Full transcript of the Tom Rowland Podcast, Episode 875 with Dr. Chris Malinowski of Ocean First Institute.

Introducing the Spinning Fish Mystery

Tom Rowland: What's going on, everybody? Today we are going to talk about something that is on a lot of people's minds, but there's not a lot of information about it. There have been a lot of reports of sawfish, small tooth sawfish, dying and struggling in the Florida Keys. No one quite knows exactly what's going on. There's some research being done by many different organizations trying to figure out what's happening. In addition to that, there's some fish behavior that's somewhat troubling — fish exhibiting a spinning or upside-down behavior — and very little information out there. So I reached out to the scientific community, people who've been friends of the podcast, wondering if they knew anything. Many were reluctant to come on yet, because while they do know some things, they didn't feel like they knew enough of what was going on to come on the podcast. I respect that. But a lot of people have reached out to me with questions — what is this, can you get someone on? So I continued to reach out to scientists and had Dr. Chris Malinowski from the Ocean First Institute, which is in Key Largo, come on. I agreed that we'd talk about the things we know about this, but also the things we don't know. He said, if I don't know, I'll tell you. So I really want to thank him for coming on as the first person to have a conversation about what's going on here. There are a couple of resources I want to give out right away. One is the FWC — the Florida Fish and Wildlife Commission has a fish kill hotline. If you see a fish kill anywhere in Florida, whether it's the Florida Keys or somewhere else, you're encouraged to let them know, and you can also submit a fish kill report on the myfwc.com website. Then, specifically on the sawfish, because this is rare and unprecedented, and because the sawfish is already an endangered species in trouble, they have a special sawfish hotline, and you can also email sawfish@myfwc.com. If you have questions or comments about this episode, you can always text (305) 930-7346, or email podcast@saltwaterexperience.com. So without any further information, we're going to move on to this conversation I had with Dr. Chris Malinowski from the Ocean First Institute. Again, I want to thank you for coming on. Here we go.

Dr. Chris Malinowski: I'm Dr. Chris Malinowski from Ocean First Institute, and this is the Tom Rowland Podcast.

Meet Dr. Chris Malinowski

Tom Rowland: Chris, how are you doing, man?

Dr. Chris Malinowski: I'm doing great despite all the circumstances of why we're meeting today.

Tom Rowland: I really appreciate you coming on. This is a very important podcast, because I want to figure out — everybody wants to figure out — what it is that's happening. Could you give us a sense of who you are, what your credentials are, and what Ocean First Institute does, and then we'll get into the spinning fish and sawfish situation, which is what we intend to talk about today.

Dr. Chris Malinowski: Absolutely, and I'm very excited to be here, so thank you for having me. My name is Dr. Chris Malinowski. I grew up in Wisconsin, so I'm a Midwestern fisheries biologist, I guess, or fish biologist. I started my career there with an undergraduate degree, then moved to Florida to start a master's degree at Florida Atlantic University, and got a PhD at Florida State University, all along building a career around fish ecology and toxicology. A lot of the work I specialize in is based on how humans impact the environment, so it's conservation-based work — overfishing, coastal development, pollution, which is a lot of what we'll talk about today, and how that impacts our fish populations and ecosystems. So my background spans a lot of avenues of conservation, including toxicology, fish behavior, ecology, and overall human-impacts ecology.

What We Know So Far

Tom Rowland: Let's talk about where we are with this issue that's hit the national news lately. It's probably been going on quite a bit longer, as far as scientists, fishing guides, and people who've seen strange behavior in fish are concerned. Where do you think we are with this? How long has it been going on, and can you explain a little about what the issue is? A lot of people read these stories — I saw one from what I think was a public radio station, WLRN or something, saying there's some strange spinning fish behavior, and of course the sawfish — over twenty sawfish have died in a particular area in the Lower Florida Keys, which is obviously very troubling. Can you give us an update on how long this might have been going on, and whether we have any idea what it is?

Dr. Chris Malinowski: I'll give a brief background. The first report of this current incident came, I believe, on November 7th. So it's been going on for a little while now, and it reached popularity in the media once the sawfish started dying. That's an incredible concern, because sawfish are an endangered species that have had a very slow recovery in this state, and they're endangered throughout the world — there are four other species, including the smalltooth sawfish in Florida, and all of them are not doing well. So losing what's now reported as twenty-one sawfish in this short period of time is very alarming. What's interesting is that spinning fish, as it's being colloquially called — because nobody knows exactly what to call it — is a symptom. It doesn't necessarily mean that every time spinning fish has been observed over the last five or ten years, which some reports say isn't a new phenomenon, that it's based on the same underlying cause. That's the mystery. There have been cases of viruses or bacteria that have caused whirling fish in other parts of the country in the past, and people are looking at all those commonly identified culprits, but those have mostly been ruled out at this point. So that's why there's a big mystery right now — scientists have looked at all the primary suspects and haven't gotten a positive result so far. Basically, in the area we're discussing, Big Pine Key primarily is the hot spot down to Key West, and the first reports started coming out in November.

