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Karen Murchie, Ph.D., Shedd's Director of Freshwater Research, smiles warmly in front of Shedd's Great Lakes exhibit. Karen Murchie, Ph.D., Director of Freshwater Research

Essay: This Shedd scientist is changing the way people view freshwater fish

For most of my life, I have lived near one of the Laurentian Great Lakes. I have fond memories enjoying perch (yellow perch) and pickerel (walleye) dinners with my family on Lake Erie. It was on Lake Superior where I learned how to expertly solo a canoe. And all five of the Great Lakes have been the setting for countless moments with friends on boats and on beaches.

Like most things, you don’t always have a full appreciation of their value until you start looking at them with a new lens. I had never been far from a large body of freshwater until I lived in The Bahamas full-time for 5 years. It was upon returning back to the Great Lakes region when I started my job with Shedd Aquarium in 2016 that I had a renewed appreciation for the immense resources that these grand bodies of water hold, and how fortunate the US states and Canadian province that border these lakes are.

Researcher Dr. Karen Murchie standing in a stream in a forest.

Aside from boasting 21% of the world’s supply of surface freshwater and providing drinking water to more than 40 million people, they are also home to amazing aquatic animals – my favorite being the fishes! The commercial, recreational and tribal fisheries these animals support is culturally and economically significant. More than 75,000 jobs are related to these fisheries, and the annual value is over $7 billion. Celebrations centered around Great Lakes fishes are part of the fabric of the region, with people making their own memories associated with these freshwater gems daily.

There are several threats to our incredible Great Lakes resources from invasive species, pollution, loss of habitat and climate change, but there is also a significant collaborative effort to manage, protect and rehabilitate the fisheries. I am excited to play a role as a fishery biologist at Shedd to understand more about the migratory fishes in the Great Lakes and contribute that knowledge to effective conservation.

Two sucker fish swim among mossy rocks in a wild river.
A Shedd researcher stands in a stream, writing down observations.

Our work at Shedd involves filling in the data gaps around the most abundant migratory fish family in the Great Lakes — the suckers. These native fishes are swimming superheroes and you may not have ever heard of them before because they aren’t the more common recreationally fished species, nor are they typically served at lake-side restaurants. BUT we call them the wildebeests of the Great Lakes for a reason.

In the spring, they make remarkable migrations in large numbers, from hundreds to thousands into individual creeks and rivers from one of the main bodies of the Great Lakes. Over a period of a couple of weeks, the suckers spawn, which is important to sustaining sucker populations. What is less obvious is that during their spawning, they are also adding a buffet of nutrients into the tributaries, right after these creeks and rivers are emerging from their long winter’s nap. These nutrients, like nitrogen and phosphorus are gobbled up by the base of the food chain. Algae grows faster, aquatic bugs grow bigger, and that activity gives the food web a nice kick.

However, shifts in climate may start to shift the timing of when suckers show up to reproduce, which could have a cascading effect on the food web. To investigate this further, we have harnessed the incredible power of volunteers across three states (IL, WI, MI) to monitor the timing of sucker migrations in tributaries of Lake Michigan and Lake Superior and assist with understanding the local impacts of global climate change.

Shedd researcher Karen Murchie, Ph.D., stands in a cold local stream taking measurements.
Two white suckers, well-camouflaged with their brown scales , huddle against the rocky, pebbled floor of a river.

Over the last 5 years, over 45 citizen scientists have made it possible to simultaneously collect data on 15 tributaries in both urban and more rural settings. I have witnessed the enthusiasm and passion that volunteers exhibit to assist with gaining more information on the cues that suckers hone into for their migration timing and sharing their observations with others. Additionally, volunteers are raising the profile of the underappreciated sucker species, like longnose suckers and white suckers, becoming ambassadors of Great Lakes migratory fishes.

At a time when we need to make sure the public is engaged to advocate for protection of our natural resources, this program demonstrates the dedication and energy that people have to get involved to make a difference for our Great Lakes and the animals that call them home.