Ask Dr. Fish

[Stuart Carlton]
Welcome to Ask Dr. Fish, your monthly show in which we ask our Drs. Fish our fish questions, our science questions, and our life questions. My name is Stuart Carlton. I work with Illinois Indiana Sea Grant and we are proud to be joined today by not one, but two Drs. Fish. First one is Titus Seilheimer, Wisconsin Sea Grant. How's it going Titus?

[Dr. Fish (Titus Seilheimer)]
Good morning. Beautiful day. Great to be here.

My favorite time to get together and talk fish every month.

[Stuart Carlton]
Every month. First Monday of the month, unless we forget. Also joined by another doctor. I mean, how lucky are we?

The double doc. We got the double doc. Katie O'Reilly, Dr. Catfish.

[Dr. Catfish (Katie O'Reilly)]
Hey, good morning everyone. Happy June.

[Stuart Carlton]
Happy June.

[Megan Gunn]
It's not a lot of months to start on the first of the first of the month.

[Stuart Carlton]
You're right. We should appreciate that for a second.

[Megan Gunn]
This is crazy.

[Stuart Carlton]
We should appreciate that it's the first Monday on the first.

[Megan Gunn]
Yeah.

[Stuart Carlton]
That's Megan going to Lake Lover. How's it going Megan?

[Megan Gunn]
It's good. The sun is shining.

[Stuart Carlton]
The sun is shining. Yep. And since this is replacing Teach Me About the Great Lakes, not full time people, but we're behind our recording schedule now for various reasons, we actually have an Ask Megan question to start the show today.

So that's exciting. Megan, what lake adventure are you hoping to do this summer?

[Megan Gunn]
Just splash around.

[Stuart Carlton]
Just splash around.

[Megan Gunn]
I want to take my nephew out to Lake Michigan.

[Stuart Carlton]
Well, that's exciting news. All right. But that's not why we're here.

We don't care what Megan says. It's just a segment. We're just doing a segment.

We're here to ask Dr. Fish some Ask Dr. Fish questions. All right. First topic.

Oh, we're jumping right in. We actually have a theme this week, this month. This has been Megan's huge, huge contribution.

We have a theme. What is our theme this month, Megan?

[Megan Gunn]
Our theme this month is angling, free fishing and species to fish for and to eat.

[Stuart Carlton]
We're going to lean into the eat part.

[Megan Gunn]
Yeah.

[Stuart Carlton]
Just a minute.

We're talking about eating stuff. One issue with eating anything these days, in particular fish, is contaminants and how healthy is it? But here we have some new research saying that PFAS levels are declining in Great Lakes fish.

PFAS levels are declining. Let's start here. Katie O'Reilly, what are PFAS exactly and why should we care about them in fish?

[Dr. Catfish (Katie O'Reilly)]
Yep. So PFAS are per and polyfluorinated compounds, but essentially they are a chemical compound, a group of chemical compounds that began being used in consumer products in the mid 20th century, so 1950s or so. When you think about things that we use in our everyday life, stuff that is water repellent or no stick pans, firefighting foams, anything that is kind of, again, that water repellent-ness.

[Stuart Carlton]
Like fancy Gore-Tex.

[Dr. Catfish (Katie O'Reilly)]
Fancy Gore-Tex, exactly. Those all are sort of PFAS related compounds. And the reason that we've been talking about them is because even though they've been in use for about 50, 60 years, it's only relatively recently that we started to understand their proliferation in the environment and what that means for not just the health of the environment, but human health.

[Stuart Carlton]
That makes sense. And so in fish, Titus, PFAS have been found to be in fish even causing some consumption advisories at times. Is that right?

You're a big fish eater. Tell us about PFAS in fish and eating.

[Dr. Fish (Titus Seilheimer)]
Yeah. So like many compounds, these PFAS can bioaccumulate, which means as fish get older, they can actually accumulate more of this PFAS chemicals into their bodies. And then when we eat them, that can cause, then we get that PFAS into ourselves.

And contaminants in fish is not something new. Like mercury has been a long-term compound of concern in fish. Also PCBs, which are pi-chlorinated biphenyls.

[Stuart Carlton]
Easy for you to say.

[Dr. Fish (Titus Seilheimer)]
I know. I was going to give Katie a hard time because she forgot the alkyl group in that PFAS.

[Stuart Carlton]
Oh, you can't forget the alkyl group.

[Dr. Fish (Titus Seilheimer)]
I know. There's like all the chemists are like, oh, I mean, but you know, really we're fish biologists.

[Stuart Carlton]
John Scott is buzzing me right now.

[Dr. Fish (Titus Seilheimer)]
They said it wrong. Yeah. You know, so we are, we are fish biologists, so we're not getting this.

[Stuart Carlton]
Well, so tell me, how does this, let's talk about bioaccumulation for a second and then we'll get back to contaminants in fish. So this is a process, right? By which things, as you move up the food chain is my understanding, they sort of, they become more concentrated.

How does that work, Titus?

[Dr. Fish (Titus Seilheimer)]
Well, so that is biomagnification. So we have bioaccumulation, which is just the accumulation in animals. Biomagnification can be, so if you have a very small concentrations of things like algae, but then as you move up, then the zooplankton eat the algae and it can actually magnify and get more concentrated as you move up in the food web.