Tom Rowland: And the first reports were of a sawfish, or the spinning fish as well?

Dr. Chris Malinowski: Spinning fish as well. People are reporting this happening more at night, when they're shining lights on the water, but they're also seeing it during the day. We just reported one with Ocean First Institute up in the Upper Keys — we think it's related, we don't know for sure, because these are symptoms, a behavior, which is why it's being called a behavior. But it's likely all connected — it's just too early to tell. It's been happening with over thirty species now, and the first reports were not of sawfish. Once sawfish started dying, I'll say that the mortality rate in sawfish is likely related to the spinning fish behavior, but it's not even determined that it's connected at this point.

Tom Rowland: I was wondering why a sawfish, which would seem like a pretty hardy animal, would be so susceptible to this.

Dr. Chris Malinowski: Again, that's a mystery. Of the twenty or twenty-one sawfish recovered from this mass mortality so far, FWC, led by Greg Poulakis, has been doing necropsies on these animals to try to figure out exactly that — why sawfish, after all this time and all the recovery, would be the animal impacted the most, or seemingly the most. They're also very apparent, striking animals, so if one is dying or swirling at the surface, it's going to be noticed more than, say, mullet or mojarra. This happens with every mass mortality event, from red tide to other harmful algal blooms to cold or warm water events — we only see what's on the surface, and it's really difficult to get a complete mortality estimate on all the species impacted by a large-scale event like this.

Behavior Versus Disease

Tom Rowland: When you're talking about the difference between a behavior and a disease, what is the difference in scientific terms, and what does that mean for the research — whether you call it a behavior versus a disease or something else?

Dr. Chris Malinowski: That's a good question. A disease would technically be defined as a deviation from some normal set of standards — physiology that leads to some sort of behavior. So the behavior could be a symptom of a disease, but that's indeterminate at this point. Calling it a behavior is just a way of saying we don't know. We can't talk to a fish the way a doctor can ask a human patient about their symptoms — we have to look for signs in fish, and the last behavioral response we'd see before a fish dies is something where it's moving erratically and can't control its behavior. Eventually it's in a state where — and this is another unknown — we don't know if they can recover from this or not. So what we do know is that fish are dying, and the spinning phenomenon is happening. We know it's mostly concentrated from Big Pine Key down to the Key West area, mostly around Big Pine, but it's potentially not isolated to just that area — we've had reports of fish in the Upper Keys in Key Largo, in Biscayne Bay, off Boynton, and I just got a message today about an adult goliath grouper offshore that was reportedly spinning in the same fashion on one of the major spawning aggregation racks. We don't know if it's the same cause. The first thing we want to know is what are the immediate things impacting these animals — water quality parameters, bacteria, virus, nutrient pollution. Those are all unknowns. Then we get into where that comes from, because a lot of people want to know the sources so we can target mitigation. At this point, we know it's likely not bacterially caused, and likely not from a virus or other pathogens. It seems unrelated to the water quality parameters we'd typically measure, from dissolved oxygen to temperature to salinity — those seem fairly normal in the area. It doesn't seem to be caused by the normal players of nutrient pollution, like harmful algal blooms and red tides — those have all been more or less ruled out.

The Ciguatera Lead

Dr. Chris Malinowski: One avenue some water scientists are pursuing is another dinoflagellate — to start, when you talk about harmful algal blooms, Karenia brevis is the microalgae most people know as red tide. There's another dinoflagellate, in the Gambierdiscus family, that is potentially causing a neurotoxin called ciguatera, or ciguatoxin, and that's one avenue, because the measured levels of this dinoflagellate are higher than normal. But the interesting thing is that it typically hasn't manifested in fish or sharks the way it does when humans eat fish — that's usually when humans eat grouper, barracuda, or reef fish and then get sick. There are very few reports of this actually impacting fish and sharks the way we're seeing now, so it's the only abnormal thing that's really been found so far, but it may or may not be connected.

Tom Rowland: I saw something in one of the articles I read that said the levels of ciguatera would be a lot higher in the water or in the fish species, but I wasn't clear — if they sample the fish, is it higher in ciguatera? I haven't heard of an outbreak of ciguatera from people eating fish.

Dr. Chris Malinowski: It's been found in the water so far, from what I understand. Fish are being tested currently, and I don't know all the details, because everybody is sort of figuring this out at once, forming coalitions and collaborations so we're not redundant in our efforts. I haven't heard that anyone's found it in fish yet — the reports I've heard have been in the water. But I have the same sense you do, Tom — if fish were really concentrating these toxins, you'd expect an outbreak of humans being impacted by ciguatera poisoning right now, and that piece doesn't seem to be in play. I'm not ruling anything out, but I feel like that piece would be there if ciguatera were a big, prominent cause of what's happening.

