Science & Nature
The Unglamorous Sucker Fish Plays a Key Great Lakes Role. A Shedd Scientist and Her Band of Volunteers Want to Tell You Why
As a kid growing up in Wisconsin, Frank Langley learned the difference between game fish and rough fish.
Game fish are the ones anglers want to catch. In the Great Lakes, this include bass, walleye, trout and northern pike, among others.
Rough fish, or “bottom feeders” as Langley and his fishermen pals called them, are the species no one’s actively trying to hook: suckers, carp, bullhead and the like.
“Most people don’t eat them,” Langley said of rough fish. “Although you can, most people don’t.”
But these days, Langley, who’s now semi-retired, can’t wait for the annual springtime rush of suckers, when the fish migrate from Lake Michigan into creeks and streams near his Door County home.
“It’s really quite exhilarating,” he said. “Typically you’ll see the trout before you see the suckers, and they’re just racing up and down these creeks. And then when you see the suckers, the suckers tend to come in droves. They come in large groups and it’s really amazing to see as many coming in like that.”
Adding to the excitement, Langley said: “Karen gets very enthusiastic about the initial sightings. Like, ‘Oh my god, thanks for telling me.’ It’s a lot of fun.”
“Karen” is Karen Murchie, director of freshwater research at Shedd Aquarium. And Langley is one of the dozens of volunteers Murchie has recruited over the past eight years to monitor the arrival of suckers in Great Lakes tributaries.
“We’re missing tons of life history aspects for suckers; they just aren’t as well studied,” Murchie said. “And an important thing for migratory fish is knowing ‘Hey, what’s the cue they’re responding to? How do they know when it’s time to move and go reproduce?’”
Now she has an answer.
In analyzing the first seven years of data collected by her cadre of volunteers, Murchie has been able to determine the best predictor of sucker movement. It’s water temperature: 43.3 degrees Fahrenheit, to be precise, which is essentially the sucker equivalent of “on your mark, get set, go.”
Murchie recently published these results in the journal Environmental Biology of Fishes. In the paper, she name-checks every single one of the 80 volunteers who’ve participated in the project, be it for a single year or all seven.
“I thought it was an important thing to do, instead of just a blanket ‘Thanks to all the volunteers.’ I wanted to call them out specifically,” and acknowledge their contributions to “real, meaningful, publishable science,” Murchie said.
Of equal significant, she said, is the way the project demonstrates the value of community science not only in terms of the gathered data but in the creation of advocates for wildlife and the ecosystems they inhabit.
“They become real champions to talk about these species,” Murchie said of her monitors.
And suckers (Catostomidae) need all the fans they can get.
Karen Murchie, director of freshwater research at Shedd Aquarium. (Patty Wetli / WTTW News)
Raised in the tiny one-stoplight Canadian town of Norwich, Ontario, Murchie didn’t set out to be the preeminent authority on an underappreciated native freshwater fish.
“I was going to be an optometrist,” she recalled. “Because I had had a couple of eye surgeries, I was like, ‘Oh, eyes are interesting.’”
So off she went to optometry school, but in her third year at university, a funny thing happened.
Murchie went snorkeling for the first time, as part of a field course in Jamaica.
“A little fish — half purple, half yellow, called a fairy basslet — immediately came right up and swam at my mask. The entire time I was in the water, I was like, ‘Fish are the coolest.’ And that was the moment,” she said. “That was it.”
Her immersion in fish studies has, over the years, taken her to posts in Yellowknife — the capital of Canada’s Northwest Territories — and the Bahamas, where she spent a decade researching bonefish (Albula vulpes).
The shores of the Great Lakes may seem like a come down after those comparatively exotic locations, but Murchie insisted the opposite is true.
“In all honesty, I feel like this is the best place for me,” she said. “This is where I really can shine and be a champion, and not just for the suckers, but also highlighting the importance of freshwater not just as something for us humans to use but as a home for all these amazing animals.”
Think of all the attention given to migratory species like the wildebeest, the monarch butterfly or salmon. The movement of suckers is every bit as dramatic and awe-inspiring, Murchie said, if not more so — with close to 100,000 once counted in a single tributary — but it’s largely ignored because the fish is less visible and is considered less charismatic and not as tasty. To people, that is.
This human-centric bias is one of the biggest challenges facing Great Lakes’ fish in general when it comes to attracting interest and rallying people to protect these native fish and their habitat.
Compared with, say, the Caribbean, freshwater systems aren’t as inviting. They can be cold or murky, hampering access, and the aquatic species aren’t as brightly colored, which in turn has led to fewer photographs, videos and documentaries. In an era dominated by visuals, there simply isn’t the same level of imagery or storytelling surrounding Great Lakes fish, Murchie said.
Suckers, which are sometimes labeled a “trash” fish, are triple cursed: neither a tourist draw nor popular with recreational anglers or commercial fishing operations, and as a result not a priority for government or academic research.
The opportunity to fill a niche no one else was pursuing appealed to Murchie.
“That’s really how suckers chose me,” she said. “I’ve loved all the species I’ve worked with, but suckers have an extra special big part of my heart because they are kind of the underdogs in a lot of cases, in being misunderstood. They’re not flashy — we say drab is the new fab. And when you do look at them, you’re like, ‘Yeah, look at their cute little faces.’ They’re really neat.”
