Fish Fry Day: If You Build It, Will Pike Come?

For many species of fish, spring spawning migrations are a crucial part of their life cycle. They swim upstream to habitat both more suitable for them to deposit eggs and where young fish that hatch from those eggs can avoid predators and grow. That’s why state agencies, environmental non-profits and anglers groups spend millions each year to restore spawning habitat and remove barriers to these migrations. But one lingering question often remains – if you build it, will they come?

A northern pike heads upstream to spawn in a tributary of Green Bay. Photo: Solomon David

A northern pike heads upstream to spawn in a tributary of Green Bay. Photo: Solomon David

In the case of northern pike, an important top predator and popular sport fish across the northern hemisphere, the answer appears to be “Yes.”

To reach that conclusion, researchers at the University of Wisconsin Madison’s Center for Limnology had to first answer a very basic question about pike behavior. While salmon are famous for making long trips back to their birthplace to spawn, there are hundreds of other migratory species that scientists know far less about. Northern pike were one of those species – did they also return to their home, or natal, streams to spawn or would any suitable wetland do? Continue reading

Notes from the Northwoods: Wading to Trip

by AnnaKay Kruger

Michaela Kromrey clips herself into her bulky waders, fitting the straps over her shoulders and sealing herself into their protective rubber lining. We’ve dropped anchor near the shore of Jute Lake, and waves whip the side of the boat vigorously in the high wind. It’s a beautiful day, utterly devoid of cloud cover, but the wind is sharp and swift over the water, forcing us to don our sweatshirts and windbreakers to stave off the chill. Michaela and I, both UW-Madison undergraduates, wait in the boat while Ellen Albright, a student at Minnesota’s Macalester College, wades along the shoreline, dragging a tape-measure behind her.

2015-06-05 10.24.58

Ellen and Michaela wade through the shallows of Jute Lake, looking for submerged logs as part of the Regional Lakes Survey. Photo: AnnaKay Kruger

Ellen paces out fifty meters and drops a small orange buoy into the water. Michaela explains that they’re looking for fallen logs, otherwise known as “coarse woody habitat”. Large logs with many branches are the ideal habitat for juvenile fish populations because they provide protection for fingerlings, or fish that are not yet fully developed but have fins and scales, and are capable of feeding themselves. (Editor’s note: CFL research underscored the importance of coarse woody habitat last year).

The prevalence of suitable habitat for fish populations in inland lakes is one of many variables being investigated in the Regional Lakes Survey out of Trout Lake Field Station. This ongoing study will happen every six years and primarily involves analyzing lake conditions for the purpose of mapping changes that occur over time. Continue reading

Limno-Week: Four Center for Limnology Public Events in Three Days!

Summer is our field season, which means you’ll see a lot more “UW-Limnology” boats out on Wisconsin waters. But it’s also when we ramp up our outreach programming. This is an especially busy week as, from Wednesday, June 10th through Friday the 12th, our faculty, students and staff will be speaking to public audiences everywhere from Madison to Milwaukee to Minocqua.


Science on Tap-Minocqua – Forest Ownership and Conservation in the Northwoods – June 10th,  6:00PM, Minocqua Brewing Company, Minocqua

Chequamegon National Forest, WI Old growth eastern white pine. Donnelly Austin Photography

Chequamegon National Forest, WI
Old growth eastern white pine. Donnelly Austin Photography

Forest ownership and conservation are changing in the Northwoods and throughout the United States. Private and public forestlands are critical for natural resource production, outdoor recreation, wildlife habitat and water quality, yet they are increasingly threatened by development, invasive species and other local and global changes. Changes in large forest ownership have been some of the most dramatic over the past 15 years. Adena Rissman, assistant professor in Forest and Wildlife Ecology will speak at our very popular science cafe event where guests are invited to grab a drink and a chair and join in the conversation. The following day, a group of interested citizens will head out for a field-trip led by Adena Rissman and Trout Lake Station director Tim Kratz (among others) to see the forest AND the trees for themselves. More information is here.

