Invasive carp leap when disturbed and can injure boaters. Photo: U.S. Fish and Wildlife Service
Editors note: This story is part of a series relevant to the International Joint Commissions biennial meeting next Wednesday and Thursday in Windsor.
Two approaches to keep ravenous carp and other invasive species out of Lake Michigan are gaining ground, but both could be years from completion.
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Electrical barriers in the Chicago Sanitary and Ship Canal are the only obstacles keeping silver carp and other aquatic invasive species from entering the lake. The carp could harm native Great Lakes fish that use similar resources. And silver carp can injure boaters when they jump out of the water.
The roots of the problem go back to 1900 when the Mississippi River and Great Lakes watersheds were connected by the canal. Water flow was reversed on the Chicago River, preventing waste from flushing into Lake Michigan, a source of drinking water for Chicago.
The Asian carp originally spread to the ship canal via the Mississippi River. Arkansas catfish farmers imported the fish in the 1970s to clean their ponds of algae and other debris. Some of the ponds filled with water from large floods in the 1990s, introducing carp to the river basin.
Now they’re getting close to the Great Lakes: Silver carp were detected about one mile south of the electrical barrier in mid-September.
The International Joint Commission, which advises the U.S. and Canadian governments on Great Lakes issues, is planning what to do if that barrier is breached. A proposal will be discussed next Wednesday at the group’s 2009 biennial meeting in Windsor.
“We’re looking at it as basically a second line of defense–an eradication effort where appropriate if your prevention measures fail,” said Mark Burrows, secretary of the Binational Aquatic Invasive Species work group and the IJC Council of Great Lakes Research Managers.
Rapid response
Currently, there is no plan approved by Canada and the United States to quickly respond to invasive species that can upset an ecosystem and cause devastating economic problems.
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Great Lakes agencies “would basically have to organize around the particular incident and set up a response on the fly instead of having something that’s already been thought out ahead of time,” Burrows said.
Some experts recommend a response system developed by forest firefighters in need of quick agency organization and approval. The system has been used to respond to oil or hazardous chemical spills, forest fires and other emergencies. It was also adopted following Hurricane Katrina, Burrows said.
Use of the plan to combat invasive species requires a strong mandate from both national governments and could take two or more years to establish, he said. A funding source has not been identified.
Separating the Mississippi River and Great Lakes basins
Burrows said the binational commission thinks stopping invasive species with a physical barrier also merits consideration.
“I think that’s feasible, and it’s something that could be done over the long haul,” he said.
That’s the plan favored by the Alliance for the Great Lakes, a coalition of environmental groups.
“I think the smartest way to be sure that we’re not going to have this conversation at five or 10 or 50 years from now is to re-engineer the system so water and critters don’t move between the Mississippi River system and the Great Lakes, and to me that means physical separation,” said Joel Brammeier, president of the alliance.
Brammeier was the lead author of a 2008 alliance study that addressed the merits of six sites where a physical barrier, such as a concrete wall to stop water flow, could be placed.
It took two years and $120,000 to complete. A new $400,000 study begun earlier this year by the Army Corps will consider the physical barrier and other alternatives. That study will expand on the alliance’s work, including invasive plants, mussels and plankton in addition to fish.
It will take time to consider the economic and social aspects of such an undertaking, said Chuck Shea, project manager of the Corps’ electrical barrier project. And Brammeier does not suggest completely stopping major industries from using the Chicago Waterway System.
“The goal is really to maintain and improve the ability of the waterways to support the economy of the Chicago region while recognizing we have a problem to solve,” he said.
But each site has varying amounts of cargo ship and recreational traffic that could be affected. Accommodating it with boat lifts without a process to sterilize water, for instance, may still risk invasive species transfer.
Putting a Band-Aid on invasive species invasion
The electrical barriers continue to operate but remain vulnerable.
“It’s not a failsafe,” Shea said. “We don’t think any fish should be getting through the first barrier. However, as I said they are electrical and mechanical systems and there are times that we will have to do maintenance on them.”
Both structures are expected to last 20 years. But even with maintenance, they are at risk of failure from natural disaster damage, accidents or human error. The barriers also can’t screen movement of smaller organisms, such as invasive fish eggs or plants.
Brammeier thinks physical separation is the next step.
“Is it going to happen tomorrow?” he asked, “No, but the conversation is already happening–the train is leaving the station. I think there’s no question that the region is serious about fixing this problem permanently.”
Related story: Chemical carp control considered at Chicago
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