And what we're looking at, you know, with this study specifically is looking at lake trout and walleyes. So kind of top predators and, you know, where they add in terms of, yeah, PFAS, which, you know, really cool, really cool dataset. And yeah, reusing the fish that they've been collecting to look at things like mercury and PCB trends over time.

And now, because they have, you know, freezers full of dead fish, they can kind of go back and look at these. Exactly.

[Stuart Carlton]
But so Katie, the levels have actually, it seems like they kind of peaked, right? It may be going down.

[Dr. Catfish (Katie O'Reilly)]
Yeah. So like Titus said, they were looking at this existing, you know, body of, you know, research that was on mercury and PCBs and had all these samples dating back to the 1980s. So we had this 40 year dataset.

And what they found is that it seems like concentrations may be peaked in lake trout and walleye in early 2000s. And since then they've been declining. And part of that they attribute to some of the regulations that have been put in place that have had the manufacturers start phasing out some of these once common, a group of specific PFAS compounds.

Like I said, there's thousands of them. So this, they were actually only testing for 45 of the most common compounds in this study.

[Stuart Carlton]
There we go. I can't figure out how to make Titus. So Titus is reacting with the, yeah.

[Dr. Fish (Titus Seilheimer)]
So my eyes pop out.

[Stuart Carlton]
Very wise. Right next to the graph. But if you are watching live, as opposed to just listening, or if you're watching on YouTube, as opposed to you'll see Titus wisely reacting to Katie, but we see this graph and they talk about this phase out of different types of PFAS. I guess is what that is.

Long chain sulfonate and long chain carboxylate. And then you'll see it declining. So that's good news, right?

That means that we can make a difference here. Is that kind of, yeah.

[Dr. Catfish (Katie O'Reilly)]
I think that's, that's one of the takeaways is that, you know, I think when we talk about contaminants and especially like when people see the fisheries advisories are like, oh, I'd never eat something out of, you know, Lake Michigan because it's so contaminated. I mean, there is some, some truth to that. Like, obviously we have spent a lot of years polluting the lakes, but there have been major strides that have happened because people have started to notice, okay, you know, I want to leave a more sustainable lake for, you know, my children, my grandchildren.

And so taking those steps like regulating, you know, what compounds can be used in manufacturing, how companies might dispose of them. I think that's, it's all. Yeah.

I think all to say it's not necessarily hopeless. You know, there is the signs of recovery.

[Megan Gunn]
I mean, we probably should still not eat things that are right outside of a wastewater treatment plant or not right outside of one of the industrial mills, but it is safer.

[Dr. Catfish (Katie O'Reilly)]
That's a really good point, Megan, because, you know, this study was looking kind of broadly, but there are hotspots of PFAS, especially near places like airports or military bases that do a lot of like, for example, using firefighting foam. And so some of those places have really elevated concentration of PFAS. And so it's one of those things like, yes, in general, things have gone down, but depending on if you live by a particular hotspot, you really want to make sure, you know, kind of what consumption advisories are in your neck of the woods.

[Dr. Fish (Titus Seilheimer)]
Yeah. And you can, you can go to the States for that. Like Wisconsin has, you know, it's like specifically to, you know, counties in general.

Like if I, if I wanted to eat a fish from Lake Michigan I think generally we have kind of one, one guideline for most places, but then, yeah, there are specific places. We have a pretty, like there was a firefighting foam manufacturing and kind of testing area up in Green Bay near Menomonee. And that is, you know, one of the kind of high, high hotspots for PFAS.

And there are specific like species that you need to avoid in those areas.

[Stuart Carlton]
Titus, is this unique? Well, we share about consumption advisories related to fish, but never to other proteins. It seems to me outside of something like don't eat deer with chronic wasting disease.

Like, like, is this something we just don't have to worry about in beef and pork and chicken? Or is it just something that fish for some reason are studied more?

[Dr. Fish (Titus Seilheimer)]
Well, I mean, part of it is just, it's different. Like we're not out hunting our own, like if, if we had a, you know, hunting of cows and you, you know, harvested your own, like consumption advisories that the states put out are specifically so, you know, anglers, people who catch their own fish can make smart decisions. But like when you buy, like when you go to the store and buy fish, like that's actually, there's a whole different regulation system and that's actually the FDA has like specific levels of, you know, things like mercury and PCBs and PFAS that, you know, it needs to be under that.

So you don't actually see that when you're buying things like fish in the store, but, you know, similar for, for, you know, beef and chicken, like they have, it's just kind of regulated differently. Like you have to, you can't sell it if it's above, you know, certain levels. And I, and I think in a lot of cases, you know, I years ago, I remember there was a, you know, a report about how, you know, although PCBs, you know, people were, PCBs are elevated in fish because people don't, you know, Americans don't eat enough fish anyway.

Like they were generally getting more PCBs just from beef because it, it is in the environment. It's at very low levels, but they ate so much more of that. So yeah, it's, it's kind of different, different systems.

And I think there's always confusion about, you know, like what these regulations or what these advisories mean and how they're set.