Yahara Lakes 101 – June 11th, 7:30AM, The Edgewater Hotel, Madison 

Spiny water fleas can be distinguished from other zooplankton by their exceptionally long tails. Photo: Jake Walsh

Spiny water fleas can be IDd by their exceptionally long tails. Photo: Jake Walsh

The Clean Lakes Alliance’s series of aquatic educational talk features the CFL’s two “Jakes” – Jake Vander Zanden, a professor, and Jake Walsh, his grad student. The title of their talk is “Lake Invaders: How Spiny Water Flea Have Degraded Water Quality in Our Lakes,” and, after folks get settled with coffee and a pastry, they’ll delve into the drama behind our murky Lake Mendota, its sporadic fits of clear water and what can be done about invasive species. For more information on cost, location, etc – go here.

Wisconsin Ideas – Let the World Know – June 11th, 4:30PM, Wisconsin Center, Milwaukee

John Magnuson, always dedicated to outreach about the science of our inland waters, explains algae.

John Magnuson, always dedicated to outreach about the science of our inland waters, explains algae.

The second event in a new and unprecedented UW outreach series is put on by the Wisconsin Alumni Association and will feature some of the world-class research conducted here at the University and focus on how that science has led to innovation and change in the state and around the globe. The event is, essentially, one big mixer, featuring gourmet Wisconsin food and drink, special guest appearances by Bud Selig, Herb Kohl,  exploration stations, remarks from Chancellor Rebecca Blank – all emceed by former Badger and Packer, Mark Tauscher. Open to anyone interested in the UW, but especially alumni. Details here.

Hasler Lab Open House – June 12th, 2-6:00PM, Hasler Lab, Madison

IMG_9739Bucky, Babcock ice cream and Boat rides! Come one, come all! Come rain or shine! We’ll have plenty to do and see – fish to touch, aquatic bugs to catch, plankton to ogle under a microscope, and a host of top-notch faculty and student scientists willing to answer any freshwater question you’ve got. The open house is a darn good time, we promise. And we hope to see you there. Besides, we’re just down the lakeshore from Memorial Terrace, which is where you want to be on a Friday night anyway, right? More here.


Video: Up-Close Look at Lake Mendota Water Clarity

On June 4th, after a week of clear-water conditions in Lake Mendota, some of us here at Hasler Lab decided that our window for swimming in clear water was closing. So we decided to take an up-close and personal reading of conditions.

It turns out that our timing was perfect for a refreshing (read: cold) dip. After peaking at a Secchi depth of more than 7 meters (meaning that’s how far down you could see into the lake from the surface), things started getting a little murkier on Lake Mendota yesterday. A reading from the middle of the lake came back at right around 5 meters. That still put the lake in “clear-water” phase, as any reading  deeper than 4 meters qualifies.

But, today, June 5th, after a full week of clear conditions, the Secchi couldn’t even make it 3 meters off of our pier before disappearing from view. Official reading? 2.75 meters. Official verdict? 2015 clear-water phase has come to a close.

But that doesn’t mean you still can’t help us #monitormendota! Send Secchi readings, pictures, videos, anything showing us the current state of the lake to, or on Twitter or Instagram @WiscLimnology. Bonus points if you choose the “full immersion” option like we did!

Happy Friday! (We’ll get fish back on the menu next week!)

Notes from the Northwoods: Heavy Lifting on Sparkling Lake

by AnnaKay Kruger

“Well, that was an adventure!” says Aaron O’Connell, a UW-Plateville undergraduate, looking down at his bare feet as he steps gingerly across the gravel driveway. In one hand he carries his sodden shoes, and like me, he is covered from head-to-toe in lake grime. We have just spent the last two hours helping Tim Meinke launch a buoy into Sparkling Lake off of Highway 51 in Vilas County.

Ben Kranner and Tim Meinke team up to anchor the buoy to the bottom of Sparkling Lake. Photo: AnnaKay Kruger

Ben Kranner and Tim Meinke team up to anchor the buoy to the bottom of Sparkling Lake. Photo: AnnaKay Kruger

The buoy itself is an impressive device—substantial in girth, equipped with everything from weather antennae to a pressure sensor that records rainfall. A large solar panel hangs on one side, and the whole contraption is strung with a variety of complex wiring that is well beyond my expertise.

