Editorial: Stopping true Asian carp invasion of Great Lakes calls for extraordinary measures, including poison

on November 24, 2009 at 12:52 PM, updated December 01, 2009 at 12:55 PM

Like some horror movie monster from the deep, Asian carp are moving ever-closer to Lake Michigan. Unlike beasts in film, however, the carp will wreak real ecological and economic damage if it is allowed in the Great Lakes.

New evidence shows the fish have breached an electronic barrier erected to keep them out of the big lakes. DNA tests found evidence of the fish north of the Chicago Sanitary and Ship Canal, about eight miles from Lake Michigan.

The threat is so urgent that extraordinary steps are merited. In this case, that entails dumping poison into the canal to kill the carp and other organisms while maintenance is done on a new electronic barrier. Allowing the carp to slip through while our defenses are down would be an irreversible mistake.

It will be up to the Environmental Protection Agency, the U.S. Army Corps of Engineers, the U.S. Coast Guard and state agencies to find longer-term and more effective solutions. Central to this task will be Cameron Davis, appointed in June by President Obama to coordinate the administration's many-agency effort to protect and clean up the Great Lakes.

The carp were imported to the United States in the 1970s from China and Siberia to act as biological vacuum cleaners for retention ponds and fish-breeding facilities. The same voracious appetite that made the fish so effective in that capacity turned them into a danger when, in the 1990s, flooding washed them into the Mississippi River. They have since moved toward Lake Michigan.

There are four distinct species of the carp -- bighead, silver, black and grass. The fish are prolific breeders, spawning many times in a season. They grow to as large as 110 pounds and four feet long. They consume up to 20 percent of their body weight in food every day. In addition, the fish jump out of the water in reaction to motion and noise, threatening to pummel anglers and others unlucky enough to be in their path. Last year, an Arkansas teenager was knocked unconscious and had his jaw broken by a jumping silver carp as the youngster was dragged behind a boat on an inner tube.

The carp are the latest wave in the invasive species threat that has ravaged the Great Lakes ecosystem and wrought billions of dollars in damage. Earlier invaders included the zebra and quagga mussels, the lamprey eel and others that can elbow out native species and damage water intake pipes and other infrastructure.

Even among these damaging organisms, Asian carp are a uniquely serious threat. The fish dominate ecosystems where they are introduced, disrupting the food chain by robbing other organisms of plankton. The Great Lakes are an ideal environment for the carp. The temperature is right, and no natural predators would threaten them. The carp could devastate the $7 billion Great Lakes fishing industry.

The immediate solution is to fill part of the Chicago canal with Rotenone, a poison drawn from tropical plant roots. Rotenone robs the waters of oxygen, killing fish. The operation along six miles of waterway is planned for early December. It's an extreme step, but one called for by the circumstances. The poison will be neutralized by another chemical before it heads downstream. The dead fish will be taken to a landfill.

The fish kill will buy time during the barrier maintenance project. In the long term, the Army Corps of Engineers and others should continue to experiment with the electronic barriers -- including a new one slated for operation next year -- and determine whether higher voltages are needed.

Right now, the Asian carp are in a relatively controlled space. If they're allowed in the open waters of the Great Lakes, stopping them will be impossible. That's a good argument for throwing everything we have at the problem.