[Dr. Catfish (Katie O'Reilly)]
And to add off of what Titus said too, you know, again, thinking about this concept of biomagnification, where you have a cow that is mainly eating lower on the food chain, things like grains, grass, corn, et cetera, versus a predatory fish, which is eating smaller fish that also are eating lower on the food chain. So then, you know, there's that level of like, okay, PC or PCBs PFOS might be higher in a predator compared to something that's an herbivore, like a cow. Gotcha.

But then pigs eat everything. So I'm not even going to get into that.

[Stuart Carlton]
Fair enough. That sounds good. And so with the separate regulatory system, that doesn't mean that like the fish you get in the grocery store, mercury free or PCB free or whatever, it's just, it's just tracked and warned differently.

Is that, is that correct?

[Dr. Fish (Titus Seilheimer)]
That is correct.

[Stuart Carlton]
Okay, great.

Topic number two, topic number two. I'm scrolling through our thingy. The team's behind all too clear.

Oh, this is great. Lakey award-winning, Lakey award-winning. I think they won some Lakeys.

I think so. I mean, I don't see it on their website for some reason, but I think they won some Lakeys. Lakey award-winning team behind all too clear.

That's Yvonne Drebear, as we would say in Louisiana. I have no idea how Yvonne pronounces their name. And Zach Milnick.

They've got a live stream that if you're watching live, yeah, no, this definitely won last year's Lakeys. They had that cool live stream where they were going around very deep and we watched that and it was, it was cool. And yeah, they're doing another one.

Titus, I think you put this in here. Tell me about what's going on here while I share the screen.

[Dr. Fish (Titus Seilheimer)]
Yeah. So, so, you know, this, this filmmaking duo super team, they have this great drone and they send it down into, it's a remotely operated vehicle. They send it down into the great lakes and record amazing video.

And yeah, so all too clear was kind of about how water had become really clear because of quagga mussels and change, you know, the story they told was about changing food webs. And now they've been doing a series of videos and actually this upcoming Saturday, weather depending, they're going to send that ROV down to the deepest point of Lake Superior. So yeah, really cool.

So, and, and they've had a, they've had a couple of these already. They've got like a scientist and they live stream it from the boat.

[Stuart Carlton]
That looks like a sturgeon.

[Dr. Fish (Titus Seilheimer)]
It does. Yeah. That, that video there is kind of a sturgeon rock.

[Stuart Carlton]
You can always see sturgeon rock. Anyway, that's cool. So why is this weather dependent though?

I mean, they're underwater, man.

[Dr. Fish (Titus Seilheimer)]
Yeah, but well, yeah, the ROV is underwater. The boat is not. And yeah, the, the actually the freshwater Everest one, which is where they were out at this lake. Yeah. I mean, that was like, they were just really far from shore and that was, they had a perfect day, but you know, obviously you're out in the middle of, of the great lakes. I think the deepest point is kind of off the UP, but it is pretty far offshore.

[Dr. Catfish (Katie O'Reilly)]
So 30, 30 some miles is, yeah. So it's 30 miles offshore. They're going down 1300 feet and, you know, Lake Superior, even on a good day can be temperamental.

[Stuart Carlton]
There it is. There's sturgeon rock. It's coming up again.

Look at that. That's totally a sturgeon.

[Dr. Catfish (Katie O'Reilly)]
That is 100% sturgeon.

[Stuart Carlton]
Yeah. Anyway. Right.

No, no. Lake, Lake Superior kind of famously a shipwreck situation. Gotcha.

We don't want that. The footage might be good, but not worth it.

[Megan Gunn]
Not at the cost of their lives.

[Stuart Carlton]
No, no. Thank you, Megan. I want to be very clear.

Our official position is just go out next week, right? It's fine. All right.

Excellent. Well, this is cool. And so people can watch this.

They do this live on YouTube, right? And even if it already has happened, we'll, we'll have a link in the show notes to the YouTube video.

[Megan Gunn]
Yeah. Their past events.

[Stuart Carlton]
Their past events.

[Dr. Fish (Titus Seilheimer)]
Yeah. And they also, the last one they did was recently, and they were at the Bruce nuclear power generating station in Ontario. And then at the, the, where the warm water comes out of that power plant, there is this like, they called it fish city.

So it is, there are a lot of fish that kind of congregate in this warm water. So yeah, really cool to see. And I think there were a lot of, what did we see?

A lot of gizzard shad. A lot of gizzard shad.

[Dr. Catfish (Katie O'Reilly)]
And actually, you know, tying this into the May Ask Dr. Fish, they're going to have a scientist from the Michigan DNR on the live stream too, who has been working with the zombie fish that we talked about last month. The, the lake trout that are deep in Lake Superior that are coming out really skinny. So not that they're going to necessarily find out why that is, but they're just going to have, you know, have that one of the scientists who's looking into that also narrating.

[Megan Gunn]
That's really cool.

[Stuart Carlton]
And now there's a decent chance that one of them will get bitten by a zombie fish then, which.

[Dr. Catfish (Katie O'Reilly)]
You got to tune in and find out.

[Stuart Carlton]
Yep.

Who knows what might happen? Well, this is great. Hey, you're listening to Ask Dr. Fish, our monthly live stream and podcast in which we ask our Drs. Fish your fish questions, your science questions, and your life questions. They keep showing sturgeon rock here. And so every time it comes by, I get distracted by sturgeon rock. But anyway, if you have a question for Drs. Fish, send us an email to askdrfish at gmail.com.

