wild Aid and their partners in China, educating the Chinese citizens to really take a look at what their what the effect of eating shark fin soup to show how where they are in class. Because that's why they do it's a cultural class kind of significance, why they eat the soup. And to show what they're doing to the population, how they're reducing shark population, sometimes by 90%, 80 to 90% around the world. So that's been working. We've seen a reduction in shark fin soup consumption, which means a reduction in the demand of shark fins. But unfortunately, what we're seeing is we're seeing an increase in the demand for gill rakers, manna gill rakers and manna meat, which is not a good thing because that's just, you know, using it for alternative purposes. So what we need to do is we need to find out more about manna rays. We need to find we to tell people about them so that they care about them, show videos of them, show pictures, show what they're really like, and that they don't harm anybody and they're important to the ocean. Just like marine mammals are important to the ocean, just like sharks are important to the ocean. These things are gentle birds of the seas, really what they are, and they're just gorgeous. So what we're going to do today is we're going to go over manna rays and we're going to see what they're all about. I'm going to talk about, I found a page at mannatrust.org. So it's mannatrust.org. And I'm going to read some of the things that they have on manna rays because these things, they're amazing. And this, this page is a great resource for for manna rays. We're going to talk about first how they're classified. So manna rays belong to the taxonomic family mobulidae. So that family contains two different 11 species of planktony rays. Within this family, there are two genera. There's the mobular rays and the manta rays, which more normally people know or recognize are the manta rays. And they're, and more specifically within this genus, the manta rays, there are two species. There's manta by rostris, which is the giant oceanic manta. And there's manta alfredi, alfredi, which is the resident reef manna. So the two species have a lot in common, but there are also important, a few important differences in life history that exists between the two that it's always good to know to recognize if you're ever diving. Now one thing that is great is to die with the manna ray. It's on my bucket list, just like diving with the whale shark is on my bucket list. The size of these species are just amazing. And the gentleness of them and just the fact that you can watch them just just swim. It's just a it's it's a phenomenal feat. I'll put some videos, a video that I saw recently on Facebook of a woman taking a selfie, which was she was free diving. And this manna ray just kind of swimming around her. And it was just a great video. Just really fun to see how the behavior of these animals, how gentle they are, and how curious they are. But let's keep going with these manner rays. So manner rays are a cousin of the sharks. They're in the shark and ray sort of category, you might say, they're cartilaginous elasbo-brank fishes. So they are elasbo-branks. They're made of cartilage. There's not a bone in their body. It's all cartilage. And they the fact that they are fish, and they don't breathe air, but they instead use their gills to respire underwater. A manna rays keep moving in order to keep water flowing over their gills, which means that they can never stop or sleep stop to sleep or rest on the seabed. So sometimes you'll see skates and rays, which are sort of cousins of manna rays that are actually on the bottom. They sit on the bottom. They can actively respire while manna rays cannot. They have to keep keep moving. Oceanic manner rays are the bigger of the two manner ray species, or manna species, reaching a wingspan. So that's wingtip to wingtip of up to seven meters. That's 23 feet. A large oceanic manner ray may weigh up to two tons. That's over 4,000 pounds, making them a real ocean giant. Although the all smaller than the oceanic manner is the reef manna rays are still pretty big fishes growing to an average wingspan of three to three and a half meters. That's nine to 11 and a half feet and possibly a maximum of four and a half meters, which is 15 feet and one and a half tons, just over 3,000 pounds. That's what they can reach up to in in in weight. Both the species, the wingspan is roughly two and a half times the length of their body. So their wingspan is a lot bigger than the length of their body. So how do they live? This is a great page, by the way, if you go on to it, we'll put it in the in the actual show notes, which will be speakupforblue.com/session93. Research would indicate that manna has probably lived to at least 50 and possibly up to 100 years old. There is a reef manna that's named Pingpong or M12. It's a Maldivian reef manna who was first photographed by divers in 1989, when she was really when she was already fully grown sexually mature. Pingpong is still seen now at the same site almost every year. It's thought that the manna rays that the manna's are 15 to 20 years old when they reach sexual maturity, which would make Pingpong at least 40 years old. I like the name Pingpong. I think that's really cool. It's nice to see that you can actually tell that it's the same individual each time. I think that's a real indication of what you can do in terms of studying them later on. Where they found, manna rays are found all over the world. However, some important differences range in range and habitat exists between the oceanic manna rays and their smaller reef manna counterparts. Both species live in live pelagic, live lives in ocean, an open ocean, visiting reefs to feed and to be cleaned. However, oceanic manna have a wider geographic range of the two species occurring in tropical, subtropical and temperate waters. This species is more migratory in nature, commonly cited along productive coastlines with regular upwellings, which is basically cold water coming up to the surface that brings a lot of cold plankton-filled water for them to feed on. Hence, that's why they're there. Oceanic island groups and offshore pinnacles and seamounts, again, where there's a lot of upwellings and a lot of productivity in those waters, which means there's a lot of plankton, and that's where they like to hang out. So reports of the species range from 31 degrees north, which is basically South Carolina USA, to 36 degrees south, which is North Island, New Zealand. The resident reef manna are more commonly cited in shore around coral reefs, tropical island groups, atolls and bays, as well as along productive coastlines. As the name suggests, the species is more resident to tropical waters with smaller home ranges. So what they eat, essentially, they