Wisconsin’s Shrinking Panfish & New Fisheries Management Policy

Happy Fish Fry Day! Enjoy this post from the Long Term Ecological Research Network.

Bluegill hooked on Crystal Lake in northwestern Dane County, 1998. Photo: WDNR

Bluegill hooked on Crystal Lake in northwestern Dane County, 1998. Photo: WDNR

by Terra Alpaugh

Between 2013 and 2015, Andrew Rypel traveled the state of Wisconsin attending public meetings led by state and local fisheries staff— always with a set of graphs in hand. These graphs showed the steady decline in the size of panfish found in state lakes over the past seventy years. Panfish (unsurprisingly) are fish that fit nicely in a frying pan — as opposed to the larger, more charismatic, and better-regulated gamefish. Showing citizens his evidence of shrinking panfish size, Rypel and collaborating fisheries management staff asked, “What, if anything, should we do about it?”

Rypel, a fishery ecologist with Wisconsin’s Department of Natural Resources (WDNR) and the Northern Temperate Lakes LTER, published the research behind those graphs in Fisheries in May 2016. It relied on fish surveys conducted by the WDNR and its predecessor, the Wisconsin Conservation Department, supplemented by 35 years of NTL LTER surveys and some careful statistical analysis. Their study found that while the mean size of panfish was declining, gamefish were mostly getting bigger — or at least holding their ground. Keep Reading –> 

Slideshow: Highlights from Hasler Lab’s 5th Annual Open House

June 24th dawned warm and clear and it was obvious that we’d picked a beautiful day to open our doors to the public. By the time we wrapped things up at 6pm, nearly 300 people had passed through Hasler Lab and learned a little bit about their lakes and the work we do. We hope you enjoy these pictures and we’ll see you next year!

(Fantastic photography courtesy: Sarah Collins, Mark Gahler and Carol Jenkins-Espinosa)


Notes from the Northwoods: Electrofishing on Allequash Lake

This summer, Anna Krieg, an undergraduate at Arizona State University, will spend a few months in a much wetter habitat as the CFL’s summer outreach intern at our Trout Lake Station. Enjoy her Notes from the Northwoods:

by Anna Krieg – Just as the sun is setting over the trees at Trout Lake Station, Martin, Ellen, Amien, and Jim all meet by the massive electroshock boat and drive out to the lake where they will be electrofishing tonight.

Martin Perales and Ellen Albright plan their root for the night's electrofishing as Jim Miazga looks on. Photo: Anna Krieg

Martin Perales and Ellen Albright plan their route for the night’s electrofishing as Jim Miazga looks on. Photo: Anna Krieg

Electrofishing is a common scientific survey method used to sample fish populations to determine abundance, density, and species composition. A boat, dangling long tendrils into the surface of a freshwater system, uses an on board generator to apply electric current to the water to collect fish. The electric field created does not kill the fish, but temporarily stuns them. The technique allows the fish to be scooped up and handled with less stress and injury sustained than if they were pulled thrashing into the boat. Martin operates the generator and maneuvers the boat skillfully near the edges of the lake where fish tend to hang out and, especially, where predators tend to follow prey toward shore when the sun goes down.

Ellen and Amien stand at the front of the boat with giant nets ready to catch any fish floating to the surface. Jim stands behind to empty the nets into a pool, where the fish will be stored until they can be measured and weighed. Tonight the goal is to measure and weigh as many fish as possible in four separate locations on Allequash Lake.

Amien Paust measures the length of a fish caught during electrofishing. Photo: Anna Krieg

Amien Paust measures the length of a fish caught during electrofishing while another fish waits in the holding tank. Photo: Anna Krieg

This was my first time witnessing electrofishing in action. I was surprised not only by the amount, but also the variety of fish caught. Each run through our four locations yielded dozens of fish from little minnows to walleye to bluegill to large and smallmouth bass. As each fish was weighed and measured, I noticed everyone falling into their role.

