The Great Simplification with Nate Hagens - The Fish are Fleeing: How Shifting Marine Ecosystems are Upending Life with Malin Pinsky

Episode Date: May 28, 2025

For all of human history, the oceans and the life within them have remained a stable and fundamental part of Earth as we know it. Yet, for the past few decades, fisheries and scientists alike have observed massive migrations in marine ecosystems unlike anything we've ever witnessed. What is driving these unprecedented movements, and how are they rippling out to affect every aspect of life In this conversation, Nate is joined by marine ecologist Malin Pinsky, whose decades of research shed light on the dramatic migrations of marine species due to rising ocean temperatures. Malin breaks down the science behind these changes – from declining oxygen levels pushing fish toward the poles, to the cascading impacts on intricate marine food webs, as well as the growing threat of localized extinctions among key fishery species. How has a cultural disconnect from the importance of biodiversity and the interdependence of life led to such a drastic impact on the function of our oceans? What do these changes mean for humanity, including impacts on global food security and geopolitical stability? Finally, could reconnecting with the ocean's abundant, diverse ecosystems help us reduce our impact on these deep, blue pillars of life?  (Conversation recorded on April 22nd, 2025)  More TGS Ocean Episodes   About Malin Pinsky: Malin Pinsky is an Associate Professor in the Department of Ecology & Evolutionary Biology at the University of California Santa Cruz with expertise in the adaptation of ocean life to climate change and applications to ocean conservation and fisheries. His more than 120 publications have appeared in Science, Nature, and other journals.  He is a Fellow of the American Association for the Advancement of Science, an Earth Leadership Fellow, and an Early Career Fellow of the Ecological Society of America. Pinsky serves on advisory boards for the Beijer Institute of the Royal Swedish Academy of Sciences, the non-profit Oceana, and the Chewonki Foundation. He grew up exploring tidepools and mountains in Maine.   Show Notes and More Watch this video episode on YouTube   Want to learn the broad overview of The Great Simplification in 30 minutes? Watch our Animated Movie.   ---   Support The Institute for the Study of Energy and Our Future Join our Substack newsletter Join our Discord channel and connect with other listeners  

What we're seeing is probably the largest mass movement of marine life in the last 10,000 years. As waters are warming, as prey are shifting towards the poles, as oxygen levels in the ocean are going down. All of these things are making conditions inhospitable for many of the species, especially fish and the ocean. And then this has ripple effects that go through to coastal economies and fisheries, even international relations. sparking conflict in some cases between countries. So it has wide-reaching consequences. You're listening to The Great Simplification. I'm Nate Hagan's. On this show, we describe how energy, the economy, the environment, and human behavior all fit together and what it might mean for our future. By sharing insights from global thinkers, we hope to inform and inspire

more humans to play emergent roles in the coming Great Simplification. Today I'm joined by marine biologist Malin Pinsky to discuss what he describes as possibly one of the largest animal migrations in our planet's history, occurring right now in Earth's oceans. Malin is an associate professor in the Department of Ecology and Evolutionary Biology at the University of California Santa Cruz, where he has been using decades of data to research the changes and adaptations in ocean life due to climate change. He is also a fellow of the American Association for the Advancement of Science, an Earth Leadership Fellow, and an early career fellow of the Ecological Society of America. Most notably, Malin and his team have been studying the poleward shift in animal populations due to both rising temperatures and insufficient oxygen levels, which is the subject of today's episode.

We have dedicated quite a few episodes of this podcast to Ocean Systems, and I am excited to continue our exploration on this important topic, as it is my belief that oceans are one of the most impactful, but often overlooked aspects of the enormous planetary changes currently underway. Today's conversation with Maylan expands on just one piece of this complex and unfolding situation. If you're interested in learning more about oceans, we will link a few of the team's favorite episodes in the description. Before we begin, if you enjoy this podcast, one of the biggest ways you can support us is by subscribing to it on your favorite platform, as well as sharing this episode who might also enjoy it or learn from it. We believe in making this content free

and accessible to as many people as possible, and we appreciate your support. With that, please welcome Professor Malen Pinsky. Professor Pinsky, welcome to the program. Thanks so much for having me. Great to be here. You are an ocean expert, and what better place to study the oceans, then the University of California and Santa Cruz. What a lovely town and a lovely setting. It's a fantastic place to be. I'm actually looking out at the ocean right now. You know, historically, humans co-evolved near water and, well, we evolved out of the ocean. If you go way back historically. But it seems like a lot of populations today are like where I live near Minneapolis. The ocean is almost an abstraction because it's so far away and we don't get the

emotional. We don't look out the window like you are and seeing it, but the oceans are so vital to how the world works and food and climate stability and everything. So it must be good to have a daily reminder of what you're studying and how important it is. Yeah, it definitely is. I mean, a lookout right here and the edge of the horizon is the ocean. And it's at least a small reminder that this isn't really planet Earth. This is planted ocean. And so much of our trade, a lot of the food for people around the world comes from fish. Even if we don't necessarily see the ocean in our backyard daily, it is such an important part of our economy and our life. And our society is supported by the ocean.

Do you ever like just sit on the beach and look out into the ocean and imagine someone on the coast of China is doing the same thing looking at you? Yeah, no, it's a good point. You know, with there so, you know, most people actually live near the ocean as well. You know, we even in today's world. In today's world especially, most, a large fraction of humanity lives within, you know, say 100 kilometers or so of the ocean. There's a big attraction, both for trade. You know, that's where our ports are. That's where our goods get moved between cities.

