Green Bay is kind of like the land of milk and honey for lake whitefish in Lake Michigan. Commercial fishermen reel in nets and nets of the iconic silver fish all season long. Whitefish are thriving, stable even. But that’s not the case in huge swaths of Lakes Michigan and Huron, where the species is collapsing.
So, what’s going on in Green Bay? Whitefish are likely benefitting from nutrient runoff — phosphorus flowing into the bay from nearby farms and cities.
Should we be trying to replicate those conditions everywhere else to save the species? Should we fertilize the lakes?
Credits:
Host/Producer: Ellie Katz
Editor: Morgan Springer
Additional Editing: Dan Wanschura, Peter Payette, Claire Keenan-Kurgan
Transcript:
ELLIE KATZ, BYLINE: This is Points North, a podcast about the land, water and inhabitants of the Great Lakes. I’m Ellie Katz in for Dan Wanschura.
It’s a perfect evening along Green Bay. 75 degrees. The water's calm. Sun’s starting to set. Fire’s crackling. Cheryl and Ron Stern are on vacation in this cute little Wisconsin town.
KATZ: Tell me about your time in Wisconsin. Like, have you always come to Ephraim? Or do you mix it up?
CHERYL STERN: It's Ephraim.
KATZ: Ephraim. Thank you.
RON STERN: You’re welcome. We'll be here to help you.
KATZ: Ephraim is on the Door Peninsula, which juts out from mainland Wisconsin. It’s like a bony pinky finger between Green Bay and the rest of Lake Michigan. The Sterns drove up from their house in the Chicago suburbs. They’ve been coming for decades. And there’s one thing they never miss here, a Door County classic — the fish boil.
KATZ: So how many fish boils have you been to?
CHERYL STERN: Forty.
KATZ: Forty fish boils?!
CHERYL STERN: Yeah. This one.
RON STERN: Every year. It's a must. If you come to Door County, at least our rule, Cheryl and Ron’s rule, gotta do a fish boil.
KATZ: Here we are.
RON STERN: Here we are!
KATZ: So Cheryl and Ron are kicking back, waiting for the boil to start. But just a few feet away, there’s a guy running around in a frenzy covered in soot and sweat.
JEREMY KLAUBAUF: My name is Jeremy Klaubauf, and I am the boil master at the Old Post Office Restaurant in Ephraim. And everybody calls me “Torch.”
KATZ: Jeremy aka “Torch” mans this giant cauldron (it’s actually an old washing machine drum in this case), and it’s perched on top of a bonfire. First step of the fish boil: Fill it up with water.
KLAUBAUF: Soon as the water starts boiling, you get the potatoes in. They go in for the full half an hour. These go in next.
KATZ: Just a bunch of peeled onions.
KLAUBAUF: It’s a bunch of peeled onions.
KATZ: A huge bucket of peeled onions.
KLAUBAUF: Huge bucket. Yes, they soak up all the butter.
KATZ: After the onions comes the key ingredient: the fish, which Torch has stowed away in the kitchen until more people arrive.
KLAUBAUF: They're called Lake Michigan whitefish. Lake whitefish. Right now, yeah, we can always get them fresh. We never use frozen. We never have to get them from Lake Superior or anything like that. We can always get them right from our own local fishermen up here.
KATZ: Those whitefish — the foundation of the fish boil — are getting harder and harder to come by in other parts of the Great Lakes. Whitefish are on the verge of collapse in most parts of Lake Michigan and Lake Huron. But here in Green Bay, whitefish are thriving, stable. Stable enough for Torch to do his fish boil spiel three times a night, every night, all summer.
KLAUBAUF: Alrighty. How we doin’ tonight, everybody?
KATZ: Green Bay is like the land of milk and honey for whitefish, where old traditions around the fish are still intact.
KLABUAUF: How do they look?
WOMAN: Gorgeous.
KLAUBAUF: Beautiful. Keep her movin’.
KATZ: And you can get those fish right from your own backyard.
KLABAUF: Get your cameras ready. I will chuck the kerosene in, and that's it. You guys can go inside and eat. Alright, this looks pretty good. You ready? 1,2,3. Oh, yeah!