Tom Rowland: Do we have anything in the scientific record where something like this has happened in a small area before that we can look back on?

Dr. Chris Malinowski: There's one study I read recently — I think it was in Australia — where bull sharks had high levels of ciguatera, and people were eating their livers, which tend to accumulate and process these toxins, the same way organs process heavy metals, and then push them out into muscle tissue, which is what humans typically eat. In that case, people were eating the livers, and I believe eleven people died and many others got sick. That's the only study I've come across on that specifically.

Why Big Pine Key

Tom Rowland: That's really strange, especially with Big Pine being the epicenter of this — it's not the place with the most current. In the backcountry of Big Pine, it might have the least current, with all the banks and the tide differences compared to Key West, so it takes longer for the tide to move in and out there. Are we seeing this in inshore and offshore fish, both Gulf and Atlantic?

Dr. Chris Malinowski: So far, to your point, stagnant or less-flowing water would generally contain these things at a higher concentration, because there's less flow going on. So I'd think that in protected waters like Big Pine Key, in shallower environments, you'd have a higher chance for something water-quality-related to have a major impact. Most of this has been directed inshore, in protected waters — there have been few reports offshore.

Tom Rowland: But just to be clear, there's a lot of current in Big Pine — it just takes a long time for the tide to get in there. I don't want anyone to think it's stagnant water, because there's excellent tide flow, it just takes a while to move around the banks and out into the Gulf. A tide difference in the Content Keys might be five hours where a couple of miles down the beach it's four — so it takes an extra hour to get in there. But if stagnant water were the driver, you'd think we'd see this in Key Largo Sound, where there's almost no tide flow, just wind-generated water movement, not the tremendous flow you get through Key West or Long Key, which is like a funnel.

Dr. Chris Malinowski: Yeah, I used stagnant water as an extreme example, not necessarily meaning Big Pine specifically, but generally, if something isn't moving at all you'd get more concentration. I think that's a reason why whatever's happening in Big Pine may be getting more trapped than it would offshore, where it's more dilute. But again, I don't know — it's very surprising that it's not happening more in some of the Upper Keys areas, and that's one of the mysteries behind this. Why is it happening where it's happening? I cannot answer that question. I wish I could.

How Scientists Are Collaborating

Tom Rowland: One of the things I found interesting in what we've talked about so far is that the scientists are all working together — which maybe isn't that surprising. You do get different groups working on their own projects that might overlap with what somebody else is working on. When I've talked to scientists like the ones at FIU, or people who've done a tremendous amount of fish research, especially tagging fish with acoustic tags, that information all goes up somewhere, and if another study picks up one of your fish, you hear about it now because of the internet. How are the scientists working together on this one? How many different organizations and types of scientists are looking into this?

Dr. Chris Malinowski: Generally, scientists work very well together — there's some competition in certain arenas, but in situations like this, when everybody's trying to resolve an issue, it's all hands on deck, pulling resources and specialties together. Everybody's got different specialties — I'm more of a fish biologist and toxicologist, and I'll work a lot with physiology trying to understand the sub-lethal and long-term effects. That's the angle we're taking, working with collaborators on sharks that were caught before this incident in the Big Pine area, during and after, and also in more controlled regions like the Upper Keys where I work a lot, so we can compare animals that are healthy versus unhealthy and understand how they're being affected long term. To do that, we're working with tons of different agencies — nothing is fully structured yet, but we're in conversations with FWC, Bonefish and Tarpon Trust, Bimini Shark Lab, Florida State University, Florida International University, and everybody has a different take — some are water specialists, some are disease specialists — and it takes all of that to understand this. It's very likely a water quality issue, at least that's my sense, so you need water quality specialists intersecting with fish biologists to figure out how the fish are being impacted. There's also the side of things where people expect scientists to have a magic wand, and we don't — we're pulling all our knowledge together while investigating at the same time. And science is unfortunately underfunded at times — we're all figuring out how to find resources to even process the samples we're collecting. That's a major hindrance to getting this research underway. Right now, the state is awarding FWC two million dollars that's supposed to be distributed to nonprofits and other organizations, along with FWC itself, to boost this monitoring effort. So hopefully that becomes a very collaborative thing as well, but it really takes everybody, and it's not easy.

Tom Rowland: Is there some organized way this information is being shared, like a single website, or is everybody just sending it to whoever they think might be interested?

Dr. Chris Malinowski: So far it's through word of mouth and email — that's how I've been able to start communicating with people about what they're working on and how we can help each other. It's been pretty rapid, because everybody pretty much knows each other, or knows somebody who knows somebody, so you get, oh, you're doing this thing, let me put you in touch with that person. As opposed to something very structured already, like the acoustic receiver network you're alluding to — I know you interviewed Dr. Jen Rehage, who's a good collaborator and colleague of mine, and there's a whole network of people who come together every couple of months for a download and share data. If this kept going for a while, we'd likely organize like that too. Right now we're at the stage of figuring out how to organize and share resources.