And it's also, you know, property prices are high near the water as well. Clear evidence that lots of people want to live near the water, live near the ocean. Well, I mean, we're going to, your team researches marine organisms that are non-human, which is going to be the focus of this conversation. But yeah, we could spend a whole hour and a half talking about the implications for people on the coast in the coming century with sea level rise and etc. But you and your team are world-class experts in marine animal response to ecosystem changes that are happening in the world's oceans due to warmer temperature and more CO2. So to start with, can you just unpack the broad patterns that you and your team are seeing observing with animal migration in the ocean and why this topic is important? Yeah, so I run the global change research group, as you said, at the University of California, Santa Cruz.

And we collaborate with scientists all over the world to collate data on where marine species have been historically and where they are now and where they're going. And what we're seeing is it was probably the largest mass movement of marine life, at least in the last 10,000 years. towards the poles primarily, as waters are warming, as prey are shifting towards the poles, as oxygen levels in the ocean are going down. All of these things are contributing to making conditions at low latitudes in hospitable for many of the species, especially fish and the ocean. And then this has ripple effects that go from ecosystems and species interactions and the productivity of the ocean through to coastal economies and fisheries, the food on our plates,

and even international relations. It's starting to affect trade and even sparking conflict in some cases between countries. So it has wide-reaching consequences. We just met and had an introductory conversation and I reached out to you because Daniel Pauli is a friend of mine and he was on our podcast a few years ago talking about Gil Oxygen Limit Theory saying much of the same things. And so this is something that I don't think is in the public's imagination or awareness. And I have so many questions for you. And some of them will be on the naive side. For example, this. You just said this may be the greatest migration of animals. at least in the last 10,000 years,

how would we begin to know that? How do you know it's a greater migration than even 300 years ago, scientifically? So, yeah, I mean, that's a guess, but an informed one, based on a lot of the research we've been doing, tying movements over the last primarily 50 years where we do have strong observations of where many marine fishes have been

and where they've moved to. And one of the key things that we've found is that they follow their preferred temperatures quite well, so quite closely. And as those preferred temperatures are moving towards the poles, also to some extent moving towards deeper waters and further from the coast. It's not always just a clear march towards the poles. It's definitely more complicated and nuanced than that, but that's the broad brushstrokes. And because of that close link between temperature and many marine species distributions, geographic distributions, we can then sort of do that hindcast, think about what would have happened in the past.

And we're seeing right now one of the largest changes in temperature in sort of since we came out of the last glacial maximum, the last ice age. And when was that? about 12, 20,000 years ago. It's also, I mean, even beyond that, you have to go back more like 120,000 years until you find a time in Earth's history when it's as warm as it is right now.

And I think that's, that's for me, at least one of the scariest things when we think about what does that mean for marine ecosystems, but also ecosystems around the world. I'll tell you something that's even scarier. It's one of the warmest times, but and I'd like to tee you up to explain what I'm about to ask you. But the oceans have not warmed nearly as much as on land and they are acting as a buffer.

And so some warming is yet to come just because the oceans are this really slow feedback mechanism. Can you explain that? So you're right. The oceans have not warmed as much. The oceans are effectively the heat sink for the earth. More than 90% of the excess heat from anthropogenic climate change has ended up in the oceans. If we didn't have the oceans, we would already be very, very crispy toast. It would just be ridiculously hot on the Earth's surface already.

And the surface of the ocean has warmed about 0.9 degrees Celsius so far. That's quite a bit less than the land surface, which is about 1.6 degrees Celsius. And yet one of the things that's interesting is that because, the ocean buffers heat, buffers temperature so much, it absorbs heat, but it doesn't actually change temperature all that much. Species that live in the ocean actually are not adapted to changes in temperature all that much either. So even a relatively small change in temperature of the ocean has had very large consequences for ocean life. Actually, species in the ocean are shifting towards the poles about five times faster than we are seeing on land.

And this isn't a, ooh, it's a little bit cooler over there. I think I'm going to swim in that direction. It's just like a internal biological, like, oh, this is uncomfortable and I can't get enough oxygen or food, so I'm swimming in that direction. Well, it's a whole range of mechanisms, and it depends on the species. So, you know, for example, surf clams on the, on the east coast of the U.S. They've been dying off. Yeah, because they can't swim. They can't swim, exactly.

So that's been more of a die-off and then population growth further towards the poles. They have larvae, they disperse with ocean currents, they have an ability to move towards other locations, but it's largely undirected. It's not fish with fins deciding they're going to use them. Their populations have the ability to move to different locations, not the, individual bodies. Exactly. Yeah. Yeah. Yeah. Yeah. So it depends on the species. For some, it's, oh, yeah, it's uncomfortable. I need a lot. My metabolism's going up. My body's hot. I need a lot of oxygen. I need a lot of food. Let me go somewhere else that's more comfortable. But for other species, it's just survival. So you said that the ocean's surface has warmed 0.9C. Do we measure at long? levels because the ocean goes down a long ways. Do we have any evidence or metrics on deeper or

mid-level ocean temps? Yeah. So the surface is warming the fastest and then rates of warming decline as you as you go deeper. And you said that many, not just a few fish, but many different marine organisms are swimming or moving their populations northward, but are they also moving deeper because deeper might also be cooler and have more oxygen, yes? Yes, that is correct. Though there are limits to how far that goes. Because then there's not enough photosynthetic productivity that leads to food, you know, algae and phytoplankton and things like that when you're at a half mile down.