(Left to right) Ben Kranner, Tim Meinke, Aaron O’Connell, and Mark Gahler tow the buoy out onto Sparkling Lake. Photo: AnnaKay Kruger

(Left to right) Ben Kranner, Tim Meinke, Aaron O’Connell, and Mark Gahler tow the buoy out onto Sparkling Lake. Photo: AnnaKay Kruger

Meinke, a researcher at the Center for Limnology’s Trout Lake Station, is part of the Long-Term Ecological Research project (LTER) and the Global Lake Ecological Observatory Network (GLEON). Sparkling Lake is one of the LTER and GLEON research lakes, so the buoy will spend the summer collecting data on everything from water temperature to wind speed to the amount of oxygen moving in and out of the lake.  But getting that buoy in the water is no small feat, which is why Meinke enlisted Aaron, Ben Kranner, a UW-Madison undergraduate, and the CFL’s IT consultant, Mark Gahler, to the cause.

While they anchored and wired the buoy, I did my best to stay out of the way and document the experience. This proved more difficult than I had anticipated, as the team hauled in various ropes and weights, gradually filling the boat with lake debris and slime (or, as we call it in scientific circles, “muck”) from the bottom. My chance to contribute to the effort came when we had to retrieve a smaller buoy from just under the surface. It was anchored by sixty pounds worth of barbells, which I hoisted into the boat, a feat that proved challenging despite my enthusiasm. With Aaron’s help, we managed to haul the buoy and weights into the boat. I was grimy and out of breath, but proud to have been of service. Continue reading

Monitor Mendota: Water Clarity, Daphnia on the Rebound

Algal bloom. Photo: Eddie Heath.

Algal bloom. Photo: Eddie Heath.

Last week on this blog, we wondered if Lake Mendota’s clear water phase was a thing of the past. You see, last year, the algae-eating native zooplankton, daphnia pulicaria were so diminished by predation from the invasive spiny water flea, that their numbers couldn’t grow large enough to keep algae from clouding our waters. Combined with the phosphorus that runs off into our lakes and acts like algal fertilizer, well, you’ve got a recipe for a soupy mess. And this year wasn’t looking much better.

Imagine my surprise, then, when I stepped out onto the Hasler Lab pier this afternoon and saw this… Continue reading

All Aboard! 4th Annual Hasler Lab Open House

                    Join us FRIDAY, JUNE 12th for the                         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.

If you’re in the Madison area, come on down for a “behind the scenes” event and spend a half hour or the whole afternoon exploring the science behind Wisconsin’s lakes, rivers and streams.

We’ll have hands-on science, FREE Babcock ice cream and a visit from the UW’s most iconic mammal, Bucky Badger.

Friday, June 12th, 2-6pm. And Hasler Lab (680 N. Park Street)

Visitors will:

  • Take a “research cruise” on Lake Mendota with CFL researchers
  • Meet the fish, plants and insects that call Madison lakes home
  • Try their hand at using various lake research tools
  • Catch plankton from our pier and ID them under our microscopes
  • Make aquatic-themed crafts at the Kids Crafts station
  • Talk with leading scientists about Wisconsin’s freshwater
  • Enjoy free Babcock Dairy Ice Cream
  • Meet Bucky Badger
  • And  more!

Here’s a slideshow of past open houses:

So bring the kids and come on out from 2-6pm on Friday, June 12th. We hope to see you here!

Parking available under Helen C. White library after 4pm and in the the Lake Street public parking ramp near the corner of Lake and State. 

*Note: Boat rides are first-come/first-served, ice cream is served until we run out, and Bucky Badger will be at the lab from 3-3:30pm. 

Fish Fry Day: Daphnia Update & Perch (H2O) Purifiers?

Lake Monona is crystal clear, while Mendota stays murky and, on Wednesday, we asked you to help us monitor Lake Mendota as we wait to see if the native zooplankton, daphnia pulicaria, can rally and clear up the situation after being decimated by a tiny invasive predator called the spiny water flea. Read that previous post here. And see coverage of the issue courtesy of NBC 15’s nightly news!


