Lake Doctor | A Lilly Center for Lakes and Streams Podcast

Shelling Out the Facts: Freshwater Mussels with Brant Fisher

• Lilly Center for Lakes & Streams • Season 2 • Episode 13

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Nate and Suzie sit down with Brant Fisher, a Non-game Aquatic Biologist with the Indiana Department of Natural Resources. Brant brings a wealth of knowledge about the often-overlooked species that quietly keep Indiana’s waterways thriving—from freshwater mussels and darters to mudpuppies and rare invertebrates. He shares how these creatures act as early warning indicators for water quality and why biodiversity matters more than most people realize.

This conversation shines a light on the hidden world beneath the surface, revealing how small and unassuming species play an outsized role in the health of our aquatic ecosystems. Brant also discusses the ongoing challenges non-game species face, like the harvesting of shells for jewelry and the complexity of mussel reproduction. He offers practical steps we can take going forward to support conservation efforts. Develop a deeper level of appreciation for Indiana’s non-game aquatic life.  

Brant Fisher, originally from western Pennsylvania is a nongame aquatic biologist with the Indiana DNR. Brant monitors species that are not typically fished for sport like mussels, darters, crayfish, and freshwater jellyfish. When doing mussel surveys,  these biologists will often crawl through rivers and streams while scanning the bottom with their hands. Brant has worked at educational events in the past where he teaches about aquatic ecosystems. Brant has also collaborated with Purdue and other environmental nonprofits to support mussel restoration and research projects.

Learn more about the Lilly Center's work at https://lakes.grace.edu/.

Have a question we could answer on the podcast? Send an email to lakes@grace.edu or submit a comment below.

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SPEAKER_02:

Thanks for joining us on the Lake Doctor podcast. I'm Susie Light, and my co-host, Dr. Nate Bosch, is a professional lake nerd.

SPEAKER_00:

That's true. I received my doctorate from the University of Michigan in Lumnology, which is the study of freshwater lakes. In today's episode, we're excited to have Brant Fischer from the Indiana Department of Natural Resources. He's the non-game aquatic biologist.

SPEAKER_02:

We are so excited about today's episode. We're going to learn about mussels and their sex life. The doctor is in. What do you like to do?

SPEAKER_01:

Yeah, sure. Yeah. Thanks for having me today. So I grew up in western Pennsylvania. My grandparents' dairy farm was a big part of my life. A lot of people joke that I'm Amish. I'm not Amish, but I did live, live near Amish in western Pennsylvania. They had fields all around where I lived and they lived across the street from us. They came over and used our phone occasionally, you know, that's that type of stuff. But my grandparents' dairy farm is where I really grew up. So just being outside all the time, hanging out on the farms, kind of probably where I and well, kind of where it led me to doing a job where I'd kind of have a chance to do a lot of stuff outside. Went to Grove City College, which is just a small school there in western Pennsylvania. A couple kind of small short-term jobs, then off to grad school at Purdue. Okay. So go boilers. And that's why I ended up in Indiana, I think. Because after Purdue, making contacts here, I ended up getting a job, job here in Indiana. So I just love being outside, like a lot of different sports, love gardening. Um so yeah, I guess that's that's me in a nutshell.

SPEAKER_02:

So one of the things that you do at the Indiana Department of Natural Resources, DNR, is I'm gonna read this to make sure I got it right. Non-game aquatic wildlife.

SPEAKER_01:

I am the non-game aquatic biologist. Uh there's me and my assistant. We're the only ones that do the stuff that we do for the state. Most a lot of people would know a lot about like kind of our district fisheries biologists that do, they basically manage a lot of our lakes, reservoirs, and some stream stuff, but they manage manage it for species that people are interested in going out and catching, uh angling for the most part. So that's what they really focus all their work on. Then we work with all the other species of fish, the non-game, so non-sport fish. Okay.

SPEAKER_02:

What's an example of a non-game fish?

SPEAKER_01:

Well, okay. Well, yeah, I saw some right out in an aquarium outside the studio here today. Some rainbow, a rainbow darter. Okay. Although, interestingly enough, there are people that now fish for things like that. Really? Uh microfishing. Well, that's we could get a whole other topic, but microfishing, it's people that are interested in in catching the non-traditional species of fish. And, you know, a rainbow darter is a couple inches long. So micro, micro fishing. Yeah, you got to use very small hooks, certain baits. Takes a lot of patience sometimes, stuff like that. Sight fishing them, you know, like finding darters and endangling a little something in front of the hooping. Because the idea is you catch still catch it hook in line. But so micro species. And then what those people do is they keep lifeless. Just like if you are a birder, yes, and you're out there and you're like, how many bird, well, how many birds on my life list? Uh, a lot of lifelisting anglers are how many species of fish are have I caught hook in line? And so uh, yeah, that's kind of a new versioning thing. So, yeah, a rainbow darter. Sorry to get sidetracked there, but a rainbow darter would be a non-game species. Um, something like a creek chub sucker, uh, type of sucker. I mean, we could go down the list. There's there's about 200 species of fish in Indiana. Roughly maybe 40 to 50 of those would be either a sport or commercial species. Uh, would you have some commercial fishing? And then the whole rest would be kind of lumped in as non-game species. I mean, there's 50 species of minnows in Indiana alone. Wow. So, you know, most of those aren't sport fish. Right. Right.