Right. Right. We have the photic zone where lots of light penetrates. We have lots of phytoplankton, basically the plants of the ocean. that are growing. And also, you know, a lot of fish are visual predators. So they need that light to find their prey. So they, you know, going deeper to find cooler, cooler water helps to some extent, but only to some extent. So you've studied horizontally and vertically the entire gamut of ocean creatures and their responses. But what sort of breadth and variety and diversity of ocean creatures do you study?

And are you observing this phenomenon in the majority of them? They're swimming poleward or deeper. My research group in particular has focused in particular on fishes and crustaceans that are observed on continental shelves. So these are the relatively shallow parts of the ocean close to land. Here on the west coast, it's a relatively narrow. continental shelf, but on the east coast, you know, it's a couple under miles. And these are the most productive parts of the ocean. They are also the parts of the ocean that interact the most with human society. It's where most of our fisheries operate. It's also the parts of the ocean that

are best observed. So there are surveys that governments all over the world conduct on continental shelf. So it provides an opportunity for us to test our hypotheses and better understand how ocean life is responding. On the other hand, other scientists are working on marine mammals and invertebrates and many other species across the ocean. And this consistent picture has emerged of the vast majority of marine species that we have observed well enough to know where they're going are shifting towards the poles. So let's get into the core of your science a bit. I think it's intuitive to most listeners, but can you give a specific explanation of why temperature is an important factor for determining what sorts of organisms can live in a given ecosystem,

either on land or in the ocean? Yeah, temperature is sort of the metronome for life, you know, especially for what we call ectotherm, so this is fish in the ocean, but also crabs, crustaceans, pretty much everything in the ocean except for marine mammals. Their ectotherms, their body temperature is set by the temperature of the water around them. When water temperature goes up, their metabolism goes up as well. So they need more food. They also need more oxygen. It also affects protein structures.

If my body temperature goes up, do I need more food and more oxygen? You get a fever. So do I. Oh, right. You know, just a degree or so, right? And you'll feel feverish. you know, the homeostasis of the equilibrium of your body is thrown off. Metabolism and demand for oxygen relative to how much is available in the water around them,

similarly for food. And then temperature also affects protein structures. They basically get wobbly and fall apart when it gets too hot. So for some species, that's an issue. And actually, it also affects the permeability of cell membrane. So temperature is really this fundamental biological. factor that affects a whole organism. So you mentioned thermal safety margin.

One of the things that my group has been very interested in is trying to understand how sensitive marine species are to rising temperatures compared to rising temperatures on land and species on land. And one way we can make that comparison, and we've made this comparison, is to basically measure what's the temperature that? fish are living in and how close are they to the highest temperature that they can tolerate. And those are high temperature tolerances that are measured in the laboratory, sort of in experiments. And then we can compare that, that difference, that buffer is what we call a thermal safety

margin. And we compare that safety margin to then safety margins for amphibians and reptiles and insects on land. And one of the things we found that was really surprising for us and for many of our colleagues is that marine species actually live closer to their upper thermal limit in general than do species on land. So they're more sensitive to rising temperatures. And actually we've seen twice the fraction of marine populations disappearing at low latitudes and presumably moving towards higher latitudes as we've seen disappear on. on land as well. So not only are they more sensitive,

but they're also disappearing at higher rates. Let me ask you a question. So as temperatures in the water warm, two things are happening. One is they're getting less oxygen, staying in the same place, and their food might be moving northward or not be available.

Do you see any evidence where, in order to feel better and to not have a fever, metaphorically, marine organisms hold out in cooler temperature, maybe deep water

or something like that, but there's no food there. So then they have to go to where the food is. And when they're done eating, they go back to where it's cooler. Instead of maybe back in the day, those were the same location.

Is there any examples of such a thing? Yeah, no, that's a really good question. There's a very interesting study done in Norwegian fjords a few years ago where they had trackers on Atlantic cod, you know, very favorite species for the fish for people to eat all over the world. Basis of many economies across Europe, too, and especially in the couple hundred years ago. But the cod, when it wasn't too hot, the cod were feeding in very productive shallow parts of the fjord. when it got too hot, they would move deeper where it was cooler, but where there wasn't as much food. So they would sort of avoid the high temperature areas when they had to.

But as soon as it cooled off, they'd come back to the surface, the shallower areas where they could feed. I know you're an ocean expert, but is there analogs in freshwater lakes where obviously the temperature must also be warmer because it's warmer on land and warmer in the air? So are there, do fish in the Great Lakes or in the lakes in Minnesota, the land of 10,000 lakes where I live, are they hanging out at a deeper level because it feels better? Yeah, it's common in freshwater lakes and rivers as well. You can often find trout, for example, hanging out near cold water seeps in a river and then moving into warmer waters to grab some prey but then retreating to the colder locations.

But I meant is there evidence in the last 50 years that where fish are hanging out is deeper than it used to be? I am not aware of that, though there has been evidence that many freshwater species are also, populations are growing at the northern or high latitude parts of the range and shrinking in the low latitude parts. So we're seeing similar patterns in freshwater as well, similar to what we're seeing in the ocean. Though I will say moving and swimming is trickier in freshwater, right? You don't necessarily have a river going north-south. Sometimes they go east-west. Well, or you might be in a lake and you can't go north beyond where the lake is.

And we have dams and, yeah, a lot of barriers in freshwater. So you're not studying endotherms, though you have a lot of them right outside your door. The last time I was there, there were sea lines like on the promenade there in Santa Cruz. How is this impacting whales, dolphins, sea lines, other ocean megafauna? Yeah, it's a great question. Yeah, I feel pretty lucky, actually. Sometimes Monterey Bay gets called the Serenegi of the ocean. Oh, yeah.

