South Pole 6. Toothfish, Climate Genomics, and the Southern Ocean
Join us on South Pole as we delve into the fascinating world of pelagic notothenioids, genomics, climate change, and the Southern Ocean. Hosted by Clark Marchese, this episode features marine biologist Dr. Jilda Alicia Caccavo from the Institut Pierre Simon Laplace in Paris. Discover why these unique fish are vital to the Antarctic ecosystem, how they evolved to survive in frigid waters, and the significance of their antifreeze proteins and white blood. Dr. Caccavo explains how studying their genes can reveal insights into their responses to climate change. Tune in for an engaging conversation filled with scientific discoveries, surprising fish adaptations, and the broader implications for understanding our changing planet.
Episode Guest: Dr. Jilda Caccavo
More information about Dr. Caccavo on her website
Episode Transcript and more information on the Pine Forest Media Website
Follow Pine Forest Media on Instagram @pineforestmedia
Hosted, produced, written, and edited by Clark Marchese
Cover art and PFM logo by Laurel Wong.
Theme music by Nela Ruiz
Transcript:
[00:00:09.480] - Clark
Hello and welcome to south pole, the podcast that explores everything Antarctica. I am your host, Clark Marchese. And today we are talking about pelagic notothenioids, genomics, climate change, toothfish, and the southern ocean. Okay, let's break down some of those words. Genomics, very generally is the study of genes. Now, sometimes science is nice like that, and then other times things are named pelagic notothenioids. And you're like, why is that your name? So, pelagic traces back to the greek pelagikos, meaning pertaining to the open sea. And now we use the word to refer to ocean critters that live in open waters. Notothenioids. Noto comes from greek, meaning south then. Also Greek means fish, and oids means belonging to a group. So a group of fish living in the open southern ocean, pelagic notothenioids. And that is what we're here to talk about today, and to tell us all about them. I found a marine biologist named doctor Jilda Alicia Caccavo, who specializes in climate genomics. So how climate factors impact our genes? Well, not ours, the pelagic notothenioids. She is currently working as a researcher at the Institut Pierre Simon Laplace in Paris. All this time I've been underneath Paris, I had such a fun time recording this episode.
[00:01:42.330] - Clark
Doctor Caccavo and I were just nerding out and having the best time. We talked about why these fish are important to the southern Ocean ecosystem, why their blood doesn't freeze, and also why it's white toothfish, which are the size of me, how studying genes can help understand how species are responding to climate change and how they might continue to in the future. And so I hope you enjoy our nerd out session, and I will see you on the other side of the antarctic circumpolar current. All right, Doctor Caccavo, thank you for coming on the show today. I guess to start, maybe we'll just have you introduce yourself and tell us a bit about your work.
[00:02:31.270] - Dr. Jilda Caccavo
Oh, thank you so much, Clark. My name is Jilda Caccavo and I'm a marine biologist based in Paris who focuses on antarctic fish and in particular using genomics and other kinds of approaches to study the health and vulnerability of their populations and also understand how climate change may be impacting them now and in the future.
[00:02:53.280] - Clark
That sounds like such a cool job, and we're going to get into all of what that means. But one question I ask at the top of the show is, I'm wondering, have you ever been to Antarctica? Has your research ever taken you down there.
[00:03:04.260] - Dr. Jilda Caccavo
So, unfortunately, I have not been to Antarctica yet, so I don't have much exciting things to share about that. I've been lucky that all of my samples have already been able to come to me from other researchers. And in particular now, for the past few years, I've been studying a species that is commercially fished around Antarctica. And all of the fishers of this species have to collect a certain amount of samples to put aside for science, to understand how those stocks are holding up with the fishery, and also to better understand the species generally. So it's super easy to get samples of those species because they're already being collected in a commercial context.
[00:03:44.820] - Clark
Okay, that actually sounds like a really cool collaboration, and, I mean, it's always fun to hear stories of people who have been down there, but I think we also like to make a point on the show that you can still do really important work and engagement with Antarctica from anywhere in the world, and that's what you're doing. And from Paris, no less. I'm curious, is there a lot of research going on in Paris about Antarctica?
