Sturgeon Survey on the Couderay River

As I peered into the deep pool below the bridge through my polarized sunglasses, the four-foot-long, dark gray torpedo slid smoothly above the pale, sandy bottom near a school of giant catfish.

This hole on the Couderay River near Radisson, WI, is a favorite hangout for lake sturgeon. Max Wolter, Fisheries Biologist with the Wisconsin Department of Natural Resources (WDNR), knows this because his crew had caught them here before—including in 2019, the last time I joined them on the survey. Still, knowing a fish is there, and catching it, are two very different things.

In 2019, the guys had first attempted to hook the sturgeon using a worm as bait. This year they went straight to a tactic that proved to be more successful. Fisheries Technicians Evan Sniadajewski and Scott Braden unwound a gillnet—basically a nylon volleyball net on moveable poles—and waded upstream of the pool into waist-deep water. Lee Dubois, a Masters student at UW Milwaukee, got the humongous landing net out of the canoe. Its diameter was about the same size as the circle my arms would make if I was telling a whopper of a big fish story. Max—standing in the stern of his canoe—herded a sturgeon toward the gillnet.

The fish rodeo was exciting and quick. Before I could even see a way to help, the guys had stopped the sturgeon’s upstream escape with the gillnet, and Lee had scooped it safely into the landing net. After some excited whoops, the tagalongs—me and four Museum members—all waded over to Max’s canoe to process our first big catch.

Lee Dubois and Evan Sniadajewski—fisheries biologists with the Wisconsin Department of Natural Resources—are studying sturgeons’ natural return to the Couderay River following the removal of a dam. Photo by Emily Stone.

As Evan showed us this magnificent fish, he began to wax poetic about their adaptations. Sturgeons are bottom feeders. The whisker-like barbels on the underside of their snout are covered with chemoreceptors to help them “smell” food underwater. “It’s probably the most sensitive part of their body,” he said admiringly. When those barbels sense food (snails, insects, leeches, crayfish and small clams), the sturgeon thrusts its tubular mouth downward to suck up prey. Any gravel that gets sucked up in the process is expelled through their gills.

Sturgeon barbels are covered in chemoreceptors.

We all took the opportunity to run a hand over the sturgeon’s skin, and I was astonished to find that it was sandpapery—like a shark’s skin. Max also pointed out the smoothly arched dorsal fin—which, when we eventually let her go, cut through the surface of the water just like a mini Jaws. Sturgeons are pretty ancient fish. They evolved just as the dinosaurs blinked out 100 million years ago, and have undergone very little anatomical change since then (although the 29 species of sturgeons worldwide have quickly evolved a wide range of body sizes to fit various niches.)

Max waved his hand-held tag reader over the sturgeon’s head. The scanner beeped! The WDNR has been tagging sturgeons on the Couderay River for enough years that it’s more likely to find a tagged fish than an untagged one.

Since the Grimh Dam in Radisson was removed in 2011, the Couderay now flows freely into the Chippewa River—where sturgeon populations are healthy enough for harvest. The WDNR is documenting the sturgeons’ natural recovery into one of their historic haunts, now that the fish are no longer cut off by the dam. In Wisconsin, lake sturgeon is a species of “special concern” with regulated harvest, but sturgeons are listed as threatened or endangered in 19 of the 20 states within the fishes' original range.

Since this sturgeon was only 41 inches long, and the one we’d caught here in 2019 was 50 inches long, we knew that they couldn’t be the same fish. The guys would compare data back at the office, and learn more about the movement of sturgeon in the river.

Over the course of the day (only 3 river miles long), we captured three sturgeon, all with tags. We were thrilled to see those fish, and to watch the guys use all their skills to catch them. It was a little anticlimactic for me, though, because in 2019 we had caught 10 sturgeon on this same stretch of river.

When I asked Max where the others might have gone, he cited the dry spring and said that they’d probably moved down river, or perhaps not migrated as far upstream as normal, in response to lower water levels. Recent rains have brought the river back up to normal, but the fish haven’t followed.

I could tell that these guys have a passion for fish and fishing that I’ll never match. Many of their field days include pushing through overgrown creeks under the constant attack of mosquitoes and horseflies. This spectacular day on the river was a real treat—to put their skills in fishing and fish handling to work in a beautiful setting. It’s because of their passion—and the funding you provide through your fishing licenses—that sturgeon (and trout and bass etc.) will only vanish deeper into a pool, and not disappear from our state.

Author’s Note: portions of this article were published in 2019.


Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our exciting Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Woops!