Amien, who is still learning how to identify the fish that live in the Northern Lakes region, would measure the fish and call out his best guess as to what it was. Martin would write down the measurements and weights, while double-checking Amien’s identification. Ellen weighed the fish and released them safely back into the water. Jim surveyed the scene, offering his expert fish identification knowledge whenever everyone was stumped. I was lucky enough to sit back and watch, learning from everyone else as they explained things like the different markers of fish, the time of year different species spawned, and the number and type of spines.

As an added bonus, we couldn’t have picked a more beautiful night to be on the water. It was cold and clear and we had millions of stars overhead to keep us company.

The Sound of Science: Paul Hanson Mixes Music and Limnology

Below is an excellent article from Isthmus.com on CFL research professor, Paul Hanson, and the music he hears (and makes) in science. By Allison Geyer.


Data collected from sensors on a buoy in Lake Mendota map the ebb and flow of the algal blooms that each year turn the lake green with phytoplankton. A look at the patterns created over time shows a confluence of interconnected cycles driven by season, temperature, sunrise and sunset.

To most people, that sounds like science. A lyrical description perhaps, but well within the realm of what is observable, measurable and repeatable — the necessary conditions for a scientific experiment. But to UW-Madison researcher Paul Hanson, the data — and the forces of nature behind them — have the power to transcend his empirically driven discipline.

Hanson, a distinguished professor of research with the university’s Center for Limnology, is also a musician and a composer. For the past several years he’s been collaborating with local musician Chris Wagoner and others to write and record songs inspired by both science and nature.

“There are three Cs that connect music and science,” Hanson says. “Creativity, communication and collaboration.” – Read the full article at Isthmus.com

Notes from the Northwoods: Launching a Study on Shoreline Development

This summer, Anna Krieg, an undergraduate at Arizona State University, will spend a few months in a much wetter habitat as the CFL’s summer outreach intern at our Trout Lake Station. Here’s Anna’s first Note from the Northwoods:

Anna Krieg.

Anna Krieg.

by Anna Krieg – It’s looking like it will be a beautiful day as I walk to the Main Lab at Trout Lake Station. I am meeting with Martin Perales, Amien Paust, and Ellen Albright to follow along on their search to find lakes for the fish habitat study Martin, a new graduate student at the UW-Madison’s Center for Limnology, is launching this summer in the Northwoods. I have been at the CFL’s Trout Lake Station for less than a week and this is my first time going out into the field with a research team so I don’t really know what to expect.

My first five days here at the Station have been eventful to say the least. I have met new people, learned what is expected of me in my position as the Communication and Outreach intern, and experienced more rain in the last week than I have in my entire life. As a Phoenix, Arizona native, the Northwoods of Wisconsin are certainly a break from what I am used to, so I am very excited for today. Continue reading

Boats, Bucky & Babcock Ice Cream: 5th Annual Hasler Lab Open House

Visitors board the Limnos for a "research cruise" on Lake Mendota.

Visitors board the Limnos for a “research cruise” on Lake Mendota.

MADISON – For more than 120 years, scientists at the UW-Madison’s Center for Limnology have studied the waters around Madison, the state and the world. They’ve helped build much of our knowledge about how freshwater ecosystems work and, on Friday, June 24th, they’re opening the doors to the lab for our 5th annual open house – a “behind the scenes” tour of a world-class research facility.


From 2 to 6pm, visitors can talk with scientists, try their hand at using various research tools and meet some of the creatures that call Lake Mendota home. Free Babcock Dairy ice cream will be served and attendees will even get the chance to take a cruise on Lake Mendota aboard our research vessel, the Limnos*.

2012-06-22 14.07.10Other stations will explore topics like fish migrations, lake dynamics and future projections for the Yahara watershed. Kids will be able to make aquatic-themed crafts, and Bucky the Badger himself will make a guest appearance at 3:00pm.