[00:04:06.310] - Dr. Jilda Caccavo
Paris is just one of multiple hubs around France with an antarctic focus, like others are. Like, there's a small town in the Poitou called Chise that has a big research group in Strausberg. It sort of depends. We're all over the place. Again, coming back to your previous comment that there's really people all over the world studying Antarctica, because nobody's in Antarctica full time studying, so that the samples have to be brought back somewhere. But in Paris in particular, there are two main reasons why there's a lot of research going on about Antarctica. The first is that Paris is a climate change research hub, and so there's a ton of institutes that are all kind of under the umbrella of this organization called the Institut Pierre Simon Laplace. And this is sort of a consortium of institutes that study different aspects of the physical system, geosciences, climate change, etcetera. And Antarctica, being one of the poles, is experiencing the impacts of climate change faster than anywhere on the planet. So that's one of the reasons why there's a huge amount of focus on Antarctica. But in addition, Antarctica has a huge importance to our global understanding of climate change, both with the acceleration of ice sheet melting, as well as the archives of past climate that are stored in the ice and snow in the interiors of Antarctica.
[00:05:26.380] - Dr. Jilda Caccavo
So Antarctica is critical. And then the second reason why there's a lot of antarctic research going on in Paris is related to the so called taf the Terre austral et Antartique francaise, which basically means these southern and antarctic lands that belong to France. These include a bunch of sub antarctic islands, subantarctic, just meaning that they're in the southern Ocean, but they're a bit further north latitude. And so France actually has some of these islands as part of its territory, including the waters around these islands. And there's a lot of active fisheries in these waters. And so the research to both make sure that those fisheries remain sustainable, as well as to understand the ecosystems of these really unique islands, a lot of that takes place through the National Museum of Natural History here in Paris, and that's happened for. That's been going on for decades. So that's another reason why there's a lot of research happening here. It's related to those sub antarctic islands that are actually part of France.
[00:06:23.950] - Clark
Oh, okay. I didn't know that second part. I think I did know that Paris was big into climate research, you know, the Paris agreement and all that. But it makes sense that Antarctica is a big part of that. So you study fish, in particular, a group called pelagic notothenioids. What are those?
[00:06:41.460] - Dr. Jilda Caccavo
Yeah, it's a bit of a mouthful. So notothenioids, which many people might have not heard of, they're this incredible group of fish that evolved something like 30 million years ago when something called the antarctic circumpolar current formed. So we look at Antarctica, we see that it's totally surrounded by ocean, and all of that ocean around Antarctica is continuous with the rest of the oceans of the world. So then how come we don't see the exact same species, you know, in the Indian Ocean or the northern Atlantic Ocean, as we do in the southern ocean? Part of the reason for that is this incredibly strong current called the Antarctic circumpolar current. It's the strongest current on the planet, and it functions as a barrier between the southern ocean, which are the waters around Antarctica, and the rest of the oceans of the world. It's not a physical barrier, like a wall, like a piece of land, but it reduces the probability that species from north of that current can pass to the south of that current. And, of course, also, the further south you go, the colder the waters get. A lot of species can't survive in those habitats.
[00:07:46.010] - Dr. Jilda Caccavo
They're not adapted to survive there. But notothenioids, which were a handful of species that ended up on the cold side of that current 30 million years ago when it formed, when, like, the tip of South America separated from the tip of the Antarctic peninsula, those species found themselves in this really unique environment with not a lot of competition around, and they exploded into a bunch of different species, a huge biodiversity. They're also studied for this, like, unique evolution that they had so recently to evolve into so many different species to take over all these habitats that were now up for the grabs, and they now make up almost 90% of all of the biomass that's closest to Antarctica. So on the continental shelf, the part of the continent that's kind of below the water, but not the super deep water, most of the species of fish that you find there or generally come from these notothenioids. And they have a lot of unique adaptations to allow them to exist in such cold waters. One of them that some of your listeners might have heard of are these antifreeze proteins. So that means that in their blood, they have a chemical similar that has the same impact as the antifreeze in our windshield wipers for our cars.
