Fish Fry Day: How Do Fish Live Under the Ice?

While we’ve been spared (so far) by any sort of climate shenanigans like a polar vortex this winter, our lakes have had a nice thick cover of ice on for a month or more. And lots of people send in variations of the question – what’s life like for a fish under the ice?

Bluegill congregate under the ice of Long Lake in Minnesota. Photo: Fargo-Moorhead Dive News

Bluegill congregate under the ice of Long Lake in Minnesota. Photo: Fargo-Moorhead Dive News

Well, the short answer is “Not much different than the rest of the year.” They eat and breathe and try to avoid becoming lunch.

But there are some interesting elements to winter life, so we asked CFL grad student, Alex Latzka to help explain. Continue reading

Field Samples: Spiny Water Fleas, Lake Mendota, and Green Water

Field Samples is a weekly Q&A asking researchers what they’ve been up to and what they’ve learned. Today, CFL grad student, Jake Walsh, talks Lake Mendota and the invasive spiny water flea.

Who are you, where are you from, and how did you get to where you are now?

Jake Walsh taking a sediment core on Lake Gogebic on the Wisconsin/Michigan border. Photo: Jake Walsh

Jake Walsh taking a sediment core on Wisconsin’s Gile Flowage. Photo: Carol Warden 

I’m Jake Walsh, a PhD student with Jake Vander Zanden. I love watching the Minnesota Timberwolves play basketball (or what they’re passing for basketball now-a-days), playing tennis, long walks through my cruddy neighborhood with my wife and dog, and the occasional video game binge.

I’m from Hastings, MN (smaller town on the Mississippi south of St. Paul) and I got my BS in Biology at Hamline University in St. Paul. I got addicted to getting paid to go out boating while doing research with Dr. Leif Hembre at Hamline University. We were doing research on spiny water fleas’ effect on Daphnia’s stress response (elevated heart rate) and some genetics work on trying to track SWF’s movement across the Great Lakes Region.

This got me interested in

1) figuring out how I can get paid to enjoy lakes

2) how I make a career out of obsessing over zooplankton (I have since expanded my interests pretty substantially), and

3) how I can help provide insights into the problems posed by invasive species which naturally lead me to Jake Vander Zanden’s lab here at the CFL.

It wasn’t until I came and visited the CFL that I found out that SWF had invaded the lake in 2009. I swear that I had nothing to do with it. Continue reading

Fish Fry Day: Fish Move as Oceans Warm

It’s Fish Fry Day, when Wisconsin puts fish on the menu and we serve up some delectable fish facts on our blog.

Friday Night Fish Fry. Photo:

Friday Night Fish Fry. Photo:

Today we want to point you toward a Q&A with a National Oceanic and Atmospheric Administration fisheries scientist who is trying to track where fish move as ocean waters warm.  In case you expected something more literally limnological (you know, those inland waters and all) the article does remind us of work our own Jim Kitchell is involved in exploring what’s happening to fisheries in the most rapidly warming lake on Earth – Lake Superior.

But, if you don’t mind some seafood on your plate…

Making the Connection Between Climate and Fisheries: An Interview with NOAA Fisheries scientist Jon Hare


Jon Hare with a video plankton recorder—which measures the distributional patterns of live plankton. Credit: NOAA

As the climate changes and the oceans warm, fish populations are moving in search of cooler waters. That is part of the reason why New England fishermen have been catching black sea bass and longfin squid in the Gulf of Maine in recent years, far north of the animals’ usual range. In other places, it’s the absence of a species that’s notable. Just ask lobstermen in the Long Island Sound, who have had little to catch since the range of this valuable species that once supported them shifted north in recent decades.

These changes present a number of challenges both to fishermen, who might need to adapt their business strategies, and to fishery managers, who need reliable information to set sustainable fishing levels.