Last time I was there was amazing. Highest diversity of marine mammals in the world as far as I'm aware. What? Really? Yeah. Wow. Yeah, it's cool. And why is that? It's very productive.

So lots of food to feed on. So we've got very deep ocean water very close to shore and a lot of upwelling. So upwelling is a particular oceanographic phenomenon that brings very nutrient-rich water up to the surface, where then it sparks phytoplankton growth. And then you have zooplankton feeding on them and fish feeding on them, and then the whales coming in and seals and sea lines coming in as well. So what's the evidence? I mean, is this impacting ocean? I mean, they're at the top of the food chain, right?

So they have to be impacted somehow. Well, and that's exactly how they're impacted largely. It's through their prey and through their food. So we also here on the West Coast, we see dolphins showing up more in Oregon and Washington. Historically, they were found around California. One of the key cases actually has been North Atlantic right whale, so a critically endangered species in the Atlantic, on the east coast of the U.S.

There are only about 370 individuals left. And they showed up, have been showing up in much larger numbers up in Canada in the Gulf of St. Lawrence. And presumably they're, well, actually we know pretty well that they're following their prey. You know, they're not as directly impacted by temperature and warming, but their prey definitely are.

They feed primarily on copepods. Basically, the protein bars, of the ocean. And with their prey more productive further north, the whales are following them as well. That's led to a number of other complications because they've also then been entangled in fishing gear. That's one of the main threats to bright whales,

but also an issue here on the West Coast. So as the oceans warm, the delta of current temperatures versus future temperatures would be highest in the northern latitudes as we approach the poles, but maybe the absolute temperature, high temperature would be near the equators.

What are the implications for your work? There will still be fish, depending on eventually how this all unfolds, but there will still be fish at the warmest ocean layers and levels around the equator, or that will just be fewer, less diverse, more simple species? Or what can you say about that? Yeah.

So it's actually already been an observation that there are fewer species at the equator than there have been historically and that the number of species is already declining. And normally we talk about the greatest number of species being present at low latitudes. Often we think about that at the equator. and the ocean it's actually at slightly higher latitudes, both north and south, and there's a bit of a dip when you get to the equator, which is really surprising.

I think one of the biggest concerns in the tropics is coral reefs. We know that corals as a species, many corals as a species can tolerate higher temperatures, but the species that are most important for building the massive reefs that we can see from space, that people go scoob diving and snorkeling on, and they're also so important for supporting fisheries in tropical countries. Those reefs do not, you know, they're very sensitive to high temperatures,

and we see global coral bleaching happening in recent years, and that leads to mortality of the corals and eventually degradation of the reef as well. So the big concern in the tropics is loss of coral reefs especially. And what's downstream from that? because the food chain has a ripple effect, or is it just the loss of coral, which itself would be a tragedy? You know, you think of corals in some ways

like the rainforest of the ocean. You know, they provide the structure and the habitat for an incredible diversity of shrimp and fish and crabs and everything else. Yeah. So you've studied how many different organisms, roughly? I can't say. I've counted, but thousands.

Thousands of species. Thousands of species. And how are you actually measuring and researching these changes as the director of this effort? Yeah. So we work with scientists all over the world who are conducting these surveys. At the moment, I'm helping coordinate a group, an effort called Fish Globe to pull together data on fish, marine fish, near the coast. all around the world and to understand observations of where these fish been observed, how has that changed through time, and then how is that linked to changes in their environment?

So we build lots of statistical models and other more mechanistic mathematical models to understand what's been happening and what's likely to happen going forward. But with thousands of species and funding now with NOAA and NASA and other scientific orgs under threat, like how do we have the actual manpower and science power to keep tabs of all these species? Is that an increasing challenge? That's part of what's been so concerning in the last couple months, right? I mean, these changes are happening in the ocean, these changes are happening in the climate, whether we see them and understand them or not.

and by cutting out the scientific infrastructure, and that's both observations, but also the experts to take those observations. You know, in government agencies like the National Oceanic and Atmospheric Administration, we don't, you know, we won't have the ability to know what's happening. It's kind of like driving quickly at night without our headlights on. We just don't know it's coming. And increasingly, our fisheries really rely on understanding what's happening in the ocean right now

and what's likely to happen next year or over the next couple of years. You know, you think about a fishing business that's going to invest in a billion-dollar permit for scallops. scholars better be around for a decade or more for that to pay off. So if you're going to make a big business investment in fisheries, you want to know that they're going to be around. And that requires the ability to forecast what the ocean conditions will be and where the fish will be. And where the scallops will be. Well, yeah, sorry, yes, the scallops will be. Totally agree.

If they'll be anywhere. I mean, so beyond migrating, are you seeing any trends in declining species populations or even the beginnings of what might be extinction for some species? So when we've looked across marine species at their low latitude range edge, so sort of as far south as they're found, half of those species have already disappeared from low latitudes and have contracted towards higher latitudes. So those are what we call local extirpations, local extinctions. There has been a species of coral reef fish that's presumably gone extinct as a result of high temperatures in the ocean. It's the Galapagos damsel. Hasn't been observed for the last few decades. And the projections going forward is that if the ocean continues to warm as much as it could with runaway,

greenhouse gas emissions, we could look at extinctions on the order of what's been seen, you know, the end-permian extinctions are the largest loss of life on Earth that we know of in the geological record, like 250 million years ago. So Corey Bradshaw is a population biologist from Australia. He was on the show and he said, and others have said, that at three degrees Celsius warming on land, we would lose half the species on Earth. And I would have to think that it would be the same in the oceans or similar magnitude.