SPEAKER_02:

That would be micro-micro fishing. Yeah, there's all kinds of well, yeah.

SPEAKER_01:

I mean, okay, if you want to go to the smallest fish in Indiana, micro-microfish, that'd be like the banded pygmy sunfish or the typical new darter. Those are big as the, yeah. Yeah, they they max out like an inch and a half, maybe two inches is a really big one. So you gotta go very specific places in the state to find those and then to target them. But banded pygmy sunfish is only in southwest Indiana and like some of our sloughs and stuff down that southwest corner that's kind of like the south that came up in Indiana, just a little bit. Tippecanoe Darter, though, you can find that in the Tippecanoe River. It's first described there. It lives buried down in like the cobble and gravel out in like the riffles and the flowing parts of the river. Um, but yeah, those are tough to catch.

SPEAKER_02:

Rivers have riffles?

SPEAKER_01:

Yes, rivers have riffles and pools and runs. Yes.

SPEAKER_02:

So what other kinds of species are you in charge of?

SPEAKER_01:

Yeah. So the Naga fish and then freshwater mussels, which we're gonna talk about today. That's a whole nother group of animals. I then I also say I dabble in snails and crayfish. That would be the area that I would uh cover. But with all the time we spend with fish and mussels, I would say those are you know a little bit on the back burner so far, unfortunately. We just don't have enough time to get to all those things. And then anything else in the water that someone doesn't really know about or a question comes to us, like what is this or what's going on here? It sometimes filters down to the non-game aquatic group, which is me and my assistant Jake. So just the two of us. And we work statewide.

SPEAKER_02:

Statewide.

SPEAKER_01:

So you travel from Mosey County down in Southwest to Lake Michigan up in the northwest to Stewben County.

SPEAKER_02:

And you're headquartered in Indianapolis?

SPEAKER_01:

Well, a little south of there, the Atterbury Fish and Wildlife Ferry, which is down in Edinburgh, but uh we don't get there a lot, honestly, in this in the summer when we're out doing a lot of stuff. So I'm in Greenwood, I live in Greenwood south side of Indianapolis. That's kind of our second base outside of our office.

SPEAKER_02:

So Indiana has mussels.

SPEAKER_01:

A lot of them.

SPEAKER_02:

Um, and there are different kinds of mussels in Indiana.

SPEAKER_01:

Yes.

SPEAKER_02:

Wanna tell us about mussels, please?

SPEAKER_01:

Just like in general these. Okay, so yes, uh historically, about 80 species of our native freshwater mussels. I got a few kind of here on the table today, and uh found anywhere. So found in any aquatic habitat, really, from a very small stream that you could jump across. There could be some freshwater, native freshwater mussels in there to the lakes, you know, right here in Costcasco County, to Lake Michigan, even at Point had it, to the Ohio River. I mean, you name it. Any aquatic habitat uh could potentially have freshwater mussels in it, native freshwater mussels in it. So horse historically had about 80 species. Unfortunately, they're probably one of our most endangered groups of wildlife in Indiana. We've probably lost in that 20 to 30 range of species from that 80. So you could still go out and find old shells of them, but in terms of finding living animals, there really aren't any that are still living, or some of them are so rare that they're just found in maybe one section of one stream.

SPEAKER_02:

So we've heard that there are mussels living in Tippecanoe River that are endangered.

SPEAKER_01:

Yes.

SPEAKER_02:

And what kind of mussels are those?

SPEAKER_01:

There's actually several species of federally endangered mussels that live in the Tippecanoe River. Um, just a few would be like club shell, raid bean, fan shell, rabbit's foot, sheep nose, snuff box.

SPEAKER_00:

Um those sound like some interesting names, right?

SPEAKER_01:

Round hickory nut. Yeah. Other names are kind of crazy. A lot of them were like, how did they come up with that? Some you can see when you look at the shell, obviously the shape or something. Okay, that makes sense. Other ones are like, I don't know what they were sitting around a campfire a couple hundred years ago, you know, drinking some moonshine or something. They were trying to figure out what it looked like. But yeah, so the Tiffany River, yes, it's still has several very rare species. I mean, when it when you have talking about a federally endangered mussel species, that means it's you know reduced to probably just a few streams anywhere in the world at this point. Wow.

SPEAKER_02:

So why should our listeners care about that?