Hello Museum Members--

I got my scheduling mixed up between your e-newsletter and what I sent to the newspapers. So, if you're surprised to be reading about monarchs instead of sturgeon, it's ok. Just know that you'll get to read about sturgeon NEXT week!

Thanks for understanding!

Emily

A Monarch’s Demise

“Have you seen the newest monarch chrysalid?” asked my coworker Mollie, poking her head in my office door. My eyes lit up. While I counted 32 monarch butterfly caterpillars outside the Museum’s front doors earlier this summer, we’d only discovered the whereabouts of three chrysalids—the next stage in their life cycle.

A monarch chrysalid

Once monarch caterpillars get fat, they travel several feet away from the milkweed plants where they’d been gorging themselves and look for a good hiding spot. Choosing a safe location to pupate is essential, and it’s a skill that they’ve developed over millennia. Caterpillars are immobile, soft, and vulnerable for about 24 hours as they attach their rear end to a leaf or other surface with a little silk pad, then curl into a J-shape and shed their exoskeleton to reveal the chrysalid. After the chrysalid has time to harden, they are a little more durable for the rest of the 8-15 days it takes for an orange and black butterfly to develop and emerge.

A monarch caterpillar in the "J" getting ready to turn into a chrysalid.

Mollie led me out the Museum’s front doors and then turned immediately to her right. There, on the underside of a stone ledge on the building’s foundation hung a delicate, sea-green chrysalid. Even though I’ve been admiring them all summer, I just can’t seem to get enough of the beauty and magic encapsulated in these Lilliputian packages. I leaned over to admire the gold dots shimmering on the pupa’s tiny ridges, and as I did, something small and black walked into view around the chrysalid’s shoulder.

The body had three segments, six legs, and two antennae. Was it an ant? No, there were tiny, translucent wings. This critter gave me a bad feeling, and using a pen I tried to shoo the little one off the chrysalid. It didn’t budge. Then the docent at the front desk got our attention to answer a question, and Mollie and I headed back inside.

The little visitor niggled at my conscience, though, so I did some Googling. As I feared, the critter looked just like a tiny wasp who has recently come to light as a parasite on monarch pupae.

The monarch chrysalid that was parasitized by wasps. You can see small, dark exit holes where the wasps emerged. The whole colony was subjected to several freeze-thaw cycles to kill the wasps for inclusion in the Museum's collections. 

Pteromalus cassotis is one of many types of Chalcid wasps who each specialize in parasitizing their own flavor of insect. Entomologists hypothesize that pretty much every species of insect, plus many plants, are parasitized by one or a few species of wasps who are specific to their host. Logically, it follows that there are likely more species of wasps on Earth than any other animal. Most of them have not yet been described by scientists.

And actually, it would be nice if they were only parasitizing the insects. Parasites steal energy from their host but don’t always kill them. Insects who make plant galls are parasites. They hurt the plant, but not to the point of death. In contrast, P. casspotis and other Chalcid wasps are parasitoids, which means that they have a catastrophically cozy relationship with their host that results in the hosts’ death.

With this sad knowledge, I took a closer look at the monarch chrysalid a week or so later. Odd, dark blotches showing through the translucent green case confirmed that it was not developing normally. I was still curious, though. Carl Stenoien, a PhD student at the University of Minnesota, only confirmed the wasp’s relationship with monarchs as recently as 2015, while working with Karen Oberhauser at UMN’s Monarch Lab. I wanted to see this phenomenon for myself.

So, I carefully scraped the silk button off the concrete and taped it to a small stick. Then I set the stick and the dangling chrysalid inside a glass jar with cloth in place of the lid, and placed it on a back corner of my desk.

About a week later, I looked up from emails and noticed movement in the jar. Hundreds of tiny wasps had appeared. According to Stenoien’s research, anywhere from 1 to 425 wasps might emerge from a single chrysalid—all raised on energy stolen from the monarch pupa. Most of them are larger, black females, and as few as nine percent are the smaller, bronze-colored males. I could see the variation of color and size in the wasps crawling around my jar. With their big red eyes, elegant, teardrop-shaped abdomens (no pointy stinger, just an ovipositor used for laying eggs), and tan legs, these little ladies were almost pretty.

Pteromalus cassotis is a species of parasitoid wasp that attacks only the pupae of monarch butterflies. The larger individual on the left is female, and the smaller one is male. The lines are millimeters.

While the population of monarch butterflies has declined by an alarming 80 percent over the last decade, natural enemies like these tiny little wasps are probably not a significant part of their demise. Human-caused issues, such as habitat loss, pesticide and herbicide use, and climate change are much more significant issues.