And assuming I have it set up right, which I mean, there's at least an 8% chance that I do, we'll get that email. We'll ask you Dr. Fish, if you're watching live, paste in the chat, just paste it right now in the chat and we'll find it. And we are going to go to our monthly recurring segment that I still haven't written a theme song for, which is sturgeon news.

And while we do that, Megan is going to paste in the private chat, the kids questions so that I can, I can, I can put them up on the screen in a little. So if you could put their names or you can,

[Megan Gunn]
I don't have names. I have the teacher and...

[Stuart Carlton]
Okay.

And if you put it in the doc, I'll paste it then.

[Megan Gunn]
Okay.

[Stuart Carlton]
All right. Anyway, um, fantastic. But now we're going to the, I have, I have the voice recording of the theme song I want to record, but haven't yet recorded the theme song because it's baseball season and all I do is baseball, but it's time for sturgeon news.

So imagine the sturgeon news theme right here. That was nice. Wasn't it?

Didn't you like that? Clever, witty while still sounding beautiful. I agree with all of your comments.

All right, let me put this off. They showed sturgeon rock again. I've got to cut it out or I'll just be watching that.

Okay. Stop sharing that tab.

[Dr. Fish (Titus Seilheimer)]
This week's sturgeon news brought to you by sturgeon rock somewhere deep in Lake Superior.

[Stuart Carlton]
There it is.

[Dr. Catfish (Katie O'Reilly)]
It's a rock.

[Stuart Carlton]
Yeah. All right, good. Well, we got sturgeon news and this one's exciting.

An hour of pure chaos. Titus, I have a feeling you're our sturgeon news guy here. Give me what you got on sturgeon news.

For some reason, it's not sharing the tab. Okay. Tell me a man sets a fishing record after battling a huge sturgeon in an hour of pure chaos.

[Dr. Fish (Titus Seilheimer)]
Yeah. So, uh, Minnesota DNR, uh, this is the new catch and release, uh, state record for, uh, Lake sturgeon in the state of Minnesota. And, uh, caught a, uh, an 80 inch long and 165 pound rainy river, uh, Lake sturgeon.

So, uh, yeah, so Northern, Northern, uh, Minnesota right on the border there. And, uh, definitely, um, pretty cool. They, you know, they have, uh, kind of a, a good, uh, population of Lake sturgeon up there and, you know, having this, uh, a healthy enough population that you can have, um, uh, catch and release or yeah, catch and release seasons.

I think people are pretty excited, um, to catch these fish.

[Stuart Carlton]
Yeah, that's cool. And so the tab I'm sure now says the comeback of rainy river sturgeon. So is this a conservation success story then?

[Dr. Fish (Titus Seilheimer)]
Yeah, absolutely. Um, you know, lots of, lots of focus on the species and, you know, they've, they've protected them and restored them.

[Stuart Carlton]
So yeah, great, great news. Katie, what are some things that we could do to protect sturgeon? Like what are they doing exactly, if that makes sense?

[Dr. Catfish (Katie O'Reilly)]
Yeah. So, I mean, one of the things has to do with fisheries management. Um, you know, we, as we've talked about in previous sturgeon news segments, sturgeon can recover, but they take a long time because they are slow growing.

Uh, they take a while to get to the point where they're able to, to spawn. They don't necessarily spawn every year. So, you know, a lot of this work has been years in the making to get to this point.

Um, you know, it's things like removing dams on spawning rivers so that they can access habitat. It's, um, having, you know, for example, a catch and release fishery as, as opposed to, you know, a harvest fishery where, where fish are, uh, taken out of the system. So there's a lot of different kind of levers that management agencies can take, but the sturgeon is one that can be kind of challenging just because even if you make those decisions, it may be 10, 20 years down the road before you begin to see, see recovery.

[Stuart Carlton]
That makes sense.

[Dr. Fish (Titus Seilheimer)]
Yeah. And if you look at, you know, this system specifically, like there was historically, uh, you know, actually the Lake of the Woods, the Rainy River was like the top, one of the top, uh, caviar producers in the world, uh, because of the, you know, they were harvesting these Lake sturgeon creating, you know, taking the eggs out. And that was, you know, just, uh, not really sustainable to a species that lives, you know, a hundred years and doesn't always reproduce right away.

Um, and then, you know, uh, also, uh, lots of pulp paper mills in the North, uh, you know, that's where the trees are. They've made a lot of paper there and the discharge, you know, pre-clean water act was, you know, not great, not great, uh, discharge. And, uh, you know, because these sturgeon were spawning, you know, we, we talked about sturgeon spawning all the time and look, we we've come back to, uh, you know, spawning fish again.

[Stuart Carlton]
Oh, sorry.

[Dr. Fish (Titus Seilheimer)]
Uh, thankfully. And, uh, the, yeah, Stuart's like, uh, I'll play him off. He's

[Stuart Carlton]
no, no, no. I was trying to subtly in the background, probably this one.

[Dr. Catfish (Katie O'Reilly)]
Oh, spawning song.

[Stuart Carlton]
Uh, anyway, so,

[Dr. Fish (Titus Seilheimer)]
so lots of, uh, you know, all this discharge from the paper mills, uh, was, you know, because sturgeon are spawning in rocky areas, the eggs are going down the bottom. And when you get kind of these polluted areas, it's not good for, uh, eggs.

