Asian carp will certainly survive and most likely thrive if they are able to make their way into Lake Michigan, according to a study released Monday by the University of Michigan.
Some researchers had theorized that the invasive species would do well in areas close to the shore where there are more nutrients but might struggle in open water where zebra and quagga mussels – also invasive species – eat most of the plankton that forms the base of the aquatic food chain.
But the new study suggests that Asian carp would be able to sustain themselves by feeding on the feces of invasive mussels and other waste products.
“The hypothesis was that they would not do well in the open water of Lake Michigan because zebra and quagga mussels have already filtered out a lot of the things that we think of Asian carp as eating,” said Molly Flanagan, vice president for policy at the Alliance for the Great Lakes, where she is responsible for leading efforts to prevent invasive species reaching the Great Lakes. “It turns out that Asian carp can eat a lot more things than we expected and can actually eat and feed on the waste that zebra and quagga mussels produce.”
For Flanagan, the new study reaffirms the importance of Congress appropriating funding to allow the U.S. Army Corps of Engineers to build defenses at Brandon Road Lock and Dam to prevent Asian carp reaching Lake Michigan.
“We are never going to eliminate Asian carp by fishing them out,” said Flanagan. “That’s why we need these additional protections that the Army Corps of Engineers has recommended at Brandon Road Lock.”
The plan involves a series of defenses including a bubble screen, an acoustic deterrent and a flushing lock designed prevent the carp from spreading further.
The big fear is that if Asian carp do reach Lake Michigan they will threaten the $7 billion Great Lakes fishing industry.
But the fish can also be a threat to recreational boaters.
“Silver carp fly into the air if they are startled by boat motors or splashing or movement in the water,” said Flanagan. “If you are in a boat and get smacked in the face by a 30-pound fish that’s not a good thing for the economy of the Great Lakes and it is also a public health threat.”
As of now, the Brandon Road project, which has a price tag of more than $800 million, is awaiting congressional approval.
“The house passed its appropriations bill for fiscal year 2020 and it included increased funding for the Army Corps of Engineers and language that directed the corps to use some of that increase to begin the pre-construction engineering and design phase at Brandon Road Lock and Dam,” said Flanagan. “The Senate has not yet passed its appropriations bill. We expect them to start moving on them in September when they return from recess.”
Gov. J.B. Pritzker has also been supportive of the plan but wants the federal government to provide more money, said Flanagan. At the moment, the federal government would pick up 65% of the cost of the project, leaving states to fund roughly $290 million in remaining costs.
And while that price tag may seem high, the cost of allowing Asian carp into the Great Lakes would be far greater.
“I think the plan to put additional protections in place at Brandon Road Lock and Dam is our best chance to stop invasive Asian carp from getting into Lake Michigan,” said Flanagan. “With Asian carp this really is a case where an ounce of prevention is worth a pound of cure.”