SPEAKER_01:

Yeah, that's I get that question a lot. Like, why care about mussels? They just look like rocks on the bottom of the stream or whatever, right? I don't know. The first thing I always kind of go to, which is a little maybe out there, but it's just like they're supposed to be there. I mean, they're part of the natural ecosystem of our rivers and streams, like some ponds. So why shouldn't we care about them if they're supposed to be there? And then the kind of off of that is they they perform uh you know a huge function for the ecosystem of the the areas that they live in. They're they're filter feeders, so they're a natural filter. So that means they're constantly filtering the water to get food for themselves, oxygen for themselves, and then through that, you know, they're building their own biomass of their body, but they're also excreting stuff, excreting waste that they they don't use, and that's picked up by all kinds of other insect larvae and other you know, uh macroinvertibs and stuff that are living there in the substrate or the bottom of the stream or river with them. Um and that that's just providing stuff for them too. So you know, it's like kind of a cycle of stuff, but they're converting stuff that microscopic bacteria, algae, plankton, zooplankton, phytoplankton that's in the water to something then that other things can eat. Animals eat other animals eat them, like river otters, uh muskrats are a huge fan of eating mussels throughout the year. Um so yeah, and then even when they die, um their shells are left behind. Uh that's really nice for us surveying because then we can get a look at a river or stream and we see what's still living there, but then we can also see all the old shell material. So you can get a really nice list of what you know, kind of a whole idea of what used to be in that river and stream. Not with fish, you know, fish, if they die, they don't you don't know if they were there a hundred years ago, but we can still find shells from you know hundreds of years ago certain streams. So uh even the shell behind, you know, a lot of uh fish use them to you know little houses or to lay their eggs in or aquatic insects, crayfish, other stuff like that, use them kind of um, you know, still use the shell material even when it's on the bottom of the stream.

SPEAKER_02:

So I envision fish recycling.

SPEAKER_01:

Fishers, I yeah, using the dead shells for stuff, yeah, for sure.

SPEAKER_00:

And those shells, too, with those being there, it also helps with the water chemistry, right? And because um these are these shells are calcium carbonate-based, similar to limestone, they help buffer the water. A lot of the the pH of our local lakes and streams here is buffered up, both because of the limestone in the area, but these shells also. So if ever the pH unnaturally is starting to move down from acid rain or for maybe runoff for fertilizers or something like that, um, other other pollutants maybe, these shells along with uh with pieces of limestone are going to naturally buffer that pH and keep it higher, which is gonna allow for a lot of the the critters, some of the more sensitive critters especially to continue to survive. And so it's a it's a good way also to to help keep that buffered up higher.

SPEAKER_02:

So is that one of the bioindicators that you have talked about earlier?

SPEAKER_00:

Yeah. So um, so muscles certainly would be an example of a bioindicator, oftentimes, especially some of these mussels that are endangered or federally endangered, as Brant was talking about, can only be found in really high quality streams or or high-quality lakes where the water quality is such that these mussels can continue to survive. But we have other ones other than mussels as well. We have on the table here a replica of a mud puppy. We actually have uh a live version here in the Lily Center for Lakes and Streams on Grace College's campus. Her name is Mabel, and uh mud puppies are our our our largest aquatic salamander here in the the northern part of Indiana and southern part. We have uh hellbenders, but um they are an indicator of good uh water quality. We have a lot of our aquatic insects, also known as macroinvertebrates. Some of them, certain classes of them are indicators for good water quality, others are indicators for poorer water quality, depending on their tolerance for pollution. And so those would be some of the things that we would look for in certain aquatic environments. And and we can take chemistry analyses and see the quality of the water that way, but that's more instantaneous. Whereas if we look at some of these biological or bioindicators, they need to stay there year-round. And so they give us more of a cumulative sort of view of of what the quality of that water might be.

SPEAKER_01:

So I would I would add some to that. So freshwater muscles, there's there's a couple different things with that in terms of bio, if they're bioindicators or not. So if you if you go to a stream and you have a really nice diverse uh population of muscles, so different species and they're reproducing. That's that's an important part of it. Then yes, I would say your stream is in pretty good shape because that means you have good water quality, the muscles can survive, they're getting the food they need. And in order to reproduce, um, maybe we talk about that in a little bit, but the the muscles need host fish in order to reproduce, and some of them need very specific species of fish. So you you have to have kind of everything's got to be in good shape for the muscles to still be living in there and reproducing. And the other thing is you can you can get a lot of false negatives, I think, in terms like so. If you have a stream, it's like, oh, it had used to have a lot of muscles, there's no muscles left anymore. It must be in bad shape. I wouldn't go that far all the time because there could have been one time event that came through that stream, you know, a really bad spill or something that just wiped the muscles out. And they just have had no way to get back in there. Like maybe conditions have improved, the habitat's really still good for them, and fish are back in there, but they they're not like fish. They can't just get up. Oh, I'm gonna swim 10 miles upstream. Right, yeah. Or oh, there's a stream. Let's go and see what's in there. You know, they they have one foot, it looks like your tongue. So, you know, try try moving around with a one foot that looks like your tongue. So as an adult, they can't really move very well, but they can move when they're when they're they're when they're reproducing, they have that, they have a parasitic stage where they attach the gills of fish. And then when they're on that fish, that's a chance kind of where they can that fish moves around. And then when they drop off the fish, that's how they can get in. But I mean, if they're wiped out completely in a stream, you know, it takes how many years for a population to get re-established and they're on its own, right? Just relying on some fish from a nearby muscle population to get infected to then swim up there and drop off, and then enough enough drop off in the right places, right habitat, near enough to each other that then a population can actually get started on. So I think you gotta be a little careful when you want to say there's no muscles in my stream. It must, you know, that must be a bad indication. I will you can't say that all the time. And just because you see a lot of muscles, you gotta know if they're reproducing. Because the muscles could be in there and and seem to be okay. They can live for some of these muscles can live 50, 70, 80 years. So they can be, you know, they can be in there for a very long time, but if they're never reproducing, you know, they're still kind of doing their job, but there's still something else going on the stream then.

