Meet the Fish Poised to Invade Fridley Waters: Asian Carp

They weigh 100 or more pounds, fly through the air and can knock out a boat's windshield—or a person. And by all accounts, Asian carp are headed Fridley's way.

The leading indicator of the coming invasion is Asian carp DNA in the Mississippi River. Scientists have found it in "Pool 2" (between Hastings and St. Paul's Ford Dam), the St. Paul Pioneer Press reported—and as far upriver as the Coon Rapids Dam:

As the carp spread northward, Minnesota officials aren't sure where—or how—to stop them.

The spread can be slowed at locks and dams, according to Whitney Clark, director of Friends of the Mississippi. It might be possible to keep them away with underwater sounds, bubbles or electric current.

But Clark said the fish eventually can get past most barriers.

Another option? Eliminate recreational boating from the lock and dams.

In some locations, that would reduce lock openings by 80 percent, slashing the opportunities for the carp to swim upstream.

Such measures would slow their spread, Clark said, but not stop it.

Early warning signs are popping up in the Mississippi River. The DNA of the fish has already been detected in Pool 2. In December, it was found above the dam in Coon Rapids.

That doesn't necessarily mean large numbers of carp are present—yet. The carp population needs to expand to a certain point before the numbers explode.

"There have to be enough males putting out enough pheromones to get the females to reproduce," [Mississippi National River and Recreational Area for the National Park Service Manager John] Anfinson said. "They need to reach critical mass."

If the population can be minimized, then that tipping point might not be reached.

But if they do become established, Asian carp can move from one body of water to another by way of rivers and streams. The Chicago area recently got the bad news that DNA of the invasive species was in Lake Calumet, acccording to the Detroit Free Press.

The Pioneer Press also reported about apparent problems with false-positives in testing for Asian carp DNA. Areas in Minnesota where scientists found DNA are due for a new round of sampling this year, the newspaper said in a blog post.

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