Webinar: What Makes Fish so Fishy?
Aired May 14, 2020
Maggy Benson:
Hey everybody. Welcome to Smithsonian Science How online. Welcome everyone. Welcome, welcome. My name is Maggy Benson and I am a museum educator at the Smithsonian's National Museum of Natural History, and while our museum is closed, I have the pleasure of connecting you to the research science and especially the experts at the Smithsonian's National Museum of Natural History. We have a pretty awesome show lined up for you today. We are going to be connecting you with Dr. Adela Roa-Varón, and she is going to help us better understand what makes a fish a fish. She's loved science since she was a kid in her career as a fish scientist, an ichthyologist has taken her around the world. Now, before we meet Adela and Adela, you can give us a little wave. We are-
Adela Roa-Varón:
Hola.
Maggy Benson:
We are going to give all of our friends just a couple moments to get into our room and get settled before we begin, and while we do that, I'm going to take a minute to go over a couple logistics for our program today. Today's program is a webinar and that means that you can't turn on your video or your camera, but you can see us and we have a lot of fun things planned for you. You can interact with us using the chat that you see at the bottom of the screen and we want you to use this chat to answer the questions that we ask you, so I see that some people have already used that chat to tell us where they are tuning in from.
So we have Jade from Virginia, Hey Jade, so you can use that chat again to answer the questions that we ask you throughout today's program. Now please note that only our team here at the Smithsonian can see the comments there. Now you can find the Q&A button on your screen. It's either going to be at the bottom or the top, and that Q&A function is where you're going to post the questions for our scientists today to answer live during the program. Now we do have a couple hundred people in our show today, so we're not going to be able to get to all of the questions, but we're lucky to have two additional ichthyologists. Two additional fish scientists join us today to help answer some of those questions by chat, so I'm going to let them turn on their cameras and say hello now.
Kate Bemis:
Hi everyone. My name is Kate Bemis.
Diane Pitassy:
Hey everyone.
Kate Bemis:
And I'm a research zoologist at the NOAA National Systematics Lab at the National Museum of Natural History in D.C.
Maggy Benson:
Thanks Kate.
Diane Pitassy:
And I'm Diane Pitassy, and I am a collection specialist in the Division of Fishes at the Smithsonian Institution.
Maggy Benson:
Thanks, Diane. When you submit questions in the Q&A you also may not see them pop up, but our team here at the Smithsonian can see all of them. You're going to have two tabs at the top of that Q&A box, All Questions and My Questions, and you'll be able to see the questions that Kate and Diane directly respond to in those windows, so make sure to pay attention to that and we'll be taking a lot of those other questions and feeding them to Adela to answer live during our program. Now, today's program, I'm just going to share my screen in a moment here. Today's program is about 45 minutes long, and first we are going to meet Dr. Adela Roa-Varón, and she's going to tell us what an ichthyologist does, how she came into this career and what she studies as a NOAA scientist at the Smithsonian. After that, we're going to take some of your questions and then she is going to give us our first lesson in becoming an ichthyologist ourself. She has lots of great questions planned throughout today's program.
And so before we move on, I want to give you one more exercise for the chat and we'll come back to these answers in a moment. I want you to now use the chat to tell us what is your favorite fish. All right, use the chat to answer our question, what is your favorite fish? It could be your favorite fish to eat, to go fishing for, to see at the aquarium, to see in a pond. There are so many different kinds of fish out there, so tell us what is your favorite kind of fish?
And while you do that, I do want to welcome some of our viewers that are joining from around the country, so we have a lot of friends from Virginia, including in Alexandria and Arlington. We have Ipswich, Massachusetts. All right, we have Washington, D.C. Hey, I'm also in Washington, D.C. We have Quebec, Scarsdale, New York, San Francisco, Mount Pocono. Welcome. I'm from Scranton, yahoo NEPA. All right, Derby England. All right. Baton Rouge, Louisiana. Lots of Virginia from all over. Arlington and Alexandria mostly. All right. Now, some of our friends favorite fish, oh my gosh, there are so many and I can't wait to read them, but first Adela, hello. Thank you so much for joining us today.
Adela Roa-Varón:
Hi Maggy. Hi everybody.
Maggy Benson:
All right. Adela, we have a lot of friends joining from Virginia, and you live in Virginia too, isn't that right?
Adela Roa-Varón:
Yes. I am in Arlington, Virginia in my household. Welcome to my house, bienvenidos a mi casa. If you have any questions in Spanish or English, I will do my best to answer them.
Maggy Benson:
All right, wonderful. Yes, if you do have questions that you prefer to ask in Spanish, then we will take those as well today, so you can go ahead and use the Q&A to enter those. Now, Adela, we have a lot of great responses to some of our friends' favorite fish, which really shows the diversity of the fish out there, so I'm going to take a moment to read some of them to you right now.
