Great Lakes invasive carp barrier moves forward after Trump memo

Underwater speakers, bubble curtains, a flushing system, electric shocks — an aquatic firewall is under construction on the Des Plaines River in Joliet, Illinois.

Planned since 2020, its purpose is to stop invasive Asian carp from spreading to the Great Lakes, including those near Wisconsin.

But a February action by Illinois Gov. JB Pritzker put future phases of the project in question. Pritzker, a Democrat, delayed a state land transaction needed to advance the project. He said he feared the Trump administration — which was pulling back money from many other programs funded by the bipartisan infrastructure law — would jeopardize federal funding already allocated for the project.

Last week, President Donald Trump affirmed his support for “preventing the spread of invasive carp” in a White House memo that promised “deadline-oriented investments of taxpayer dollars” from the federal government.

“The State of Illinois, where the Brandon Road Interbasin Project is located, must cease further delay in cooperating with this effort,” he wrote.

The memo satisfied Pritzker, who said in a statement the same day that he was “glad that the Trump Administration heard our calls.”

The statement said Illinois “received the necessary assurances” to move forward with plans.

Trump’s memo was significant, said Don Jodrey, a lobbyist in Washington for the environmental nonprofit Alliance for the Great Lakes.

“The president is recognizing the threat to the Great Lakes posed by the invasive carp,” he said. “I think that is really significant. We welcome that.”

Funding for the project came from bipartisan legislation spearheaded by the Biden administration, Jodrey said.

“Both administrations have been supportive in different ways. But I was really thrilled to see the Trump administration put it in writing,” he said.

Jodrey also praised Michigan Gov. Gretchen Whitmer’s leadership on bringing this matter to Trump’s attention. Whitmer called Trump’s memo a “huge win.”

Barrier in choke point between Mississippi River basin and Great Lakes

The Chicago-area barrier targets the main man-made connection between the Mississippi River basin and the Great Lakes basin.

“It is truly the pinch point. It is the one place where you have a large canal that connects the two,” said Jake Vander Zanden, who directs the University of Wisconsin-Madison Center for Limnology.

The two watersheds were unconnected until 1900. They had distinct ecosystems with species that didn’t previously interact, Vander Zanden said.

He said invasive Asian carp species are already common in the Mississippi River basin. They are primarily river-dwelling.

“If it gets in the Great Lakes, it’ll swim around the shores, and then it’ll colonize these river systems all throughout the basin. That’s the concern,” he said.

He said carp feed mostly on plankton and algae. Though Lake Michigan has lost much of its plankton to invasive quagga mussels, he said, plenty of plankton remain in nearby wetlands, bays and connected water bodies like Lake Erie.

Invasive carp have already been detected in western Wisconsin’s Mississippi River basin. But those populations are still at low, generally nondisruptive levels, Vander Zanden said.

In his memo, Trump said carp outcompeting native fish species for food “poses a significant risk to Great Lakes fishing, boating, recreation, and tourism.”

The U.S. Army Corps of Engineers is building the barrier. It’s still in preconstruction phases unaffected by the Illinois governor’s pause, Corps spokesperson Allen Marshall said in an email.

Last week’s resolution of funding concerns “has not delayed advancement of future construction designs,” Marshall said.

“Future construction is contingent on receipt of funding, required permits, and necessary real estate interests from the State of Illinois,” he said.