What the Public Can Do

Tom Rowland: You mentioned there's two million dollars that could possibly be earmarked for this. Does it help to write your congressman or ask your senator to pay attention to this issue? Would that lead to more resources so we could get an answer faster? Or is there anything we could do as fishermen and citizens?

Dr. Chris Malinowski: Yeah, exactly — that's generally a good way to approach it. Anytime you write to people in political power, that can help fund these things, and can go into legislation down the line once we have some answers. Putting some pressure on politicians to pay attention to this issue can definitely allow for more state or federal funding. If this grows into any bigger of a problem — and we know Big Pine is one of the most biodiverse places in the Keys, which is why a lot of fishermen, conservationists, and scientists are concerned about that area right now — the more attention we give this, the more likely funding becomes available. Also, people can donate money individually if they want to see the science move forward.

Tom Rowland: To whichever organization they've worked with in the past, and that donation would go directly toward this right now?

Dr. Chris Malinowski: A hundred percent it would, and that would give a big boost to the science that can be accomplished, if the money is put in the right hands — monitoring, and getting at the core of this issue, which is going to take some time. I know people want immediate answers, but it's going to take time.

Tom Rowland: Everybody wants answers — that's the heart of the Florida Keys, if you ask me. If you have a seagrass die-off, that's very concerning. If you have fish in distress, that's very concerning. What are the steps the scientists have to take? You have to understand the problem first — where are we in this process, discovery?

Dr. Chris Malinowski: I think we're still in a monitoring and discovery phase. What people are doing is the right thing — reporting every time they find fish acting this way, because first we want to understand the spread of this, whether it's connected to instances happening further north. Monitoring and knowing where people are seeing this behavior is very important, and people on the water every day are doing that, since scientists can't be on the water all the time. Concurrently, we're collecting as many samples as possible and figuring out how to analyze them.

Tom Rowland: If a guide is on the water traveling hundreds of miles a day in their skiff, which they definitely do, where should they report it — FWC?

Dr. Chris Malinowski: Yes, FWC has a fish kill hotline where it should definitely be reported. I also know the Lower Keys Fishing Guides Association has a reporting guideline they're working on with Bonefish and Tarpon Trust. Those are two good places to go, especially in the Keys, but you should also be reporting to FWC because they're keeping track of it.

Long-Term Ecosystem Impacts

Dr. Chris Malinowski: This could happen elsewhere — there are water quality issues happening all over the state all the time. We just had discharges from Lake Okeechobee, and people always get upset about that, and the Army Corps of Engineers and the water management district are always trying to make the best decisions on when to do that, even though it's never in public favor. There are water quality issues all around the state constantly, and things like this happen elsewhere too with large fish kills. We need to clean up Florida, and we're working on that, but that's a whole other can of worms.

Tom Rowland: I've seen the work Captains for Clean Water has done, mostly through raising attention, and they've done a good job of staying positive instead of just pointing fingers with no solutions — they come with solutions, even if they're hard to attain, like the reservoir that could make a big difference. That's what attracted me to that organization, that they have solutions rather than just complaints. Especially when your favorite fishing spot is suffering because of decisions people made, that makes you want to just stand there and scream at whoever's responsible, and I get it, but I don't know that you're making a lot of progress that way.

Dr. Chris Malinowski: Correct. There's a couple things I want to unpack. I agree with what you're saying entirely — the concern is here, and I never want to paint a doom-and-gloom picture, because yes, humans are the cause of a lot of problems, but we're also the solutions to the same problems. The Everglades are a perfect example — in the late eighteen hundreds we started draining the swamp, and even though that phrase gets used in modern political terms, we know it was overall a pretty bad thing to do, because it ruined the way the Everglades flows — it doesn't sheet-flow anymore, it's more of a pulse system, and that's where some of these issues come from. But we also have one of the largest-scale ecosystem restoration programs in the world, so we're also very smart engineers who can restore and recover habitats and ecosystems. Calling attention to problems doesn't mean it has to be doom and gloom — it's a wake-up call to come up with solutions, but the difficulty is getting everybody on board, because it becomes very political, and that's where a lot of things kind of live and die. I think we're very capable of solutions, and that's the direction we should go with this — we have this issue in the Keys right now, we want to resolve what it is, so we know how to make changes moving forward, because until we have answers, we're not going to know how to resolve the issue. The same goes for the water releases out of Lake Okeechobee — the best decisions are being made within the realm of possibilities. It's a slow process to build all these water reservoirs to control the water so it doesn't flood Okeechobee and gets cleaned up before it moves down to Florida Bay. It's a bunch of different stakeholder groups trying to minimize the impact on the ecosystem and on humans. It's very difficult, but we have solutions, and I'm not going to try to make a direct connection between Okeechobee releases and what's happening down in the Keys — we just have a lot of water quality issues in Florida overall. We've changed the entire landscape and we're trying to recover from that. People want to point the finger at Big Sugar, at the Army Corps of Engineers, at the South Florida Water Management District, and I'm not saying people are wrong to point fingers, because there are a lot of players impacting this, but so are individuals fertilizing their lawns. There's a lot we can all change, and we can press for politicians to force better decisions and put money into good restoration projects.