SPEAKER_02:

That's really so we have human intervention when it comes to repopulating using fish. Is there a human intervention or the DNR doing anything to repopulate muscles? Can you do that?

SPEAKER_01:

Yes, that's a that's kind of the the newest thing that we've been doing uh in Indiana. It's been going on in other states too. So we we really started out like 30 years ago when I started my job, was really just trying to figure out where we have muscles in Indiana and what species are where, which ones are rarest and stuff like that. We've we got a really good handle on that now. And now we're moving into that next step. Okay, what can we do to improve populations or restore populations or reintroduce populations in certain areas? So, yeah, we have several projects going on right now where we're putting muscles back in streams, very similar to what kind of what we do in some terms with fish. You know, you raise them in a hatchery setting and then you release them back into a river stream. We're doing that um with several groups. We're doing other ones where we're kind of doing it. Um we're we're using their strategies for reproduction and just stepping in in spots. And like for instance, well, maybe I should just talk about reintroduction or reproduction for just a little bit first, because you can't talk about any of this other stuff without really understanding how they reproduce. So most species of freshwater mussels, there's males and females. And as I go through this, just think of all the places along this thing that something could go wrong. Okay. So most of them, there's males and females, and some of them actually the shells look different. So you can actually pick one up and say this is a male of this species, or this is a female. Others you can't tell by just looking. Um, but so the females produce eggs that they hold in their gills, and then uh males will release sperm into the water, and the female filters that in just when they're filtering the water, it fertilizes the eggs in their gills. So start thinking right there of issues. Okay.

SPEAKER_02:

So how far apart do they need to get?

SPEAKER_01:

Yeah, right. Okay, how far that that's a great question. There's been some studies in that, and actually, a female muscle will have her eggs fertilized by multiple males, and from decent distances, you know, maybe even up to a mile or further away, it's still possible that they could be getting, you know, some fertilization from males that far away. But when you're when you get down to that critical like number of that species left in a stream, you know, then that's when it's getting tricky because think of like the Tippagania River, like further down how wide it is, how big it is. Like say you have a very rare muscle in there, there might be 20 or 30 in a stretch that are still living. Well, number one, males have to be upstream of females. Yeah when they release the sperm. I mean, you know, if they're downstream or they're on the right bank and all the females are on the left bank, you know, like the sperm has to get to the eggs to get fertilized. So that's one step where you can see there could be issues, right? So say that it works, the female has fertilized eggs. At that point, uh it's it's a larvae of the muscle and it's parasitic, and it needs to find a host to get that parasitic larvae to kind of the next step in the life cycle. So almost all of our muscles, that's a species of fish. We actually have one. Interesting, we brought mud puppy earlier, but we have the salamander muscle. It's only known host. The only thing that will work for reproduction in Indiana is the mud puppy. Wow. So it has to have the mud puppy in close proximity. And interestingly enough, you usually find that muscle, it's a very small muscle, you usually find it under large rocks. Right, go go figure, right? That's where mud puppies hang out most of their time. So, you know, for that species, when you're doing surveys for it, you got to flip big rocks and try to find the small muscle kind of in the substrate underneath the rocks. But but most of our muscles, like there's they use fish, almost all the other ones. Well, all the other ones do. And some of them are more generalists, like it doesn't really matter. They'll use about any species of fish. But then we have other ones that maybe only use one species of fish as the correct host. So they have to have that species of fish there too. Right. And then they got to get that parasitic larvae from the female's gills to the fish. So that there's a shell over there, the far one on the right, that's a fragile paper shell. The only known host for that in Indiana is a freshwater drum.

SPEAKER_02:

A freshwater drum. Drum.

SPEAKER_01:

A species of fish is finding our bigger rivers, kind of medium-sized rivers. So if you mapped out the distribution of that species of muscle, and then you overlaid what we know about where drum is, it's almost identical. Okay. We have another one. It's called the Hickory Nut. I don't have one here. It's it's the only known host in Indiana, our sturgeon species, Lake Sturgeon, shovel nose sturgeon. So if you mapped out its distribution in Indiana, it's like it's in the Wabash River, the West Fork of the White, East Fork of the White, the Ohio River, and up into a few of our bigger troops to the Wabash. And that's exactly where we have shovel nose sturgeon. You know, it's like so um there's such that play and that you need the fish, you need the host, the certain species of fish for the muscles to reproduce. And so we got to that point. So there's a it's kind of a process here. So the the males release sperm, females get the eggs fertilized, and they have that parasitic larvae. They got to get that larvae then to that host fish.