Sticklebacks. All right. Clownfish, Mola-mola. Oh, we have a friend from Chile. Welcome. Tresher sharks, blowfish, whale sharks, butterfly fish, goldfish, parrotfish, salmon, swai, cuddle fish, betta fish, striped petra. Sounds like some friends might have aquariums. Angelfish, rat tails. More betta fish and goldfish, tuna, red lip, batfish. All right, really specific there.
All right. A walleye. They are my pets, so some friends have some fish pets. Puffer fish, stingray, piranha, so we have a huge diversity of even your favorite fish friends. Some of those live in freshwater, some of those live in marine. All right. Swordfish, flying fish. Wow. Adela, can you speak a little bit to the different kinds of fish that our friends like and do you have a favorite kind of fish?
Adela Roa-Varón:
Well, my favorite fish is the gulper eel, and you know what? We have a video for you today, and your mind will blow out.
Maggy Benson:
Al right, so Adela, how did you become interested in a career in ichthyology?
Adela Roa-Varón:
I think when I was a child I always liked science, and I get super excited about dissections, even though my friends were thinking that it was gross. Then when I went to university, my first semester I have a class that was about the scientific method. A scientific method it's just you have a question, you take some data and you make your conclusion, that's good. And I use fishes, and see every project at the university I use fishes, and I just fell in love with them.
Maggy Benson:
Once you love something, it's amazing. It's never too early to find a passion you love, and-
Adela Roa-Varón:
Exactly.
Maggy Benson:
And so Adela, you are a NOAA scientist that works at the Smithsonian. Can you explain to our viewers a little bit about what you do as a scientist in both of those roles?
Adela Roa-Varón:
Well, I'm a evolutionary biologist. That means that I study the changes that fish has in space and time, so we can understand better how they evolve and how are the adaptations that they have to different environments. By knowing them better, we can help with their conservation.
Maggy Benson:
Can you share with us some images of the fish that you study?
Adela Roa-Varón:
Well, I study Gadiformes, gadi-for-mes. Maybe the name wouldn't say anything to you, but I'm pretty sure that you have seen them and I hope that many of you have eaten them, so I got to share my screen with you.
Maggy Benson:
All right.
Adela Roa-Varón:
In just one second. Wait.
Maggy Benson:
All right. We have lot of questions coming in. Thank you friends, you're doing a great job. I love seeing all of your favorite fish.
Adela Roa-Varón:
Okay, we are having here some issues. A screen sharing has failed to start. Please try again later, but let's see what we can do about this.
Maggy Benson:
All right.
Adela Roa-Varón:
Okay. I will try to stop this first. Okay, second try to share the screen. Here we go. Cross your fingers.
Maggy Benson:
All right, success.
Adela Roa-Varón:
Oh, nice. There we go.
Maggy Benson:
There we go.
Adela Roa-Varón:
These are the Gadiformes. As you can see, it's an amazing group of fishes. It has more than 600 species, and they can live almost everywhere, from shallow waters into the deepest part of the ocean up to 7,000 meters, and for you to have an idea how deep is that, it's almost 4.2 miles.
Maggy Benson:
Wow.
Adela Roa-Varón:
Now, but also you can see this is just a small amount of species that you have here, but we have, as I say, more than 600 species and you can see the diversity in shapes, colors, form. To see that some have big eyes, small eyes, et cetera, and that's just a reflection of the diversity of the habitats that they live in.
Maggy Benson:
So the diversity of fish, the number of different kinds of fish, and even though these are all related, so are these-
Adela Roa-Varón:
Exactly.
Maggy Benson:
Are these fish found in one specific place around the world?
Adela Roa-Varón:
Nope. Actually what we have seen here is a map, and the white parts are the continents. In all can see the [inaudible 00:10:53], so this is showings the abundance and the distribution of these species, but perhaps the most important about the Gadiformes is that they're really good. Most of the important is that these fishes is that we eat them a lot. They are amount of fish that we eat the most to the point that some of these pieces are in endangered, and I would get to just some few examples like Atlantic cod and the hake.
Maggy Benson:
And so these are popular fish to eat and they're also the fish that you study?
Adela Roa-Varón:
Exactly. We have a confusing taxonomy, so put something in case of the hakes. We don't know how many species that we have in the world and most of those species are overfished, so we need to know what we have in order to make any kind of product for their conservation.
Maggy Benson:
Well that actually answers a question that we have in the chat that says, "Why are you interested in studying fish conservation?" So studying these fish actually helps inform that conservation measure?
Adela Roa-Varón:
Exactly.
Maggy Benson:
All right, so do we have a question now for students to think about any other reasons that it might be important to study these fish?
Adela Roa-Varón:
Yeah.
Maggy Benson:
All right, so students tell us why do you think it might be important to study the fish we eat? Adela just told us a little bit about fish conservation, but what other reasons do you think it might be important to study the fish we eat? You can use the chat to tell us.
