Pod Insights Short Wave Spring ice is thawing earlier in lakes. What does that mean for life below the surface? About this episode Lakes are freezing later, thawing earlier and experiencing dramatic temperature swings in between. And all that throws off the delicate balance of life below the surface. And that has a major impact on the roughly 1.7 million ice fishers in the U. S. who spend millions of dollars buying equipment and guide services each year. Producer Berly McCoy https://www.npr.org/people/985775371/berly-mccoy explains how scientists are tracking those ecological changes by getting out on the ice — to fish.
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0:19 Emily Kwong? You're listening to Short Wave from NPR.
0:24 Emily Kwong? Hi, Short Wavers. Emily Kwong 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 to appreciate this one.
0:36 Speaker 02 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.
0:54 Emily Kwong? Wow.
0:54 Speaker 02 And Emily, you know how much I love to ice fish.
0:57 Emily Kwong? Yes, you live for ice fishing season, Burley.
1:00 Speaker 02 I know. And so far this year, that's been really tough here. So I recently went on an ice fishing trip with a fisheries biologist named Zach Finer.
1:08 Speaker 03 We'll say I did see one guy catch one here yesterday. So they threw it back. So there's at least one fish out there for us. But.
1:16 Speaker 02 Zach is in Madison, Wisconsin.
1:19 Emily Kwong? Wait, you left your family in Montana to go fishing all the way in Wisconsin?
1:23 Speaker 02 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 lake ecosystems, from disrupting their food chains to lowering biodiversity.
1:38 Emily Kwong? Which could have a huge impact on your fishing way of life.
1:42 Speaker 02 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 Van Lannan 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.
2:07 Speaker 04 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, end in April. Now we start in January, end in March.
2:21 Emily Kwong? 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 Short Wave, the science podcast from NPR.
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3:42 Emily Kwong? Quick reminder, everyone. Short Wave 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 picked me up at 5:00 AM. Early bird gets the fish.
4:08 Speaker 02 I'm Burley.
4:12 Speaker 02 Can I throw my stuff in the back?
4:15 Speaker 03 Some donuts.
4:17 Emily Kwong? Donuts are essential for ice fishing.
4:19 Speaker 02 They are essential. We drove about 15 minutes south to Lake Wabisa to meet someone named Tom Seehash.
4:26 Speaker 03 He's a big walleye fisherman. He is the one who gave me the intel on this spot and he's actually probably already down there.
4:34 Speaker 02 Because I wanted to catch a walleye.
4:37 Emily Kwong? Is a walleye a fish?
4:38 Speaker 02 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.
4:52 Emily Kwong? Oh, yeah, that's when ice usually melts.
4:54 Speaker 02 Exactly. And so a big part of what Zach tracks is that timing of the ice freezing and thawing.
5:00 Speaker 03 And one of the parts of my research that has really jumped out is that the timing at which the lakes thaw in the spring has gotten really variable. So, for example, the earliest in recent years, the earliest the lake has thawed has been in the middle of March. And the latest the lake has thawed has been in the middle of May. So from one year to the next, it's a two month difference.
5:23 Emily Kwong? That is a huge jump. What impact does that have on the fish?
5:27 Speaker 02 Yeah, Zach says it breaks down the normal process of what happens when a lake thaws.
5:31 Emily Kwong? Can you describe that process?
5:32 Speaker 02 Yeah, it's kind of a domino effect. So in springtime, when a frozen lake starts to get more sun and warmer temperatures, that kickstarts algae blooms in the water that feeds little critters called zooplankton. And those zooplankton are a really important food source for some fish. But if there are these massive differences in when spring starts, it messes up the whole system.
5:54 Speaker 03 All those events start to get scrambled up and mistimed. So then your food web gets delinked or decoupled. And ultimately, you end up with not having enough food around to feed small fish.
6:04 Speaker 02 Zach's research has shown that in years with huge swings and when the lake thaws, they don't count as many young walleyes the next fall. So fewer of them are surviving.
6:13 Emily Kwong? Wow.
6:14 Speaker 02 And the more that happens, eventually the less walleye there will be for people to catch and take home.
6:19 Speaker 03 And the important thing to point out is that while I've seen this in walleye, 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.
6:30 Emily Kwong? You know what I'm thinking about for some reason, listening to this? Okay, my cat is so sensitive to the slightest changes in dinner being served by a half hour, like.
6:42 Emily Kwong? And, and if it were a difference of months for his life cycle.
6:47 Speaker 02 I'm sure Zuko would scream.
6:48 Emily Kwong? Yeah, yeah. I hope I'm not making like 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.
6:59 Speaker 02 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.