The latest projections for end of century, sort of average across or middle of the road greenhouse gas emission scenario, actually is about 10% in the ocean. 10% of species? Yeah. Okay. So, you know, you can think about many marine species

can move towards. higher latitudes. They have some ability. So it's species at the poles that are most at risk. This is not, you know, it's not universal by anything. Because they have nowhere to swim pole. Nowhere left to go. So yeah, it's kind of like they're walking a plank. But there's a difference between extinction and viable population and how many organisms comprise a population. Entirely. Yeah. No, that's right. You don't, you don't need to go to zero before you're bound for extinction. That's something we call actually the extinction debt. So a population or species has declined enough or lost enough habitat that they're headed towards extinction, but it's going to take some time

until they actually get there. So the slowdown of the current in the Atlantic Ocean, we've had some people talk about that. And if that continues, the conveyor belt, Europe might be, and the waters around Europe might be super cold. And I've been thinking. thinking about that from a climate impact on land, but that would also have impacts on fish and marine organisms who would actually want to go to that cold area. Right? Yeah, no, you would see many marine species shifting back south. So, you know, North Sea Atlantic cod populations, for example, have not been doing well at all.

Part of that's overfishing, but it's also warm ocean waters. Atlantic cod up in northern Norway are booming. doing really well. So as I mentioned earlier, a couple years ago, Daniel Pauley was on the show talking about Gill Oxygen Limitation Theory, which says that what is driving the poleward movement of fish is that there isn't enough oxygen for them at the location that they currently are in the ocean. So how does this factor fit into your work? That combination of higher temperatures and not enough oxygen to meet demand is one of the key mechanisms

that's likely driving the poleward movement that we're seeing. One of the real scientific needs at the moment is actually to make that link more directly because we have good observations of temperature, but it's only in recent years that we're starting to get actually reconstructions of what oxygen availability in the ocean, especially down deep where Fisher actually found. How much oxygen is down there and how has that changed through time? How do we know how it changes through time?

Most, so we have some observations, but they're quite sparse, and that's what's made it difficult. So they get reconstructed, actually, by oceanographic models, so mathematical models of how the ocean circulates and how oxygen and other and nutrients transform as well. And at all the, take the Marianas trench, the deepest place in the ocean, there's the surface, water and then like how many miles five miles down. What does the oxygen look like from zero all the way down to 30,000 feet or whatever it is? So oxygen tends to decline as you go somewhat deeper in the ocean. We have actually a oxenum. But it's much colder though down there. So the demand for oxygen for species that live down there is also lower. So you have these sort of two counteracting factors as you go deeper in the ocean. Though you raise an interesting question, because especially offshore, this isn't

right close to shore, but we have something called an oxygen minimum zone, where there's basically enough life that a lot of the oxygen gets used up, but it's not easily replenished from the surface. because the very surface mixes with air. We have relatively large amount of oxygen rate at the surface of the ocean. But then you know the oxygen minimum zone, and as the ocean has been warming, it has two effects.

One is it tends to stratify ocean waters more. It's kind of like putting a lid on the ocean to some extent. So there's less mixing of oxygen into the ocean. And these oxygen minimum zones have been getting larger area-wise, but also getting thicker in the ocean. And it's been pushing species, many species of fish, like tunas and swordfish, into just a narrower range of depths in the ocean.

It's made them actually more accessible to fisheries. They're just kind of corraling them into the only sliver of ocean that actually has sufficient auction because this other stuff is below the minimum auction threshold. Exactly. Because the oceans are stratifying, because of all the changes we've been discussing, which leads to Peter Ward is a good friend of mine. He wrote a book called Under a Green Sky, which is about historical Canfield Oceans, where the oceans become fully stratified and there's hydrogen, sulfide gas, and other nasty things. Let's hope we're not headed in that direction.

Yeah, exactly. Yeah. So getting back to Daniel Polly and Gill Oxygen Limitation Theory, has your research yet produced? do strong evidence for this theory or are there strong inclinations that it will? So we've done some work on black sea bass. And I should say, actually, more broadly, there's the Gill Oxygen Limitation Theory. There's also related theory called the oxygen and capacity limited thermal tolerance. And these broad ideas that it's this balance between metabolic demand for oxygen and then the supply of oxygen is part of what's said

getting distribution limits for fish and other marine life. So we've done some work on black seabass, one of the fastest moving species on the east coast of the U.S. So about 190 miles further north than they were in the 1970s. When you order seabass at a fancy restaurant, is that what we're talking about? A bunch of things get called seabass. So whether it's black seabass, you'd have to ask. Okay.

Yeah. It's also Chilean sea bass. And when we compared where the black sea bass were and where they moved to, that was best explained by changes in not just temperature, but also oxygen. So interesting evidence that oxygen is a very important part of the changes we're seeing. So what questions under this umbrella still need to be researched further? And are there plans to do that? Yeah. One of the big questions actually is how important. these different ocean changes are, you know, there's temperature, there's oxygen, there's prey, it's also ocean currents. How important are these different factors so that we can start to forecast where these species will be? And there's been very few and just very initial efforts to start to forecast where these fish will be, which is important for guiding fisheries and also fisheries management. So we can start to adapt to these changes as well. One of the, one of the things

we've been observing is that these species are moving quickly, and they move across political boundaries. So they cause problems for fisheries, they cause problems for politics, they cause problems for humans. But the fish are just adapting to the ocean changes. So we need a better understanding and better ability to forecast

what these changes are going to be going forward. Are there any examples of major fisheries for human protein that have been demonstrable, changed in the last 30 years that have caused fishermen and cities and people that live in those areas have to adapt their diets and purchasing patterns. Oh, very much so. I mean, these are very real changes that are happening now. Just to give you a couple examples, North Carolina used to have quite a large local fishery for Summer Flounder. Summer Flounders now declined quite a bit off North Carolina become quite abundant off New Jersey, New York, Rhode Island.