Center for Limnology faculty and students are out in force this summer, sampling on Madison’s lakes as they study everything from the carbon cycle, to water quality, to the recent invasion of zebra mussels. This is a unique chance to come learn about these current projects as well as chat with CFL scientists about things like algal blooms, shrinking winter ice cover or anything else aquatic.


*Boat rides are limited due to space and time constraints, but visitors are encouraged to come “rain or shine,” as most stations will be indoors.

Hasler Lab is at 680 N. Park Street. There is some public parking under the Helen C. White library and more at the City of Madison’s “State Street Campus Garage” on Lake Street.

What: Hasler Lab Open House

When: Friday, June 24th – 2 to 6pm, rain or shine.

Where: Hasler Lab on the UW Campus. 680 N. Park St. Madison.

Who: You! All ages welcome and encouraged!

Guest Post: Q & A with “Our Waters, Our Future” Fiction Contest Winner

Note: this post is from our friends over at the “Yahara in situ” blog:

First place winner,

First place winner, Sally Younger (right) and Kitt Healy, who took second place in the “Our Waters, Our Future” contest.

Meet Sally Younger. She won our first ever Our Waters, Our Future writing contest, which sought short, sci-fi stories about positive futures for water and people in south-central Wisconsin.

Younger’s first-place story, “Antigone Lupulus,” will make its debut in Madison Magazine’s June issue, and is already available online. It is about a young woman learning to manage a hops farm in the Yahara Watershed amid the challenges brought by a changed climate.

If you are curious about some of the other stories we received, check back in with us each day this week, as we will be showcasing a few of the finalists.

But, today, get to know Younger, a Madison native and technical writer by trade. We asked her a few questions about her inspiration for the story and what value she found in the exercise of imagining the future of our water.

Tell us a little bit about your connection to water.

SY: As a terrestrial lifeform I don’t get very far without it. As a Madison native, Lake Mendota is my north star. The four lakes orient me, shape my path; time and the seasons are reflected on their faces. Monona, the closest to my home, perhaps takes pride of place. After 25 years together I’ve discovered she never looks the same two mornings in a row. Continue reading

Water, Women and Fisheries: CFL Researcher Awarded “Seed Grant” from Global Health Institute

Bordered by Uganda, Kenya and Tanzania, Lake Victoria is the world’s largest tropical freshwater lake and boasts one of the largest freshwater fisheries in the world. 30 million people live around its shores. It is an important source of food, water, industry and recreation but, over the last couple of decades, water quality has greatly diminished as an aggressive invasive plant and potentially toxic algal blooms spread across its surface.

Water hyacinth and harmful algal blooms as seen from a fisherman's boat on Lake Victoria. Photo: Jess Corman

Water hyacinth (aquatic plant) choke the inlet so that our boat cannot reach the pier where the yellow water taxi is docked. Cyanobacteria (also called harmful algal blooms) in the foreground give the water a pea-soup green appearance. Photo by Jessica Corman.

Water hyacinth (aquatic plant) choke the inlet so that our boat cannot reach the pier where the yellow water taxi is docked. Cyanobacteria (foreground) give the water a pea-soup green appearance. Photo by Jessica Corman.

Jessica Corman, a post doctoral researcher at the UW-Madison’s Center for Limnology recently learned that she was one of four UW-Madison researchers to receive a $50,000 seed grant from the Global Health Institute. Her proposed project, entitled “Water, Women, and Fisheries: Addressing Two Ecological Realities Impacting Human Health at Lake Victoria,” will soon take her to Kenya, to study Lake Victoria and the communities that depend on it. Continue reading

CFL at Shedd Aquarium: World Fish Migration Day, May 21st!

Center for Limnology researchers Solomon David and Ellen Hamann outside Chicago's Shedd Aquarium for World Fish Migration Day. Photo courtesy S. David.