SPEAKER_00:

Yeah.

SPEAKER_01:

And this is where it gets really interesting. The females have several strategies for that. So one is they produce this little packet of those parasitic larvae, which are called glaucidia. They they form this little package, and it'll be like a little white mucusy thing or a little white uh thing that looks like a worm or something, and they'll just expel it from their shell. So it's a package of all those parasitic larvae, and they just put it out there and wait for a fish to randomly eat it. And when that fish would eat it, it kind of, you know, when they're chewing it up in their mouth or it's in their mouth, then all those little parasitic larvae go and they attach to the gills.

SPEAKER_00:

Okay.

SPEAKER_01:

Um, other muscles, there's some females that will actually put a lure out. So the female, you know, we didn't really talk about this, but muscles are usually buried in the bottom of the substrate with a little of their shell exposed, and they'll put out a little part of the inside of the muscle or the mantle, which is the part that forms the shell. They'll stick that out and it will actually uh move it, dangle it around, and it'll try to attract the fish to them, and they they have their gills sticking out, and the fish will grab at what the lure looks like, and it'll kind of cause the gills to kind of explode. Little packets of those parasitic larvae will just explode in the face of the fish, they get sucked in and they get onto the gills. Some of those lures are crazy. So there's some that will actually have little eye spots, look like little fins, they'll look like a little fish. They actually will move it in the water. We have some videos of this on our website if you ever want to go to see some of them. And it just blows my mind because think about this. A freshwater muscle has no eyes, right? It doesn't have any eyes, it has created a lure that looks like a small fish or an insect, and even to the point it has an eye spot on it. That is amazing. So you're talking about a muscle creating a lure to attract a fish to get his parasitic larvae to to complete the life cycle. It's created something that it it's never seen, right? And it even to the point it puts an eye spot on the lure. You know what I'm saying? Like it just blows your mind when you start to think about that. God's creation. Yeah, so you're it's sitting that muscle is just sitting in the bottom, almost buried, and it's got this little lure out there, just kind of like jiggling in the water. It's got the eye spot, it's got a little coloration. That fish comes out and grabs it. Now it's on the gills of the fish. So however it gets it there, it releases that package. Uh, it's called a conglutinant of those little glaucadia or attracts the fish to it. Some put out a little like mucusy web and the fish just swims through it, and that's how they get the parasitic larvae to the gills of the fish. But then they're on that gills of that fish, and then about a month or so, they hang on to the gills, slowly transform, and then fall off that fish wherever that fish is after about that month period. So, you know, that could be in the same area. That fish could have moved 10 miles upstream. Uh, you know, who knows where that fish? Someone could have caught the fish, moved it to their farm pond. Uh people always get mussels in their farm pond, you know, like a brand new pond, and that 10 years later they got some muscles in there, right? They're like, how do all these muscles show up in our pond? I'm like, well, did you move fish from somewhere else? Right. You know, where'd you get your fish from? And they unknowingly, a lot of people, you know, could move. It's not a good idea to move fish around all the time.

SPEAKER_02:

That wouldn't hurt the pond.

SPEAKER_01:

No, it wouldn't hurt it at all. But does the um parasitic fish get damaged or injured because of the well, this your whole question asks like, what do we do to like help muscles out and how do we raise them? When we do it, so what we do is we we'll get a female, extract those glaucadia and then infect fish, the gills of the fish, and then hold those fish and wait for the baby muscles to drop off. Then we collect the baby muscles and raise them up to use and put where we want to. When we do that, yes, we can definitely put way too many of that parasitic larvae, glaucita, on the gills of the fish, and it will kill the fish. But out in nature, like when it's happening naturally, no, it that would be a very rare occurrence that it would ever actually hurt the fish, and there'd be so many on there that cause a problem. And that makes sense because the muscle doesn't want to kill its host fish. Right. You know, it needs that fish to be smart muscle. Yeah, they don't have much of a brain, but yeah, they they're definitely smart enough to figure out stuff like that somehow. But yeah, it's uh yeah, so that's what we do. Like we intervene into that life cycle and try to get to spots where then we can collect the babies and use those babies, then grow grow them up and then put them where we need to put them or put them into populations that you know need a little boost, a little augmentation.

SPEAKER_00:

How old do muscles need to be then before they can produce eggs or sperm and complete the cycle?

SPEAKER_01:

Yeah, that's that's a good question. It's about probably in that three to five year window. Okay. So they got that's about how old they need to be. And the muscles, like if you look at some of these shells, you you can actually age them, kind of get a general age by looking like kind of like rings on a tree. So this one's a little harder to see, but like this big, this kind of big ridge right there, and then one here, that would be an annulus, or that's like the winter when there's slow growth, just like on a tree when you cut a tree and you try to age it. But you can see like one, two, three, and then four, and then it slows down growth a lot. That's because like it reached sexual maturity. So now it's probably putting more energy into creating the eggs, sperm, stuff like that. So it grows really most muscles grow pretty fast for the first couple years of their life, and then it slows way down.