Tom Rowland: A lot of those things have been happening for a long time, but we haven't seen this before — I wonder if it could be a combination of factors bringing something new. When I read the very few articles out there about this, I'm not seeing any reference to a similar situation happening somewhere else, the way you often see with red tide, where they'll reference something that happened four years ago in another area. I'm not seeing that here.

Dr. Chris Malinowski: No, this is very much unprecedented — this mass mortality, fish kill without a smoking gun, is what we're looking at. We don't have a harmful algal bloom to point to as the cause, and I think that's what's so scary about it. Generally, in the past, and we've had plenty of these events in the last couple of years, we generally know the cause, even if we don't know all the factors generating the harmful algal blooms. In this case, we don't know the cause at all — it's an unprecedented situation, and on top of that, this mass mortality event is unprecedented, especially with sawfish involved.

Tom Rowland: Is it possible, like you mentioned with the dinoflagellates — it's almost like an invisible algae bloom, not the obvious yucky green water we've seen before, where fish can't breathe and get away from it or die.

Dr. Chris Malinowski: Right — when people talk about harmful algal blooms, that's the generic term people used to call red tide, but it's not always red — there's also the green water from blue-green algae. In all the reports I've heard, the water looks normal here and reads normal. So this is a different kind of situation — with typical harmful algal blooms you get toxins in the water and low oxygen from all the algae building up, and fish die mostly from the low oxygen. We don't have that here.

Tom Rowland: My experience with red tide is that humans feel it in their lungs — even a couple miles from the beach, not just on the water, you notice something. Are there reports of that here?

Dr. Chris Malinowski: Not that I've heard, no. It doesn't seem like that's connected at all in this instance.

Tom Rowland: So contacting our congressmen and senators is probably the number one thing we can do.

Dr. Chris Malinowski: And media, more attention on the issue, and donating money if people can.

Shark Research and Pharmaceuticals in the Water

Tom Rowland: What about your shark work? What do you do with sharks?

Dr. Chris Malinowski: A lot of the work we're doing currently started because we realized there's a big gap in data, especially in the Upper Keys, on overall abundance and distribution. So we're tracking those things, trying to understand how many sharks are there and what the diversity is, and eventually that'll grow into movement ecology, trying to figure out connectivity throughout the Keys. One of my students, Ethan DeWald — I'm also faculty at Florida Atlantic University and Florida International University, so I have graduate students — is working on that as his master's thesis. We've also got a couple other projects looking at pharmaceutical drugs in the environment. Dr. Jen Rehage's lab has looked at bonefish and redfish, and we're collaborating with her and others, along with a lab at the University of Miami, to understand how sharks are accumulating those same pharmaceuticals and even illicit drugs, and how that impacts their health. This might actually tie into the issue down in Big Pine, because we have samples from there as well during this event — we were initially looking at pharmaceutical drugs in sharks, and then realized we also need to look at the health of these animals in relation to the spinning fish issue, so we're trying to connect those dots right now too. Those are probably our two main things — the health of different shark species, whether there are drugs in their systems, and their abundance and distribution.

Tom Rowland: What have you discovered about the amount of pharmaceuticals in sharks? I did a show with Nick Castillo, and we tested some bonefish — he brought a centrifuge out on the boat and took blood samples.

Dr. Chris Malinowski: We're at very preliminary stages — just starting to get some results back, so it's still unknown. What's been shown in the past is that sharks don't seem to have as many pharmaceutical drugs, though there haven't been many studies done yet, which is why we're looking at it. It's interesting, because in my PhD work on Goliath grouper and mercury and heavy metals, what you generally see is that it bioaccumulates over time and biomagnifies up the food chain in long-lived, large animals. We don't know if we'll see that same trend in sharks — we would assume it would biomagnify into higher trophic-level organisms, but that's still unknown, so stay tuned. So far we've found fewer drugs in sharks than Nick found in bonefish and redfish — those results aren't mine, they're from Shakira Trabowski in Jen Rehage's lab, but there doesn't seem to be the same correlation and biomagnification we see with heavy metals, maybe because some drugs are more volatile. We're trying to look at whether the same drugs show up in sharks as in redfish or bonefish from the same sampled areas, but right now we don't know.

Tom Rowland: I'd think some species would be more susceptible than others, like bonnethead sharks and nurse sharks that hang around the same area.

