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Invasive Asian carp on verge of entering Great Lakes

The views expressed are those of the author and are not necessarily those of Scientific American.

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Well that didn’t take long: Just six months after the U.S. Supreme Court turned down requests to close the locks between Chicago area waterways and Lake Michigan to stop the spread of invasive Asian carp the giant, voracious fish has almost made its way to the Great Lakes.

Last week, a one-meter-long, nine-kilogram bighead carp (pictured) was found in Lake Calumet, along the Chicago Area Waterway System (CAWS), just six miles from Lake Michigan. According to the Asian Carp Regional Coordinating Committee, this is the first carp that has been found in the CAWS above the U.S. Army Corps of Engineer’s Electric Barrier System, a system put in place to try to control the spread of the fish.

According to the U.S. Environmental Protection Agency, Asian bighead (Hypophthalmichthys nobilis) and silver (H. molitrix) carp were imported into the U.S. in the 1970s as a method for removing algae from catfish farms. But flooding in the 1990s overflowed farming ponds and sent the fish into the Mississippi River where they have managed to outcompete, outbreed and out-eat local species.

In response to last week’s discovery, several lawmakers are calling on the Obama administration to temporarily close the Chicago locks and come up with a permanent barrier to stop the piscine gate crashers’ further advance. “For the sake of the region’s economy and ecosystem, I urge you to take immediate action to stop the spread of this species into the Great Lakes and consider the possibility of permanent hydrological separation,” wrote Sen. Kirsten Gillibrand (D–N.Y.) in a letter to the U.S. Fish and Wildlife Service and other agencies.

Sen. Dick Durbin (D–Ill.) called the discovery of the carp in Lake Calumet a “game changer” and a “wake-up alarm.”

Henry Henderson, Midwest program director for the Natural Resources Defense Council, warns in his blog, “Like cockroaches skittering across a bathroom floor, when you net one Asian carp, you can bet that there are plenty more where that one came from.”

In January Michigan Gov. Jennifer Granholm (D) said in a prepared statement, “We cannot allow carp into the Great Lakes. It will destroy our Great Lakes fisheries, the economy.” The commercial fishing industry in the Great Lakes is worth more than $7 billion a year. But closing the locks to protect the Great Lakes creates a different set of economic headaches: They are vital to commercial shipping throughout the Great Lakes region.

Photo courtesy of the Asian Carp Regional Coordinating Committee

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  1. 1. hanmeng 4:46 pm 06/30/2010

    Their meat is absolutely delicious, according to Fisheries Biologist Duane Chapman.

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  2. 2. hotblack 5:38 pm 06/30/2010

    Better hope so, cause you can kiss Lake Michigans sturgeon & trout stocks goodbye.

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  3. 3. doug l 8:35 pm 06/30/2010

    How do we know that the Asian Carp will definitely destroy the sturgeon and trout stocks goodbye? I’m not an advocate of intentionally introducting exotics but these asian carp have been in other lake and river systems and not destroyed them. I am thinking this is another ‘sky is falling’ response to those who are thinking that conservation means returning to some ideal that may have existed in the past, though we aren’t even too sure of that. The GreatLakes now have coho salmon and alewives and various introduced species of invertebrates and has accomodated them. The lakes themselves are only a ten thousand years old and have been in a slow but steady change throughout their natural history. I too have read that these carp are very desirable food fish so perhaps this change will be beneficial and help to bring the Great Lakes back up to the level of productivity they were prior to the devastation that earlier commercial fishing did to them.

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  4. 4. treehugginconservative 10:39 pm 06/30/2010

    We know they will decimate native populations because that’s what they’ve been doing to every other system as they’ve traveled north. The great lakes are about to get a taste of what we deal with in South Florida. Diversity will plummet and exotic diseases will continue to plague the survivors. Good luck.

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  5. 5. Brick 11:28 pm 06/30/2010

    This is a case in which the downside risk is greater than the upside. The introduction of a species which has such a proven record of outcompeting previously isolated species is a process irreversible by human intervention. So if the conservationists are wrong, it’s inconvenient. If Doug L is wrong, how would he propose the damage be repaired?

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  6. 6. yt000 9:03 am 07/1/2010

    Just call them Malaysian Sea Bass and the price per pound will go through the roof as fancy restaurants try and stuff foodies full of this excellent local fare…local fishermen will laugh all the way to the bank.

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  7. 7. hotblack 12:43 pm 07/1/2010

    Yes, you can eat carp. You can also eat a goldfish. But, "desirable"? Sure, if you’re starving. If you already have a lake full of trout, replacing it with a lake full of carp is not an upward move, just because for a short while there will be more carp than there were trout. Even if you don’t care about anything but money, there are several entire industries that will be cost millions… not to mention the sportfishing industry, which is not small potatoes, and will completely die.

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  8. 8. SF 3:41 pm 07/1/2010

    @yt000 There are already people who are thinking about that. For instance, Louisianans now call the carp silverfin, people in the Bluegrass state call it Kentucky Tuna, and a chef in Chicago is calling it Shanghai Bass. Take a look at a blog post I wrote about Asian carp on "Restoration and Resilience", the coastal Louisiana blog at the Environmental Defense Fund:

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  9. 9. dcary3133 1:53 pm 07/2/2010

    We’ve managed to over-fish every other species we’ve hunted; why can’t we over-fish these carp? And if they’re not the tastiest of fish, I’m sure the cat and dog food industry would love to get their paws on them.

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  10. 10. BENDEERADER 10:38 am 07/5/2010


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  11. 11. Wayne Williamson 6:39 pm 07/6/2010

    i always thought carp were vegetarians…if so, they are prey for the lake trout and salmon…then again i use gold fish to eat the mosquito larva from our pond…

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  12. 12. marcus B 6:59 pm 09/20/2010

    It’s really hard to say exactly how the fish populations in the great lakes will fair after the introduction of these carp… However, It’s highly likely that these fish will have a seriously negative impact on many of great lake systems. They feed on the the base of the food chain (plankton) and grow very rapidly (due to eating LOTS of plankton), and crowd out other species. They also pose a serious hazard to navigation in rivers (just look at the youtube videos!!).

    Just what the great lakes need… another invasive species….

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  13. 13. marcus B 7:11 pm 09/20/2010

    Unfortunately, lake trout and these carp usually occupy different habitats. Therefore, it’s unlikely that carp would be a significant food source for lake trout. There are also carnivorous fish in the upper reaches of the Mississippi and associated tributaries, carp are still going strong in that system.

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  14. 14. Waukesha Parks 4:46 pm 07/24/2011

    For as long as I can remember carp have always been a nuisance in freshwater lakes, streams, and rivers. However, recent studies appear to show that the flesh from carp may actually be better for consumption than the more popular genus of freshwater fish.

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