Nature

Published on November 20th, 2009 | by Dave Dempsey

2

Invasion of the Fish Snatchers?

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November 20th, 2009 by

Bighead carp are one of two non-native species of Asian carp causing widespread concern among Great Lakes advocates. The other is silver carp.

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Great Lakes advocates are calling it a “conservation emergency” now that non-native Asian carp have been detected within seven miles of Lake Michigan. They want an immediate closure of locks and gateways leading to the lake in a literally”last-ditch” attempt to keep the fish out.

The fear is that the giant fish will disrupt the valuable Great Lakes sport fishery by outcompeting species at the top of the Lake Michigan food web, consuming the forage fish the established species depend on — and like many of the other 180 non-native aquatic species already in the Great Lakes, causing general ecosystem disruption.

The disclosure that the carp are within a short swimming distance of Lake Michigan is inspiring recriminations among advocates and federal agencies. The U.S. Army Corps of Engineers is the prime target.  Charged with operating and maintaining an electric barrier in the Illinois River system, the Corps has appeared to shift responsibility for maintenance problems with the barrier.

The carp have been a YouTube sensation because of video showing them leaping into the water at the sound of a passing motor. The conservation coalition calls the fish ‘voracious filter feeders that can grow to more than 4 feet long, weigh up to 100 pounds and quickly dominate a body of water by gobbling up the same food that sustains native fish populations.”

Cam Davis, Great Lakes coordinator for the Obama Administration, cautions that the DNA evidence suggesting the carp are close to Michigan “is the best we have, and we believe it’s very accurate. But what we have not done is to find an actual carp body in these areas where sampling is telling us their genetic material may be. We still have not seen an actual carp show up.”

There is some disagreement about who introduced the fish to the Mississippi River system. EPA says catfish farmers imported them to control nuisance plant growth in aquaculture ponds. Others say state fish and wildlife agencies initiated the introduction. But there is agreement that the fish escaped the aquaculture facilities during floods in the 1990s and have been moving north ever since.

Photo credit:  U.S. Fish and Wildlife Service.

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About the Author

Dave Dempsey is a writer active in conservation for more than 25 years. A frequent freelance contributor and newsweekly columnist, Dave is the author of four award-winning books on the environment and a biography of Michigan’s longest-serving Governor, William Milliken. A native of Michigan who now lives in the Twin Cities metro in Minnesota, Dave served as environmental advisor to Michigan Governor James J. Blanchard from 1983-89. President Clinton appointed him to the Great Lakes Fishery Commission in 1994. Dave has also held numerous administrative, policy and consulting positions for nonprofit conservation and environmental organizations in Michigan and Minnesota. He was both policy director and executive director at the Michigan Environmental Council and Great Lakes policy consultant for Clean Water Action. Dave has a bachelor of arts degree from Western Michigan University and a master’s degree in natural resource development from Michigan State University, and has served as an adjunct university instructor at MSU in environmental policy.



  • Duane Chapman

    I don’t know if my earlier comment made it clear – I said “there may have been some ponds that flooded in the 93 flood” – but there is no record of that happening at all. If it did happen, it was not reported.

  • Duane Chapman

    Bighead and silver carp did NOT originally escape during flooding of the early 90s. The first silver carp was captured from the wild in 1972! Bigheads were abundant in the late 1980s. There may have been some ponds that flooded in the 93 flood, but the only reason there “is agreement” that this happened is because it sounds logical to the uninformed and that it has been so often repeated in the media that it is common (although probably incorrect) knowledge. There was a farm that flooded later, on the Osage River, but that was after the fish were already well established. The most logical reason for the escape of bighead and silver carp is carelessness, not the capriciousness of mother nature.

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