Dr. Chris Malinowski: Those are the two we're looking at right now, because they're benthic-associated. So far we've focused mostly on nurse sharks and some bonnetheads, finding things like cardiovascular medication and antidepressants, some basic things, and then we're going to tie that into the health aspect to see how that might be affecting them.

Mercury in Goliath Grouper

Tom Rowland: On your work with Goliath grouper and mercury, how would you test them?

Dr. Chris Malinowski: Catching and sampling them, basically. I did a lot of that work around the entire state of Florida looking at adult Goliaths and juveniles — I primarily worked in the Ten Thousand Islands catching juveniles to compare smaller and larger individuals. We primarily looked at muscle and liver tissue, taking small liver biopsies and muscle tissue, and I also looked at eggs and sperm to understand reproductive impacts. We're actually still publishing a paper on how mercury gets into their systems — they're not top apex predators like some people call them, they're more mid-level trophic predators, long-lived and large, and they'll opportunistically prey on items, which is where you get a lot of negative interaction with fishermen, since they're stealing catches. Generally, we look at all those different tissues and correlate liver toxicology with muscle, and eggs and sperm. What's really interesting is that adults have extremely high mercury levels — some of the muscle tissue I found was on the upper end of ten times what the EPA specified at the time as the safe limit for consumption, which was 0.3 parts per million. So you wouldn't want to eat anything higher than that, and their livers were even higher. The difference is that liver mercury is primarily inorganic, which is less concerning than methylmercury, the more toxic form that can cross the blood-brain barrier and is the form that bioaccumulates and biomagnifies the most. That was the general trend — some of the old, large adults had very high amounts, and even the juveniles had pretty high amounts.

Tom Rowland: A Goliath grouper or tarpon are fish known to live a long time — how old is an adult Goliath grouper? If you see one that's three hundred pounds, do you have any idea on age?

Dr. Chris Malinowski: We actually just published a paper with Dr. Dunmore at University of Florida on the aging and growth of these animals — we did all non-lethal sampling, and compared size and age with mercury concentrations. Some of the largest individuals in the population might be twenty to twenty-two years old. Juveniles that are still in the Everglades, before they leave the mangrove habitats to move offshore with the spawning populations, are only in there for about five or six years, maybe a foot long, sixty or seventy pounds at most, before they move offshore and mature. Full adults might get up to three hundred-plus pounds. The interesting thing with adults is that we know they can live to at least thirty-six years of age — that was before they were fished to near extinction before 1990. Since the 1990 protection, other than a recent limited juvenile harvest, we only see individuals that have grown since that period, so because there were so few individuals when they started to recover, we're not getting that many old individuals in the population yet, because of that bottleneck.

Tom Rowland: So if you see a really big one now, chances are it wasn't alive in 1990.

Dr. Chris Malinowski: It was not — we measured over four or five hundred fish for that study.

Tom Rowland: Is it safe to say that for an older fish, say twenty-five or thirty years old, you'd be ingesting more mercury eating that fish than a juvenile of the same species?

Dr. Chris Malinowski: Oh, absolutely — it's a direct correlation between size, age, and mercury concentration.

Tom Rowland: And it stays there and accumulates over time?

Dr. Chris Malinowski: Generally, yes, though they do get rid of some of it by pushing it into muscle tissue, which is what humans would eat if they ate it — their liver is constantly demethylizing mercury and pushing it out, and males and females also get rid of it through their gametes, their sperm and eggs. One really interesting thing I showed in a published paper is that the amounts of mercury in their sperm and eggs were at the same level or higher, on average, than what was saved for consumption in muscle — which is significant, because those are the most vulnerable early life stages. If reproduction did occur, that level of mercury would almost certainly have some impact on the ability of that fertilized fish to survive — that's a very high level of mercury for something to survive.

Tom Rowland: Wow. So you're saying it probably has a reproductive effect.

Dr. Chris Malinowski: Yeah.

The Shark Depredation Debate

Tom Rowland: What about your studies with sharks — are you studying the overall population in Florida? That's a hot topic too, just like the Goliaths, with the depredation issue — taking catches.