SPEAKER_02:

Do these muscles produce uh pearls?

SPEAKER_01:

Uh they can, yes. And it's not like a pearl that you're, you know, beautiful, perfectly round pearl. It's just kind of a nugget of shell inside the shell. So it would just be like a little, a little bump on the inside of the shell. And honestly, people used to just harvest thousands and thousands of muscles and just cut them all open looking for freshwater pearls. And then they just cut them out and sell the freshwater pearls. Not good for the muscle, because once you cut them open, they're dead. Once if you've ever tried to open a muscle, they're really hard because they have muscles inside. The muscles are constricting and keeping them tightly closed from predators, other stuff. But once you open them, they're dead. They're not, there's no chance that they're going to survive after that. So, yeah, there was a huge industry in Indiana where people were just looking for freshwater pearls. So they were just collect thousands, open them all up, see if they could find one pearl out of, I don't know, a thousand mussels.

SPEAKER_02:

You know, but there were other industries that used these shells. Um, and I think you brought an example of button pearls. Button Yeah.

SPEAKER_01:

So if you're living back around 1900s, early 1900s, all your buttons on your shirt would have been made uh from a probably freshwater mussel shell. So basically what they do is they'd harvest the shells and then they would bore out um part of the shell. This would be like uh a blank, you know, that they would have cut out so one of these holes, like on a bigger muscle. And then they would just, you know, polish that up, put in the holes, you know, and you kind of get what a that's beautiful. What a muscle. This is one interestingly, this is from a looks like probably one of our purple inside species, which a lot of times they didn't use those, so that's kind of interesting. But yeah, so there's a huge industry for um the butt to make buttons from our muscles. It would be the thicker shelled species that you could actually cut you know this out of and then shine it up and use it. So yeah, we had freshwater pearls. Well, if you want to go way back, you know, Native Americans and people who lived here probably ate them, used them for tools, stuff like that. But then there was freshwater pearls, the button industry, and then after that was the cultured pearl industry, which they would the thick-shelled species, you'd cut down the shells into what looked like a little cube, then you'd grind down that cube that would look to look like a pearl. But then you would take that nucleus of a pearl and stick it actually in a pearl oyster. Some of the Asian countries would do that, and then uh leave it in there for a year or two, and then harvest that back out, and that's a cultured pearl. So the but the nucleus and most of that cultured pearl is just a piece of shell from like a muscle from the Midwest.

SPEAKER_02:

Oh my god.

SPEAKER_01:

So that was going on until in Indiana till 1991, and then to harvest that yeah, it's a really low water year. So many people were out collecting dollar bills off the bottom of rivers and streams, basically. You know, every muscle was worth some. Money that we had to put a stop to it. And we so we shut down the harvest of mussels in Indiana. So since 1991 till now, it's illegal to take a live muscle or even a shell of a muscle. So like if you're out canoeing and you happen to see a cool shell and you pick it up and put it in your pocket, take it home. Technically, you're that's illegal. Um you're not you're not supposed to do that. Um and I know some people still probably occasionally will see a live muscle on the edge, maybe take it, use it for fish bait, you know, use it for bait trying to fish or something. That would be illegal technically, too. So they are all of our muscles are currently protected from take.

SPEAKER_00:

We want to see them rebound in our streams.

SPEAKER_01:

Yeah. So, you know, start thinking about all these things that are adding up against muscles, right? We we had all these huge industries that took thousands and thousands. I mean, you we were talking earlier about seeing the pictures of guys sitting on top of these mounds of shell, you know, at a button factory, like the hundreds of thousands of muscles that were harvested to use for that. And then the culture pearl industry. Um, and then just think how they reproduce, you know, all the things that go could go wrong there. Um, you know, just start adding all these things up. It's not too surprising why a lot of our muscles are pretty rare. They're one of the more danger groups.

SPEAKER_02:

Humans have been predators of muscles. Do they have any natural predators?

SPEAKER_01:

Yes, for sure. This is a great year for uh mussels to get eaten. It's a really low water year. And muskrats are probably our large, you don't think a muskrat's always eating stuff like that, you know, think more plant material and stuff like that, but they for sure eat a ton of mussels. And they uh so muskrats will eat them, and river otters will occasionally eat them. And, you know, will a raccoon maybe eat one or something else. Yeah, but they're not like swimming out in the water, diving down, picking one off the bottom, bringing it back to the shore. They're they'd be more opportunistic. There's some birds, probably small ones. We have some fish that eat them as well. But yeah, the one shell on the table, and if you look close, you can actually see the scratch marks from the claws of whatever was trying to eat it, you know. So um, you can kind of get that. And I like I said, this year we did some surveys on the Wabash River, certain areas, thousands and thousands of shells that were in what are called middens. So middens are just piles of the shells that are kind of left over after an animal will eat them. And muskrats are notorious for leaving just huge piles of shells in one spot. They just seem to like to eat in the same spot, I guess, over and over. But they uh there were thousands and thousands of muscles that had gotten eaten this year. The low water, I guess it's just very opportunistic year, easy, easy food item.