You get, uh, there's, uh, I think with, with pulp paper discharge, like a lot of, uh, biological oxygen demand. So it really can go anoxic and low oxygen in those areas. So, um, not good, but you know, uh, these populations have been protected over time.

You know, those, those, the harvest for eggs was closed a long time ago, uh, clean water act. And now, you know, decades and decades later, um, recovery and now a season for them. So good news.

[Dr. Catfish (Katie O'Reilly)]
Yeah. And I think it's another thing, you know, even though it is Minnesota, it's not part of the rainy river. Um, you know, Lake of the Woods system is not technically part of the great lakes.

And I think it's just a reminder that, you know, obviously we talk about Lake trout in the context of the great lakes, but Lake trout are found outside of the basin. Um, and have had similar challenges as we, as they faced in the great lakes.

[Dr. Fish (Titus Seilheimer)]
Yeah. And if we really want, you know, they're not part of the Laurentian great lakes, but of course the rainy river does connect into the, uh, the Lake Winnipeg system, which is another global great lake. So we've checked all the boxes.

[Dr. Catfish (Katie O'Reilly)]
Now we're, now we're going to debate great lakes. Are we going to go into Lake Champlain being a great lake?

[Stuart Carlton]
Uh, no, we are not.

[Dr. Fish (Titus Seilheimer)]
I mean, I Agler was just there last week in, uh, Winnipeg. So the international association of great lakes research, uh, you know, a great lake and, you know, let's, let's be honest here.

Uh, Lake, uh, Lake Winnipeg, Lake Manitoba, they're bigger than Lake Champlain. So sorry, Laurentian watershed. Uh, but you know, Canada has some, some pretty big lakes as well.

In addition to the Laurentian great lakes.

[Dr. Catfish (Katie O'Reilly)]
Leg fight.

[Stuart Carlton]
Good to know that our Canadian parochialism is still, uh, still part of the show. Uh, excellent. So on managed fisheries, why am I the one tying this bet?

This is an unusual role for me to play. Uh, but, but it seems my recollection from when I used to do fishery stuff, which now has been 20 years, um, was that typically speaking managed fisheries were usually in pretty good shape, right? That once, once you were actively managing fisheries, they were usually steady to even increasing.

Is that still the case? Like once you put in those measures, they tend to work.

[Dr. Catfish (Katie O'Reilly)]
Oftentimes. Yes. I won't say it's a hundred percent.

Um, because, you know, fisheries management has certain levels, the levers they can pull. Yes. But then you add in environmental chaos.

Sometimes that happens. Like sometimes you have weather events over certain years that mean like an entire year class, maybe not the entire, but you know, your class maybe isn't as successful as it was. Um, so then, unless you adapt and change to take that into consideration, your management may not be successful.

You can also have, you know, the whole human aspect of, uh, fisheries management in terms of our people, you know, adhering to the management rules or regulations. Um, and, you know, I think, yes, there are certain things that, and obviously, you know, the agencies are doing great job, collecting science and data, but there's this famous quote about fisheries management that always sticks with me. And it's like, you know, fisheries management is hard harder than like managing a forest because your trees are invisible and they're always moving.

And so, you know, you're dealing with a system that is, you know, somewhat just inherently by its nature, challenging and dynamic.

[Stuart Carlton]
Gotcha. That makes sense. Hey, you're listening to Ask Dr. Fish, our live stream and podcast in which we ask our doctors fish, fish questions, science questions, and life questions. And this is exciting. We're going to close today. We're going to close today with a series of questions from, from, uh, uh, Ms. Amy Trumper's class at the Oswego Community School District in Illinois, not Oswego, New York, where I just spent a lovely week as part of the Great Lakes Sea Grant Network meeting. Um, had some good, uh, actually had a really good New Orleans cocktail of Sazerac there, but it didn't end up on my bill. So either someone bought me one or, you know, you give a little wink and a finger point and sometimes good things happen. But my point is this, we're going to have questions, but here's the deal.

This is also going to be our game this week. So Titus and Katie, your challenge is to not only answer these questions successfully, but I want you, since we're talking about eating fish this week, I want you to do the best job you can tying your answers in to fish sticks, which is a classic fish food. And so the better that you can tie them into frozen fish sticks that you make in your toaster oven, the more points you will score.

Okay. So there we go. Question number one, this one is for you, Titus, you're going to start.

Do fish get classified by what they eat and are they all omnivores? Go.

[Dr. Fish (Titus Seilheimer)]
Yes, they absolutely do. Uh, you know, we have planktivores, we've got herbivores, they're eating plants, planktivores eating plankton, uh, omnivores, you know, certainly who eat a wide variety of things, the piscivores, which each eat fish. Um, that is definitely, uh, something that we look at and really something we've already talked about in this episode.

So it all ties ties in. So, uh, piscivores might have more PFAS in them, um, because of bio accumulation and magnification.

[Stuart Carlton]
There we go. Uh, Katie, do you have anything to add, such as making even the most basic tie into our game in which you're supposed to feed your fish sticks?

[Dr. Catfish (Katie O'Reilly)]
I will. So I will say that, you know, as Titus said, they're different classifications. And when we think about, you know, what humans are eating, it's oftentimes better to eat fish that are lower on the food chain.

