Holy carp! Exotic fish are costing the U.S.’s limping economy boatloads of money as they launch a full-scale invasion of our waterways. The Washington Post reports that invasive exotic species, such as the Asian silver and bighead carp, cause environmental losses and damages of nearly $120 billion a year.

As seen yesterday in MNN's Daily Briefing, “The invasion of Asian carp up the Mississippi River and into the Great Lakes is one recent example — putting the region's $7 billion-a-year fishing industry at risk, and leading to a Supreme Court showdown between Michigan and Illinois — but almost no part of the country is safe from alien species infiltrating our borders.”

The problem has become so pressing that a team of scientists led by the University of Notre Dame has gotten involved. The researchers revealed yesterday that the silver carp are dominating parts of the Mississippi River. The Washington Post says, “The federal government had spent $22 million on electric barriers in the Chicago Sanitary and Ship Canal to keep carp out, but it clearly wasn't enough. An additional $33 million is going into the effort next year.”

Six Great Lakes states and the Canadian province of Ontario are fighting hard in an effort to persuade the U.S. Supreme Court to shut down two major locks to hopefully halt the spread of the Asian carp. The Army Corps of Engineers says it’s still too early to resort to such drastic actions.

"It sometimes takes dramatic evidence to bring public attention to something that's been a problem for some time," said Tom Strickland, Interior's assistant secretary for fish and wildlife and parks.

Why are these invasive carp causing such a problem? In the 1970s, catfish farmers in the South imported them from China to help keep their ponds free of algae. Everything was peachy keen until many carp escaped their ponds during flooding and invaded native waters. Their voracious appetites threaten the Midwest’s $7 billion fishing industry. Sam Hamilton, director of the Fish and Wildlife Service, said exotic species are "probably the single greatest threat in our country to our native wildlife."

Unfortunately, there's no agreement on a solution. Illinois officials argue that shutting down locks to control the problem could “have a devastating effect” on their economy. Meanwhile, Michigan Attorney General Mike Cox cites the Army Corps of Engineer’s statement that, "The prevention of an interbasin transfer of bighead and silver carp from the Illinois River to Lake Michigan is paramount in avoiding ecologic and economic disaster."

Phil Moy, a fisheries and invasive species specialist at the University of Wisconsin Sea Grant Institute, thinks keeping carp numbers low —however that is accomplished — is just a Band-Aid on a gaping wound. He says, “We've got to move towards this ecological or hydrological separation.”

Also on MNN:

42 tons of poison to be dumped on island to eradicate rats.

Invasive exotic animals costing U.S. billions of dollars
Pythons, Asian carp, and other invasive exotic plants and animals quickly becoming one of the most expensive problems facing the U.S. government.