Some of those boats, the boats that are big enough, are now fishing 600 miles further north. It means they burn a lot more diesel to get there. Whereas a lot of the small fishermen, small boat fishermen, just had to leave the business. There was a, I mentioned surf clams earlier. There was a processing plant in Virginia. That closed down, a new processing plant moved, opened in, Massachusetts, close to where the population is more productive and where the fishery has moved. In Europe, northeast Atlantic mackerel expanded north and west into Icelandic waters,

had historically been a fishery shared by the European Union and Norway and a couple other countries. Iceland then became involved because there were mackerel in Icelandic waters. Iceland, European Union, and the other parties couldn't agree it became a trade war. Trade war is now resolved, but they still haven't agreed, actually, on how to share that fishery. So in addition to climate migration, in addition to energy resource sort of wars, the mid-latitude countries, if you look forward 20, 30, 40, 50 years, it's the northern and the maybe southern like South America areas that the fish are going to move towards. And this has a international trade and fishery implication for the future, as you've alluded to. Yeah, it does.

And, you know, one of the really interesting cases with the mackerel example that I told you earlier is the, so the countries haven't been able to agree how to share this fishery. So actually, it's been overfished, meaning too many fished. are being removed, more fish are being removed from the population than they can replenish each year. And so actually they lost a sustainability certification from the Marine Stewardship Council. And so a number of companies are actually helping them, pushing the countries to agree so that they can fish sustainably and get this certification back, which is important for business. Are there any types of fish that are popular for human consumption that aren't as sensitive to increase, in temperature or reduction in oxygen.

Maybe a slower metabolism fish, for instance. Yeah, I can't say I can really, really think of one. Okay. Necessarily. I'm just thinking of a barracuda. They're just so thin and wiry and fast, and probably they would be really sensitive, and then maybe a grouper would be less so,

but I'm not a fish scientist, so. Yeah, you know, there are many different ways to make a living as a fish, but they're all sensitive to temperature. Sure. And oxygen. And oxygen, yeah. So what are the implications, the broader implications of your findings and your colleagues on these trends for overall biodiversity and integrity of the physical planetary systems? Yeah, massive.

You know, part of what we, one of the things we recently found is that in parts of the ocean, they're actually on land and in freshwater as well, in places where, temperature is changing the fastest, up to half of the species are getting replaced every decade. It's a massive scrambling. So if you have a hundred species, total species, where you are on some coastline in the earth, that in a decade, 50 of those will have moved on. Potentially replaced by, you know, especially if you're at mid-latitudes, potentially replaced by 50 new species.

Right. And that affects how productive these ecosystems are. It affects what we can catch in fisheries. It affects the food webs. And the problem is we don't know necessarily. I mean, there's so much we don't understand about how these ecosystems now function. There's a reductionist way to catalog the census of these different organisms. But I had a recent podcast on with Thomas Crowther, who's an ecologist, who talks about biocomplexity,

which is the interactions and symbiosis between other species with. in an ecosystem. And how do you measure that when half of the species are displaced? Right. I mean, it's sort of like taking, it's like the ocean's a snow globe and we're just shaking it really hard. Obviously, you love and care about the oceans. And, you know, in our previous conversation, I can tell how, how, you know, solid a scientist you are, but also as a human, how you deeply care about these things. Do you ever just take a step back at the arc of the trajectory that we're on and just get incredibly sad? There are moments.

Yes. Though, you know, it's also, nature is incredibly resilient. We don't necessarily know in what ways. We don't know which species are going to survive. We don't know what these ecosystems will do and whether they'll continue to sustain our way of life in the same way going forward. And I think that's, those are some of the really big scientific. questions. You know, what are these ecosystems going to look like going forward?

I could make a case that we could regenerate local ecosystems on land by planting a lot of trees and there's a lot of things going on in Africa right now with Crescent farming and capturing moisture and building ground table waters up and things like that. I just can't imagine a way that oceans cool and have more oxygen in the coming century or so. Is there a plausible way for that to happen? If we can stop omitting so many greenhouse gases. I mean, that's the biggest thing when it comes to ocean climate. But it will still warm and still have less oxygen, just at a slower pace than the default. I'm talking about actually like going the other direction. Is there any possibility of that. So the

climate projections that involve, I mean, a really massive societal effort to halt emissions and even go towards negative emissions don't involve a lot of ocean warming. Okay.

Yeah. Yeah. And does you know, ocean can stay below 1.5 degrees Celsius of surface warming. We're pretty much at that limit. But that's that's the worrying part when people talk about the specific heat what does that mean so it's how much does the temperature go up um for a either for water or for air or any other substance

when a certain amount of heat is absorbed so specific heat of water for example uh is substantially higher than air so water can absorb a lot of heat but not actually warm up very much I mean, you can see that just in your daily life, how long is it take a kettle of water to boil on your stovetop? It takes a while. Yeah, yeah. Or how much energy goes into your hot water heater rather than, you know, a furnace or something in a home. So do you teach? Yeah, yeah, I do.

What classes do you teach? I teach primarily ecology. Oh, that must be fun. Ecology and evolution in tandem? No, I teach an upper level ecology course. One of my other colleagues teaches an evolution course and their pair. And how does all this land with your students learning about ecology and living on the ocean and presumably you share some of your research on these things?