They’re also vital to the Great Lakes ecosystem, forming a foundation on which other organisms depend, from macroinvertebrates to bald eagles.
As they move into creeks and streams to spawn, suckers add a buffet of nutrients like nitrogen and phosphorous — things you might find in fertilizer — basically acting like gardeners. These nutrients are taken up by algae and invertebrates, with studies showing algae growing 50% faster in areas where suckers were present, and some aquatic insects bulking up by 12%, according to Murchie.
“If you were a trout, and you love to eat (those insects) and you can eat a bigger one, it’s like upgrading from a hamburger to a quarter pounder. It’s more calories per bite and that’s a big win,” she said.
Suckers themselves are prey at every stage in their life cycle not only for other fish, but also birds including eagles and osprey, and even wolves.
Trout will gorge themselves on sucker eggs, Murchie said, and other fish species will hang out at the mouths of creeks and rivers to feast on the “smorgasbord” of young suckers as they head back into the lake.
“There’s this big connection to terrestrial and aquatic habitats and so many other organisms that rely on suckers directly and indirectly,” she said.
Yet because of suckers’ rough fish label, the intricacies of this delicate food web have been poorly understood and the information vacuum has, in some instances, led to disheartening actions.
“I’ve seen, unfortunately, in locations where there’s been large numbers of adult suckers hauled out and left on shore to die,” Murchie said. “It’s really just a lack of knowledge of how important these species are for an ecosystem as a whole.”
In many ways, she said, her work with suckers is as much about public relations as it is science.
Karen Murchie places a depth ruler in a stream in advance of sucker fish migration. (Courtesy Shedd Aquarium)
At the beginning of every monitoring season, Murchie lugs equipment like temperature gauges and measuring sticks to some 15 to 20 tributaries up and down the west coast of Lake Michigan — from Highland Park to the tip of Door County — and the south shore of Lake Superior. Volunteers have told her that the year’s first Murchie sighting has become one of the most reliable harbingers of spring.
Some of the gear registers the movement of suckers Murchie has microchipped, like you might tag a pet cat or dog. One of the first things she learned was that the fish will return to the same spawning site year after year (unlike salmon, suckers don’t die). It’s the kind of site fidelity that would charm birders (think Monty and Rose returning annually to Montrose Beach) but doesn’t generate the same excitement for fish, she noted.
Murchie also discovered, courtesy of the microchips, that large groups of suckers will congregate outside a tributary, apparently waiting for their temperature cue, with the exception of a few advance male “scouts,” who make forays upstream overnight to scope out the situation.
Still there’s only so much technology can tell her. And because there’s only one of her, Murchie came to rely on a network of volunteers to help document suckers arrival at numerous locations.
“We need somebody with a pair of eyes to go look in the creek and be like, ‘Are the suckers here yet? Nope? OK, here’s what I’ve noted: this is the date I’m here, the time, basic weather conditions if it’s windy, sunny, rainy,’” she said.
Volunteers log their observations daily, sometimes for months as they wait for suckers to appear.
“When they’re at the site, they’re there maybe about 20 minutes in total, but it’s every day,” Murchie said. “I have volunteers, there’s been more than a foot of snow will have fallen and they’re like, ‘Must get to site,’ and they’ve strapped on their cross-country skis.”
Murchie has fostered that kind of dedication by emphasizing relationship building versus the transactional collection of data. She maintains steady communication with monitors, rewards them with custom-made “sucker swag” like keychains and neck gaiters — “It’s very exclusive merch,” she joked — and meets up in person when possible.
In return, Murchie was able to obtain the kind of detail she needed to determine the water temperature that triggers suckers’ migration.
Sucker fish enter a stream in droves as they prepare to spawn. (Courtesy Shedd Aquarium)
Volunteers have also assisted with the gap in storytelling that Murchie referenced. For every person Murchie can regale with anecdotes about sucker spawning — “They’re all vibrating and it makes this noise underwater, and even from above the water you can hear the splashing,” she said — her volunteers can reach so many more.
Frank Langley’s monitoring site of Heins Creek is well-known to anglers looking for trout. He’s run into folks not only from Wisconsin, but Illinois, Minnesota and even Iowa.
“They’re always quite curious, because I’m sitting there in front of a depth stick, with a backpack and writing stuff. So then we have conversations and I tell them what I’m doing,” Langley said.
The majority of the people he encounters are familiar with suckers as a rough fish, a misconception Langley then has a chance to correct, just like Murchie did for him.
“You’ll say, ‘Well, their excrement, their excess spawn and quite honestly themselves all are feed to the animals and plant life in the creek, as well as when they exit the creek,’“ he said. “When you tell them what’s happening and why they’re so important, the lightbulb comes on.”
While Murchie continues to fill in pieces of suckers’ life history puzzle, when it comes to developing conservation strategies for the species, half the battle will be in dispelling the notion of suckers as a trash fish, she said.
To that end, the kind of peer-to-peer exchanges related by Langley are crucial in changing perceptions and educating the public, Murchie said.
“That volunteer aspect, not just the science but the incredible advocacy for the animals, for the environment, I can’t do that alone,” she said. “This amazing community of volunteers that are rallying for this underdog group of animals ... that’s a beautiful thing.”
Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]