eat small organisms, small organisms in the sea. They are plank divorce feeding, especially on zoo plankton, tiny animals, such as copobods, mices shrimp, and arrowworms. Mantis are known to take to make seasonal migrations in order to take advantage of particularly abundant areas of food. So they will go wherever there's higher productivity. Now they do reproduce. They have a bit of a courtship, which is kind of interesting. The female will start a little bit of a race where she will go as fast as she can, and there will be a trail of about 10 to 12 males behind her. They will go as she basically wants to get the fastest and the person, the manna person. The manna that can keep up with her, dip and dive around reefs and crevices and whatnot and see who is the fittest and most persistent of the males. So that will that will be highly genetically sought after. Once they mate, they mate belly to belly, and the manna will actually is oviviparous. So that means the female will actually hold the fertilized eggs and grow within the female's uterus for up to a year. And then it will give birth to one single pup. Sometimes they'll do two if there's two developing embryos. However, most of the time it's one pup and they reproduce basically one to every one to two years. So the reproduction is slow. Their gestation is slow. And so that means they are a slow growing population, and you have to be careful with fisheries. So are there any threats to manna rates? Well, we talked about yesterday. Yes, there are threats. So just like all wild animals, manta, just all like wild mantas have a number of natural predators. Certain species of sharks, as well as orcas and false killer whales, have all been recorded predating on manta rays. Shark bites are seen within every population of manna rays that are studied. Often these bites are taken from trailing edges of the manta's wings. And in many cases, these heal up quite well and leave the manna with no lasting damage. In addition to natural predation, manna's face significant threats from humans and our activities. Fishing line can cause severe entanglement, resulting in deep and often life threatening lacerations in manta's. If manta's become entangled in it, gill nets and other fishing nets also cause mantas to become entangled, usually resulting in death. Unfortunately, manna's cannot swim backwards. And so attempts to disentangle himself, often result in greater entrapment. Manta's which become entangled in nets quickly die because they are unable to actively pump oxygen rich waters over their gills in order to respite. So once they're entangled, if they're not if they're not moving and they're trying to get out of this entanglement, they can die because they don't get enough oxygen. Essentially, they suffocate. Okay, most recently, manna rays have become a desirable catch in a number of countries around the world. The reason for the increase is what we talked about yesterday is their gill plates, which have become highly desirable in the Chinese medicine trade. The manna gill plates are a cartilaginous finger like projections of that branch off into gill off the gill arches and are used by the mantas to filter the plankton. They planktonic prey from the water. The trade in these plates has increased significantly in recent years, posing a worry, worrying threat to manta and mobile populations around the world. Now these, the conservation status is considered vulnerable. However, there's not much known about their population. So they're considered vulnerable at more as a conservative status. However, more research will detail what they are doing. How their populations are doing giant mantas have also recently been listed on appendix one and two under the conservation of migratory species, which is important to know. Because of their just the way they are, the way they migrate, it's important to know how far they migrate and that it for management purposes, you have to manage them over multiple countries because they will cross political boundaries. Just like Peru and Ecuador and Indonesia understand their protected areas and their fishing regulations will be will cross borders to better protect them. So, you know, looking at the two species, there are important management effects. The reef species, the manta alfredi is more of a resident species. So it won't travel as much oil travel between reefs. So it'll be important to protect specific reefs within those ranges of each population to protect the diversity of their populations. Manta, the oceanic manta rays, which will be the manta rhibosterous, it will be highly migratory, much more migratory than the reef species, resident reef species. So they will have a longer range. So there will be more protected areas to protect those mantas and fishing regulations across different countries. So as you can see, knowing the different ranges and the different behaviors of these species is very important to make sure that our management systems adequately protect these species. So that's the species. If you want to find out more, we're going to put the link to mantatrust.org on the where I've read and looked at most of these, most of the information on the species. There are also a couple of videos that we're going to post in bed into the session notes, which will be speakerforblue.com/session93. So you can get all that information there. I think it's important to know about manta rays. One, they're a phenomenal species to get to know, and I think I'm looking forward to research. There's the research paper that we pulled out on them and seeing what we can find out more about them. And I just think sites like the manta trust and to find out what they're doing are fantastic. So feel free to peruse them. It is mantatrust.org. So I think it's important. I'm going to be looking over on these sites and maybe grabbing if they have some research, grabbing some research papers from there to talk about on research Thursdays coming up this week. So thank you very much. This is all for this episode. If you want to support the Speak Up for Blue podcast, you can do so at speakupforblue.com/patreon P-A-T-R-E-O-N. All you have to do is just do a simple, if you're not already registered on the site, all you have to do is just a simple registration, your name, your email password, and then you can donate or you can support to us on a monthly basis. So remember, it is a monthly basis to not to overpay and you don't realize it. So something to look out for, but we appreciate any kind of support that you can give us. And of course, there are different incentives to get you to pay at different levels. So thank you very much for listening. You've been listening to Speak Up for Blue podcast. I am your host, Andrew Lewin. Happy Tuesday, happy species Tuesday, and happy new conservation. [Music]