Adela Roa-Varón:
To know who they are, but also where they live. That would be cool.
Maggy Benson:
Absolutely. Also, why is it important to understand where these fish are? So we have a lot of questions rolling in already and I'm going to read a couple of those responses. "For understanding nutrition so we don't overfish. To know which ones are poisonous. To save the fish for the future. Indicator of the health of ocean ecosystems. To understand food webs. To know what you're eating. To be safe. To understand diseases. To protect them and make them safer. To know where they are. To understand diseases." So it sounds like we have two major responses, to be able to ensure human health, to understand what's poisonous and what's nutritious, but also fish health and ocean ecosystem health. These two things. How are students doing? Are they on the right track?
Adela Roa-Varón:
Amazing. I don't have to say anything else, is all. Totally agree, so one of the first things we really need to know what we are eating. We want make sure what we buy in the grocery store is what we are eating, and this is called mistaken identity, is that sometimes they sell you something that is more expensive for something, using something that is not the fish that we are really buy. Also it's important, some of the participants mentioned that is good to know that we are not eating any species that is endangered. Also, there is mixing identities in which you have multiple species identified as one, so when the net comes out and all the fish are in the ship, we need to make sure that we are not overfishing and depleting the stocks, because that affect the species as well as people live in that space.
Maggy Benson:
Our friends were right on there with the overfishing?
Adela Roa-Varón:
Exactly, so this is the overfishing that we were talking about. Now also it's important to know where they came from so we can help to preserve their habitat, and also if it's safe to eat them. There's something that is going on at the same time and it's lot of worrying and the ocean is you can quickly be shown. Oceans are actually most of excess of CO2 in the atmosphere, causing by burning fossil fuels. Which can [inaudible] fish brains being affected, modifying their behavior. For example, their sense of smell is effective as well as the perception of the data, so that makes them more vulnerable. Also, fishes are getting smaller and smaller and smaller, and that's one more reason affecting the fisheries and the people's livelihoods.
Maggy Benson:
And so this also impacts human health? So we are talking about fish health and ecosystem health and human health, but they're really all very connected.
Adela Roa-Varón:
Exactly. If something happens in any part of the ecosystem of the ocean, is affecting the other parts of the ocean.
Maggy Benson:
With all of these different factors at play, Adela, I'm sure a lot of people ask you as an ichthyologist a scientist who studies fish, "Do you eat fish?"
Adela Roa-Varón:
I do. I do my work.
Maggy Benson:
What's your favorite fish to eat?
Adela Roa-Varón:
I will show you. Once I went to visit some family in Spain and we went to a restaurant, so I asked the waiters, "What is the best fish that you have?" And the person said rapé. I say, "Okay, let's see rapé." And when I started eating it and I started seeing the bowls, I was like, "Okay, I need to meet the rapé and I need to meet the chef." And I went to meet him and voila. I was eating a monkfish and has be much delicious fish that I ever try. We have to be brave, but make smart choices, and always ask the locals. The locals know what is good.
Maggy Benson:
All right. I wonder if any of our friends would eat that fish if they had seen it before it landed on their plate. All right, so what are some of the common questions that some friends may ask you when they learn that you are an ichthyologist and you study fish?
Adela Roa-Varón:
Okay, so it's time to how you 101 fish class, and one, and today I'm giving you a head start in the world of fishes with this. Tell me how you call this, fish or fishes? And we'll do this together.
Maggy Benson:
All right. This is a common question definitely at the Museum of Natural History. Is it fish or is it fishes? So take a look. One fish. Do you call that fish or fishes? I think that's a pretty easy one. And we already have responses in our chat that respond fish.
Adela Roa-Varón:
Yes. Good job guys. What are three fish of the same fish called?
Maggy Benson:
Okay, so three fish of the same kind are they fish or fishes? Okay we have mostly fish. Some people say fishes. Some people say two or more fish are fishes. What is it?
Adela Roa-Varón:
Fish, definitely. Okay, and now what we call a group of different kind of fish.
Maggy Benson:
We have a couple, we have lots of fishes now. All right.
Adela Roa-Varón:
Yes, exactly. Fishes. The point here is that we are not counting the number of individuals. What we are counting here is the number of species, so if you have 100 monkfish, you see we call them fish, but if you have a bluefin tuna and a monkfish, we call them fishes.
Maggy Benson:
Al right, so that is our foundational understanding of becoming an ichthyologist. A lot of different kinds of fish is fishes.
Adela Roa-Varón:
Exactly, that's number one.
Maggy Benson:
Let's take a couple questions before we dive into a little bit more about your research, and so we're going to start with a question from Anderson. Who asks, "What do you like about your job?"
Adela Roa-Varón:
Oh my gosh. I love the combination of the pure science with applied science. I like to discover where they live, what they eat, but I also like to see how equally affect life in the fishermen or the communities and how we can make life better for them by preserving the fishes.