Jon Hare is the director of the NOAA’s Northeast Fisheries Science Center Laboratory in Narragansett, Rhode Island, and he studies how physical conditions in the ocean affect fish populations. Hare is a fisheries oceanographer, and his work straddles two disciplines. “When I’m with fisheries people, I’m the oceanographer,” he says. “And when I’m with oceanographers, I’m the fisheries guy.” Keep reading –>

Q&A Article by Rich Press, NOAA Fisheries science writer

Center for Limnology on YouTube

Just in case you didn’t know, the CFL is on YouTube chronicling our adventures both in the field and in the lab. Here’s a new trailer for the WiscLimnology channel that we hope you’ll enjoy!

On the channel, you’ll find playlists with headings like “Fish on the Run,” “Know Your Invasives,” “In the Lab,” and more – all there to keep you up-to-date on the research we conduct in waters right here in Wisconsin and around the world.

Got feedback? Video ideas? Comment here, or send them to hinterthuer (at)


Humanity Crosses 4 of 9 ‘Planetary Boundaries,’ Q&A with Steve Carpenter

PB_FIG33_upgraded_mediaBLANK_11jan2015The journal Science published an article online today that says civilization has crossed four of nine “planetary boundaries” due to human activity.  According to an international team of 18 researchers, climate change, the loss of biosphere integrity, land-system change, and altered biogeochemical cycles (like phosphorus and nitrogen runoff) have all passed beyond levels that put humanity in a “safe operating space.”

The article is entitled, “Planetary Boundaries: Guiding human development on a changing planet,” and is available online on the Science Express website.

Steve Carpenter, director of the Center for Limnology at the University of Wisconsin-Madison, is one of the report’s authors. He says the study should be a wake up call to policymakers that “we’re running up to and beyond the biophysical boundaries that enable human civilization as we know it to exist.”

For the last 11,700 years, Earth has been in a “remarkably stable state,” says Carpenter. During this time, known as the Holocene epoch, “everything important to civilization,” has occurred. From the development of agriculture, to the rise and fall of the Roman Empire, to the Industrial Revolution, the Holocene has been a good time for human endeavors. But, over the last century, some of the parameters that made the Holocene so hospitable have changed. Continue reading

Accepting Applications for 2015 Trout Lake Station “Artist in Residence”

BOULDER JUNCTION, WI — The Center for Limnology at the University of Wisconsin-Madison is now accepting applications for our summer 2015 “artist-in-residence” fellowship at Trout Lake Station.

Allequash Lake, plein air painted watercolor by 2014 "artist in residence," Helen Klebesadel, near Boulder Junction, WI, June 2014

Allequash Lake, plein air painted watercolor by 2014 “artist in residence,” Helen Klebesadel, near Boulder Junction, WI, June 2014

The artist in residence program is designed for visual artists, writers and musicians who have specific interests in exploring the relationship between people, lakes and landscapes, as well as the long-term scientific investigations of the National Science Foundation-funded North Temperate Lakes Long Term Ecological Research (LTER) project, which is part of a national network studying long-term ecological change. Continue reading

Field Samples: Fish Earbones Tell Story of Kingston Coal Ash Spill

In this addition of our weekly Q&A asking researchers what they’ve been up to and what they’ve learned, Brenda Pracheil, a former CFL post doc and current research at the Oak Ridge National Laboratory, talks fish earbones, coal ash, and environmental monitoring.

Who are you, where are you from, and how did you get to where you are now?

Pracheil once wrangled big fish on big rivers. Now she studies smaller structures in a big lab.

Pracheil once wrangled big fish on big rivers. Now she studies smaller structures in a big lab.

My name is Brenda Pracheil and I am a research staff member at Oak Ridge National Laboratory in Oak Ridge, Tennessee. I am originally from South Sioux City, Nebraska—a town of about 10,000 people in the northeast corner of the state where Nebraska, Iowa and South Dakota meet. I have done a lot of research on fish and large rivers which is an interest that probably stems from growing up on the banks of the Missouri River and spending a lot of time fishing with my grandpa when I was a kid.

My path to where I am now has been circuitous one. All told, I have received training from five colleges/ universities including three undergraduate institutions (University of Nebraska-Kearney, Western Iowa Tech Community College, University of Nebraska-Lincoln) before finally graduating with a BS in Biological Sciences and BA in Philosophy. I also attended two universities for grad school (MS: Michigan State University, Zoology, PhD: University of Nebraska-Lincoln, Natural Resources), and held postdoctoral positions at two universities (University of Wisconsin-Madison, University of Nebraska-Lincoln). I joined the staff at ORNL in January 2014.