[00:09:00.840] - Clark
If the listeners have heard of that, they've heard of more than me. How does that work?
[00:09:04.770] - Dr. Jilda Caccavo
So it reduces the temperature at which water or a liquid will freeze. And so for the in a car, it allows your windshield to not freeze. In the fish, it prevents their blood from freezing, despite the fact that they're living in waters that are minus two degrees celsius. So that was one important adaptation. And another special quality that some of these species have is some of them don't have red blood. They actually have white blood. And these are a special group of notothenioids called ice fish. Now, this isn't necessarily a positive adaptation, but it's something that they were able to kind of persist having because of this unique environment. So, basically, what makes a lot of our blood red is this protein complex called hemoglobin that binds iron, and that has iron in it, rather, and it binds oxygen, and that allows us to be able to have enough oxygen to survive, et cetera. In super cold water, you have a lot more oxygen than you would in super warm water. So you almost don't even need to have the special protein complex to concentrate oxygen in your blood. The oxygen could just diffuse through your blood into your systems.
[00:10:19.490] - Dr. Jilda Caccavo
And so this particular group, these ice fish, lost their hemoglobin. So that's why their blood is white. And because there's so much oxygen in the waters in Antarctica. And because they had so little competition, they were able to continue to persist, to flourish, despite losing this protein complex that most species need in order to survive, in order to have a normal metabolism. So those are just two examples of what makes Notre then incredibly unique and so specialized to the environment that they live in?
[00:10:52.860] - Clark
Wow, science is so cool, right? I do have a couple of questions, though. First, why is there more oxygen in colder water? And then also you mentioned that there's many different types of species. I'm wondering, is it too broad of a category for me to ask you? What do nodithenoids look like? Or could they look like lots of different things?
[00:11:11.850] - Dr. Jilda Caccavo
Well, the first question is more of a chemistry question, which is not 100% my specialty, so I hope I don't say anything wrong, but I think the simple answer is that depending on the temperature of a liquid, you can dissolve more or less things. Think about if you want to make a cup of tea. If the tea is hot, the honey dissolves more easily than if it's cold water that you put it in. I think in a similar way, you can think about oxygen. The carrying capacity of water when it has, when it's colder, can take more oxygen, whereas it's the opposite if it's warm. So I think the honey analogy is the most helpful way to think about it. And then with respect to what they look like, I mean, they look like a huge number of things because they've colonized almost every type of habitat you can think about in the southern Ocean and especially this continental shelf ecosystem from, like, the seafloor, where they might just hang out in one little spot their whole lives, to being, like, near the continental slope, so really far from the continent. In very deep waters, they go from being a couple of centimeters long, like four to five, six, seven, 8, being up to 2 meters long.
[00:12:19.410] - Dr. Jilda Caccavo
For example, some of the fish that I study, antarctic toothfish, they're even bigger than I am. So, yeah, so there's a huge diversity of what they look like. I wouldn't say that they look so different from your average fish that you would picture in your head. On a global scale, they're not necessarily a certain color. They don't necessarily have certain appendages that are unique. It's really what goes on inside of them that's more unique than what they actually look like. If you had a lineup of antarctic fish and just a regular deep sea fish, I don't know if you would be able to tell just by looking at them which one is which.
[00:12:56.610] - Clark
Wow. 2 meters. That's huge. I'm not even 2 meters. So then a general question I have, how are they doing?
[00:13:06.090] - Dr. Jilda Caccavo
So it really depends on the species for the most part. I would say they're doing relatively well considering the state of many species globally. I mean, the Antarctic remains a relatively untouched ecosystem despite the fact that climate change is having impacts now. It's not necessarily having the same impact as, for example, species that have to deal with human encroachment or more pollution or more fisheries impact and so on. There were species that were overfished in the past that are now being fished or not, either not fished at all or fished in a way that's more sustainable. So those populations are coming back. And another positive piece of information is that when we use genetics to understand the health of a population, we ask the question, are these populations connected? That means if we look at population a, b and c from maybe regions a, b and c around the continent, is there evidence that there's genetic information traveling between these species? And that's a good thing. That means that the populations are healthy because genetic variation and genetic connectivity are all associated with good health of a population. You can think about the idea that, for example, if siblings are not necessarily supposed to reproduce because you increase the probability of having, like, recessive genetic disorders that come up because two people that have very similar genetic information are reproducing.