Maggy Benson:
All right. Melana wants to know are sharks fish?
Adela Roa-Varón:
Excuses?
Maggy Benson:
Are sharks a kind of fish?
Adela Roa-Varón:
Oh, we will answer that in few minutes, so stay on.
Maggy Benson:
All right, so keep watching. Are there any fish species that do not look like fish at all?
Adela Roa-Varón:
I think so, like aliens. You would look at them and say, "Man, that's when I'm moving." Yes, definitely.
Maggy Benson:
All right, and this one is from Martin. "What are you interested in about fish conservation?"
Adela Roa-Varón:
Fish conservation. For me, the key is that if we don't know what we have, how we can make the conservation of your species, how we can do it if we don't know what we have?
Maggy Benson:
All right. Ila wants to know how you can tell all those different fishes are in one group.
Adela Roa-Varón:
Oh, we'll find out few minutes about that too. Glad you asked.
Maggy Benson:
We're going to learn a lot about sorting and identifying fish today. Okay, and this one is from Addie. "How big do sunfish get?"
Adela Roa-Varón:
Well, big but not as big as the biggest fish, but it is the heaviest fish.
Maggy Benson:
All right. It is a very heavy fish. If you want to look that up after our program, the Pacific sunfish is very big or a Mola-mola. It's one of somebody's favorites. Okay, last question before we move on. This one's from Yile. "Do you scuba dive?"
Adela Roa-Varón:
Yes I do.
Maggy Benson:
It's an excellent way to see the underwater world. Even snorkeling or sticking your head under there sometimes, everybody should try it at least once.
Adela Roa-Varón:
Definitely.
Maggy Benson:
Okay, Adela, we have some great questions still in our queue, but let's move on and you're going to help us understand what features all fish have in common, and you have some questions lined up for us throughout this, and so let's dive in and get our first ichthyologist lesson under our belt.
Adela Roa-Varón:
Okay, so I will share the screen with you.
Maggy Benson:
All right.
Adela Roa-Varón:
Okay.
Maggy Benson:
And well done everybody on the great questions. You can keep sending questions to us through the Q&A.
Adela Roa-Varón:
Okay. Can you see my screen?
Maggy Benson:
We can, but if you can go into presenter mode.
Adela Roa-Varón:
I did. What about there?
Maggy Benson:
I think-
Adela Roa-Varón:
Can you see?
Maggy Benson:
Yeah, I think you are in, when you're sharing your slide screen, you're in presenter mode. If you could share it as a regular slideshow.
Adela Roa-Varón:
Okay, let me see if I have it. Share screen. Okay, what about there?
Maggy Benson:
Perfect.
Adela Roa-Varón:
Awesome, so let's keep going. I have a question for you. Is a whale shark a fish? Yes/no, but why?
Maggy Benson:
Okay, so tell us, and we had this question in a chat just a moment. Is a whale shark a fish? Tell us why you think. Okay, so we have a couple really quick yesses, but why do you think it is a fish? All right, why do you think this is a fish if you do think it is a fish? We have a lot of responses, lots of yesses, a couple of nos, and some people think that it is a fish because it has gills, it has fish structure, lots of gills. It has fins, it is cold blooded. They are vertebrates, it has a backbone, because of the fin, it has gills, it has bones. All right, it doesn't give live birth. It has scales in gills. Some people do think it is not a fish, it doesn't have lungs, it doesn't have to breathe air, it has scales. Whale sharks are called whales because of its size, but they are classified as fish. All right. Okay. It is not a bony fish, but it is a cartilaginous fish, because it lives in the water. How are our friends doing?
Adela Roa-Varón:
Amazing. Amazing. Definitely. The whale shark is a fish and it's the largest non-mammalian vertebrate. Let's think about what makes a fish a fish, and I will tell you five tips. The first one, they're vertebrates, so they're animals that have a spine and they live in the water.
Maggy Benson:
So well done to our friends who said they are vertebrates. Good job.
Adela Roa-Varón:
Indeed. Second, fishes have gills that suck oxygen from the water around them, so they take the oxygen-rich into the mouth and then the oxygen-deficient is what water is pushed out. Number three, most fishes have scales covering their bodies, but some of them lack the scales or they have them modified. Then number four, limbs modified into fins for swimming, so we can see here in this fish that they have one dorsal fin, but other fishes would have two or three dorsal fins, one anal fin or two anal fins, and we have the pelvic fins or the pectoral fins, so that means that they are two, and the pelvic fins over here, and finally the caudal fin, and they're helpful for swimming.