Pretend we just boarded an elevator and you only have a one-minute ride to tell me about your work. (in this case, otolith related stuff). Can you capture it a few sentences?

Much like trees, the rings of an otolith can help researchers determine the age and growth rate of a fish.

Much like trees, the rings of an otolith can help researchers determine the age and growth rate of a fish.

Fish earbones, or otoliths, are one of the most incredible structures in the animal kingdom because they not only form rings on them every year (like rings on a tree) that can tell us how old a fish is and how much it grew in a year, but they can also tell us where a fish has been. Fish otoliths incorporate the water chemistry signature of their habitat that allows us to see the chemical fingerprint of the environments where they lived. These techniques have frequently been used to determine migratory history of fishes; something that we have done with my past work in Wisconsin.

My ongoing work with otoliths at Oak Ridge National Laboratory uses otolith microchemistry to understand the impact of an environmental disaster (Tennessee Valley Authority Kingston Coal Ash Spill) on a riverine ecosystem. For this study, we will use otolith material that was formed prior to and after the disaster, allowing for a comparison of pre-spill and post-spill environmental contamination. Practically speaking, the pre-spill/ post-spill snapshots of contamination enable us to assess progress in clean-up efforts. Continue reading

Top 3 Posts From 2014: Ice, More Ice, and Murky Water

Happy New Year’s Eve!


We here at the Center for Limnology wish you a 2015 filled with opportunities to get out on your favorite lake, river, stream or wetland. As a final post of the year, below are snippets of our top 3 posts from the year. As usual, stories about ice and clear water led the way!

1. Ice is Nice: Three Perks to the Polar Vortex

We get it. It is cold. Face (and mind) numbingly cold. But that’s not an “all bad” thing. There’s a lot to like about a real winter. And it begins with ice. Here are three things to celebrate during the winter that brought “polar vortex” into our vocabulary!

1. Ice Caves

Icicle "stalactites" hang from one of Lake Superior's famed "sea" caves. Photo courtesy: UW Superior

For the first time in 5 years, winter temps have been frigid and consistent enough to form lake ice safe enough to walk out to the caves. This recent blog post from our friends at the University of Wisconsin Sea Grant Institute takes us there, courtesy of Marie Zhuikov’s short entry. Or check out this from – full of beautiful pictures. If you live within driving distance of the Apostle Islands, this should really be on your bucket list. Just check the ice conditions first. There’s no quicker way to ruin a hike to the ice caves than turning it into a swim! Continue reading

2. Thickest Lake Ice in Decades May Last Into Spring

Ted Bier, our senior research specialist for the Long-Term Ecological Research program, was recently photographed on Lake Monona holding this massive chunk of ice in front of the Madison skyline.

Ted Bier hoists a two-foot thick chunk of ice on Lake Monona. Photo: Kirsten Rhude

That picture led to the following story on The Capital Times website.

3. Clear-Water Phase: Are We Missing Lake Mendota’s Window?

Lake Monona's already doing it, why aren't Mendota's waters this clear? Photo: A. Hinterthuer











As always, thanks for reading! We’ll see you next year.

White sucker. Image courtesy of New York DNR.

Fish Fry Day Video: White Suckers Can’t Go Home Again

You can’t go home again. While the sentiment means something a bit more figurative to those of us who traveled for the Holidays, for Great Lakes fishes the statement is all too literal. In fact, there are more than 275,000 reasons a fish might not make it “home.”

This amazing animation is from our new Fish On The Run website and was produced by Ellen Hamann. We look forward to more great content about our Great Lakes fishes in 2015, and hope to tell not just the story of an unlucky white sucker, but also how CFL researchers are helping get fish moving again.

White sucker. Image courtesy of New York DNR.

White sucker. Image courtesy of New York DNR.



The Study, Science & Stories of Our Inland Waters