Dr. Chris Malinowski: What I found really interesting, and I might broaden this back a little from a conservation or population-recovery perspective, is you see this time and time again — we've seen it with wolves, with bears, with Goliath grouper, and now we're seeing it with sharks. Anytime you have protection on an organism or population and there's recovery, especially of predators, there's some negative human component once they start to recover — people will complain. I see this as nothing new — sharks have had a bad reputation for most of their existence, and there was a continuous, big effort to try to protect them, and some populations have come back, which is a good thing, but with that comes negative interactions, especially with fishing. My take is the same as it was with Goliath grouper — I've had to deal with the depredation issue, even though it wasn't called that, for years with Goliath grouper stealing catches, and all the complaints that led to that fishery even opening up in the first place. The same thing is happening with sharks now. I'm not studying that directly, but we've been talking to people who are, and the questions are whether it's the same repeated animals, whether they're actually more abundant, or a combination of both, and whether it's more prominent in certain areas — that's going to take a lot of collaboration between fishermen and biologists to figure out how to mitigate what people are calling a shark problem. I don't see it as a problem — I see it as a conservation success, same as with Goliath grouper, wolves, and others. But I think as humans we constantly have to make decisions on how to manage humans alongside predators — this is Africa with lions, it's a hard place. We have over a million registered vessels on the water in Florida, so we've got a human problem too — more people on the water than ever before, and all of that has to be factored in. I think it's a good thing — we can study it and figure out a solution everybody's happy with.

Tom Rowland: I don't think you're going to come up with a solution everybody's happy with.

Dr. Chris Malinowski: Let me walk that back — that's true, there won't be a solution everybody's happy with.

Tom Rowland: There are so many people on the water — my experience is you can go two miles from the dock or two hundred miles from the dock and the experience is the same. More sharks than I've ever seen, more aggressive than I've ever seen, and you can be somewhere completely by yourself, drop down, catch one fish, and the sharks are on it immediately. People say they're conditioned to the sound of the motor, but not two hundred miles away with nobody else out there. There are a lot of people very concerned about the number of sharks, and a lot of people who won't accept that sharks could be in decline worldwide while having an explosion of abundance in Florida and up the Eastern Seaboard — to some people, they won't even have that conversation, which I'd think they'd be happy about if they're a shark advocate. But is it also safe to say that if there are that many sharks, the fishery is healthy enough to support them, and isn't that also a good thing?

Dr. Chris Malinowski: I would say all of that is a great conversation. You have to consider that Florida is still a very biodiverse ecosystem, and we want to maintain and improve that. We've had a lot of impacts on our fisheries and sharks over the years — we've lost mangrove habitat, a major nursery area, water pollution, overfishing — and around 1990 there were big management decisions made to try to recover a lot of imperiled species, and we've seen some recovery because of that. Now we're kind of backing away from some of that. So the question is whether people are willing to accept that we're improving populations of things like sharks, and accept that there's going to be some negative interaction, meaning catches being stolen, and yes, people are going to be mad about that. There's also a concept I always come back to called shifting baseline syndrome — we come back to that with Goliath grouper too. If you talk to older fishers who are sixty, seventy, eighty years old who saw higher catch rates of sharks or were diving with bigger populations, they'd say this is a success story, even though there's still nothing like what it was in the fifties, sixties, or eighties. Younger fishers, seeing it grow from nothing to more and more, are going to have a sense that there are too many. It depends on perspective for a lot of these population-improvement scenarios. We also have to work on our messaging around sharks — there's a negative association with them being dangerous, and scientists and conservationists have worked hard to show more respect for these animals and that they're less scary, but now we've got this nuisance-species framing, and we need to tread carefully, because if we just look at them as a nuisance, we might go backwards in conservation efforts. Sharks and other large predators are an essential part of the ecosystem, whether we like it or not, and they're a good sign that there must be healthy resources, or they wouldn't be here — so they should be looked at as a sign of conservation success.

Tom Rowland: I think you have to be a little careful about the messaging that they're not dangerous — I'm not saying that's what you said, but there are television shows where people are feeding tiger sharks and it looks like a ballet, and the person is obviously very skilled with a tremendous amount of experience, but sharks are dangerous. There are places where if you go in, you're getting bit — they're biting people's trolling motors, outboard motors, the sides of boats, things that aren't even fish, unprovoked.

Dr. Chris Malinowski: Yeah, dangerous is an interesting term — I just always choose to have a healthy respect. It's their world, and you need to understand that. I agree that it's a careful thing to show people that these are beautiful animals that need to be respected, which often means keeping distance from them when there's a lot of them in the water or certain water conditions — it doesn't mean jumping in with them every time. You need to know how to read the environment. I'm a fisherman, an avid diver, in and around the water all the time, and I've had some scary encounters, but I put myself in that situation, and I would never not advocate for shark conservation, because it's their world and I'm just there observing and being respectful. There's a set of risks when you're in and around the water — boating, diving in general is dangerous, sharks aside, all kinds of environmental conditions to be aware of. You can't have your cake and eat it too — you need to always be cautious of your environment. I've seen people walking around Everglades National Park thinking it's Disney World, with alligators right next to them and they don't even notice, on their phones. People have a false sense of security, and it's not true — I don't think everything's out to get us, but we always need to be careful.