Still, it would be easy to frame these little parasitoid wasps as villains, since they attack a beautiful, charismatic butterfly—but nature is not that simple. Those uncountable species of parasitoid wasps do us a favor by killing insects who cause crop damage. They also help keep wild nature in balance. There is such a thing as a world with too many caterpillars—at least in the opinion of the plants who those caterpillars eat, and the other herbivores who might also need those plants, and the animals who need to eat those herbivores, and so on up the food chain.

Whew! That was quite a journey. By simply going outside to look at something pretty, I ended up reminding myself that even the smallest critters have important roles to play on Earth.

I’m a lot bigger than those wasps. What does that say about the impact I could have?

A monarch butterfly that metamorphosed successfully!

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our exciting Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Underwater Eyes

Small fish dart among plants and algae in the Namekagon River. This world becomes visible only when you have a different way to see. Photo by Emily Stone.

The low, gray clouds of an approaching storm made the humid afternoon feel extra dark. Preparing to head home after work, I strapped on my bike helmet and latched my pannier to my rear rack. My sunglasses, however, got tucked into the back pocket of my high-vis vest. It was just too dark to wear them comfortably.

A few miles in, I came to regret that decision.

The county highway is scheduled to be repaved soon, and I bumped and swerved among the cracks, rough spots, and loose gravel. When a truck blew past me, barely getting over to pass despite a clear, straight road, its tires sent up a spray of sand and dust. Blinking, I could feel bits of fine grit in my eyes. Wouldn’t it be great, I thought, if I could have slipped on some eye protection just as the truck flew past?

In fact, many animals do have goggles that they can engage and put away at will. This third eyelid is called a nictitating membrane. This science word has great rhythm, and I love making students pronounce it with me: nik-ti-tey-ting. We have upper and lower eyelids, I explain, and these animals also have transparent or translucent eyelids that move horizontally.

Birds of prey like peregrine falcons use their nictitating membranes during high-speed dives in order to protect their eyes from dust and debris in the air, and also as windshield wipers to clean that dust off of their eyes and keep them moist. Nictitating membranes are often engaged at the point of attack, and sometimes while the chicks are getting fed, too. Actually, most birds, even little chickadees, protect their eyes this way.

After a few more miles of blinking opaque eyelids, my eyes felt ok again. By then, the bridge over the Namekagon River was coming into view. Even without sunshine, the afternoon felt uncomfortably hot, and the crystal-clear water of the river sparkled refreshingly. At the last second, I made my decision, checked my helmet mirror for cars, and swerved into the river landing.

The water there was only knee deep, but by sitting on the rocky bottom, I was able to cool off up to my shoulders. I reveled in the touch of the current supporting and massaging my back, and let my gaze relax into soft fascination with the patterns of light and the bed of eelgrass waving next to me like a river nymph’s hair.

When something bumped my bare ankle, I peered into the water and tried to squint past the surface glare. Even with polarized sunglasses now actually on my face where they belonged, I couldn’t make the shapes resolve into anything identifiable. Was that a fish? A crayfish? A floating leaf? A river monster?

I stood up and walked to shallower water. Still, any moving shapes were camouflaged beneath the surface glare. Oh sure, I could have put my face into the water and opened my eyes to see better, but then debris would wash in and my contact lenses would wash out. I’ve always struggled with getting swim goggles to seal, and anyway, I didn’t have any stashed in my bike panier today.

Once again, I thought longingly of nictitating membranes. Water animals have them too. Exotic ones like sharks, sea lions, crocodiles, and manatees, but also our locals, like beavers, frogs, fish, turtles, ducks, and loons can close their third eyelids underwater. While many mammals (like us) have lost this amazing adaptation, lions, cats, camels, polar bears, rabbits, aardvarks, and those busy beavers still have this cool trick in their eye pocket.

As I stood there wishing for a way to see underwater, a sudden jolt of brilliance hit me. My new Olympus Tough camera—with its waterproof casing—was tucked inside my panier. Within minutes I was hitting record and submerging it into the current. I couldn’t see to aim it, or hold it still in the surprisingly strong flow, but this was better than nothing. I pulled it out, stopped recording, and hit play.

On the LCD screen, dozens of small fish, about the size of cigars, each with a dark stripe from eye to tail, darted over mini hills of sand and among green plants. In one patch, chartreuse green algae undulated like soft feather boas in a graceful dance.

