Shedd Aquarium Scientist Expands Study to Unravel the Mysteries of Migratory Suckers with Support from Door County Land Trust

Shedd Aquarium’s Dr. Karen Murchie has performed hundreds of fish surgeries on various species. Now, she can add longnose suckers (Catostomus catostomus) to the list. This spring at a creek in Door County, Wis., Murchie and other aquatic experts fitted 30 longnose suckers with small acoustic tags as part of a new study led by Shedd Aquarium and funded by the Door County Land Trust.

This project is the first longnose sucker study examining spatial ecology. Researchers will track the tagged fish and observe their movements to see whether longnose suckers return to the same spawning site year after year, how far they move during the year, what type of habitats they prefer, and whether there is a difference in movements between males and females.

“There’s still a lot we don’t know about suckers, and we can’t protect what we don’t understand,” said Murchie, director of freshwater research at Shedd Aquarium. “Tagging longnose suckers allows us to paint a better picture of their behaviors and needs so we can ultimately help these important fish thrive in the Great Lakes.”

During this year’s spring spawning migration, Murchie and experts from the U.S. Fish and Wildlife Service’s Green Bay Fish and Wildlife Conservation Office traveled to Heins Creek where longnose suckers were present. The team worked together to carefully catch the fish and transfer them to floating bins in the creek. One by one, the fish were moved to a surgery table and placed on their backs with water flowing in their mouths while Murchie performed a quick surgery to insert the acoustic transmitters, followed by two small sutures. Then, the fish were outfitted with external tags on their back to inform resource managers or anglers that the fish are part of Shedd’s study. This whole process only takes about five minutes from start to finish. After the tagging is complete, the research team briefly monitors the fish before releasing them back into the creek.

The Door County Land Trust purchased 30 acoustic transmitter tags for this study, enabling Murchie to tag and track this species of sucker.

“Suckers contribute to the incredible biodiversity in Door County that includes trout, walleye, herons, osprey, bald eagles and other beautiful animals,” said Emily Wood, executive director of the Door County Land Trust. “This tagging study is integral in understanding how we can best protect suckers as we continue our work to preserve Door County’s lands and waters for future generations.”

After tagging the longnose suckers, Murchie will gather data on their movements by utilizing a network of acoustic receivers that are part of the Great Lakes Acoustic Telemetry Observation System (GLATOS). As the tagged suckers swim around, the acoustic tags broadcast a series of “pings” in the water that are picked up by nearby receivers, allowing researchers to follow each individual fish’s movement through different waterways and observe where each fish spends the most time. Shedd is also tracking white suckers (Catostomus commersonii) using the same GLATOS network.

“The collaborative effort across different organizations is what truly makes this work possible,” said Murchie. “The more people care about suckers, the more we’re able to do to help them thrive.”

This study is ongoing and will continue to expand with plans to tag more longnose suckers next year thanks to a grant from the Fund for Lake Michigan. The findings on this species’ movements in Wisconsin can also help inform conservation strategies in Illinois, where longnose suckers are state threatened and much less common.

BACKGROUND: Suckers are an understudied and underappreciated group of migratory fishes in the Great Lakes. These native non-game fishes are often perceived as having no value, but they are an essential part of the freshwater ecosystem as they are the most abundant group of migratory fishes in the region. Suckers serve as a food source for other animals, including gamefish, mammals and birds, and add important nutrients to the water during their spawning migrations.

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Photo Credit: Name on files (Shedd Aquarium or Door County Land Trust)