Center for Limnology researchers Solomon David and Ellen Hamann outside Chicago’s Shedd Aquarium for World Fish Migration Day. Photo courtesy S. David.

This coming Saturday is World Fish Migration Day and, from 10am to 4pm, visitors who come to Chicago’s famed Shedd Aquarium will get more than just the usual stunning displays of amazing aquatic life – they’ll also get a chance to meet aquatic scientists who are studying how and why fish move.

Visitors can undertake a scavenger hunt of sorts as they fill in their “Migratory Fish Passport.” See migratory species up close and on display. Talk with fisheries researchers about how they monitor fish populations and what they’re learning. And, of course, get a photo of their heads in our amazing “fish face cut-outs.”

Stop by the Shedd on Saturday and get your picutre taken AS our very own Solomon David!

Stop by the Shedd on Saturday and get your picture taken AS our very own Solomon David!

Why are we so concerned about the world’s migratory fish? Well, because a lot of species need to reach upstream habitat for a healthy life cycle. Dams, road culverts and other barriers often stand in their way. With hydropower projects proposed on some of the world’s biggest rivers, these fish species that are both ecologically important and essential sources of protein for many cultures are in danger of being greatly diminished.

World Fish Migration Day and the Center for Limnology’s participation at the Shedd Aquarium is just one way to help spread the word about the importance of reducing fish migration barriers and getting fish back on the run!

Hope to see you Saturday! 10am to 4pm at the Shedd Aquarium!

In the meantime, we’ll leave you with a remarkable video shot by CFL grad student, Andy Stevens, of a white sucker run in a Lake Michigan tributary. Enjoy!


Guest Post: Earth’s Current Sea Change a Warning to “Respect the Slow”

by Steve Carpenter

Around the Baltic Sea in Sweden there are dozens of abandoned Viking settlements. The odd thing about these sites is that they lie a few kilometers inland. The Vikings were seafaring people, and the settlements have the remains of large sea-going ships.

Viking Burial Ground. Photo: telefotomedia on Flickr

Viking Burial Ground. Photo: telefotomedia on Flickr

Anders Celsius, a prolific scientist who, among other things, invented the temperature scale that bears his name, was curious about these old Viking settlements. He proposed that sea level was falling. Celsius went to the shore and carved lines and dates on rocks at the waterline. He persuaded other scientists to do the same thing at different locations around Scandinavia during the early 1700s. This turned out to be the first long-term network for scientific observation.

This rock is now high and dry not because sea level was falling in the Baltic, but because the land was rising. Image: BALTEX - The Baltic Sea Experiment

This rock is now high and dry not because sea level was falling in the Baltic, but because the land was rising. Image: BALTEX – The Baltic Sea Experiment

Sure enough, over the years it became obvious that the carved lines were rising above the water, or vice-versa. Even now, 300 years after Celsius worked, you can find his lines on rocks around the Baltic Sea. Now the lines are about six to twelve feet above sea level.

Why were the carved lines separating from the water surface? Celsius thought that sea level was falling. He died before the matter was resolved.

By a few decades after Celsius’ death in 1744, it was obvious that the distance between the sea surface and the carved lines varied from place to place. If the sea was falling, the gap would be the same everywhere. Therefore the sea was not falling. The land must be rising!

By 1865, scientists knew that massive glaciers once covered the northern hemisphere. They reasoned that the melting of the glaciers removed a great weight from the land, allowing the land to rebound. By about 1890 this idea was generally accepted, and it remains so today.

Two centuries after Celsius asked the question, scientists confirmed their understanding of why the Viking ships were so far away from the seashore. The rebound of Earth’s surface from the weight of the glaciers has gone on for 10-15 thousand years and is still happening today at a rate of a few millimeters per year.

Slow changes, like melting glaciers and terrestrial rebound, create legacies. By dictionary definition, a legacy is property or money left to someone in a will. But humans create other kinds of legacies that we leave to our planet. Continue reading