KATZ: But here’s the weird thing: Green Bay is actually pretty polluted. So what the heck is going on with whitefish there? And should we be trying to replicate it elsewhere? That’s after the break.
KATZ: Lake whitefish are part of Anishinaabe creation stories. And tribes have been catching them since they arrived in the Great Lakes region thousands of years ago. Those silver schools of fish were part of what drew white settlers.
KATZ: Commercial fishermen, both white and tribal, reeled in net after net of the humpbacked fish across the Great Lakes. Whitefish were delicious, mild. They became the key ingredient of things like fish boils and fish fries in the Midwest, and they also got shipped across the country. In the 90s, whitefish started going nuts. And for years, it seemed like they were doing well everywhere.
SCOTT HANSEN: It was just kind of like, “Oh, wow. This is great.”
KATZ: Scott Hansen is a fisheries biologist for the Wisconsin Department of Natural Resources. He works on the Door Peninsula.
HANSEN: We've got things going on on both sides of the Door County peninsula that are really …happening for whitefish. Until about a decade ago.
KATZ: About a decade ago, it became clear that something was changing with whitefish out in the open waters of Lake Michigan and Lake Huron. It started getting really hard to find baby whitefish. This spot along the Door Peninsula was one of the most vibrant spawning areas in all of Lake Michigan. And almost all of a sudden, there was no new generation of whitefish. It took a while to figure it out, but the main thing destroying these baby whitefish was invasive quagga and zebra mussels.
VAL KLUMP: Well, the Great Lakes are big environments, and yet quagga mussels moved in a period of about two generations.
KATZ: This is Val Klump. He’s a former dean at the School of Freshwater Science at University of Wisconsin-Milwaukee.
KLUMP: So it really, you know, it just dramatically changed the system.
KATZ: By the mid-2000s, mussels carpeted the bottom of Lake Michigan and Huron.
KLUMP: And because they're such efficient filter feeders, they've stripped everything out of the water column.
KATZ: Here’s what happened. Instead of nutrients floating around in the water column, the mussels started slurping them up and locking them down at the lakebed — where nothing could get to them. Nothing like plankton, essentially the base of the food chain in the Great Lakes. Young whitefish out in the open waters of Lake Michigan suddenly had no food to eat, and they were dying. But on the other side of the Door Peninsula, in Green Bay, things for whitefish just kept getting better, which was ironic. Scott Hansen again.
HANSEN: Green Bay, over the last century, was not really the place where you would expect white fish would be doing really well– would be their kind of their refuge, so to speak. It is now.
KATZ: Commercial fishermen started setting their nets in Green Bay more and more. And then things got even weirder: they started catching even more whitefish in southern Green Bay. Which is surprising because it’s marshy, it’s shallow, it’s kinda warm and, historically, it’s been pretty polluted.
HANSEN: That's not whitefish. Whitefish are more associated with colder waters, deeper waters, clearer waters, more like we have on Lake Michigan.
KATZ: As Scott told me: No self-respecting whitefish should be in southern Green Bay. But there they were. Now, to be clear, scientists aren’t exactly sure why Green Bay has become a refuge. But there’s one pretty likely piece of the puzzle: The bay is clogged up with nutrient pollution.
KLUMP: The main nutrients coming in are really nitrogen and phosphorus.
KATZ: Nitrogen and phosphorus – two building blocks for life on earth – but kind of hazardous if there’s too much of them. Green Bay is long and skinny. And at the very bottom, it’s fed mainly by the Fox River.
KLUMP: A third of the total nutrient load to the Lake Michigan system enters into Green Bay from the lower Fox River.
KATZ: You got that? Almost a third of all the nutrients flowing from rivers into Lake Michigan come through the Fox River.
KLUMP: They're mostly from, well, from runoff. So, it's farm fields, urban streets.
KATZ: Fertilizers, cow poop, private septic — those kinds of things. They wash into the Fox River and other tributaries and come flowing into the bay, where they get trapped.
KLUMP: Particle trap and nutrient trap, so most of that material stays in the bay and doesn't make it to Lake Michigan.