How are these 1920, 21-year-olds reacting to this stuff? They are, they care so much about the future of this earth. and the environment that they're moving into, you know, they often come and think about taking a course in ecology or evolutionary biology because they care about nature and they care about the future of the Earth. So, you know, they see these changes as really important and they want to know why are they happening and what can we do? And what can we do? What do you tell them?

What can average people do who want to get involved in supporting marine life? and this goes beyond your wearing your science hat, but how do people watching this podcast who care about this go in support of marine life and ocean ecosystem integrity at large? I see two big things. One, you know, don't underestimate the power of your voice and your skills, whatever that may be, whether that's science or art or literature or organizing, express your opinion and make it clear that continued climate change is not a good direction for the earth to go.

And we really need action politically, pushing our political leaders to act faster. I think the other thing is that climate change is not, so that's one. A second thing is climate change is not the only stressor on the ocean. So we as individuals can also make choices and choose sustainable seafood. Given everything is going forward or deeper, is sustainable seafood an oxymoron? Not at all. No, it's actually more important than ever. What is sustainable seafood? Sustainable seafood are fisheries that are not depleting populations too far.

Okay. And we know that more abundant populations, they have more genetic diversity, they have more geographic diversity, they're better able to cope with changing temperatures. Can you give an example of such a fishery? Yeah, I mentioned summer flounder earlier. It's one of the species that's shifting north. It's actually very interesting. It was heavily overfished right around, sorry, through the 80s around 1990.

It's actually a species that is a country we have recovered largely. So I do remember seeing at some fancy restaurants, which I rarely go to, here are our sustainable fishery options, and they change over time depending. So I've seen that. But of course, my buzzkill systems ecologist question is, if everyone starts to choose sustainable, seafood, won't there be too much demand for it to remain sustainable? certified sustainable, not just because they're abundant, but also because they have an effective management system in place. And, you know, we actually have some of the best fisheries regulations in the U.S. and they mandate rebuilding if populations become small. And for that reason, many fisheries around in the U.S. have recovered. So buying U.S. sourced seafood actually is

almost always a sustainable choice. If you want to get more nuanced, there are Monterey-based, seafood watch cards, Water Bay Aquarium, seafood watch cards that can be useful guides. There are labels like Marine Stewardship Council that can also be useful.

Let me ask you a question that I asked Daniel Pauley not to put you on the spot. What's the deal with farmed versus wild salmon? What's the consumer supposed to do there or no salmon at all? Yeah, I'd prefer to eat

frozen wild caught salmon. Farmed salmon, they're predators. They eat a lot of fish in order to grow. Aquaculture industry is trying to change quite a bit. They're substituting soybeans and other things. Still, I mean, soybeans have their own environmental impacts.

Eating low on the food chain is also a good choice. You know, you're basically eating fish that are closer to sunlight. Like things like sardines and anchovies, but also filter feeders, things like blue mussels or oysters. But farmed shrimp, farmed salmon, not great choices. There are some exceptions, but they're harder to find. So wearing your science hat but tilting it a little bit, given all the data that you've looked at and the fish and marine organism movements over the last 50 years, can you, before I turn to my closing questions,

can you give us kind of a best case, base case and worst case scenario for your work and the species you observe in the coming decades, if you might? Yeah, I think best case if climate change is kept mostly under control. We're talking about species moving a couple hundred miles further north, but not a thousand. miles further north. That's when things start to get really disastrous. There will be surprises to maintain sustainable seafood. It's going to require our managers, but also supply chains being nimble and knowing what's happening and better understanding what's coming, being able to forecast not just when marine heat waves are happening, but what are the impacts going to be on fish and other marine life. That's the piece we don't understand.

well yet. I'm going to let you get to base case and worst case, but here's a question I forgot to ask. What about kelp and the plants on the coastlines that are home and part of the ecosystem? Is there a change in movement of them as well due to lower oxygen and higher temp waters? Yeah, I was actually just talking to a student last week who does a bunch of field research up in Alaska. and he was talking about giant kelp appearing further north and also further west, if you think of Gulf of Alaska, then they historically have been observed. Similarly, at the other end, giant kelp goes all the way down into Baja, California. And some of the farthest south populations largely disappeared in the marine heat wave around 2014 through 2016,

and they haven't come back. They have come back in some other locations. So actually there's a lot we still don't understand about where are those refugia? What exactly creates a refusium for giant kelp. And as you probably know, kelp is really important as nursery for small fish, rockfish that then feed our fisheries. Also really important for abalone. You know, a very prized invertebrate on the coast of California and on the west coast of North America. So getting back to your, you talked about.

But the best case, which is we're going to end up having a 200-mile northward migration. What's the base case and worst-case? Yeah, so that's sort of base case, if we can keep things under control. Worst case, we're talking about species, at least here in North America, in some cases, a thousand kilometers further north. I mean, that is really scrambling. Our fisheries really changing. And what happens to the ones that are within a thousand kilometers of the North Pole?

Well, exactly. That means some of them losing. their available habitat. I mean, species is going extinct. It also means large-scale loss of coral reefs in the tropics. That makes me really worry about food supply in coastal communities throughout the tropics. Coral reefs are often the source of food of last resort. Sort of if you can't do anything else, I do a lot of field work in the Philippines.

it is scary to think about what would happen if core reefs were not available as a source of food and those and other parts of the tropics. Yeah, not to mention all the other ripple effects in the world if that comes to pass. I want to ask you some personal questions that I ask all my guests, but just out of curiosity, you know, you run a lab and you have students and you're a very busy man. Can you name one or two, like, specific research projects you're working on right now that you're kind of passionate about or just give me the crazy titles that I wouldn't understand? Hopefully I can make it not too crazy and somewhat understandable. So one, we're trying to forecast where marine fish will be in the coming years and decades. So we're not talking about long-term end of century, where will they be in 2100? but where will they be in 2027 or 2030?

