Carp present an imminent threat to the Great Lakes

Carp present an imminent threat to the Great Lakes

If there’s a nuclear option for dealing with the Asian carp, now is the time to unleash it.

These fish, which escaped fish farms in the South and have made their way up the Mississippi, wreaking ecological havoc as they go, are dangerously close to invading the first of the Great Lakes, Lake Michigan.

And as Lake Michigan goes, so go the other lakes.

Last week, University of Notre Dame and Army Corps of Engineers scientists revealed that water samples taken from beyond an elaborate electric barrier on the Calumet-Saganashkee Canal showed evidence that the carp had breached the barrier. That puts them right outside Chicago and dangerously close to Lake Michigan.

Asian carp are prolific, large and voracious consumers of the plankton that provides the baseline for fresh water habitat and the other fish that live in it. They easily grow to 50 pounds and can reach 100. They’d be a fisherman’s dream, if they took the bait. But they don’t. They just cruise along, sucking in plankton — as much as 40 percent of their weight per day.

Just as the Great Lakes are making a comeback, and two months after Congress approved $400 million for cleaning up and restoring the Great Lakes, they face their latest and possibly greatest threat. The bill did include money for control of invasive species, but it may not be enough to deal with this threat.

Aggressive action

Immediate plans call for closing a section of the Chicago Sanitary and Ship Canal to all traffic next week during which a section of the waterway will be treated with rotenone, a poison that is toxic to fish, but not to other wildlife or people.

That sounds like a drastic action, poisoning a section of river, but it only goes to show how serious a threat the Asian carp is to the Great Lakes ecosystem. Maintenance work will be done on existing electric barriers, which send a shock through the water and presumably repel fish swimming up the canal toward the lake. And additional barriers are planned.

If Asian carp become established in the Great Lakes, they could cause a catastrophic decline in native fish species and severely damage the Great Lakes sport fishing industry, valued at $7 billion.

No one who knows anything about the potential threat is taking the Asian carp lightly. The Asian Carp Rapid Response Workgroup includes the Illinois Department of Natural Resources, U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, U.S. Coast Guard, USDA Animal and Plant Health Inspection Service, various Chicago departments, the Great Lakes Commission, Great Lakes Fishery Commission, International Joint Commission, and Wisconsin Sea Grant. Fishery management agencies from Indiana, Wisconsin, Michigan, Minnesota, Ohio, Pennsylvania and New York also provide support to the operation.

The Great Lakes are the largest single resource for the seven-state area bordering the lakes. Staving off this immediate threat from the invasive carp and then working to eliminate a fish that has no business in North American fresh waters is a daunting challenge, but one that must be met.

The Asian carp is just the latest in a long line of stories about the bad things that happen when nonnative animals and plants are brought into an area without considering the long-range consequences.