KATZ: And nutrients in the lake — they’re like sugar. Without them, things can’t grow. In most of Lake Michigan and Huron, a lot of that sugar is crusted along the bottom where nothing can get to it. But, in Green Bay, there’s a firehose of sugar constantly pumping in. Enough of it, and you feed life. But too much of it, and you suffocate life.
HANSEN: It is quite a paradox, isn't it? And it is a double edged sword, for sure.
KATZ: It’s not like southern Green Bay is some Goldilocks zone, with just the right amount of nutrients to feed all the fish and the mussels and still keep the water clean. It’s out of balance. Scientists say there are way too many nutrients.
KLUMP: If you spend any time in the lower bay, water quality there is not great, the swimming beaches are not great.
KATZ: Every now and then the water turns green. And the whitefish caught there are generally safe to eat, but DNR advisories say only once a month. You sometimes get big algal blooms and huge dead zones with no oxygen. Those kill fish or force them to go somewhere else for a while. But, so far, whitefish seem to have adapted. They’ve made it work.
HANSEN: They're going where there's food: Fox River, southern Green Bay. Having somewhere to get enough food to sustain them, because it's likely not happening in much of the rest of Lake Michigan proper.
KATZ: The sun’s just starting to rise. And Will Henriksen is out on his fishing boat in southern Green Bay. There’s a little iridescent circle in his long beard, shimmering almost like a sequin.
KATZ: You've got a scale in your beard. It's a very poetic moment.
WILL HENRIKSEN: I always get asked, “What do you do for your beard?” “Just fish oil.” And people are like, “Wow! That really works?” And I’m like, “Well, when you’re a commercial fisherman, that’s about all that gets in it.”
KATZ: Ah, that’s great.
KATZ: Will’s been fishing off the Door Peninsula since he was a little kid, which means a lot of early mornings, a lot of Mountain Dew, and a lot of fish slime and fish scales flying around.
COAST GUARD RADIO: Radio check loud and clear. This is Coast Guard central Lake Michigan. Over.
KATZ: There's a little bit of a breeze, but the water’s pretty calm. Will and three other guys start hauling in a huge net.
(sounds of net being hauled in mechanically)
KATZ: They hold the mesh open and use handheld nets to scoop out the whitefish swimming inside.
(sounds of fish being tossed in buckets)
HENRIKSEN: This is actually a pretty good net.
KATZ: The whitefish that are big enough to keep will go on ice and eventually get delivered to customers across Door County. And once they’re done with that net:
HENRIKSEN: We just slide back out from underneath it where we started, and next thing you know, it refills with fish.
KATZ: Hopefully.
Will says they fish out on southern Green Bay a lot more than they used to. It’s just where the fish are. And when he talks to fishermen from other parts of the Great Lakes, they wanna know about Green Bay and why there’s still fish there. There’s one question he always hears:
HENRIKSEN: If there's ways that it's possible to possibly manufacture some of the water qualities that we have in southern Green Bay.
KATZ: Manufacture Green Bay water somewhere else, so whitefish can thrive in other parts of the lake again.
Scott Hansen, the fisheries biologist, gets a lot of the same questions: Why is Green Bay still hanging on? How can we replicate it everywhere else? It feels a bit like being under a microscope, he says.
HANSEN: What's happening or happened in Green Bay has been a dream for a fish biologist, while at the same time watching exactly the opposite thing let the air out of that balloon in Lake Michigan, right? And knowing that there's not a lot you can do about it.
KATZ: The main thing scientists are trying to figure is out how to control the mussels. But they haven’t gotten there yet. So, there’s a wonky other option. If we can’t unlock the nutrients from the bottom of the lake, can we just… put them in ourselves? Can we fertilize the lakes in places where whitefish are disappearing, in the same way Green Bay essentially does? Has anybody tried it?
KLUMP: Not to my knowledge, but it has been done in the ocean.
KATZ: Freshwater scientist Val Klump again.
KLUMP: So years ago, there was an experiment called the iron experiment.