SPEAKER_02:

So we've been talking about um muscles that are native to Indiana. Are there muscles that are invasive or not native to Indiana?

SPEAKER_01:

For sure. I'm sure most people by this point have heard of zebra mussels. In fact, every time I go talk about muscles, I think people we've done a really good job of educating people about the invasive, non-native zebra mussel. Because they were like, oh, zebra mussels are bad, right? Yeah, they are bad, but our native muscles are not bad. They're good. So the yeah, so we have zebra mussels, quagga mussels, uh, Chinese basket clam. Uh that's the genus Corbicula. It used to be called the Asian clam. They just changed that name recently to Chinese basket clam. That's another one. Um, and actually, there's a couple different species of that Chinese basket clam or the genus corbicula that are found in Indiana now. So those are the ones that are probably most known. And most people have I'm most people have heard of zebra mussels for sure.

SPEAKER_00:

But yeah, and those zebra mussels have caused some pretty big changes in our lakes here uh throughout northern Indiana and really throughout um most of the Midwestern United States. So the zebra mussel, as Brant was talking about before, like other mussels, it's a filter feeder, and in our lakes, it's eating a lot of the phytoplankton. So we've talked on this podcast before about the food chain in a lake, right? Where we've got the nutrients feeding the phytoplankton or algae, which are feeding the zooplankton, which are then feeding the little fish, the planktovores, and then the big fish, the pisovores. Well, the zebra mussels are eating one of those middle layers, the phytoplankton or the algae, and sort of pulling that out of the food chain, which then can starve some of those other layers. And zebra mussels are really, really, really good filter feeders. I don't know how they compare to some of our natives, but they can filter large portions of the water column in a lake every day, and they actually can shift the entire ecosystem. In in one way, they make the lake look clearer because there's less phytoplankton, there's less of the algae in the water. So the water will have will have more clarity, which some people will say, oh, well, that's great then. They came in, they cleared up the lake. Well, unfortunately, they're picky eaters. They like to eat some of our good types of phytoplankton, like diatoms, green algae. They don't like the bad type, which is the blue-green algae, cyanobacteria that can produce toxins. And so they have shifted our algae populations in some of our lakes towards more of the blue-green algae, which can produce toxins. Some of our lakes actually don't have zebra mussels yet. And so we've been doing some research on how many zebra mussels are in different lakes and looking at um at uh when they're starting to colonize some new surfaces. We'll put some samplers under people's piers in some different lakes. And so some of our lakes don't have zebra mussels yet. And so it gives a good opportunity to study the impact of zebra mussels in certain lakes throughout Casciasco County, which has good implications. I'm surprised that you still have lakes that don't have them in it. Yeah.

SPEAKER_01:

It doesn't take much, right, to move them around. I mean, you could unknowingly um by just moving a bucket of water or water in your live well of a boat from one to the other, could be moving thousands and thousands of the the larval form. So they they don't that you know, I we just talked a lot about how our native muscles reproduce. The zebra mussels, they don't need a host. So they just um they just they have uh just uh a floating velager or the the larval form that just can float in the water, doesn't need a host to live, and then it eventually settles out. So um that's why they've probably been moved around so much and much easier because you don't just have to move the adults, you could be moving the the larval form like crazy and not even know it. But yeah, it is surprising they're not in most lakes at this point because they are in well, I hate to say, but most lakes have public access. They are they are into most of those lakes. They're you can find them in the Wabash River, you can find them in a lot of our rivers and streams. They don't do as well in our rivers and streams, the flowing waters they do in the the non-flowing waters, they're in the entire stretch of the Ohio River along the Indiana border.

SPEAKER_00:

So yeah, they're pretty much throughout the state. And those zebra mussels not only compete with our native mussels for food, that same phytoplankton, um, but they will actually, I've I've seen reports of where they start to uh grow on our native mussel species and and start and they can actually grow over sort of the seam of where it opens, right? You want to talk about that a little bit, Brant? Like how can these non-native muscles cause problems for our native muscles?

SPEAKER_01:

Yeah, we've seen this happen uh in a lot of our natural lakes that we've looked at. So, yeah, so the zebra mussel will colonize any hard surface on the bottom of a lake or wherever they're living. Well, our native muscles that are buried in the bottom, they still have a part portion sticking out. And some of our lakes, you know, there's not a lot of other hard substrates, natural hard substrates in some of those lakes, other than the native muscle sticking out of the bottom of the substrate. So, yeah, and I I kind of always think too that our native, they're also filtering water to themselves. So they can kind of be filtering those velgures. I know they can be kind of almost sucking some of those zebra muscle velgers towards themselves. But anyways, yes, they they will attach to our native muscle, the shell of our native muscle, then they attach to each other, and they eventually just clog up the entire filtering system of our native muscle, the point where they can't filter water anymore to get food and oxygen, and they can't reproduce anymore, and it it literally just kills them in place. Yeah. We've seen that happen a lot of our lakes. There's several lakes that zebra muscles. There were native muscles in the lake, zebra mussels came in, and now there's really no native muscles in the lake anymore. Wow. So they don't only do all the stuff you just mentioned with water quality and other stuff, they can also just directly kill some of our native species of muscles.