And then how can we best provide that information to fisheries managers, but also fishing businesses and other ocean activities that need to adapt to these changes? So you're almost building a model and then by 2027, if they are where you expected, then that becomes something of predictive capability? Exactly. I mean, that is the danger of making forecasts. We might very much be wrong, but it also means it's how we learn. And actually, what we do is we, you know, to test ourselves, we rewind the clock.

You know, we pretend it's 2020. Yeah. Would we have been able to forecast what happened in 2025? And that's how we tune things. But there's this disconnect right now, you know, so much of what we talk about when it comes to climate change is really long term. And yet fisheries and fishery managers are making decisions about next year or a few years out. And so we need the science that provides that information at the same time scale. Any other projects?

The second one I was going to mention is, if you'll permit me, I'll mention two, but they're related. Please. One is effectively genomic time travel. We're trying to figure out if evolution is an important part of how some marine species are coping with climate change and other ocean changes. So one of the projects is a collaboration with the Smithsonian National Museum of Natural History. They have one of the largest collections of fish in the world. And for a fluke of scientific history, they were collected in sugarcane alcohol from the Philippines in the early 1900s. They've effectively been fish in vats of rum for 100 years.

What it means is that their DNA has been quite well. preserved and it's an incredible archive of the evolutionary history of these populations just 100 years ago. So we're working with an amazing set of Filipino collaborators to redo these collections and understand to what extent evolution these coastal fishes have evolved over the last 100 years. We've already found some evidence that they have. And we're doing similar things now here on the coastal California, but with giant kelp. And trying to help the state of California and other conservation groups and managers better understand how to help kelp be more resilient to further increases in temperature. If you don't mind, I'm going to ask you

some closing questions that I ask all my guests. Now taking your scientist hat off and just putting your human hat on. What recommendations do you have for general people being alive today, being aware of climate and polarization and geopolitics and economic problems and all the things. Do you have advice? I think the biggest advice is find your passion and how you want to contribute, right? It's, we all have incredible skills, whether that's art or organizing or science. And bring that passion to me. making the world a better, better place. We know, we know it can be and, you know, don't ever

underestimate the power of one person inspiring others around them. You know, and a lot of this, I think, really can start, start locally and build up from there. And how would you change that advice for 19, 20, 21-year-olds who are your students? That largely is the advice I give to the 19, 21-year-old students that I, that I advise. Also older, you know, the older grad students, even the, you know, they've, they've picked, you know, marine biology, marine climate science as their career. But still, it's what's so important. And, you know, to have that, that motivation to continue when, when things are hard, you really have to be passionate about what you're doing. And that's a balance between what you're doing, but also take care of yourself.

You know, make sure that you're, if you get, if you get joy by being outside on the water, or in the mountains like I do, make sure you take time for that too. Don't burn out. What do you care most about in the world, Mainland? My kids, you know, I've got two boys.

Love being outside with them. They love it too. And just seeing them light up, I hope we can, I hope to help find a way to pass on a world as relatively intact to them so that they can continue to enjoy it

the way I was able to. How old are they? Nine and twelve. When I was a little boy, I grew up in Seattle, which is quite different than Santa Cruz, but I know there's one thing in common, those banana slugs. You have slugs in Santa Cruz, so I'm sure your boys have had much experience with those slugs. Banana slugs are amazing, amazing animals. Yeah, they're very cool.

Does anything eat them? You know, if you want to listen to the UC Santa Cruz athletic department, they'll tell you there's no known predator. Right. So that's the slogan for our, many of our sports teams. Yeah, yeah, yeah. You know, raccoons and, yeah, things do eat them. So if you could wave a magic wand and there was no personal recourse to you or your status or reputation,

what is one thing you would do to improve human, planetary, and ocean futures? Capture the past and future greenhouse gas emissions that we admit, store them away. Okay, that would require a magic wand. That really would require a magic wand. Yeah. I was keying off the bait you said on magic. Yeah, yeah. But I hear you.

I hear you. So if you were to come back in a year back on this show, is there any specific thing about the ocean that you are particularly passionate and interested about that is relevant to the future of our oceans, that you would be willing to take a deep dive on that one nerdy scientific topic. It would be really interesting to go in one of two directions. Start thinking about the role of evolution in coping with global change right now

and whether that really can play an important role helping natural systems adapt. The other direction would be how dig in more on those ripple effects. You know, it's not just shifts in where fish are, but then how does that ripple through fisheries, supply chains, politics, international businesses? Thank you so much for your continued work and your time today. Do you have any closing thoughts for our viewers and listeners? We're all connected to the ocean, whether we realize it or not. It's a place of wonder, an astounding beauty, but it's also on the front of the ocean. lines of climate change right now.

Professor Malen Pinsky, thank you so much. Thank you. It's great talking to you. If you enjoyed or learned from this episode of The Great Simplification, please follow us on your favorite podcast platform. You can also visit thegreat simplification.com for references and show notes from today's conversation. And to connect with fellow listeners of this podcast, check out our Discord channel. This show is hosted by me.

Nate Higgins, edited by No Troublemakers Media, and produced by Misty Stinnett, Leslie Batlutz, Brady Hyann, and Lizzie Siriani.