[00:14:37.500] - Dr. Jilda Caccavo
We have the same issue in wild populations. So if wild populations don't get exposed to individuals that are enough, not related to them, we can have issues where they're not as genetically robust, they can have certain diseases, they're less able to deal with environmental change. So this is kind of a metric we use in genetics to say, hey, is this population doing well? Does it have a lot of genetic diversity? And the answer is, for antarctic fish. They have a lot, for the most part, because of these really strong current systems around the Antarctic, and because a lot of these species have early life stages that are conducive to connectivity, meaning that an egg or a larvae will remain in the water column or near the surface for like six months or a year. And that gives a lot of opportunities for it to pass to different parts of the continent. And that means that there's a lot of exchange, even if it's just a handful of individuals between population a and b, that's enough to keep the genetic diversity of those populations robust so that they're ready to confront whatever challenges the environment might confront them with.
[00:15:43.690] - Clark
Okay, so that's good news. And that was also a lot of information. So just to recap what you said, because I think people don't always think of genetic diversity as an indicator of species health, but there are two reasons for that. The first is that high levels of diversity avoid those genetic complications that you mentioned that can be a result of inbreeding. This can also be referred to as endogamy. And if it gets too severe and the gene pool is too small, a species can even be classified as extinct, even if there are still a few of them roaming around, if their numbers fall below what we call a critical number. The second is that the high genetic diversity increases overall resilience of a species. If, let's say, an unexpected environmental pressure is particularly challenging on one genetic variation, there are others that may be more equipped to survive. Now. Species that are thriving in this capacity have either evolved to carry out certain behaviors or evolved in certain environmental conditions that ensure this high level of genetic diversity. You just told us that the ocean currents distributing the larvae across great distances can explain this for the notothenioids.
[00:16:49.430] - Clark
But with birds, for example, we oftentimes see males will leave the nest and fly far, far away once they reach sexual maturity. And all this is very related to your work, which is trying to find out what is exactly the level of genetic diversity among these notothenioids. In addition, though, I'm curious, what other things are we trying to find out about them?
[00:17:07.220] - Dr. Jilda Caccavo
Yeah, so up until a few years ago, my focus was really just on this genetic diversity or variety question, using this as like a metric to the health of the populations, because for many populations of antarctic fish, we just didn't have the answer to that. Like, you can't start asking questions about climate change if you don't even have a baseline to compare to. So with the work that I and many of my colleagues have been doing in the past ten years, we have a general sense of what the baseline of a lot of the genetic diversity and variety of a lot of the species of antarctic fish are. Most of them are relatively healthy. Most populations are relatively connected. There are some exceptions here and there, but we have more or less an understanding of that now. The next question is, once we have this information, what are the other external factors that could be influencing population health now and in the future? And one of those is, of course, climate change. So the question is, can we use genomics to detect climate change impact?
[00:18:12.750] - Clark
Can we?
[00:18:13.560] - Dr. Jilda Caccavo
With population genetics, we look at genetic markers that are representative of population effects. Like if a couple of individuals from population a go to population b, how do the genetic markers change for climate change? We want to look at some adaptation, which is a very different type of impact on the genome. Because changes in genetic markers related to adaptation result from an outside force, there's a real selection pressure that you can identify in these types of markers. And so we use these different, different types of markers that are indicative of adaptation to understand how climate change might be forcing species to adapt to changes in their environment. So not only do we use markers that indicate adaptation, but we associate those markers with certain aspects of climate change in the physical environment that could be pushing this forward. So, for example, what can climate change impact in the antarctic environment? Well, the temperature of water, that's one thing for sure. The amount of sea ice that's in a given area, the salinity or saltiness of the water, because, for example, when sea ice or ice shelves melt, they're releasing a lot of fresh water into the sea.