On the surface, all I could see was sparkling light and impressionistic shapes and colors. I could feel fish nipping at my ankles, but could see almost nothing. The world that the camera revealed was full of motion, light, color—and also life. Soft green fuzz topped the rocks, ribbon-like plants undulated playfully, and many sizes of those fish darted easily among the bubbles my wrists stirred up as they resisted the flow.

I may not have my own built-in swim goggles, but my underwater “eye” is pretty special, in its own way: I can share what it sees with you! Visit my blog or the Museum’s YouTube channel to watch the fish dart and algae dance. It may really open your eyes to what’s underwater!

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our exciting Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

A Kid’s Eye View

Back in 2013, I took a group of kids on a paddling trip down the Namekagon River. Lately, I’ve been thinking back on that trip, and this week I’d like to share that experience with you again.

As the six kids gathered at the river landing, I saw looks of shyness, uncertainty, and excitement. The paddling lesson brought looks of concentration and some confusion, then boredom when they got it. As John Kudlas, our favorite river ecology instructor, taught about water quality, the faces of these mostly sixth and seventh graders showed focused interest. Here, with school out and a classroom without walls, I could see them learning.

Before embarking, we dipped our nets into the riffles and caught macroinvertebrates (the immature stages of insects that spend part of their life in the water before gaining wings and flight). As water quality indicators, the species we caught showed that the river is healthy.

Grant points out a turtle on a log. Photo by Emily Stone.

As we paddled, I noticed marsh marigolds in bloom (it was June), scouring rushes starting to poke up through the water surface, and a couple of dragonflies. Birds sang from every bush and tree in a cacophony of joy, aggression, alarm, and plain chattiness.

I marveled at the bald eagle, sitting calmly in the white pine as we floated underneath. I noticed the power and grace with which the great blue heron rose from its hunting spot. I observed the many aquatic plants still just barely breaking the river’s surface, while last year, with the early spring, they had been in bloom or already gone to seed.

But what do the kids see? Sometimes I worry that in this age of television, video games, and internet, kids will lose interest in nature, and lose the ability to notice things in the unfamiliar complexity of the wild.

So I was excited when, at the campsite on our second morning, the kids took the small digital cameras I gave them and eagerly disappeared into the woods to take photos. Besides giving them an excuse to look closer, compose a frame, and enter our photo contest that summer, it also gave me a glimpse behind their eyes.

What did they notice? The first photos on each camera show smiling faces as the kids “labeled” their cameras with a self-portrait. Then came the images of sparkling water and green trees, sunlight glinting off the rapids the kids were all eager to run, and the river disappearing around corner into the great unknown.

The photos show close-ups of bugs—a dragonfly and stonefly that came to visit our picnic table. We’d found the aquatic nymphs of both insects with John the day before. One photo even shows a backlit oak leaf, its veins and chlorophyll glowing in the morning sun.

The fascinating patterns made by leaves in a patch of jewelweed must have captured the attention of one youngster who used their juicy stems to sooth mosquito bites. His observant eye also caught psychedelic reflections of light and leaves on a pool of water between three rocks.

Here we saw a proud angler, pole and tackle box in hand; there we saw his sister, stretched out on her belly, taking photos from an ant’s eye view. On her camera, I found that photo of the grass jungle, each delicate seed head silhouetted against the clear blue sky. Other, taller bunches of grass arch gracefully in the morning sun.

For a different view, several kids looked up into the trees, and caught the magnificence of old growth white pines reaching their gnarled braches to the sky. Then they looked down, and captured gaywings (small, hot-pink wildflowers) in ethereal morning light, and pure white starflowers against the backdrop of a fallen log.

Some photos were blurry, a few were crooked, and some include the photographer’s thumb, but overall, I was thrilled. These kids could still see nature. They will be our next generation of scientists, conservationists, journalists, and engineers. Their ability to see nature will help make sure that it is not overlooked.

Katie takes one more photo with her dad. Photo by Emily Stone.

I don’t get to lead another canoe trip for kids this summer, but I am excited to see the world through the eyes of others again. The Museum’s Northwoods Babies Photo Contest just opened for submissions, and photos from kids and adults are already rolling in. Between now and September 1 (the submission deadline) I hope to see gaggles of goslings, backyard fox kits, and hungry caterpillars pour into my inbox.

We’re holding the photo contest to get everyone thinking about what it’s like grow up wild in the Northwoods—which is the subject of next year’s exhibit. With the help of a sponsorship from James Netz Photography in Hayward, and many other local businesses, we’re able to offer cash prizes to the winners and a prize raffle for all participants. The public will be able to vote on a People’s Choice award on our Facebook page in September! To find all of the rules and instructions, visit cablemuseum.org/photo-contest/.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our exciting Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.