City Takes Wait-And-See Approach to Invasion of Asian Carp

In his nine years as the manager of River Grove Harbor in Inver Grove Heights, Dennis Plante has seen floods, drought and high winds—and each time, the business he works for has survived.

Which is why Plante is relatively unconcerned over the latest curveball the river may throw his way: Asian carp.

In September, the Minnesota Department of Natural Resources took a series of water samples at multiple locations on the Mississippi and St. Croix Rivers—including tests near the Ford Dam on the Mississippi River.

The agency was hunting for DNA evidence that would indicate the presence of Asian carp, an invasive species that poses a significantly threat to the river's ecology and native fish species. The tests at the Ford Dam, which is upstream from Inver Grove Heights, came back positive, although commercial fishermen hired early this fall by the agency to search for the carp below the dam were unsuccessful.

Without finding a live fish, the DNR can't say for certain that Asian carp are in the river below the Ford Dam, or how large the population may be, according to Tim Schlagenhaft, the Mississippi River coordinator for the DNR.

Despite the warning signs, Inver Grove Heights Parks and Recreation Director Eric Carlson isn't too concerned by the possible appearance of the invasive species—simply because Inver Grove Heights isn't in a position to prevent Asian carp from establishing populations upstream, Carlson said.

City officials have adopted a wait-and-see approach, and plan to pass any fish sightings or reports along to the DNR, Carlson said. But for the most part local officials will rely on the DNR to do what it can to prevent the spread of Asian carp upriver. 

Even if silver and bighead carp do become well-established, Carlson doubts their presence will have an impact any of the city's parks or facilities near or on the river, including the Rock Island Swing Bridge—which juts hundreds of feet out into the river.

If anything, he speculated, the spectacle of silver carp leaping out of the river at the sound of a boat motor may draw people down to the pier to watch.

The effect on local waterfront businesses may be slightly more dramatic, Schlagenhaft said.

Asian carp, which feed on plankton, could outcompete many native fish species in the river if they reach a high enough concentration, Schlagenhaft said. That, in turn, may hurt recreational or commercial fishing along the river. The propensity of silver carp to jump out of the water may also discourage boaters from using the river, he added.

The DNR, Schlagenhaft said, is pushing to close the locks at either the Ford Dam or at St. Anthony Falls to prevent the carp from spreading further north. To view the DNR's action plan regarding Asian carp, click on the PDF file posted with this story.

But Plante says he's more concerned about the rising price of boat fuel than the presence of Asian carp.

“We're used to natural disasters down here," Plante said, laughing. "It’s just a new adventure, just something else to watch.”