JUANA SUMMERS, HOST:
Dr. Yi-Kai Tea loves to talk about fish. His social media handle is @KaiTheFishGuy. And he recently joined a research expedition to the Indian Ocean that turned up all manner of unusual creatures. There's the cute, dumpling-like deep-sea batfish, the rather scary-looking highfin lizardfish, and then there's the bony-eared assfish.
YI-KAI TEA: You know, one of my colleagues actually lectured us on the etymology behind assfish. I, for the life of me, cannot remember because I was too busy laughing (laughter).
SUMMERS: Dr. Tea, who is a biodiversity research fellow at the Australian Museum in Sydney, says that the Indian Ocean expedition found thousands of specimens. About a third of them could be new to science, and each is a marvel of deep-sea evolution.
TEA: It's funny to poke fun at these creatures, and it's, you know, good to have a laugh, but these are things that have been around for millions of years. They've been around, you know, way longer than we have. They are masters of their realm. You can't, you know, live in 3,000 meters of water and not be a master at what you do. It's just an inhospitable environment, and the fact that these creatures are living down there to the best of their ability, thriving and making the most out of these habitats, that's, to me, a remarkable feat, you know? So we can laugh at the assfish all we want, but it's just that they deserve the respect that we give for all animals equally.
SUMMERS: Well, Dr. Tea - a.k.a. @KaiTheFishGuy - recently talked with Aaron Scott on Short Wave, NPR's daily science podcast, where he gives us a glimpse of life three miles below the ocean's surface.
AARON SCOTT, BYLINE: Give us a little sense of what the environment is like down there. I mean, this deep-sea ocean as compared to the coral reef ecosystems that you tend to study, what is it like for the creatures that live there, and what are some of the things that they've adapted or evolved in order to live in that space?
TEA: One of the main differences, obviously, is temperature. Water is really, really cold down there. And the other differences would be light and pressure. So there's absolutely no light down there, and the water pressure is a lot higher than what you would have up in the shallower realms. But the animals that live down there, they're really, really well adapted to living in these environments. Because of the cold temperature and because of the lack of food there, a lot of animals have really, really low metabolic rates. So they don't - they're not very active. They don't really swim much. They kind of just spend their lives either floating through the water column or just sitting at the bottom of the seafloor. A lot of them have really big teeth that allows them to not only, you know, capture prey items, but make sure that whatever they're catching is not escaping.
And to deal with the water pressure, a lot of them have really low muscle density as well. They're really gelatinous. They're really blobby. So the pressure keeps them in shape. But when you take them up to the surface, you'll just see that they just kind of melt onto the table in a way. They're just really gelatinous. The water - their flesh is really watery.
SCOTT: Gelatinous creatures with big teeth.
TEA: Yeah, and the lights, too. So a lot of animals down there are bioluminescent. So they produce their own light. And bioluminescence in animals can arise in two different ways - either intrinsically, so they're actually producing light based on chemicals that they're producing innately, or they're doing it symbiotically with bacteria that - light-producing bacteria that they house in special organs called photophores.
So it's really interesting, actually. You have, you know, all these creatures down there that can produce light, but they're producing different colored lights, and they're producing lights in different ways. They're producing lights in different areas. But they're all kind of doing it to achieve the same thing - either for camouflage or for communicating or for attracting prey.
SCOTT: It sounds like a fish discotheque.
TEA: It is. And it's really - it's - I mean, look, I mean, Aaron, like, you read about these things in books, right? Like, I've known about lanternfishes my entire life. I've known about, you know, anglerfishes and all these light-producing things. But seeing them in person and holding them in your hand and looking at the photophores - I mean, these are just remarkable creatures. The photophores are so beautiful. They just - you know, such luminescent organs. And they produce purple and blue and red lights. And it's just, you know, stunning. Yeah. You know, truly an experience of a lifetime.
SCOTT: In some ways, like you said, it's like Christmas pulling...
TEA: Yeah.
SCOTT: ...This net up. Can you tell us a little bit about some of the favorite critters amongst all the things you guys pulled up? What were some of the highlights for you?
TEA: We found a bunch of new - potentially new species. We got a few, you know, really exciting finds, things like the viperfish and pelican eels and tripod fishes; things that, you know, you read about your entire lives, but you never thought you would actually see one. And these were just, you know, childhood favorites of mine that I've known about, you know, basically since I was 10 but have never thought in my wildest dreams that I would see and hold one in person.
SCOTT: The deep-sea batfish really seemed to make some waves on social media.
TEA: Right? Yeah. Oh, where do I even begin?
SCOTT: They look like ravioli or pierogies or dumplings.
TEA: To me, it looked like a deflated soup dumpling. But these are sometimes called pancake fishes, and they are very flat. And if you look underneath the body, their fins are modified into tiny little - almost legs, and they use it to basically crawl along the sea floor. So these are things with, you know, very, very poor dispersal mechanisms. They move at a pace that is just glacial. But they have enormous distributions. I mean, some of these species are found across the equator. Like, how are they dispersing? And how are they getting, you know, across the oceans? And are they really one species?
So these are the kind of questions that we're really interested in answering, right? We want to know more about not only what these fishes are, but how are they getting here, and why are they living here? And whether or not this population that's found in the Cocos Island, you know - are they the same as the ones that I found in Japan, for example, or Asia? These are all questions that, you know, we are really interested in answering.
SCOTT: So dozens of scientists spent 35 days on this boat. You all pulled up, I'm going to guess, like, thousands of actual specimens. So much work and...
TEA: So much work.
SCOTT: ...And I mean, which - I feel like we need to almost end with, like, what is the big goal? I mean, why, to you, is it important that we are putting all this work and all these resources into cataloguing this life?
TEA: Well, you know, I think it's really, really important to, you know, first of all realize that, you know, we live in a world with very finite resources. And things that are living down in these areas are not - they're not immune and they're not impervious to the threats that are faced from the shallow water, you know, counterparts in shallower coral reefs, right? And in order to protect these things, we need to know what they are first. So the first step in any biodiversity sampling is to understand what's living down there, you know, and then to put names on things that don't have names.
It's helping us to understand what's living down there at this point in time. So it's not just the research that's conducted today, but also the research that's conducted down in the future, you know, for future generations to come and other scientists around the world to access and better understand our world collectively through the stuff that we're collecting to better understand what's living in our world so that we can protect it better.
SUMMERS: Dr. Yi-Kai Tea, or KaiTheFishGuy, talking with co-host Aaron Scott on NPR's daily science podcast, Short Wave. Transcript provided by NPR, Copyright NPR.