Blog Redux: Fish Ears, “Tree” Rings and a Sectioning Saw

We thought we’d dig through the archives to see what we were up to in previous Novembers. Enjoy this look at “Limno in the Lab” from four years ago!

Aaron Koning uses a sectioning saw to cut a slice of otolith that will be mounted on a slide and polished, enabling him to see it clearly under a microscope.

Originally posted 11/13/12 – After the spring and summer field seasons, it’s time to return to the lab to work up all the specimens collected in the field. For many grad students at the Center for Limnology, this means days, if not weeks, hunched over a circular sectioning saw and buffing wheel.

What are they doing using equipment more appropriate for a jewelry store? Cutting and polishing fish ear stones, of course.

These ear stones, or otoliths, are small disks of calcium carbonate that grow on either side of a fish’s brain. Much like the inner ear in humans, otoliths help fish hear, sense vibrations, and maintain balance and orientation. While certainly an essential little piece of anatomy for the fish, otoliths are nearly as essential to fisheries researchers. 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

Fish Fry Day: Jumpin’ Muskies

Well, we’ve once again made it to the day when fried fish dominates Wisconsin menus, which means it’s Fish Fry Day on the blog!

Every spring, fish all over the world feel the warming waters and head upstream to spawn. And every spring, millions of fish run into one insurmountable obstacle to their inner drive – dams.

A muskellunge tries to clear the Wingra Creek Dam in Madison, WI. Photo: Brenda Pracheil

A muskellunge tries to clear the Wingra Creek Dam in Madison, WI. Photo: Brenda Pracheil

Here in Madison, the Wingra Creek Dam is a good place to spot big muskies trying to leap their way into Lake Wingra. They’re not exactly champion jumpers of the fish world, but it’s still a cool display. Luckily for them (and folks who like to fish for them) other muskies have better luck in more accessible tributaries. This year’s run has wound down, but we’ve got some good shots to tide you over until next year.

Here’s an amazing slideshow of jumping muskies in Madison from M F Davis’s Flickr stream. And a nearly viral video taken right here in Madison!


Fish Fry Day: Northern Pike

Well, it’s that time of the week again. The day in Wisconsin offers up its fabulous fish fry dinners and the day here at the blog where we celebrate some of our favorite fishes. If you missed the first installment of “Fish Fry Day,” you can learn more about that beautiful panfish, the pumpkinseed, by reading this blog post. Today, though, we’re featuring a fish with a bigger, well, bite. Ladies and gentlemen – the northern pike.

CFL grad student, Zack Lawson pulled this impressive pike out of Lake Mendota this winter right outside Hasler Lab's doors. Photo: Dane Oele

CFL grad student, Zack Lawson pulled this impressive pike out of Lake Mendota this winter right outside the doors of Hasler Lab. Photo: Dane Oele

This time last year, the blog was up in Green Bay with CFL grad student, Dan Oele, trying to catch some of these beautiful and popular sport fish on their annual spring spawning runs. Thanks to crazy warm weather in March, though, most pike had already headed back out to the bay before we arrived. Luckily, we did find one slow-moving specimen. Continue reading

Introducing “Fish Fry Day”



Here in Wisconsin, the end of the work week is often celebrated with a dinner of lightly battered, deep-fried deliciousness. We’re talking bluegill, perch, walleye and, for those not yet hip enough to eat our delectable native fish – cod.

Here at the blog, we decided we’d celebrate the quintessential fish fry by taking some time at the end of each week to single out a freshwater species living in our world’s lakes, rivers, streams and wetlands.

A pumpkinseed fish, member of the sunfish family. Photo: Shedd Aquarium

A pumpkinseed, member of the sunfish family. Photo: Shedd Aquarium

“Fish Fry Day” won’t be all about just panfish, we’ll try to keep the photos of our staff holding up trophy muskies to a minimum, and we’ll even venture out of Wisconsin once in a while. We hope you enjoy.

For round one we’ll pretend that the current weather is actually Spring deciding to show up around here. This video was shot a few field seasons ago by Gretchen Anderson Hansen, a postdoc here in Hasler Lab. It shows a sneaky pumpkinseed trying to get some of his own genetic code into the mix as a much larger male woos a female on his nest.

As you can see, keeping out interlopers is all part of the game when it comes to spawning.

A fun fact about pumpkinseeds – the males are doting fathers, guarding over their newly hatched brood for a week and a half and even returning the young back to the nest in their mouths, should the little ones get too adventurous. For more on pumpkinseeds, here’s an info sheet from our friends at the University of Wisconsin Sea Grant Institute.

Tracking Northern Pike in Green Bay

CFL grad student, Dan Oele, is trying to see if pike return to their “birthplace” to spawn or if any ol’ tributary will do. Thanks to funding from the Great Lakes Restoration Initiative, Oele is out in Green Bay working on an answer. Watch (or read) below:

GREEN BAY — It’s the second day of April and Dan Oele is cruising the tributaries of Green Bay on the hunt for northern pike. Continue reading