Wednesday, March 28, 2012

Years-long Efforts to Kill off Asian Carp Have Been Met with Limited Success

In the fight against Asian carp, humans have long struggled to deter their formidable foe.

Large, prolific and incredibly adaptable, silver and bighead carp have endured netting, electrocution, poisoning and even a public relations campaign to recast the scorned filter-feeder as a catch-of-the-day delicacy fitting for the finest Chicago restaurants.

An electric barrier erected in the Chicago Sanitary and Ship Canal is now the only thing standing between the carp and Lake Michigan, where some fear the carp may destroy the fragile Great Lakes ecosystem.

So in recent years, federal and state governments have decided to re-energize their carp-fighting campaigns.

Beyond the Asian carp bio-bullet, new efforts include an underwater carp camera, fine mesh nets intended to snare larvae and a large water gun that creates a barrier by emitting sound waves under water. To lure the carp to their deaths, scientists are also working on an enticing buffet of female carp urine containing sex pheromones and highly concentrated algae.

"I think we actually have a fighting chance," said Leon Carl, regional executive for theU.S. Geological Survey's Midwest area.

Scientists don't want to stop at Asian carp either. They are now working to develop a particle that could deliver a toxin to zebra mussels.

"We are looking at this as a production line," Carl said.

Although he acknowledged that there are potential hazards to wading into such new technological waters, Carl stressed that the payoff could be huge if they are able to selectively kill invasive species.

"You are risking the money and the fact that you might fail, but if you succeed, the results are going to be very, very valuable," Carl said.

A study by a coalition of Great Lakes states and cities has also explored a more controversial solution: Permanently cut the fish off from Lake Michigan by using sheet pile or impermeable land bridges that would effectively re-reverse the flow of the Chicago River.

The multibillion-dollar plan proposed three options that would be rolled out in multiple stages over the next several decades. A 2010 lawsuit by five Great Lakes states that is pending in U.S. District Court is also seeking to close locks in the Chicago area.

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