[00:19:29.770] - Dr. Jilda Caccavo
And changes in salinity or saltiness of the water can have downstream effects on the types of microorganisms that can live there and so on. We look at these environmental parameters, like salinity, like temperature, like sea ice concentration, and we can associate those with different concentrations of adaptive markers that we identify in the genomes of species. And we use that information to say, hey, this population over here, where let's say there's been a marked increase in sea surface temperature over the past number of years, well, they're showing a greater level of adaptation in their genome than, let's say, a population b, where maybe there's been less environmental change. And once we see that, we can say, hey, okay, this species is particularly vulnerable to temperature change. And then we can say, well, what do the climate change predictions say to us? Climate change predictions say that in 100 years, the temperature is going to be three degrees higher, let's say for not only population a, but population b. So now we can say, hey, even though population b doesn't look like anything's happening now, but in 100 years, that's going to be a place that those individuals are going to be experiencing a lot of pressure from environmental change.
[00:20:44.940] - Dr. Jilda Caccavo
So these types of analyzes, these climate genomics analyzes, allow us to not only understand how species are being influenced now, but it gives us a way in which we can see how these species are going to be impacted by environmental change in the future.
[00:21:00.510] - Clark
Okay, I have a handful of questions, please. So we know some species are already adapting to climate change, some of them very quickly. So my first question is, are these nodothenioids adapting to climate change? And if so, how is that happening? And then really quickly for listeners, the difference between genotype and phenotype. So a genotype is a characteristic reflected in a gene sequence, and then a phenotype relates to how that expression of the gene manifests so an example is eye color. The genotype would be whatever gene makes your eyes green, and then the phenotype would be your green eyes. And phenotype is not always just visible appearance. It could be behavioral, for example. So then my second question relates to that, which is, is your analysis only looking at the genotype? And if so, again, what changes are we seeing there? But if your analysis also extends to the phenotype, how are these changes you see in the gene sequences affecting behaviors, physical features, or other phenotypical things about these fish?
[00:21:55.590] - Dr. Jilda Caccavo
These are all fantastic questions, and the answer is, we don't know yet because the research is ongoing. So everything that you asked are kind of all the different steps in the process. So when we look for adaptation in the genome, we're not even necessarily saying, oh, we see adaptation in this gene that, I don't know, controls temperature regulation. We're just seeing that there are certain markers that are indicative of adaptation, and we see more of them in one group versus another group. That's the first step. And then we associate, you know, these adaptive markers with changes in environmental parameters like salinity, temperature and so on. Then once we've done that, we can make predictions about where do we expect to see more adaptation in the future. But on top of that, we can start to answer the questions that you've posed. For example, where are these adaptive markers in the genome? Are they part of genes that regulate temperature, that regulate reproduction, that regulate metabolism? That's a next step that we can do to sort of understand the mechanism behind these changes. And then with the phenotype question, that's something that we can also look at, but that's something that will potentially come later.
[00:23:05.690] - Dr. Jilda Caccavo
So just looking at phenotype, you already have to have the genetic change to be selected for and so on. And then maybe you might end up with a phenotype that's visible to the naked eye, but maybe you don't, because a lot of these changes could be internal, could just be related to internal processes that you wouldn't see. So definitely looking at phenotypes is important, but we could miss a lot by only looking at phenotypes. So I think I got to all of your questions, but, oh, right, you're asking, do we see something now and again, the answer is, it's ongoing. That's sort of the work that I'm starting here in Paris. These types of climate genomic studies have already taken place in other parts of the world on other species, like birds in North America or insects in Europe. These types of methods have been used to answer questions about species in both marine and terrestrial realms, but they've never been applied to antarctic species, to the southern Ocean. So this work that I'm doing with colleagues is sort of the first of its kind, and we're starting with one particular species, the Antarctic toothfish, which I'm happy to talk more about later, but the idea is to eventually apply it to multiple species, because, of course, we want to have an idea of climate change impacts on the wider ecosystem itself.
[00:24:22.700] - Clark
Okay, you did actually hit all of my questions, um, but now I do have another one. So you said that one of the steps along the way is being able to make predictions. My question is, are we at that stage yet? Are we able to predict how these groups will fare in the onset of climate change?