So things that maybe aren't piscivores eating other fish, um, just in terms of how many contaminants there can be in them, because as we talked about with the concept of biomagnification, fish that are eating more like plankton or, um, you know, invertebrates generally may have fewer toxins than fish that are eating other fish.

[Stuart Carlton]
I mean, do you want the point or not? It's one example. All right.

I didn't give a good example. I did a poor job. Uh, so one thing you could do.

So for example, some of these piscivores, if they find themselves eating fish, either live or like if they cook them up in the form of fish sticks, it might lead them to bioaccumulate more. I mean, how hard was that? I'm giving myself a point.

[Dr. Catfish (Katie O'Reilly)]
You know what I'm saying? I think Stuart gets the point on that one.

[Stuart Carlton]
One point for me.

[Dr. Fish (Titus Seilheimer)]
And of course, a fish species like lake trout, which, uh, you know, notoriously will eat anything that fits in its mouth, uh, would just gobble up a whole box of frozen fish sticks. You don't even have to cook them.

[Stuart Carlton]
You see, you could have done that moments ago.

[Dr. Fish (Titus Seilheimer)]
Throw them in there.

[Stuart Carlton]
You could have done that.

[Megan Gunn]
They needed the example.

[Stuart Carlton]
Yeah, that's fine. That's on me. I did a poor job.

All right. Question number two from Oswego, Illinois. Uh, there we go.

Would a fish, this one, Katie, I would like you to start, would a fish eat its brethren or sistren, anyway, uh, if it was starved, if it were starved and needed food?

[Dr. Catfish (Katie O'Reilly)]
A fish would eat similar, you know, either its siblings or just other fish of the same species, even if it wasn't starved and needed food. Cannibalism is incredibly common among fish. Um, I know when I was doing my, my dissertation, we found that one of the main foods that some yellow perch were eating were younger yellow perch.

Um, and I know that it's really common in bass and yeah. So, I mean, they don't have to be starved and need food to, to eat it. Um, and you know, maybe that is where the, the lake trout eating the fish sticks comes into play.

Like they don't really care. They're going to, it's food and they're not going to discriminate.

[Stuart Carlton]
Excellent. All right. This next question is for Titus.

Oh, this is a good one. I was thinking about this with the sturgeon actually, because we're talking about a catch and release fishery, right? And so one issue with catch and release fishery is potentially, um, that you wear out the fish and that ends up causing a fitness problem.

Uh, in saltwater, uh, for example, with, with marlin, a lot of times when you catch and release marlin, they will then become essentially shark food, um, because they're too tired to swim away from sharks. I saw an interesting presentation about that back when I worked at Florida Fish and Wildlife Conservation Commission. Is that an issue with sturgeon, like, like a catch and release?

Do we know what the survivorship is on that?

[Dr. Fish (Titus Seilheimer)]
Uh, you know, it's hard to say, like it's, you know, they are big fish and they don't, you know, there's not a lot of predators like that are going to take a bite out of them. So, um, you know, that is definitely like catch and release, uh, you know, survivorship is something you have to, it's fairly hard, you know, it's kind of complicated to, to measure, but it has been, uh, done on the great lakes. They've looked at, you know, things like lake trout, uh, and they were comparing and actually, uh, I think Sean Sitar, who, you know, as a call back to the, the deep dive and zombie fish, uh, I think he, he was, uh, involved in that study where they, uh, they tagged fish, lake trout that were caught in trap nets.

So sort of a non-played or, or sport fish caught fish and compared survivorship with these fish they tagged that were caught by, uh, anglers. And at least in that study, um, you know, they found that, you know, angled lake trout did have higher, uh, higher mortality when they were released. So, um, yeah, again, you know, you throw them back, they disappear.

And, uh, do you, do you, it's hard to track kind of what, what happens with those fish.

[Dr. Catfish (Katie O'Reilly)]
Yeah. And I will say there are like, you know, things that anglers can do to help or, you know, help maybe minimize the stress on the fish, like trying to keep them in the water as much as possible. Um, you know, not putting them on the ground to take a picture because that interferes with the slime coat, which protects them.

[Dr. Fish (Titus Seilheimer)]
Um, wet hands, keep your hands wet.

[Dr. Catfish (Katie O'Reilly)]
Exactly. Like just basically trying to minimize the exposure of the fish to, you know, outside the water.

[Stuart Carlton]
All right. Well, this brings us to our next question from Miss Amy Trumper's class, Trumper, Trooper, I apologize. Uh, in Oswego, Illinois.

And that question is this, this one's for you, Titus, and don't forget the fish stick tie-in. Uh, what is the main predator to fish in the Great Lakes?

[Dr. Fish (Titus Seilheimer)]
I mean, in the Great Lakes, so of course it's a complicated answer. Um, I'm going to say the simple answer is it's all those folks who, uh, you know, who, when they're, when they're out there, people catching fish kind of a top predator in the Great Lakes, um, uh, because they don't want to eat fish sticks for dinner. They want to catch their own fish.

And, uh, so yeah, so I w you know, I would say people are definitely a part of that, but you know, things like sea lamprey as well, like they are a top predator. Um, and then if we, you know, just, I was kind of thinking about adult fish, but then if you look at, you know, early like eggs and larval fish, like, you know, anything bigger, uh, you know, bigger fish will eat smaller fish. Um, so it, it just depends how big you are.

