Spring ice is thawing earlier in lakes. What does that mean for life below the surface?

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You're listening to shortwave. From NPR. Hi shortwaveers Emily Quang here with producer Burley McCoy and part two of her changing lake ice reporting. Don't worry if you haven't listened to the other episode. You don't need to. I appreciate this one. Definitely not Emily, but quick recap. Last episode we talked about how changing ice conditions are making it less safe to be on the ice,

which is true where I live in Montana. Not only have there been warm spells, which make the

lake ice less safe. This year ice wasn't safe enough to walk on until the second week of January.

Wow. And Emily, you know how much I love to ice fish. Yes, you live for ice fishing season. Burley. I know. And so far this year that's been really tough here. So I recently went on a nice fishing trip with a fisheries biologist named Zach Finer. Let's say I did see one guy catch one here yesterday, so they threw it back to the least one fish out there for us. Zach is in Madison, Wisconsin. Wait, you left your family in Montana to go fishing all the way in Wisconsin

in a heartbeat. There's just no commitment more serious. But really, I wanted to get on the ice with Zach to talk about how lakes everywhere are losing ice and the impact that that's having on like ecosystems from disrupting their food chains to lowering biodiversity, which could

have a huge impact on your fishing whale life. Exactly me and about 1.7 million other ice

fishers in the US. Ice fishing is a huge industry that generates millions of dollars through equipment sales and guide services. I talked to David VanLanan about how one of his favorite seasons ice fishing is shrinking. He grew up on a dairy farm south of Green Bay, Wisconsin, moved to Madison for work in 1971 and he says he's been fishing the area for decades. We've lost a good six weeks off of our ice fishing season since I started back in the 1980s.

We used to start in December and in April now we start in January and in March. Today on the show, how losing lake ice is affecting life below the surface. And what that means for ecosystems and people who enjoy them, you are listening to shortwave the science podcast from NPR. Support for NPR and the following message come from the William and Florida Hewlett Foundation, investing in creative thinkers and problem solvers who help people, communities and the planet

flourish. More information is available at Hewlett.org. Quick reminder everyone, surewave comes out

four days a week. That's Monday, Tuesday, Wednesday and Friday. So to make sure you never miss an episode,

look for the follow button on your podcast app and give it a tap. Thank you so much. Okay,

“Burley, let's get into this. How was this reporting trip to go fishing in Madison, Wisconsin?”

It was packed. Zach, pick me up at 5 a.m. Early bird gets the fish. I'm Burley. Can I throw my stuff in the back? Donuts are essential for ice fishing. They are essential. We drove about 15 minutes south to Lake Whatbysa to meet someone named Tom Sihosh. He's the big wildlife fisherman. He is the one who gave me the intel on this much. He's actually really great out there. Because I wanted to catch a

walleye. Is a walleye a fish? Yes, they are one of potentially dozens of fish that are sensitive to changing lake ice. Their populations are doing okay right now in a lot of places, but biologists like Zach are keeping an eye on them because they spawn in the spring. Oh, yeah, that's when ice usually melts. Exactly. And so a big part of what Zach tracks is that timing of the ice freezing and thine. And one of the parts of my research that has really jumped out is that

the timing at which the lake's thaw and the spring has gotten really variable. So for example, the earliest in recent years, the earliest of the lake has thought has been in the middle of March. And the latest lake has thought has been in the middle of May. So from one year to the next

“is the two months difference. That is a huge jump. What impact does that have on the fish?”

Yeah, Zach says it breaks down the normal process of what happens when a lake thaws. Can you describe that process? Yeah, it's kind of a domino effect. So in springtime, when a frozen lake starts to get more sun and warmer temperatures, that kick starts algae blooms in the water, that feeds little critters called zooplankton. And those zooplankton are a really important

it messes up the whole system. All those events start to get scrambled up in this time.

So then your food web gets de-linked or decoupled. And ultimately you end up with not having

enough food around the feed, small fish. Zach's research has shown that in years with huge swings and when the lake thaws, they don't count as many young wallize the next fall. So you were of them are surviving. Wow. And the more that happens, eventually the less wallize

“there will be for people to catch and take home. And the important thing to point out is that”

while I've seen this in wallize, lots of other species are seasonal spawners. They spawn in the spring or in the fall. So you could see these effects probably happening for a lot of different species. You know what I'm thinking about for some reason, listening to us? Okay, my cat is so sensitive to

the slightest changes in dinner being served by a half hour. Like, and if it were a difference

of months for his life cycle. Sure, Zuko, it's crazy. Yeah, yeah, I hope I'm not making a false comparison here. It's just like, I'm appreciating there's so much sensitivity for these species that a difference that could seem small to us is actually life or death to them. Yeah, especially if the food is just no longer there anymore. And this is true for lakes outside of Madison as well. Scientists are really just kind of starting to study this.

