Asian Carp: Great Lakes Ecosystem Hanging in Balance

Below the water’s surface lurks danger. A voraciously monstrous creature devours nearly half its body-weight each day in an attempt to cure its insatiable appetite. An unsuspecting boater enters the territory, and the beast breaches the water, violently hurling itself through the air toward the boat’s startled and horrified occupant.

Sound like another creature has risen from the Black Lagoon? If only it was so, but this creature is not fictional. Last February, I wrote about the Emerald Ash Borer’s destruction of millions of our country’s native ash trees, and now there’s another invasive species making headlines as it threatens to invade the Great Lakes Region.

It’s the Asian Carp, and it has the ability to quickly dominate every waterbody it enters … and it’s about to enter the largest body of freshwater in the world. I first heard about Asian Carp a couple of months ago when I read about a massive fish kill planned by the Illinois Department of Natural Resources. The kill was to take place when the electrical barrier in the Chicago Sanitary and Ship Canal was shut down for routine maintenance. Both the barrier and the kill are efforts to keep the fish out of Lake Michigan.

An electrical fish barrier – the world’s largest, designed to keep fish from the world’s largest freshwater supply? Planned massive fish kills? Asian carp? Call it a case of being unaware until it hits close to home, but I had no idea these things existed.

The Asian carp though, have been in this country since the sixties when they were brought to Arkansas by the U.S. Fish and Wildlife Service as a biological control for aquatic weeds, and for use as pond cleaners in fish farms. Though they may have escaped earlier, it’s thought the Mississippi flooding in 1990 escalated the problem. Because the fish are prolific breeders, they are now the dominant species in many parts of the Mississippi, Tennessee, Ohio, Missouri, Illinois, Columbia and Platte Rivers, and their tributaries, making up to 97 percent percent of the fish population in areas of heavy infestation. There are two electrical barriers which operate much in the same way as do electrical livestock fences. They are considered the last line of defense between the Mississippi River Basin and the Great Lakes Basin, but must be shut down periodically for maintenance.

Native to China, Russia, and Vietnam, four species are lumped under the generic term “Asian carp.” All four species – the black, grass, bighead and silver carp – have no known predators, and can quickly deplete the food supply of other fish species. Feeding on plankton, they consume up to 40 percent of their body weight, effectively starving out other fish. The effects eventually make its way up the food chain so that scientists fear even the bigger game fish – sturgeon, salmon and trout – may become endangered.

The biggest threat comes from the bighead and silver species. The bighead – a fish without a stomach – constantly eats, growing to lengths of 4 feet, and weighing in at 85 to 100 pounds. It is an eating, reproducing machine. The smaller silver carp, weighing a mere 50 pounds, is a danger to boaters, jet-skiers and other recreational water vehicles, as it has a tendency to leap from the water when disturbed, causing broken bones and other serious injuries to humans unfortunate enough to get hit by the airborne fish. Full of “free-floating” bones, the fish are considered useless commercially for human consumption.

I respect Lake Michigan; I feel lucky to live on her shoreline and would not dream of living anywhere else. I hate to think how the carp will destroy the lake I love. But the carp problem goes far deeper than do the beautiful waters of the lake. If the fish make it into the Lake Michigan, the estimated dollar amount impact is between 4.5 and 7 billion to commercial fishing and recreation industries … which does not figure the impact they’ll have on the ecosystem. And it doesn’t stop there. Once they’ve gained entry into the Great Lakes, speculation says they’ll eventually infest Canada’s river system, and possibly enter our eastern states via the St. Lawrence and Hudson rivers.

Michigan filed lawsuit with the Supreme Court, with the backing of Indiana, Ohio, Minnesota, New York, Pennsylvania, and Wisconsin, in an attempt to force the closing of the Chicago Sanitary and Ship Canal. The man-made canal, called one of the greatest engineering feats of the 20th century, is the only link between the Mississippi River Basin and the Great Lakes.

It’s thought that closing the canal would halt the Asian carp and any other invasive species from entering the Great Lakes, and is critical for preservation and restoration of the lakes. Quoted in USA Today, Marc Gaden of the Great Lakes Fishery Commission, jointly operated by the United States and Canada, says “We have to take care of this problem permanently. We need pure biological separation between the Mississippi River basin and the Great Lakes basin …We don’t have time to wait … this is an emergency.”

My gut-reaction is to close the canal, and do it immediately. But the solution is not so simple. I live on the Michigan side of the lake; Chicagoans view it from a different perspective. Forcing the canal’s closing would mean a loss of billions of dollars in revenue from Chicago’s fishing, shipping, and tourist industries.

In late January, the Supreme Court rejected Michigan’s suit, citing shipping loss and the fear of Chicago flooding as reasons. The same day Chicago shippers and fishermen rejoiced the court’s decision, carp DNA was found in Lake Michigan – though the presence of DNA does not mean the carp have actually entered the lake yet. The first day of a mid-February two week fishing expedition on the canal yielded no actual carp, the cold winter waters possibly keeping them inactive and on the bottom of the canal.

The debate still rages at public hearings in both Michigan and Chicago. A February 17th article in the Milwaukee, Wisconsin, Journal Sentinel, quotes Robert Agra, a Chicago cruise line operator as saying, “Closing the locks in the Chicago area will not stop the carp, but it will destroy the Chicago tour boat industry.”

The rebuttal from the environmental group, Clean Water Action, is that closing the lock is the best option right now. “Protecting the narrow shipping interests cannot outweigh protecting the Great Lakes from an economic and ecologic disaster,” says Susan Harley, spokeswoman for the group.

It deeply saddens me to know the beauty and ecology of one of our greatest natural resources hangs in the balance while humans try to decide how to correct yet another problem we, ourselves, have created. What’s your opinion?

For a dramatic look at Asian carp on the Mississippi and its tributaries, check out this two-part mini-documentary on YouTube. Filmed in 2006, the videos, totaling about 15 minutes combined, give a good perspective of the destruction this invasive species has caused.

Asian Carp Invasion Part I

Asian Carp Invasion Part II

(Photo of silver carp courtesy of the Illinois River Biological Station)

  • Published on Feb 26, 2010
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