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Fish Fence Fail?

By JoshMogerman in News on Dec 29, 2013 9:00PM

Asian Carp = Invasive Species [jmogs]

It is the last line of defense to fend off what might be the most infamous infestation Chicago has ever seen. But the electric barrier built to keep Asian carp out of Lake Michigan may not be as stout as advertised.

That’s the troubling takeaway from a new Army Corps pf Engineers assessment that found the virtual fish fence on the Chicago Sanitary and Ship Canal near Romeoville to be…well…leaky.

Think of those invisible fences designed to keep dogs in their suburban yards. That’s what the Corps has been banking on to keep carp out of Chicago’s Waterway System and Lake Michigan.

With the clock ticking on the famous fishes’ advance, this week’s report confirmed fears held by many about the barrier’s effectiveness, outlining an array of spectacular weaknesses. The electric barrier is intended to rebuff the famous fish below the water while allowing boats and goods to move unabated on the surface.

Alas, the barges crossing the canal are reportedly sucking fish through the electrified waters, thus weakening the charge enough that the fish can actually swim through. (A sonar camera showed schools of fish swimming past in 61 percent of their video samples).

The barrier already had a suspect record. Its charge was not initially strong enough to repulse small fish and at least one power outage left the ramparts wide open for the carp.

When the Chicago River was reversed, the connection between the Mississippi River System and Great Lakes made the waters in our town a potential highway of transmission for dozens of invasive species queued up to move between the ecosystems on both sides of the barrier—leaving two of North America’s most important freshwater ecosystems at risk.

The timing of this news could not be worse for the Corps, as it is set to drop a report, mandated by Congress, on potential solutions for the carp crisis in the New Year.

The Detroit Free Press has been following the process closely:

The Army Corps of Engineers says its study — years in the making and due Jan. 6 — will outline options for controlling the spread of invasive species between the Mississippi River basin and the Great Lakes, but stops short of choosing among them. Officials instead say the report is intended to aid “more educated decision making” as to next steps.

Despite worries that the species collectively known as Asian carp may have already breached electric barriers in Chicago waterways or otherwise reached the Great Lakes, the Corps seems set on letting Congress and the public decide among the options, any of which could cost billions and set off regional squabbling.

The Corps has said its report — which is expected to include eight options — complies with all the legal requirements set forth by Congress and analyzes, even if it does not outright recommend, physical separation.

Expect to hear plenty more carp crap in the coming weeks—but probably less about the effectiveness of the electric barrier as a long-term solution. The new report has likely zapped its support.