Now we have, most fishes as some of the participants mentioned they're cold blooded or ectothermic. Which means that they cannot regulate the body temperature, so its body temperature fluctuates according to the environment, but in some cases, not very common we have fish that are warm blooded or endothermic. That means that they can, they're able to maintain constant body temperature independently of the environment. Some of the cases, some of the examples that we have here is this opah, some tunas like bluefin tuna, some sharks like mako shark or even the great white shark, and swordfish. Now I do have this five characters that will be helpful to take a look before you say if it's a fish or it's not a fish.
Maggy Benson:
All right, so we have five characters there that unite all fish and even though there are some exceptions along the way, and those five just to recap are that they all have vertebras, right? They all have a backbone, they all have gills or most have gills where they use gills to extract oxygen from the water. There are a couple exceptions there too, right? They have scales with a couple exceptions. They have fins, like many of you mentioned with the whale shark example, and almost all are ectothermic. They get their energy from outside rather than generating their own body heat, endortherms, but there's a couple of examples there too. Adela, those are a lot of features and there are a lot of exceptions to some of those rules, and with 32,000 fish species, how do you sort those as an ichthyologist?
Adela Roa-Varón:
That's a great question. Actually, we have more than 32,000 kind of fishes or species. Today I will show you the three main ones, and I will start with this one. This's one of my favorite, so let's start here. Take a look at this picture, this hagfish and lampreys, and tell me what do you think that they have in common? And what they have in common, actually something that is missing?
Maggy Benson:
Okay, so this is one of the major groups of fish that all fish are organized into and these fish are united by something they lack. What don't these fish have that brings them together in their own special group? And while you're responding to that in the chat, Adela, we did get a couple questions asking, do some fish have lungs?
Adela Roa-Varón:
Yes, exactly. I didn't want to confuse you showing all the bits, but they have exceptions. But yes, we have lungfishes and they have lungs like we do and they have to get out of the water and take a gulp of air for breathing.
Maggy Benson:
All right, so we do have responses to what these animals on our screen have in common and I'm going to read some of them. We have a lot of answers that say they have, they are jawless, they do not have a jaw, they do not have fins, they do not have gills, they do not have a backbone. I would say that lacking jaws and fins are the most popular answer right now.
Adela Roa-Varón:
I think we have some fish specialists here, because they're getting all of them. Yes, they are the jawless fish, they don't have a jaw, and they're the most primitive fishes. For example, the lampreys, they can be, no both of them have a round mouth and the body shape is elongated and they don't have various things. Do you remember those ones has a pelvic and the pectorals? Okay, they don't have them. The lampreys are marine and fresh water, and they can be parasitic or non-parasitic species, and those that are parasitic stick by burrowing to the flesh of other fish to suck its blood.
Maggy Benson:
Oh, cool.
Adela Roa-Varón:
Now, the other one is a hagfish, that is one of my favorites. They're called or know as slime fish, and it has glands all around the body to produce sticky slime that it uses as a defense mechanism. The hagfish also can twist its body into knots and is for clean off the slime and also as escape from predators. They are all marine species and they sip on invertebrates, but also they could be scavenging on dead and dying fish. I want to show you their mouth. I think it's super cool. They have these four pairs of teeth over here, and also they have three pairs of barbels that are tactile, because they're almost blind. Just think about that. You close your eyes and you have, instead of two arms, you have six arms and you are touching all the environment. So that's it. It's helpful this thing that you see there. They help it to bore into fish and they devour everything but the skin and the bones.
Maggy Benson:
These are really fascinating fish that don't have jaws and they don't have a lot of that protective skin covering, but they have other adaptations-
Adela Roa-Varón:
Don't have.
Maggy Benson:
To help them survive, and we're going to show a video of that right now and I'm going to show, and I'm going to share it from my computer screen right here, so let me share.
Adela Roa-Varón:
Wait, before you get showing. The question I want to ask you, this is war between shark and hagfish. I want you to tell me who is the winner, the hagfish or the shark?
Maggy Benson:
Okay, so we're going to show you a video right now that was captured at 681 meters below the surface, and who is going to be the winner of this? The hagfish that we just learned about or the shark. Okay, so I'm going to press play. Take a look at my video. You can see the shark on the right. The hagfish is in the middle. Adela, we have a lot of people predicting that the hagfish wins this battle. Oh, there we go. Shark comes in.
Adela Roa-Varón:
There we go.
Maggy Benson:
All right, I think it comes up again one more time so you can see it up close. You see the shark chomping, and then wow, that is incredible. We have one of our friends has said that the slime blocks the gills. Is that what-
Adela Roa-Varón:
Yeah, I saw that. That's amazing. It's exactly what happens. The excess of the slime just gets stuck in the shark and there's no way. The hagfish is the winner here.
Maggy Benson:
Wow, and you can see in that video, I don't know how clear it is because it's a dark video, but there's a big white cloud underneath that shark's mouth. That's all slime. Wow. That's an incredible adaptation.
Adela Roa-Varón:
Exactly. I'm going to share with you my screen again. Okay?