Uh, birds will eat you too, great fish, like all kinds of stuff. So really everything eats fish because fish are great.

[Stuart Carlton]
But it is different, right? Because we think about, I mean, I come from the salt coast and you think about like the idea of there's a shark and there's a really well-defined sort of food chain. But I think we talked before that the Great Lakes food web is more like a, one of those murder boards or whatever, right.

Where it's just all the, it's really, everybody's connected.

[Dr. Catfish (Katie O'Reilly)]
It's less of like a vertical as more of like a circle. Everything eats everything. Yeah.

[Dr. Fish (Titus Seilheimer)]
If you're a big enough lake trout, you know, you can eat everything, but if you're a smaller lake trout, a bigger lake trout might eat you and it's a, it's a risk.

[Stuart Carlton]
It happens. Katie, how do fish know when the bugs are about to hatch or come up to the surface? So we were in, uh, we were in us, last week and I was walking across the bridge over the Oswego river and upon me descended 100 squigillion caddisflies and, uh, uh, caddisflies are disgusting.

Um, and I was thinking of our good friend, Carolyn Foley, uh, because she loved these stupid things. Um, and, and, and right. And well, they're amazing.

I've got a certain level of terror to me. Uh, and, and so there's nest like qualities and it was very uncomfortable. Uh, so what, uh, how do fish know?

So I imagine the fish were like, yippee, I'm going to eat me some caddisflies. Uh, Katie, how do they know when they're there?

[Dr. Catfish (Katie O'Reilly)]
You know, I, I mean, they know when they're there, obviously, because there is a lot of food all of a sudden, and you know, this is the emergence of, of, uh, things like caddisflies or mayflies often causes these big feeding, essentially a feeding frenzy. However, you know, I don't know if the fish know when that's necessarily coming, but we think about all the cues, environmental cues that lead to that. So, you know, more light because there's longer days, warming temperatures, um, all of those come into play with this concept called phenology, which is like the timing of events in nature.

And so, you know, a fish may not know necessarily that, okay, the, you know, bugs are going to come out this day, but based on the time they spawn, based on the time they may travel to an area, it typically coincides with these big emergencies so that they can take advantage of this really big pulse of food to their ecosystem.

[Stuart Carlton]
And so that annual timing though, that's, uh, that's something that's changing now it's under threat, right, Titus, thanks to climate change and what have you.

[Dr. Fish (Titus Seilheimer)]
Yeah. So, you know, timing can be very, uh, related to, to things like temperature and season. Uh, so, uh, you know, you can get mismatches as well.

Like if the fish aren't there at the right time when the hatch is happening, uh, that can affect them. But, uh, yeah, you know, a lot of it is like, you know, it's surface feeding for bugs, especially like if you're a trout fish, you know, if you're fishing for trout, uh, with things like dry flies, you're going to be like, what is hatching now? Like what is available?

Uh, you're going to try to match that with your fly and then you're, yeah, match the hatch. You throw it on the surface and then the fish eat it. Cause they are, you know, these, uh, you know, because I'll really like invertebrates are really fun and it's, you know, a pretty cool thing to think about.

Like a lot of these caddis flies spent most of their lives under, in the water as aquatic, uh, you know, the, these juvenile kind of nymph forms and, uh, you know, and then they're, they're laying their eggs and these fish are just gobbling them up. So, uh, you know, if you're a bug, if you can pulse all your, if everybody comes out at the same time, there's a better chance that you can lay your eggs and maybe one of your siblings will get eaten.

[Stuart Carlton]
Oh, right. It's, it's a flood the zone situation, right? Um, where they all do that at once.

No, that makes sense. And we hope that somebody else comes in fishing with different lures, like with a fish sticks or something.

[Dr. Fish (Titus Seilheimer)]
And Stuart, you know, caddis flies, it was, it was fine, but I mean, if it had been big hexagenia mayflies, that would have been, uh, that would have been Certain version of awesome. That is, we're going to try it. We'll try to, uh, I think the timing we're going to have it in green Bay this meeting next year, but, uh, unfortunately it'll be in the fall or the late summer.

So we won't have a huge hatch of mayflies for you guys. All right.

[Stuart Carlton]
We got one more for you this week, I think. Um, and this was, this was a good, this one's a, this one's a puzzler, Megan.

[Megan Gunn]
I like it.

[Stuart Carlton]
This one's a puzzler. All right. And so, uh, I'm going to toss this one out to Dr. Catfish herself to start, uh, do fish get thirsty?

[Dr. Catfish (Katie O'Reilly)]
Ooh, that is a great question from the class. So you think, you know, something that lives in water is not necessarily going to get thirsty.

[Stuart Carlton]
Exactly what you, in fact, that's what I do.

[Dr. Catfish (Katie O'Reilly)]
Exactly what you would think, but actually fish in freshwater kind of have almost the opposite problem. Um, in that they are like, so constantly, they are constantly having to regulate their internal body chemistry to prevent. So if you think about a fish in saltwater, it's trying to not lose all of its moisture to the out, you know, outside environment, very simply put.

