An experimental underwater speaker system designed to repel invasive Asian carp is up and running in Genoa, University of Minnesota officials confirmed this week.
The announcement is a win for researcher Peter Sorensen and his team from the Minnesota Aquatic Invasive Species Center, who have been raising funds for the project since April, but at least one local stakeholder is voicing concerns about the project’s impact on the Mississippi River.
Mark Clements owns and operates Clements Fishing Barge below Lock and Dam No. 8, where the speakers are installed. He fears the sounds emitted — which researchers say have been proven in a lab setting to drive away invasive Asian carp — will impede the migration of native fish species.
“Our sole business is fishing,” Clements said. “A lot of these small river towns really survive on the fishing business. If that were to be crippled or hindered in any way, it could mean millions of dollars up and down the river.”
Sorensen, who declined an interview this week, has previously said that his experiment will not affect native fish. He and other project leaders will host a media conference Monday, at which point they will provide full details about the multi-year project.
“The native fish are just as important to me as keeping the Asian carp back,” Sorensen has said.
The Mississippi River is home to dozens of migratory species, such as lake sturgeon, paddlefish, flathead catfish, northern pike, walleye and bass. They regularly pass through the river’s lock and dam system in search of food and spawning habitat.
From bluegills that migrate just a few miles to sturgeon that have been tagged and tracked 800 miles away, “almost all the fish in the Mississippi River migrate,” said Ron Benjamin, Department of Natural Resources fisheries supervisor for the Upper Mississippi River.
There’s even a species of eel whose females spend their lives in the Upper Mississippi while males live in the river’s southern estuaries. When it’s time to mate, females swim south, meet up with the males and travel to the Sargasso Sea east of the Bahamas to spawn.
“These fish evolved to live in a big river, and for almost 10,000 years they learned to move to the habitat they need.”
The lock and dam system, completed by the U.S. Army Corps of Engineers in the 1930s, is an important tool used to control the river, but the construction also had a significant impact on fish migration, Benjamin said.
Strong swimmers and species with a longer lifespan have a better chance of making it through the system — they’re either powerful enough to propel themselves through, or they live long enough to move through naturally during periods of high water.
Slower swimming, shorter-lived species are more likely to be affected. The skipjack herring, once common in the region, essentially became extinct in the Upper Mississippi River after the lock and dam system construction, as did a species of mussel, Benjamin said.
It’s difficult to predict the impact of the underwater speakers, but Benjamin says Clements’ concerns are “valid.”
“It’s a big question mark,” he said. “I don’t know what the impact is going to be on native species.”
Sorensen and his team received permission for the project from the U.S. Army Corps of Engineers. The DNR does not have jurisdiction or permit authority over structural additions to the lock and dam system. It could request that the experiment be stopped if concerns arise, but Benjamin emphasized that the speaker system is just a temporary modification to a high-traffic area.
“If it were farther away on the spillway or further down the tam, that might be something that we’d be concerned about, but there are great big 5,000-pound tows going through that lock,” he said.
Benjamin also said efforts to stop the spread of Asian carp up the Mississippi may be too late. The invaders have been caught near the mouth of the St. Croix River and in Pool 6 near Winona. There are established Asian carp populations in southeast Iowa, and with the high water conditions earlier this summer, there’s a good chance they’ve already migrated north.
“(Sorensen) is not going to solve the whole invasive species problem by doing this, but he may find an effective way to contain them in a place where we don’t have them yet,” Benjamin said. “That’s the way science works. It’s a learning process.”