Maggy Benson:
All right, so that was our first group of fish. All 32,000 species of fish get grouped into three groups and we just learned about the jawless fish, so now we're going to go onto the next group.
Adela Roa-Varón:
Exactly. The second group is this. Think carefully about this one. Why do you think that all these fishes have in common?
Maggy Benson:
Okay, so just-
Adela Roa-Varón:
And please use your observation skills.
Maggy Benson:
All right. We already have some responses. If you want to use the chat to tell us what do these fish have in common? This is our second major group of fish. I will read the responses now. All right. They are cold blooded, they have tails, they have cartilage, they're cartilaginous fish. They have cartilage instead of bones. They do not have bones. Their shape, they do not have scales. Their fins are similar.
Adela Roa-Varón:
That's amazing.
Maggy Benson:
They're eyes. Great observation. They do have eyes, they are cold blooded. The way they lay their eggs. No scales, but I would say most of our responses so far from our friends are that they have skeletons made of cartilage.
Adela Roa-Varón:
Well yes, this is the cartilaginous fish and they're known as chondrichthyes. It's a fish with a skeleton of cartilage rather than bone, and I'm pretty sure that you are very familiar with shark, rays and skate. So let's take a look at chimaeras today.
Maggy Benson:
All right, so I have the videos on my computer because they've played back a little quicker, and I have a video here of a chimaera that Adela would like to share with you, so I'm going to press play. Randy says they love chimaeras.
Adela Roa-Varón:
They're lovely, I agree with you. They are known as ghost sharks and they prefer deep water, although some species could be in shallow water, however different to their cousins the sharks, these fishes don't have the sharp and the amount of teeth that the shark replace through their lives, because they have just three pairs of plate tooth. What they use this plates is for crushing hard preys like crabs or starfish for example.
Maggy Benson:
And they have another unique adaptation with their spine, don't they?
Adela Roa-Varón:
Yes, it's true. It's totally true. Thank you. They could have in front of the, some of the species, not all of them, they could have a spine in front of the dorsal that is poisonous, that is the difference.
Maggy Benson:
Or venomous, where they can inject venom into other animals. That's not something a shark has, its cousin. All right, so we do have some comments. That was a very cool video, so now we've learned about the two major groups of fish and we have about 10 minutes left, so let's keep moving to learn about the third group.
Adela Roa-Varón:
Okay, let's move. We have a third group that will be this one. Once again tell what do you think what they have in common.
Maggy Benson:
We see different colors and shapes among these fish. What do these four fish have in common? They are our last group of fish that we're exploring today. All right. They're colorful. They are bony. All right, Teleost. All right. We have responses that they don't, some don't have bones, some have scales that they don't have fins. They are all pretty and cool, that they have bones and scales, so it looks likes bones are the most popular answers for now.
Adela Roa-Varón:
Is true. They are the bony fish. Scientific name is osteichthyes, fish with a skeleton of bone. That's it. We are finishing the three major groups of fishes and this is the group of fish that has more species among the three groups.
Maggy Benson:
And so as an ichthyologist Adela, your first step is to be able to sort any of the fish that you study into three major groups, and these are the major groups. You have the jawless fish, which include those lampreys and those slimy hagfish. You have the second group which are the cartilaginous fish that include the chimaeras and the sharks and the skates and the rays. Then you have this third group which is the largest, which includes all of the bony fish. You mentioned in the beginning that you study a kind of fish that we eat, the Gadiformes. Where do they fall in these three groups?
Adela Roa-Varón:
Well they have bony fish, all of them. All the 600 species.
Maggy Benson:
And do you have to sort those? How do you sort those to be able to identify them? Because I'm sure as an ichthyologist that does that every day you have to go well beyond identifying which group they belong in and identify the other features, and where do you do that? Do you do it out in the field on a ship or do you do it in the lab at the museum?
Adela Roa-Varón:
In both, actually. For example, as an ichthyologist, if you decide to follow this path, you will have opportunity to sample in freshwater species, in freshwater environments. I have been also research cruises for a month, and I have a great opportunity to be in a dive and see all those fishes we see there, but are still alive, that was amazing. You have some sorting in the field, because we need to take some samples like [inaudible 00:40:44] that have little bones between the fishes that help them to, for the [inaudible 00:40:50] and swimming. Also, we need to take tissue samples for genetic samples et cetera, but the most important is when you come back into the lab or to the museum in this case, because we need to identify those fishes and this is very important because it contributes to the museum development, but also provides information for the conservation of the commercial species and the species that we don't know much about their natural history.
