Bighead, silver, and black carp—not to be confused with bigmouth buffalo or other native bottom-feeders—are all invasive species that exist in the Mississippi River basin and are on the doorstep of the Great Lakes.
These three species of invasive carp were introduced to the U.S. from Europe in the 1970s to knock down algal blooms in aquaculture facilities and wastewater plants, as well as for human consumption. However, they quickly escaped and started wreaking havoc. Besides knocking people out of their boats, these invasive carp species pose a huge risk to the biodiversity of the waters they occupy, including threatening the survival of many species of fish that we like to catch and eat.
Researchers and managers have identified the Brandon Road Lock and Dam site on the Des Plaines River as a pinch-point for silver, bighead, and black carp attempting to migrate into Lake Michigan. Now, the task is to set up a series of barriers to keep these invasive carp from crossing over this line.
For the better part of the last decade, this project has been contemplated as a part of the Water Resources Development Act (WRDA), a huge piece of federal legislation that funds all sorts of hydrologic infrastructure. The construction of this project was authorized in the 2020 WRDA. Members of Congress aim to fund the project in the 2022 version of the bill, which is being considered this summer.
Like most invasive species, bighead, silver, and black carp don’t have any natural predators where they occur in the United States. While these three species don’t currently occupy the Great Lakes watershed, common carp, goldfish, and grass carp do live in the basin.
Due to the voracious omnivorous appetites of all these invasive carp, they cause serious damage to forage fisheries and aquatic plants. These effects ripple into other fisheries throughout aquatic ecosystems, and the impacts would only increase if these carp make their way into the Great Lakes.
The Great Lakes basin is incredibly diverse. It ranges from Lake Superior's extremely cold and deep waters to the shallow bays, rivers, inland lakes, and bayous that dot the coastlines. Those differences in hydrology support vast numbers of fish species—many of which we like to catch and others invaluable to supporting the rest of the ecosystem.
“Invasive carp pose a massive threat to the biodiversity of the fisheries that they invade. From the game fish that we consume as anglers to the forage fish that provide for the rest of the food web, invasive carp compromise biodiversity wherever we find them,” Drew YoungeDyke, Director of Conservation Partnerships at the National Wildlife Federation’s Great Lakes Regional Center, told MeatEater.
Silver and bighead carp also have a tendency to jump up to 10 feet out of the water when they feel the vibrations from boat motors, geese taking off, or when they’re disturbed by something below the surface. This erratic behavior causes all sorts of problems for people who like to spend time on the water—namely, the fear of being knocked out of a boat by a flying fish.
Spencer Neuharth has his fair share of these experiences with invasive carp.
“I grew up 30 miles from Gavin’s Point Dam on the Missouri River in South Dakota. It's the last dam on the Missouri. In my lifetime, I saw that stretch of water go from having no silver or bighead carp to being one of the most invasive carp-infested waterways in America,” he said. “It dramatically hurt the walleye fishery and ruined a lot of recreational boater opportunities. It also makes sampling much more difficult for biologists who now have to deal with invasive carp filling up every gill net and trammel net they set. This isn't just annoying, but it also impacts their studies on paddlefish and sturgeon in a portion of the Missouri that's incredibly important to both.”
Apparently, invasive carp are pretty tasty, but that doesn’t mean we want them to harm other fisheries or our opportunities to enjoy them.
The U.S. Geological Survey has spent years researching the potential impacts of black, silver, and bighead carp in the Great Lakes, specifically Lake Michigan. USGS found that within a mile of the shoreline, there is plenty of food for these invasive carp to eat, especially connected to the drowned river mouths and bayous that dot the coastline of Lakes Michigan and Huron. Essentially, these shoreline aquatic habitats are nearly ideal sites for invasive carp to invade. These place also happens to be a really good recreational fisheries for largemouth bass, panfish, and pike.
Similarly, the National Oceanic and Atmospheric Administration has been researching to model the risk of these invasive carp on walleye and perch populations in Lake Huron. Those studies suggest that when invasive carp are present at nearly any rate, perch would take a big hit. When these species of invasive carp are present in large numbers, both walleye and perch stocks will decline.
All those fish support robust recreational fisheries available for all of us to enjoy, but they’re also very economically important.
“Fishing on the Great Lakes generates more than $7 billion in economic impact which supports jobs, businesses and communities along their 9,000 miles of shoreline,” Chad Tokowicz, a former policy manager for the American Sportfishing Association, said in a press release.
However, that impact will be felt even harder in Michigan where most of that shoreline exists.
“Michigan’s recreational fishery, the towns, communities, livelihoods and people it supports, are all at stake,” said the Executive Director of Michigan United Conservation Clubs, Amy Trotter. “This issue of keeping invasive carp out of the Great Lakes has festered for too long. They pose a risk to our waters, wildlife, and recreational opportunities that could collapse a two-plus-billion-dollar industry that Michiganders depend on.”
That’s something that we really can’t afford to lose.
The spread of silver, bighead, and black carp is a national problem, but the focus right now just happens to be at the intersection of two of the nation’s major waterways.
“Illinois is where the Great Lakes and the Mississippi River basins connect, putting us on the front lines of the spread of invasive carp,” Colleen Callahan, director of the Illinois Department of Natural Resources, told MeatEater. “The Brandon Road Lock and Dam project in Joliet will create a primary barrier system to help prevent the spread of invasive carp into Lake Michigan. It’s a project that is important to the ecological and economic health of the entire Great Lakes region.”
The Brandon Road Lock and Dam is the last barrier to keep these invasive carp species from entering the Great Lakes basin, but it needs some improvements to ensure that these fish can’t pass from the Mississippi River basin into Lake Michigan. These include air bubble curtains, electric barriers, and acoustic deterrents to keep these invasive carp from traveling further upstream.
In 2020, the Army Corps of Engineers began the planning and design phase of this project by drawing up specific plans, looking for contractors, and determining the feasibility of the project. Since then, huge coalitions of people have focused on getting the rest of the money to pay for this build.
The House version of WRDA recently passed out of that chamber, and the Senate is preparing to consider its own version of WRDA. Both versions would fund a big chunk of the Brandon Road Lock and Dam project (80% and 90%, respectively) but would not cover all the costs.
Many are excited to see this finally come to fruition but are still advocating for the federal government to fund the entire project balance.
“The Brandon Road Lock and Dam is a project of national importance, so we’d really like to see full federal funding of the project to ensure the continued health and vitality of those fisheries for future generations,” YoungeDyke said.
This is our last and best chance at keeping more invasive carp species out of the Great Lakes, and this project needs all the support it can get.
If you’d like to help get this project to full funding, call the U.S. House switchboard at (202) 224-3121, have that office connect you to your Representative’s staff, and tell them that you support full federal funding for the Brandon Road Lock and Dam Interbasin Project in the Water Resources Development Act. When you’re done there, use this call sheet to call your two Senators and tell them the same thing.
Feature image via Wikipedia Commons.