[00:24:37.480] - Dr. Jilda Caccavo
So, unfortunately, that's still up in the future. So the stage that we're at right now, we've identified in the particular species that we're looking at, this Antarctic toothfish. We've identified a set of adaptive markers in the genome that are indicating that there's some adaptation going on. But the question is, adaptation to what? What is it linked to? And so now we're doing those analyzes that allow us to link statistically the adaptation that we're identifying in the genome and the environmental parameters like temperature, sea ice, and so on, that might be driving those changes. And so we're doing those analyzes now as the first step for sort of the present conditions, and then the next step will be to look to the future, to how those present associations, if we project those to the future, how those might influence future populations.
[00:25:26.060] - Clark
Okay, so for any future researchers out there or anyone who's interested in science, it looks like there's still a lot of work that needs to be done 100%. So now, please tell me anything and everything you can about a toothfish.
[00:25:37.280] - Dr. Jilda Caccavo
Yeah, so, antarctic toothfish are this crazy, huge species. They're 2 meters big. They're the largest fish predators in the southern Ocean, together with the closely related Patagonian toothfish. So that's the thing that's really unique about this species. They're both called toothfish, but one of them lives south of the antarctic circumpolar current, and one lives in and around the current and north of it. So the antarctic toothfish, you only find around Antarctica. The Patagonian toothfish you can find as north as Peru, because there's a current called the Humboldt Current that goes west of South America with very cold water all the way up the coast of Chile to Peru. So this patagonian toothfish can be found as north as Peru off the coast of Argentina, around the subantarctic islands. And they're extremely closely related species. The only difference being patagonian toothfish don't have antifreeze proteins. Antarctic toothfish do. There are more differences between them than that, but that's a critical difference, which makes it such that patagonian toothfish can't live where antarctic toothfish live. So what's interesting about studying toothfish is that we can look at two incredibly closely related species and see how climate change is impacting them in their sort of unique environments by almost looking at a species that is only varying by a very small amount by this ability to live in either frozen environments or not frozen environments.
[00:27:03.890] - Dr. Jilda Caccavo
And on top of that, it's commercially fished. So both in and around South America and the sub antarctic islands, as well as near Antarctica, this species is collected, and it's sold not as toothfish, but it's sold as something called chilean sea bass, which many of you may have heard of. There are some individuals that come from the waters of Chile, but many more that do not. And so this was sort of a marketing name that was put on the fish some decades ago because toothfish didn't sound as appetizing. And so the fact that this species is fished means that there's an added stressor on top of it. And while international organizations work hard to regulate the fishery in such a way that it's not impacting the populations of the species itself or the ecosystem in a negative way, these organizations move rather slowly. And one thing, one issue with the management of toothfish species is that climate change is not really taken into consideration. So the types of things that they consider. Okay, we caught this many fish last year. How many did we catch this year? What are the changes in our estimates of the total biomass?
[00:28:15.910] - Dr. Jilda Caccavo
It is the total number of fish. If we see that that's going down, we'll fish less next year. If we see it's going up, we'll fish slightly more. That's the basic kind of information that they use. It's very standard for most fisheries to use this kind of info. But in this day and age, from one generation to the next of fish, there could be huge differences that are related to outside impacts, like climate change, like the things that come with climate change, like increased pollution, pathogens. That would not just be considered if we just look at these population level processes. So this work that I and other colleagues are doing to try to understand climate change impacts is especially urgent for commercially fish species like toothfish, because if we don't integrate this type of information into their management, we could be overfishing them in a way that is damaging not only to them, but to the ecosystems that they depend on. These species are very important for even bigger species. Now we're talking about our charismatic megafauna like seals and whales and other types of organisms that live in the southern Ocean that rely on tooth fish as part of their diet.
[00:29:25.530] - Dr. Jilda Caccavo
So if they're being overfished, it's not only bad for tooth fish, but it's bad for these organisms as well. So those are sort of the two reasons that it's really exciting to apply this research as a first pass to toothfish, both because of the patagonian antarctic perspectives that the two species represent, but also because of the fact that they're fished and the urgent need to understand how climate change will impact those populations.