SPEAKER_00:

No, our native species have a little more of a foothold than in our streams because as you were saying, the zebra mussels don't do as well in the streams. Is there non-native mussels also moving into streams that are causing problems for our native?

SPEAKER_01:

Well, so I mentioned the Chinese basket clam or Asian clam. It literally is in almost every stream in Indiana, even some of our smallest streams. It's not like the zebra mussel, it doesn't attach. It doesn't have those bissal threads. The abissal threads are what they use to attach to substrates. They just live in the substrate side by side with their native muscles. So it's a little less clear what impact they're having. And usually they can be found. There's uh uh Chinese basket clam, there's probably a lot of lakes around here too, but they're they're they're highly abundant, a lot of the rivers and streams. And so they're just sitting there next to our native muscle is filtering away, too. Um, usually food isn't necessarily an issue, but you know, think about a very rare muscle, the male's releasing sperm, and it's got to go past 10,000 Chinese basket clams filtering the water, you know, and then until it gets to finally to the female. So, you know, it could be interrupting in a lot of different ways, other than just competing for space and food. It can be competing that way too. So it's a little less well understood what impact they're having. Most people would say that they are invasive, you know, that they are having they're having some issue, but we see other streams where very good populations of native mussels side by side with tens of thousands of Chinese basket clams, too. So there's it's a little less understood exactly what impact they're having.

SPEAKER_02:

Much like the Lily Center, I've heard you say we do a lot of research and now we're addressing problems. How are you funded?

SPEAKER_01:

That's a great question. And so a lot of like a lot of the DNR division of fish and wildlife, a lot of the stuff we do with sport fish and other game species is funded through um federal dollars we get back. That's you know, small tax on if you go out and buy a uh you know, a gun or or a different tackle for fishing, and then all of our sales of fishing license, hunting license, trapping license. That's where almost most of the money comes, it funds that. But for what we do um in Indiana, we a lot of our funding we get federal money, but we need dollars to match the federal money that we get. So we've had a program around for a very long time. It's the uh uh Indiana Non-Game Wildlife Fund. And it used to be very easy. Um I assume most people have to pay state taxes at some point, probably. So there used to be a little eagle on the state tax form and said, hey, you want to donate and help non-game species in Indiana and just give us some of your refund, you know. And that was a great way, and it and it gave us a lot of money. But then I don't know, gosh, it's probably close 10 years ago now, they took that off the state tax form, and you had to do go to another form, and there's competing groups now to get your tax refund dollars. So the Indiana Non-Game Wildlife Fund, um, you know, we're we're really working to still make people aware of that. So we can get you can give a donation, you still give your tax refund, straight donations on our website. Um, but we use that uh as match to get federal dollars. So there's a program that's been in place since about 2000. It's a state wildlife and travel grants program, and that's money that gets pushed out to the states to help with work being done with species of greatest conservation need, which are all of our state listed species. So we have two categories like endangered, special concern is like a step down from endangered. So that that helps with all the work that's been done with our birds, species of greatest conservation needs of birds, mammals, uh, amphibians, reptiles, and then all the non-game aquatic stuff. So uh, you know, donations that fun just helps us get all those federal dollars.

SPEAKER_02:

So I could find like a donate now button on the DNR website.

SPEAKER_01:

We definitely, yep. Just go to our website and it's on there.

SPEAKER_02:

And so my contribution to that, um, you said that you use state dollars from donors to leverage federal dollars.

SPEAKER_01:

Yep.

SPEAKER_02:

Is it like a one-to-one match?

SPEAKER_01:

No, it's actually much better than that. So for most of the money that we get, it's uh state has to provide a 35% match. So 65% federal dollars almost.

SPEAKER_02:

Yeah, almost. That's that's good.

SPEAKER_01:

Yes, that's much better.

SPEAKER_02:

Because investing in things like the Lily Center for Lakes and Streams and the DNR work is so important because the we've learned through the Lake Doctor podcast, monocultures are bad, right? And you're addressing the breadth of m mussels in Indiana. Good stuff.

SPEAKER_00:

That's good, important work. Thanks.

SPEAKER_02:

We're really glad you were here today sharing all this wonderful information. And I I wish that our listeners would look to our YouTube channel so they could see these beautiful shells and this lovely mud puppy, mud puppy. Yeah. Fun stuff. Thank you so much for being here today, Brant. We really appreciate it.

SPEAKER_01:

No problem. I was glad to be here. Yeah, thanks, Brant.

SPEAKER_02:

Thanks for listening to this episode of the Lake Doctor Podcast. You can share your thoughts or submit a question by leaving a comment or sending an email to lakes at grace.edu.

SPEAKER_00:

Listening to this podcast is just the first step to making your lake cleaner and healthier. Visit lakes.grace.edu for more information about our applied research and discover some tangible ways you can make a difference on your lake.

SPEAKER_02:

Be sure to like and share this podcast. We'll see you next time the doctor is in.