KATZ: Like phosphorus in the lake, you gotta have iron to grow stuff in certain parts of the ocean. But scientists had a different goal for the ocean: they wanted to see if they could use iron to trap carbon dioxide. So they tried fertilizing a small patch. The idea was that iron fertilizer would cause a bloom of plankton — the base of the ocean food chain. Those plankton would suck up carbon dioxide: taking it out of the atmosphere. And then, hopefully, they’d die and sink to the ocean floor, locking the carbon there.
KLUMP: They sprayed a solution of iron.
KATZ: In a small patch on the surface of the Southern Ocean. And then they watched it. And they were right that plankton bloomed. But whether they actually sank to the bottom full of carbon, and kept that carbon there, was more questionable. There have actually been several experiments like this over the years, all with the goal of sequestering carbon. All with mixed results and questionable side effects. The UN actually put a moratorium on ocean fertilization in 2008, except for small scientific studies. These experiments are controversial for the same reason fertilizing the lakes is.
KLUMP: You don't know what would happen. What would you do? What would happen if you were to stimulate— you don’t know what the consequences might be.
KATZ: There’s this whole laundry list of theoreticals we just don’t even know about. Like we aren’t even 100% sure that adding fertilizer would beef up the base of the food chain. A lot of it could just go into what Val calls an ecological dead end.
KLUMP: It goes into algal production. It doesn't enter the food chain.
KATZ: Creating more of those big algal blooms and dead zones. Or even if it didn’t do that, would the mussels just win anyway? Sucking it all up?
KLUMP: Would we just feed that system more?
KATZ: Or would we undo decades of cleaning up runoff just to maybe benefit a few fish species? Overall, water quality in the Great Lakes has gotten way better.
KLUMP: I would be reluctant to say, “Well, let's loosen the tap now and let more phosphorus get into the system.”
KATZ: For scientists like Val, and for Scott at the DNR, there are just too many unknowns.
HANSEN: At the scale of Lake Michigan and the Great Lakes, it’s pretty hard to imagine. It really is. As a fisheries biologist, it doesn't seem reasonable.
KLUMP: Yeah, we just don't know enough to play God. That's the bottom line.
KATZ: Or at least we don’t know enough to try to play God. We’d just be turning random dials in an ecosystem that’s already out of balance.
KLUMP: No, no. That's a bad idea. We just have to accept the system that we have, and let Mother Nature control it, rather than try to manipulate it ourselves.
KATZ: But in accepting what we have, whitefish — this iconic native species of the Great Lakes — might disappear even more. Green Bay is a land of milk and honey for whitefish right now.
HANSEN: It's still good. I would just say there's some cracks in the armor starting to develop.
KATZ: Like, climate change is messing up ice cover and water temperature. That could knock out Green Bay’s whitefish. Or something else we don’t even know about yet. There’s only so much they can adapt to.
HANSEN: What really concerns me right now is that Green Bay may very well be following the same trajectory. It just was delayed.
KATZ: For Scott, who’s worked with lake whitefish for over 20 years, who knows the whitefish that have carved out a living in Green Bay — it hurts.
HANSEN: I've grown old with some of these white fish. Yeah. When I hold them, to know that they are— that they have held on longer than a lot of other native species in Lake Michigan have, and are still holding on, and they're still doing their best to survive … I guess it's just a lot of admiration for the fish, for the resiliency of the fish, the adaptability. But that only goes so far.
KATZ: Instead of trying to bring whitefish back to the rest of the lakes, we might just have to settle for meeting them where they are.
(sounds of restaurant)
SERVER: So for bread, we have lemon, pumpkin, and marble rye bread. On the table we have malted butter and Curt's seasoning. It's really good on the potatoes and fish. Don't be shy. And you might find a little bones, not so many, okay.
KATZ: I like it, keeping it rustic.
KATZ: At the Old Post Office Restaurant in Ephraim, Wisconsin, I finally get to try some Green Bay whitefish.
KATZ: A squeeze of lemon. I’m going in for the first bite. Yeah, that's really good. Just a nice, mild, flaky fish. I don't know, it's just whitefish. It's just whitefish. Pretty awesome — eating a plate of white fish staring out at Green Bay.