I need show some kind of the data that I'm taking. This is my current project right now. We have hakes, these are species that they live everywhere in the world. They're commercially important, but we don't know how many species we have. I take some measurements like externally and we call them meristics, so that means that you are counting for example the number of the rays or the number of the archers or things like that. We have morphometric that is measuring, so I want to compare the size of the eye of this fish with the size of the eye of this other fish. Also we need information from the inside of the fish, so we have a couple of techniques like dry skeletons, and we have this one on the bottom that I really like it. It's clear and stained and we use some chemicals, and what you see in red are bones and what you see in blue are cartilage, and something that complements this information is the DNA, that is the genetic information that we have that make us unique in the world. That's it.
Maggy Benson:
So, Adela-
Adela Roa-Varón:
Those are the characters.
Maggy Benson:
You've just shared us some techniques that as an ichthyologist for NOAA at the Smithsonian, you use to further identify and understand fish as we've been discussing, using their bones, using the features on the outside of their body, the features on the inside of their body and even their DNA, but there's another tool that you use that you have prepared for our students today. Which we use to sort all sorts of life, not just fish. We have one last activity before we get to more of your questions. We do see that we have a lot of them and we know that we're running up to the end, so let's do this activity and then move on to some questions.
Adela Roa-Varón:
Today we will learn how to use the dichotomous key, and this is an essential tool for any scientists that want to identify any species. It could be plants, animals, whatever. This is an example, we have a fish that has, we will concentrate in theses pictures. That will be the dorsal fins, the anal fins and the chin barbel, so my first question is that ... I forgot to mention that the dichotomous key means that they have also, they have always two options. You decide one or the other one. Okay? So let's start together. This fish have a chin barbel and I'm showing you where is the chin barbel, so whether you think they have it or they don't have.
Maggy Benson:
Okay, so Adela is showing us the chin barbel. We're going to pick one or the other option in a series of questions, so does this have it or does it not? Okay. And yes, our viewer.
Adela Roa-Varón:
Yes.
Maggy Benson:
Yes, it does.
Adela Roa-Varón:
Definitely. It have a barbel on chin. Let's see the second character. This fish has one or two dorsal fins or three dorsal fins, and here you will see the fins.
Maggy Benson:
All right, so our viewers are our scientists in training. We have lots of people who are already responding that they have three dorsal fins.
Adela Roa-Varón:
Yes, there we go. We have the next character. Now tell me, it has one anal fin or two anal fins?
Maggy Benson:
Okay, so on the bottom there, how many fins do you see? One or two. Okay, we have mixed responses here. Maybe you can use your cursor to show us which ones you're talking about.
Adela Roa-Varón:
So this is the anal fins, so how many do we have? No, the fish has.
Maggy Benson:
All right, two.
Adela Roa-Varón:
Good job guys. We chose to identify it using a dichotomous key, Gadus morhua, the Atlantic cod. It has three dorsal fins, two anal fins and the chin barber. Good job.
Maggy Benson:
And this is the fish that you study, correct?
Adela Roa-Varón:
Yes. This is one of the species that I study and actually is one of those species that we overfish it to the point and we deplete their population, and we are trying to recover it.
Maggy Benson:
All right, and yes, this is the Atlantic cod, which is probably familiar to folks from something you might eat or we used to eat. We are going to move right onto questions. We have a lot of them and we're going to try to get to as many as we can, and we are going to start with this question from Samantha, "During your research travels, how often do you come across a species that you've never seen before?"
Adela Roa-Varón:
Well, for me some of the most fascinating moments in my life is when the net came into the back of the ship and you never know what is coming, so that's always super exciting. Always there is something, maybe it's not fishes, maybe it's something else that is great.
Maggy Benson:
All right. Louise asks, "What is the chin barbel for?" That was that thing that hung off its chin right there?
Adela Roa-Varón:
Yes, exactly. That's a very good question. Fishes could have one or two or three pairs of barbels and they're tactile, so they help them to see where is the food, what is in there, so it's like a little hand.
Maggy Benson:
That must mean it lives near the bottom.
Adela Roa-Varón:
They have to be associated with the bottom, so then you call them demersal fishes. Yes.
Maggy Benson:
Okay. The De Jesus family would like to know what part of the fish's body is affected by water's salinity? So salinity is how salty the water is.
Adela Roa-Varón:
Sorry, could you please repeat the question?
Maggy Benson:
Which part of a fish's body is impacted by the water salinity? Perhaps why can't a freshwater fish live in a marine environment, a salty environment?
Adela Roa-Varón:
Well, I would say that is the gill arches, and that is something that will change when the fishes are moving from freshwater into marine waters or from marine waters into freshwater. If a fish can do, that is anadromous and catadromous, that's okay. They are able to do it, but if they're not able to do it, that will be really bad, so they die. That is not the habitat that they used to.
Maggy Benson:
All right, we have a couple different questions about some of the biggest fish and some of the smallest fish. Can you remind us what that biggest fish was and maybe make a guess at how small the smallest fish may be or if you know?