A fish in freshwater, however, is trying to keep its like internal chemistry constant when it has, you know, kind of too much water outside. Um, again, this is the biochemists are going to be like freaking out, uh, and with this definition, but essentially, you know, it's trying to keep homeostasis of their body with the environment. So in the case of some fish, they have to pee more often in order to regulate, whereas other fish, you know, are just trying to hold on to all of like, you know, things like electrolytes salts that are in their body.

Um, so all that to say, you know, our fish in the great lakes are not necessarily need, you know, needing to take a drink, um, but they're needing to keep their body chemistry, um, from, you know, essentially being altered to, to a level that they couldn't survive. And that's, you know, fish that can live in both salt and freshwater have really advanced systems to deal with the differences between, you know, having to regulate for saltwater versus freshwater.

[Dr. Fish (Titus Seilheimer)]
Makes sense. So would you say that... And to steal the point, um, if you were to, uh, if you were to boil your fish sticks, they would be bad, but if you deep fry them in oil, uh, which is, you know, the opposite of water, they would be delicious.

[Stuart Carlton]
Oh, look at that because there you're good. You get too much water in them through the boiling. And I got, you know, semi-relevant.

That was well done.

[Dr. Catfish (Katie O'Reilly)]
That was a nice one.

[Dr. Fish (Titus Seilheimer)]
Soggy breading on a fish stick, yuck. No thank you.

[Dr. Catfish (Katie O'Reilly)]
You need like a nice salty crunch.

[Stuart Carlton]
You do. You do. All right.

Well then I won't, I had written down, I won't repeat it because the point's gone now, but I written down, uh, they put the P in PFAS, uh, there. We'll save that one for another time when we're on Ask Dr. Fisher. With that, I will now report back the score.

Katie had like a half point, I'll be honest, at best. You excel at many things. You do not excel at, at working, um, fish sticks into the conversation.

I managed to get two points, um, despite the fact that I'm not even allowed to score. Uh, so that was an impressive job by me. Uh, Titus, you also had two points.

However, since, uh, you are an actual contestant and I'm the moderator. Titus, we're going to give you 30 seconds of soapbox time. There it is.

Oh, go Titus, go.

[Dr. Fish (Titus Seilheimer)]
All right. Well, uh, it is, uh, you know, we, we've been talking about watching fish spawn and now it's time to look for baby fish. So if you're out there, uh, you know, look for these tiny little fish that are maybe a three quarters of an inch long.

I've just been seeing some at my local Creek where I do sucker monitoring. So that got me thinking, are these suckers? So I will find out and report back.

[Stuart Carlton]
There you go. Totally nailed it. That's fantastic. Please don't play again.

Oh my God. I thought it was going to repeat. That's wonderful news.

Hey, wait, have you done any, we're supposed to do the credits before? Have you done any more of your shorts? I forgot to look online for your shorts.

[Dr. Fish (Titus Seilheimer)]
Uh, yes, we have not, but there is a longer video out just now about a fish leather. So that came out last week. Um, we did a fish leather workshop at UW Madison.

[Stuart Carlton]
I asked Titus for his shorts and he showed me his leathers. Another time we'll go over that, but for now they're leather shorts. Well, they're longer.

So they're more like pants. More like pants. That's fine.

Where's the theme song? There it is. Excellent.

Ask Dr. Fish is brought to you by the fine people at Illinois, Indiana Sea Grant, Wisconsin Sea Grant, and Goby Dog Media. The show is produced and hosted by Stuart Carlton. That's me with Megan, the lake lover gun.

That's you. Well, not you listener. Anyway, Dr. Catfish, Katie O'Reilly, Dr. Fish, Titus Seilheimer, Megan, I think you're supposed to do this one.

[Megan Gunn]
The podcast version of this show is edited by Sandra Savota and the podcast artwork is by Ethan Kosak and you can view his portfolio at ethankosak.com. That is K-O-C-A-K. There we go.

[Stuart Carlton]
If you have questions for our Drs. Fish, send them over to askdrfish at gmail.com. You can also use the social media hashtag askdrfish. No, you can't.

Like, are we doing the, like, where would they use that?

[Megan Gunn]
Uh, probably on Facebook?

[Stuart Carlton]
On Blue Sky. Blue Sky or Facebook? Do they have hashtags?

[Megan Gunn]
You can put hashtags everywhere. Can you? Yeah.

[Dr. Fish (Titus Seilheimer)]
Yeah. I've checked. I have not seen anyone using it.

[Stuart Carlton]
Yet. Thank you for checking. You gotta have a growth mindset, Titus.

All right, well, then do it at pound sign askdrfish or just say it out loud and it'll just appear. Anyway, the point is this, do that or call our hotline at 7654-9644-74. That's 765-496-4474.

Leave us a message. Our hotline has been too hot over the last six years, but maybe this month is the month. Maybe this month is the month.

Hey, everybody. Thanks for listening. We'll see you live on Facebook and YouTube at 1030 a.m. on the first Monday of every single month.

[Megan Gunn]
And that's Eastern time. Eastern time. Not Central time. We won't be there yet.

[Stuart Carlton]
No. No. Central time.

You'll still be drinking coffee, eating a fish stick or two. First Monday of every month. Anyway, in between now and then, if you have fish questions, you have science questions or life questions, just ask Dr. Fish.