[00:29:51.470] - Clark
Okay, I was also going to ask you why you chose to study the toothfish, but you actually already answered that question with a lot of very important reasons. Also, I googled them while you were speaking, and they're huge and also kind of scary looking. But let's see. Based on the work that you're doing, it could serve as a very crucial foundation for policy. You also wrote something called a summary of southern Ocean ecosystems for policymakers. What can you tell me about policies that you recommend when it comes to the Southern Ocean ecosystems?
[00:30:16.780] - Dr. Jilda Caccavo
Well, I think the number one thing to think about is caution. There is so much that we don't know about how species are being impacted now by climate change, how they will be impacted in the future. And on top of that, and I'm not a physical scientist, but there are many questions that physical scientists and climate scientists that study climate change have about how climate change is even going to happen. You know, there are certain predictions we can make now, but those are statistical estimates. They can be far worse than what is actually being predicted now. You know, everyone's working as hard as they can to put forward the best available science, but there remain holes. And so if we just make policies based on sort of the least conservative estimate of how species will be impacted and how the environment will change, well, that could result in very bad outcomes. If it turns out that species are impacted in a much more grave way, or that the environmental impacts are much greater than what we thought, this extra level of caution that should be built into policy would be my number one thing. And, for example, this is what we would hope to do one day.
[00:31:27.830] - Dr. Jilda Caccavo
I mean, it's a sort of policy suggestion that my colleagues and I are working on, but it's, can we integrate information about potential climate change impacts on toothfish into the estimates for how many fish are caught each year?
[00:31:44.150] - Clark
Well, I think that sounds like a very smart policy, and I think that should happen right away.
[00:31:49.250] - Dr. Jilda Caccavo
Thank you.
[00:31:50.950] - Clark
I want to ask a question about the nature of adaptation. We might assume that it's a good thing always, right? You're responding to a pressure, you're becoming better fit for your environment. But climate change is a pressure that's going to force species to adapt really quickly. So my question is, is that an assumption we should be making? Is adaptation always advantageous?
[00:32:10.770] - Dr. Jilda Caccavo
I would say that in a world without humans, or rather in a world where there were no other pressures on a given species or population, adaptation is the point. They're not going to persist if their environment is changing unless they adapt or, you know, if they have competition from other species and so on. The issue is that adaptation is not a perfect process. Adaptation, you know, comes when there's a mutation in a gene, and that mutation happens to result in something positive, a new protein or enzyme that actually helps the animal to reproduce, and then it. It persists. But not every mutation, first of all, has any impact or has a positive effect. They could have negative effects. And so this process of capturing change in the genome is sort of a trial and error. Let's say, if we think on the level of the whole population, to persist when adaptation is happening, that comes at an energetic cost. Again, as you said, we typically think of it, and it is a good thing, but it doesn't come without its costs.
[00:33:13.000] - Clark
Sure. And then also it's probably hard to guarantee that any adaptation will be either advantageous in the long run or advantageous to every pressure. Right. Because these organisms, these toothfish, are trying to adapt to all these different pressures at once. And so one adaptation might make them more fit to address one, but maybe more vulnerable towards another. Right. And then also the climate is changing so quickly, and so it just probably makes it hard to predict, which makes your job really hard as well.
[00:33:38.310] - Dr. Jilda Caccavo
That's an excellent point. You couldn't have said it better. And this variability, this increase in variability is one of the hugest problems in the southern Ocean in the polls generally, because these were places where up until, you know, a few hundred years ago, things were stable, stable, stable. We're not talking about, you know, the northeast Atlantic or what have you, where there's much more variability in conditions from day to day or from season to season. The poles are places where animals are specifically adapted to very specific conditions. And it's not only that those conditions are perhaps incrementally changing in one direction, they're also just changing how stable they are. And it's super difficult for species to adapt to variability.
