GRAND RAPIDS, Mich. (WOOD) — The Illinois Department of Natural Resources has confirmed an invasive carp has been caught past the electric barriers in the Chicago-Area Waterway System. However, a Michigan biologist is telling people to back away from the proverbial ledge.
According to a news release, the fish was caught Thursday in Lake Calumet — just 7 miles away from Lake Michigan — by crews from the IDNR and the U.S. Army Corps of Engineers. The silver carp was approximately 38 inches long and weighed approximately 22 pounds. It was found days after an angler reported seeing the fish in the lake.
Invasive carp, formerly known as Asian carp, are considered a major threat to the Great Lakes. The imported fish have no natural predators in the Mississippi River system and have overtaken ecosystems there, in some cases comprising up to 70% of an ecosystem’s fish population.
Biologists worry that if enough invasive carp made it into the Great Lakes and established a breeding ground, they could devour the food resources of many other popular fish, including walleye and rainbow trout, not only upending the ecosystem but hurting the Great Lakes’ billion-dollar fishing industry.
According to the IDNR, it is the third time an invasive carp has been found past the electric barriers. A bighead carp was caught in Lake Calumet in 2010 and a silver carp was caught near the T.J. O’Brien Lock and Dam in 2017.
Seth Herbst, the manager of the Aquatic Species & Regulatory Affairs Unit, within the Michigan DNR’s Fisheries Division, told News 8 that while it’s never good to find an invasive carp past the boundaries, there are a lot of positives to take away from this incident.
“It’s very encouraging that this was a report that was provided to the Illinois DNR by an angler,” Herbst told News 8. “We have hundreds of thousands of anglers on our waterways, seemingly every day and certainly every year. They see way more than what any resource agency would be able to see just with our professional staff. So, increasing awareness among our anglers has always been a priority for invasive species reporting.”
Herbst also said context is important when seeing a headline about invasive carp. Three fish have been confirmed — and caught — above the barriers, while more than a million pounds of invasive carp are harvested every year from the sections of the Illinois River below the barriers.
“We have thousands of environmental DNA samples that are collected on an annual basis throughout the Great Lakes Basin. We have prioritized various locations in Michigan waters, and we haven’t had substantial evidence that points to any bighead or silver carp establishments in the basin,” Herbst said.
Currently, the primary barrier to keeping invasive carp out of the Great Lakes is a series of electric barriers near Romeoville, Illinois. The barriers put an electric current into the water that stuns fish to prevent them from continuing upstream. Unlike other treatments for invasive species, the electric barriers impact all fish species. Herbst says that any potential impacts on the ecosystems further upstream are a small price to pay for protecting the Great Lakes.
“It’s a trade-off that resource agencies are willing to make. It (does) prevent some of that natural connectivity of native species. But in terms of overall resource management, resource protection, it’s a critical piece of infrastructure,” Herbst said.
Studies have shown that the electric barriers do have some deficiencies. The barriers have a greater impact on larger fish compared to smaller ones, and boats that go through the barriers can create a back current that pushes the small fish through the barriers. That’s why Herbst and leaders at the Michigan DNR are pushing for more action — notably the Brandon Road Lock and Dam Project — a natural chokepoint in the water system.
The U.S. Army Corps’ plan for the Brandon Road Lock and Dam was presented to Congress in 2019. It is estimated to cost around $850 million, with Michigan, Illinois and federal funds covering the bill.
According to a Michigan DNR spokesperson, the first construction contracts are expected to be awarded in the next two years.