Adela Roa-Varón:
I would say that the biggest fish is the whale shark, of course that would be the biggest. I have, my cousins that are reviewing fish encyclopedia for kids, they answer for this smallest fish. The smallest fish is by those Paedocypris protegenica.
Maggy Benson:
All right?
Adela Roa-Varón:
Oh my gosh. Yeah, that's it. I don't see the families. One of the experts that are in the chat, because we have some fish experts in the chat today.
Maggy Benson:
Al right, so are there any fish that are dangerous to humans?
Adela Roa-Varón:
Yes there are. For example, we have a one [inaudible] form that is fugu. It's an Asian fish and it's poisonous and you can eat. They used to it, the fish in Asia is very common, but they know how to cook it, but if sometimes they bring it here and it's not properly cooked, you can die.
Maggy Benson:
We have a question here about an evolutionary biology question. "Do dolphins have dorsal fins?" Because of course dolphins are not fish, they're mammals.
Adela Roa-Varón:
Yeah. Excuse me?
Maggy Benson:
Why do dolphins have dorsal fins?
Adela Roa-Varón:
Oh, for swimming. Is what keeps you part of that direction. Whatever lives in the water, they need the fins for swimming.
Maggy Benson:
All right. "Are all fish cold-blooded?" This one's from Amelia.
Adela Roa-Varón:
No, not all of them. I just mentioned a couple of cases as well, but not all fishes are cold-blooded. Some are warm-blooded. That means they can regulate their internal temperature.
Maggy Benson:
We have several question that's asking what is the rarest fish? And maybe you can use this to tell us a little bit about why we should care so much about studying the fish you study, the Gadiformes and what's making them become a little bit more rare, some of those species?
Adela Roa-Varón:
Well for example, I have a case in my group of fishes that we have just one species within this family and don't know much about the natural history or the biology. We don't know if we're affecting the environment, if they're being affected in their populations, nothing, and it's because they're unique. It's just one species within this huge group of fishes.
Maggy Benson:
And so that is also answering somebody else's question about how some scientists don't know everything about all of the fish. There's still a lot unknown about different fish species in the world, correct?
Adela Roa-Varón:
Yeah, exactly. I think it's just important and keep us working, because we always learn something new, but the most important is that we are training the next generation for becoming ichthyologists, and that's when I hope that some of you will join us in the future.
Maggy Benson:
There is a lot of work to do.
Adela Roa-Varón:
Yes, and it's a fun job to do.
Maggy Benson:
Okay, we're just going to take a couple more questions here because I see most of our viewers are still with us here. We have a question from Jade and we had a program yesterday on our video webinars about Biosphere where there's people creating their own habitat to live in. "If you were to live on another planet, what are some fish species you would bring with you to create an ecosystem on another planet?"
Adela Roa-Varón:
Oh my gosh.
Maggy Benson:
That's a creative one.
Adela Roa-Varón:
That's an amazing question. Definitely I will bring from the three groups that we talked today. I will have a representation of all of them, at least. From this [inaudible] an environment. Well, it depends on the planet. In the planet you have all the environments that they can supply. I will study first the planet.
Maggy Benson:
All right. Adela, can you give our viewers some tips on how to continue studying the world around them and even fish if they're interested in becoming ichthyologists or biologists or just conserving the world around us?
Adela Roa-Varón:
Well, let me share my screen.
Maggy Benson:
All right.
Adela Roa-Varón:
I think for me the most important message more than knowing about fishes is that it's never too late or too soon to find your passion. Perhaps it's to learn from the bumps the road. I hope that you find your passion and even if it's not fishes.
Maggy Benson:
Adela, thank you so much for joining us today and giving our first lesson in ichthyology and letting us meet you and learn about how you study fish and the fish that you study. It's been really fun and some of those images and videos are just so cool. I can't wait to look them up later.
Adela Roa-Varón:
Thank you so much for inviting me and thank you, all of you for joining.
Maggy Benson:
All right, and thank you all so much for joining us. I do want to say that we are ... Sorry, I'm going to share my screen here. If you leave this program, we would love if you could fill out our survey. It will be available in the Zoom browser window once you exit our program, so please fill out our survey and we continue to strive to bring you programs that you want while our museum is closed.
Too, I wanted to share that we do have Fossil Friday, tomorrow and we have another drawing exercise on Saturday, and next week we have another marine-themed program where we're going to be exploring deep ocean discovery, octopods and squids with Dr. Mike Vecchione, another NOAA scientist at the Smithsonian. Then we will be back again for Fossil Friday and drawing dinosaurs on Saturday mornings at 11.
If you're ever looking for our programs, make sure you go to the Natural History Museum's website, naturalhistory.si.edu, and look for the live video programs. You should be able to access it from the home page, and that has a listing of all of our live programs. We have them about four to six times a week. We hope you can join us for another future program. Thank you so much for joining us today with Adela, and we hope you have a great rest of your week and you all stay healthy and safe. Thank you so much.
