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Lake Michigan, Home to Two National Lakeshores, On Brink of Being Invaded By Voracious Asian Carp


USFWS Biologist Heidi Keuler leaves leaping silver carp in her wake. USFWS photo.

If you thought round gobies and zebra mussels were scary invaders of the Great Lakes, brace yourself for the arrival of Asian carp, a voracious fish that could decimate the lakes' native fisheries. Capable of growing to 4 feet in length and 100 pounds in weight, these carp -- there actually are three species, bighead, silver and black carp -- have the capability to take over ecosystems. According to the Natural Resources Defense Council, 90 percent of the lifeforms in some stretches of the Illinois River are Asian carp.

Filter feeders, Asian carp were introduced to the United States in the 1970s to help keep wastewater treatment facilities and aquaculture ponds clean. Floods in the 1990s enabled them to reach the Mississippi River, and they've been headed north ever since.

According to the Illinois Department of Natural Resources, "Bighead carp are capable of consuming 40 percent of their own body weight in food each day. Silver carp are smaller, but pose a greater danger to recreational users because of their tendency to jump out of the water when disturbed by boat motors. They have severely impacted fishing and recreation on the Illinois River. They can spawn multiple times during each season and quickly out-compete native species by disrupting the food chain everywhere they go."

Against this background, federal authorities on Friday acknowledged that an electric fence that was being counted on to prevent the carp from reaching Lake Michigan has failed, leaving carp just just one lock from being able to swim the final 25 miles to the lake, home to both Indiana Dunes and Sleeping Bear Sand Dunes national lakeshores. Groups worried about the carp reaching the lake have called for the immediate closure of all waterways and locks leading from Chicago into Lake Michigan.

At the Natural Resources Defense Council, Henry Henderson was not surprised by Friday's news.

“Today’s announcement that Asian carp have gotten past the electric fish fence is sobering, but predictable. The responsible federal and state agencies have known about this problem for 13 years, but have utterly failed to act with the urgency that this threat requires," said Mr. Henderson in a statement. "The prospect of 100-pound fish off of Oak Street Beach and leaping out at boaters in the Great Lakes should spur action that should have been undertaken years ago. We have seen how zebra and quagga mussels have literally transformed Lake Michigan, and I fear that the Asian carp could do far worse to the ecosystem.

“The Army Corps of Engineers needs to stop reacting to events, and get ahead of this problem with real solutions. Physical barriers in the waterways need to be put in place quickly, along with a clear plan to move aggressively toward closing off the Chicago Diversion and returning the ecological barriers that used to protect the Great Lakes from these threats. The only thing aggressive about the virtual fish fence has been its multi-million dollar price tag."

In perhaps a last-ditch effort to keep the carp out of Lake Michigan, in early December the Illinois Department of Natural Resource plans to poison the six miles of canal between the electric barrier fence and the Lockport Lock and Dam with rotenone, a fish-killing poison, to prevent the carp from breaching the barrier and traveling some 25 miles upstream to Lake Michigan.

If the carp are able to reach Lake Michigan and then spread to the other Great Lakes, it's feared that they'll quickly overwhelm the lakes' $7 billion sport fishery.

"Once in Lake Michigan, this invasive species could access many new tributaries connected to the Great Lakes," said the Illinois DNR. "These fish aggressively compete with native commercial and sport fish for food. They are well suited to the water temperature, food supply, and lack of predators of the Great Lakes and could quickly become the dominant species. Once in the lake, it would be very difficult to control them."

At the Alliance for the Great Lakes, acting president Joel Brammeier said, “We’ve missed every other opportunity to protect the lakes from these fish and their devastating legacy. It’s imperative we put the health of the Great Lakes -- the world’s largest surface freshwater system -- first.”

The carp are known, along with their appetites, for their aggressiveness. They've been known to leap out of the water and knock boaters into the water. National Park Service officials are aware of the threat the carp pose, and some units have been looking into ways to control the fish.

To gain some understanding of these fish, and the threat they pose, check out this video:


Why don't they just drag a large fishing net behind them to catch those damaging jumping carp? Looking at the pictures and films, this seems to be easy to accomplish. Also, if native fish are caught during this 'fishing' process, they can be released back into their water leaving the carp for disposal. It seems that this could be a new sport for fishing for those enthusiasts to see how many they can dispose of before there is irreversible damage done to our fresh water lakes, rivers and streams.

way too many dumb***** in charge is why things like this always happen. they should have never been allowed to be imported in the first place. just like pythons now in florida, foreign ships allowed to dump bilge in our waters, hence gobys and zebras, killer bees, fire ants, wild boars, and so on and so on. we need to start holding our so called leaders responsible for the policies they allow. jailings and executions will stop there ... moves and there greed for the almighty dollar.

They need to backfill every body of water in Chicago that connects to Lake Michigan and stop this disaster from happening. If they get into Lake Michigan the city of Chicago and the state of Illinois should be held financially responsible for all of the fisheries destruction created in the Great Lakes and all its tributaries by these Asian carp. They have the opportunity now to put an end to this and block it from happening. If they do nothing ... they should be legally held responsible. Should this occur we as a people are obligated to file suit in federal court against the city of Chicago and the state of Illinois for this deliberate destruction of the Great Lakes. Get off your hands people, the time to act is ... NOW !!!!!

Why Ill. , how were they freeed in the first place, these are the people to sue!!!

I've been advocating restoration of this water divide for YEARS; at first it was thought just a crackpot idea. Having majored in Geography in college, I can tell you the learned name for this portage is a "break-in-bulk" point. You have to unload the cargo, put it in parcels that can be transported across the divide, and then put it into boats/ships on the other side. With modern technology, we can graduate from canoes, to railroads and ships using some containerized cargo. Some cargo would be best transported by railroad from some more distant point, perhaps a port in Illinois, Indiana, or Wisconsin. Of course we can figure it out! Some bulk cargo just won't fit easily into shipping containers, so it would go in railroad cars already made for it. I just don't know the percentages of types of cargo which are transported across this breached water divide now. But part of the higher cost of respecting a restored water divide would go as income to many businesses which would benefit from the break-in-bulk point(s), and perhaps more use of other ports in this region, that have railroad connections. As for the "Sanitary" function of the S&S Canal, it's way past time we should have been converting to waterless toilets, both composting and incineration types. There's no justification for Chicago to be sending sewage discharge downstream. The non-domestic sewage must be treated on land thoroughly, so that any water effluent can be safely returned to the watersheds draining into Lake Michigan.

Great article Kurt. And interesting exchange from commenters---

As to where they came from and why the Asian carp have not been netted...there's just too many. The fish were brought to this country by southern fish farmers (not to eat---apparently, they are not considered an appropriate food item---but to keep fish pools clean of waste and algae) and escaped into the Mississippi River system via floods in the mid-90s. The carp have made their way up the Mississippi and into the Illinois River where they now make up 90% of the biomass in some parts of the river. That is startling---9 out of 10 living things (plant and animal life, big and small) are these fish. They simply take an ecosystem over, eating everything they can (and starving out anything they can't eat) to the tune of 40% of their body weight per day. There are fishing operations in the Illinois River hauling in tons of these fish every day---but that doesn't make a dent.

As the commenters point out, it is time to bring back the natural ecological barriers that separated the Great Lakes from the Mississippi River system. It is the only way to deal with this problem---and problems like it that will continue to swim towards the Lakes. There are studies out there that show a limited economic impact on the movement of goods, particularly when compared with the multi-billion dollar sport fishing industry on the Great Lakes and the more important healt of the system that accounts for a full 1/5 of the world's fresh water resources!

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