[00:34:21.460] - Clark
Right. Well, I guess it's a good thing we have scientists like you keeping an eye on these things. We've talked about a lot of things today. So as we get towards the end, I want to ask if there's anything that we missed when we're talking about toothfish, southern Ocean genomics, climate change, nodothenioids.
[00:34:36.950] - Dr. Jilda Caccavo
I guess one answer could be these species continue to surprise us. You or some of your listeners might have heard this news story that came out, I think it was last year, or if not the year before that, about all these hundreds of fish nests found in Antarctica in this part of it, in part of the Southern Ocean called the Weddell Sea, that had never been discovered before. And I mean, people have been going to Antarctica like, for 5100 years, or like, doing proper undersea investigations for at least 50 years, and yet suddenly this huge new behavior of a certain species, huge type of way of modifying their own habitat by making all these nests, was discovered. And so we can try, you know, as researchers, to, when we're writing our proposals for funding and so on, to say, okay, I'm going to do this, and then in five years I'm going to do this, and based on that, in ten years I'm going to do that. But as creative and imaginative as we can be, we can never be as creative and imaginative as actual nature. And things will continue to surprise us. And a bit like how policy has to make room for uncertainty.
[00:35:45.140] - Dr. Jilda Caccavo
Scientists have to make room for these amazing discoveries that just happen every now and then and change our whole way of thinking. I think it's just maybe the humbleness for scientists themselves to be open to the wonder of the environment and what we learn and how things might change and everything, I'm telling you now, maybe in five years I'd have a totally different spin on it. But, you know, we do the best we can with the information we have, but we learn so many new and exciting things every year that, you know, everything will have to change a bit.
[00:36:14.670] - Clark
Okay, there were some inspiring quotes in there I think I'll probably have to make into a t shirt. The last question is, where can people find you and follow your work, of course.
[00:36:22.840] - Dr. Jilda Caccavo
Well, so I have a website which is just my name.com comma jilldaCaccavo.com and there I have links to all of my science, social media, researchgate, Google Scholar, things like that, all the organizations I'm involved with. And I also have links to all of my publications, presentations, everything like that, and my contacts. So I would encourage folks to check out that website as a source to then find all of my presence online and my work. And I'm more than happy to talk to anyone at any time. I think it's also a responsibility of scientists, especially government funded scientists, to talk about their work to people, to help people understand the importance of science generally, antarctic science, climate science. And you know, it's going to help us to push the policy that we want if the public is supporting that policy.
[00:37:16.810] - Clark
Okay, well, I'll make sure to put a bunch of those links in the episode description. And she's not lying, people. She will speak with you. I'm just a stranger and you know, we're here today doing this, so she means it. This is the part where I say thank you so much for your time today. Thank you for teaching me about Antarctic toothfish. And perhaps most importantly, thank you for your very important work in this space.
[00:37:35.730] - Dr. Jilda Caccavo
Thank you.
[00:37:49.900] - Clark
Okay, a major thank you to doctor Jilda Caccavo. I'm gonna put a photo of toothfish in our social media because they are really interesting looking. I love what Doctor Caccavo said at the end about being constantly amazed by the wonder of nature and science. I'm having a similar experience as I continue learning more and more that I never knew about this southern polar region, but also about science in general. And today it was the toothfish. So science is just so cool. And I think we talked about a lot today, so I'll leave it there. Thank you guys so much for listening and we'll talk soon. If you've been listening to South Pole, you can find more information about this week's guests and links to their work in the episode description. Cover art for the show was done by Laurel Wong, and the music you're listening to was done by Neela Ruiz. I am your host, Clark Marchese, and this episode was produced and engineered by me. So if you found it interesting, send it to someone you know. South Pole is part of a larger network of sciency podcasts called Pine Forest Media. We've got one on plastic, one on drinking water, and a couple new ones coming out soon.
[00:38:56.060] - Clark
You can find more information about us in the episode description or on our website@pineforestpods.com, we are also on Instagram and TikTok at Pine Forest Media. And if you love the show and you want to support science communication like this, a five star rating across platforms and a review on Apple Podcasts is one of the best things you can do to help us reach more people and for the entire network to grow. Alright, thank you to all of you who have made it this far, and we'll chat soon.