So in our last episode, we talked about how many lakes have already lost weeks of ice coverage each winter season. And thousands are predicted to stop forming ice entirely before the end of the century. And these are lakes where the ecosystems have evolved to be icy in the winter. Yeah, I've been wondering about this ever since your last story. What is the ecological impact for organisms that have adopted to live in an icy lake? Yeah, I mean, while I are this

cool water species that could really suffer in the coming years as the climate continues to warm. And they're one of many where this could happen, right? I really wanted to experience being on a walla lake while they're still around and doing okay. So back at Lake Wabiso, we unloaded the fish and gear from the car in a neighborhood cold asack with just one house near the end of the road. I added three here, I've got joys of urban ice fishing. I followed Zach through the dark

to a tall chaneling fence next to the house while he pulled the sled that had all the gear in it. After a few minutes, the tree lined path opened up to a dark open experience with one green

“light in the distance. This is tall. Yep, I think so. How great Gatsby of you. What was the green light?”

The head lamp. So we had our head lamp saw and we walked out onto the lake. I've heard. I'll see your face with all the spotlight in my eyes later. No, no, everybody's going. All the cool kids are wearing that. Yeah, Zach sets up his insulated pop-up tent and drill some holes in the ice to fish through. We've got some electronic machines to help us out. One is so nah that can tell you something is moving in the water and where

another is an underwater camera. Both of these things help you find fish. So I'm picturing all standing in the dark on this icey lake and there's a line down in the hole and you're like waiting. We're watching the sonar because it looks like there's something down there. Does it look like it's still there? It doesn't, unfortunately, it's problem with fish they move. But eventually, there's

“we're going to find out. Got one. Yep. Blue gills. Oh, a blue gills fish, so not a walleye?”

A blue gill. Yeah, not a walleye. Zach's blue gill are a warm water fish and one that will probably do better in waters like these as climate change continues. So I take the fishing pool,

I give it a try. Oh, you see, new species. Oh, okay. I've never thought it'd be before.

Crapy, not a bad word, just a different type of fish. Also a warm water fish, actually. And oh, now as an avid ice fisher, I'm always looking for reasons why I'm not catching the fish that I want to catch. So I ask Zach if changing ice from year to year could be the reason we're not seeing walleye today. It could be one of the reasons why. Yeah, yeah. I mean, it's uh, it's tough. There's a lot of lakes where, um, walleye have declined really significantly. And

now the only reason they're walleye in there is because we have to stock them. Oh, stalking. Yes, I learned about this the one time I've, I went ice fishing and main. Stockings where humans are putting young fish in the lake. Yeah, often thousands to keep up their numbers. It's done for conservation and for people like me who like to fish. And it happens in a ton of places, including the lake, I fish in the winter. Now Zach says the question becomes, when do people stop stocking? If a lot

them in a lake that isn't habitable for them? Right? Like if ice keeps shifting rapidly and significantly

“knocking down walleye populations, how long should people continue adding them back? And maybe for”

example, switch to supporting warm water fish that people like to catch that would thrive in these warmer waters. If you have this traditional connection to walleye, maybe that's a harder change to, to accept or to deal with. This would be a big change for the fishing community to ask someone to do something that they've done their whole life differently. I guess climate change asks that of all of us. Does that have any idea though how people are going to handle going

“for warm water fish instead of these cold favorite? Yeah, he says through surveys, he's found people”

have definitely noticed a change in lake ice, which is a big first step to get people to think about

then how to make changes. When you're faced with what to do about climate change, especially regard to like fish or other things, like it's hard to to control the amount of a carbon in the atmosphere, right, at the local level. But you can think about the things you can control. Maybe that means you make different harvest decisions. You keep fewer walleye, maybe decide

“to go fish for something else, right? That might be more resilient to harvest, like a”

large amount of that sort of bluegeal that are more of a warm water fish.

This story is reminding me how people who fish and people who hunt are actually paying often more attention to the environment than most. So it's cool to be hearing this from them directly, you know? Yeah, that's so true. And Zex says it may also get people to think about what else they can do to help lake systems like protecting the habitat that's certain fish like like walleye. As for you, Fisher Burley, did you ever get any walleye? I did, but

not the way I wanted. I'll have the fried walleye. You got one served to you a different way. On a point, I did. It was lovely. It was delicious. I had it with some fried cheese curds. So no walleye, I'll just have to go back and maybe it'll be for a different kind of fish. If you liked this episode, do us a favor and share it with a friend, because your vote of confidence is actually what ensures we can keep making this program. I also suggest you check out

part one of Burley's changing lake ice series and gorgeous photos from Burley's fishing trip. We will link to them both in our show notes. This episode was produced by Rachel Carlson, edited by our showrunner Rebecca Ramirez, and fact check by Tyler Jones. The audio engineer was Quaci Lee. I'm Emily Quang, and I'm Burley McCoy. Thank you for listening to shortwave from NPR. Support for NPR and the following message, come from the William and Flora Hewlett Foundation,

investing in creative thinkers and problem solvers who help people, communities, and the planet flourish. More information is available at Hewlett.org.