7:25 Emily Kwong? Yeah, I've been wondering about this ever since your last story. What is the ecological impact for organisms that have adapted to live in an icy lake?
7:33 Speaker 02 Yeah. I mean, Walleye 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 Walleye lake while they're still around and doing okay. So back at Lake Wabisa, we unloaded the fishing gear from the car in a neighborhood cul-de-sac with just one house near the end of the road.
7:56 Speaker 03 We're headed through here to the joys of urban ice fishing.
8:00 Speaker 02 I followed Zach through the dark to a tall chain-linked 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 expanse with one green light in the distance. This is Tom?
8:16 Speaker 03 Yep, I think so.
8:17 Speaker 02 How Great Gatsby of you. What was the green light? This is a headlamp. So we had our headlamps on. We walked out onto the lake.
8:26 Speaker 06 Early? I'll see your face without a spotlight in my eyes later.
8:31 Speaker 02 Oh, yeah, sorry about that.
8:32 Speaker 06 No, no, everybody's got one. All the cool kids are wearing them.
8:35 Speaker 02 Yeah. Zach sets up his insulated pop-up tent and drills some holes in the ice to fish through.
8:44 Speaker 02 We've got some electronic machines to help us out. One is sonar that can tell you if something is moving in the water and where. Another is an underwater camera. Both of these things help you find fish.
8:54 Emily Kwong? So I'm picturing you all standing in the dark on this icy lake, and there's a line down in the hole. And you're like, waiting?
9:00 Speaker 02 We're watching the sonar because it looks like there's something down there.
9:05 Emily Kwong? Does it look like it's still there?
9:09 Speaker 03 It doesn't, unfortunately. That's the problem with fish, they move.
9:13 Speaker 02 But eventually.
9:18 Speaker 03 We're gonna find out. Got one.
9:24 Speaker 03 Yep.
9:26 Speaker 03 Bluegills.
9:28 Emily Kwong? Oh, a bluegill's fish, so not a walleye?
9:32 Speaker 02 A bluegill, yeah. Not a walleye. Zach's bluegill 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 pole, give it a try.
9:45 Speaker 07 Hey, game on. Fish on.
9:49 Emily Kwong? All right.
9:49 Speaker 07 Crappy. New species.
9:51 Emily Kwong? Oh, OK. I've never caught a crappy before.
9:54 Speaker 02 Crappy, not a bad word, just a different type of fish. Also, a warm-water fish, actually. And 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.
10:13 Speaker 03 It could be one of the reasons why, yeah, yeah. Yeah, I mean, it's, uh, it's tough. There's a lot of lakes where walleye have declined really significantly. And now the only reason they're walleye in there is because we have to stock them.
10:27 Emily Kwong? Stocking, yes. I learned about this the one time I went ice fishing in Maine. Stocking's where humans are putting young fish in the lake.
10:35 Speaker 02 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 of those fish are just gonna die.
10:53 Emily Kwong? Right, like, are you setting them up for doom if you're putting them in a lake that is inhabitable for them?
10:58 Speaker 02 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.
11:13 Speaker 03 If you have this traditional connection to walleye, maybe that's a harder change to to accept or to deal with.
11:18 Emily Kwong? 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 Zach have any idea, though, how people are going to handle going for warm water fish instead of these cold favorites?
11:34 Speaker 02 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.
11:44 Speaker 03 When you're faced with what to do about climate change, especially with regard to like fish or other things, like it's hard to control the amount of like 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 you decide to go fish for something else, right? That might be more resilient to harvest, like a largemouth bass or a bluegill that are more of a warm water fish.
12:09 Emily Kwong? 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?
12:19 Speaker 02 Yeah, that's so true. And Zach says it may also get people to think about what else they can do to help lake systems, like protecting the habitat that certain fish like, like walleye.
12:29 Emily Kwong? As for you, fisher burly, did you ever get any walleye?
12:34 Speaker 02 I did, but not the way I wanted. I'll have the fried walleye.
12:42 Emily Kwong? You got one served to you a different way, on a plate?
12:45 Speaker 02 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.
13:00 Emily Kwong? 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 Burleigh's Changing Lake Ice series, and gorgeous photos from Burleigh's fishing trip. We will link to them both in our show notes.
13:19 Speaker 02 This episode was produced by Rachel Carlson, edited by our showrunner Rebecca Ramirez, and fact-checked by Tyler Jones. The audio engineer was Kwesi Lee.
13:28 Emily Kwong? I'm Emily Kwong.
13:29 Speaker 02 And I'm Burleigh McCoy.
13:30 Emily Kwong? Thank you for listening to Short Wave from NPR.
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