Tom Rowland: For sure. Sharks are an interesting topic because they split shark advocates from fishermen, but they also split people who spend their entire life on the water — spearfishermen versus divers who want to feed sharks, somebody who makes their living harvesting fish underwater versus somebody who makes their living on the water with tourists. Those are very similar people, probably similar backgrounds, both love the ocean, but one is doing a shark tour and the other is spearfishing, and either way there's chum in the water and sharks and people in the water. And then you have anglers who never get in the water but the sharks are taking their catch, and other people who like to look at sharks. It's a hot topic right now. Have you ever gone to one of the FWC commission meetings where they've made decisions on these issues?

Dr. Chris Malinowski: They get heated. My shark-related ones get heated, and you get all these various stakeholders at each other's throats, which isn't productive, but I think the different voices can be valuable if it's done the right way. The meetings don't always go as planned — I've often given statements at these meetings, and they almost never go in my favor as a scientist. There's a lot of different stakeholder interests, especially in Florida when it comes to wildlife, because the whole state is built around that in many ways, and those conflicting interests — I wish there was a better result where people came to agreement, especially when it comes to the science behind it. As a scientist, that's my biggest wish — that some of the non-state scientists, university or otherwise, had their science listened to more than some of the stakeholder voices, because that should be directing more of the management decisions being made in Florida, alongside stakeholder input as part of that process.

Tom Rowland: It's a good thing to wish for, but I don't think any decision made at one of those meetings is going to leave one group happy and the rest unhappy — or rather, leave everyone happy. I don't know what the answer is, but I believe it's communication, being open to talk about things with people you disagree with, so you can understand where they're coming from and they can understand you, and maybe find some middle ground — though a lot of people would say that's just compromising yourself.

Dr. Chris Malinowski: It's the same thing with politics right now — it is a political game. The best way decisions get made in this country, regionally or otherwise, is people with opposing views coming together, being open-minded, and working through differences — that's ideal, and we've become rarer and rarer at doing that. I'm forty years old, and in my lifetime, this is one of the more polarizing times we've been in, and it goes that way with fisheries issues as much as any other political issue. It's really hard to talk to people who don't agree with the science.

Tom Rowland: I'm sure that's very frustrating.

Dr. Chris Malinowski: It's extremely frustrating. The whole point of being a scientist is to inform society — we have a vital role in that, and we do this work in an unbiased fashion so we can inform policy and management. When the science isn't listened to, and people's opinions supersede the science and push management in a direction, that's very frustrating as a scientist, and that's kind of the direction we've gone in with some things.

Tom Rowland: It would also be frustrating on the other side, as a fishing guide who spends three hundred and twenty days on the water, to look at a scientist and ask how many days they spent on the water, and hear forty-five, and think, I've been on the water forty-five days in a row and this is what I'm seeing, and it's different from the scientific data. That's a place where a lot of the hardcore fishing guides who spend a lot of time on the water have a hard time with the science.

Science, Fishermen, and Working Together

Dr. Chris Malinowski: I totally get that, and I've talked to a lot of fishermen who have that view, and we have conversations about it — I'm very willing to talk about it, I'm not trying to preach. I think one of the best ways to conduct science, especially fish ecology or fisheries science, is to work with fishermen — if you don't listen to them, because they have so much knowledge, often way more observation hours than scientists do. But the difference in why the two need to work together is that scientists work in a standardized way, with data collection methods that let you make broader conclusions. That's the difficulty — a lot of people don't understand that observations on the water might be localized to that area, but when you're talking about something broader — I heard you in your podcast with Jen Rehage talking about red snapper, or Goliath grouper, which are all over the place — what scientists like myself do is look at all the data from all the places. We can look at what's happening in the Everglades, or all of Florida, or the entire historic range of an animal. Goliath grouper historically range from North Carolina through Florida, the Caribbean, the Gulf of Mexico, down to Brazil and West Africa, so understanding the overall population trends over that entire range takes a lot more than an individual observation — but those individual observations are key to understanding what's happening in that specific environment. So it's not one or the other, you need both.

Closing and How to Help

Tom Rowland: I agree fully, and I think that's probably a good place to end this, because I want to thank you very much for coming on. There were a lot of other scientists I reached out to who were uncomfortable coming on this quickly, but one of the things we talked about was that I'm not looking for an answer — I'm as interested in the things we don't know as the things we do know, and I feel like my audience really wants to know what's going on. So I really appreciate you coming on and telling us what you know and what you don't know, and being open and honest about that. I'd love to have you on again, and hopefully we'll be able to share some good news about what's going on.

Dr. Chris Malinowski: Thank you, and hopefully I shed a little light on the scientific process and what we're all going through, and how we're going to keep working on this issue and others. Hopefully we can chat again down the road about what we've found.

Tom Rowland: Let's stay in touch — really appreciate it. Tell people how they can support your organization or your work.

Dr. Chris Malinowski: Absolutely — you can go to our website, oceanfirstinstitute.org, and we have a donate page there. If you can donate to our cause and others, that would be amazing.

Tom Rowland: Great, thank you, Chris — I really appreciate it.