Lake Mendota, May 21st, from the Hasler Lab pier. Secchi depth .75 meters. Photo: Adam Hinterthuer

Yesterday, CFL graduate student, Jake Walsh sent in these updates on the current conditions on both Mendota and Monona, as well as his thoughts about how we might go about tackling the spiny water flea problem. Fortunately for us, it involves our very favorite fish fry species! 

Continue reading

Help Us Monitor Mendota: Is Clear-Water Phase a Memory?

 by Jake Walsh

Spiny water flea under the microscope. Photo: Jake Walsh

Spiny water flea under the microscope. Photo: Jake Walsh

We’ve written before about how an invasive zooplankton called Bythotrephes longimanus, or “the spiny water flea” (SWF) is eating our native algae-grazing friends, the tiny crustaceans called Daphnia.

This is important because, as phosphorus pollution leads to algae blooms and lower water quality, we are also losing the critters that keep that algae at bay and give us our annual spring “clear-water” phase. 

Since SWF was first detected by a group of UW-Madison undergrads in Lake Mendota in 2009, we’ve lost over 80% of our Daphnia pulicaria (the big Daphnia that eat a ton of algae) and over 2 feet of water clarity in Lake Mendota.

Image: Jake Walsh

Daphnia abundance and Secchi depth before and after spiny water flea detected in Lake Mendota. Image: Jake Walsh

However, 2014 may have been the worst yet. The intensity of SWF predation on Daphnia in the fall of 2014 was twice as high as any other year we’ve observed. It was so bad that, on September 2nd of 2014, the voracious spiny water flea caused the collapse of Lake Mendota’s Daphnia community and they still haven’t recovered as of today.  Where I used to pull in hundreds of thousands of Daphnia pulicaria in a single sample, I’m now often only finding a single tiny individual in my net.

If you love clear water, then these little Daphnia pulicaria are your best friend!  Are we losing them in Lake Mendota?

If you love clear water, then these little Daphnia pulicaria are your best friend! Are we losing them in Lake Mendota?

While we’ve seen “tough times” for Daphnia before, we’ve never witnessed anything like this in the four decades the Center for Limnology and Long-Term Ecological Research (LTER) scientists have monitored Lake Mendota.

As a result, water clarity in Lake Mendota has been downright dismal this year while Lake Monona, which doesn’t have a large SWF population, is looking nice and clear. In fact, last year’s average water clarity was BETTER in Monona than Mendota for the first time since we’ve been keeping records. Continue reading

Fish Fry Day Redux: Sneaking and Spawning

We’re swamped here at the CFL, so apologies for the slow posting. Today, though, we’ve dug up a classic post on one of the aquatic rites of spring – the crazy sex life of bluegill.

These guys can't wait for ice-off so they can start sneakin' Photo: Fargo-Moorhead Dive News

These guys can’t wait for ice-off so they can start sneakin’ Photo: Fargo-Moorhead Dive News

I know, I know, bluegill aren’t exactly a rare species. In fact, they’re often the first fish kids learn to catch and, as any avid fisherman can tell you, they sure are tasty! But did you know about their secretive (and sorta sordid) sex life?

Ted Bier gives tips for Fish IDs at CLA's "Yahara 101" event. Photo: A. Hinterthuer

Ted Bier gives tips for Fish IDs at CLA’s “Yahara 101″ event. Photo: A. Hinterthuer

A couple of summers ago, Ted Bier, a senior research scientist with the Long-Term Ecological Research program here at the CFL gave a talk at the Clean Lakes Alliance‘s monthly Madison-lake education series, “Yahara 101.” And that’s where I learned that, at any given time, there are THREE different kinds of male bluegill in our lakes.

And that all has to do with how they pass on their genes – or at least try to.

For a much more comprehensive read on this, may I suggest “The Secret Life of Bluegills,” by Dr. Dave Willis from South Dakota State University. But, here’s the lowdown –  Continue reading

The Study, Science & Stories of Our Inland Waters