Invasive Fish Could Threaten Watershed

August 23, 2005

Release from: Jesse Garza
Milwaukee journal Sentinel

Asian big head carp, an invasive species of fish that was discovered this week in the Rock River at Rockford, Ill., could now pose a threat to that watershed in Wisconsin, natural resources officials in both states said Tuesday.

Three Asian carps, which compete with native fish and hurt habitat, have been caught near the Rockford Dam, said Dan Sallee, a spokesman for the Illinois Department of Natural Resources.

Officials at the Wisconsin Department of Natural Resources have been monitoring Wisconsin rivers for the Asian big head and say it's only a matter of time before the fish is found in the state.

"We're pretty much expecting them," said Mike Staggs, director of fisheries at the Wisconsin DNR.

"How far and how quickly they move remains to be seen."

Sallee said it is the first time the species has been found in the Illinois portion of the Rock before it feeds into the Mississippi River.

"If they made it all the way to the (Fordam Dam) there's no reason they couldn't make it to Wisconsin," Sallee said, noting that the river is dammed at five points between Rockford and the Mississippi River.

"If five dams weren't enough of a barrier, there's no reason they won't make it to Wisconsin."

The 285-mile Rock River begins in southwest Fond du Lac County and drains the Horicon Marsh, which could be threatened by the fish if they continue to make their way upstream.

The Rock flows south into the Mississippi River below Rock Island, Ill.

Asian carp eat plankton and have the potential to wreak havoc higher up the food chain.

"Where we have seen them come in (in Illinois), they have had major impacts on other fish," Staggs said.

If the fish made it up to the Horicon Marsh, their eating habits most likely would make a serious impact on native fish communities, such as northern pike, panfish, blue gills and bass, he said.

They consume the same food as native fish and tend to force those fish out, Staggs said.

"Wherever these carp have expanded, they tend to become the dominant fish species," he said.

"These fish are migratory," Staggs said. "We have had confirmed reports of them in the Mississippi (River) in Wisconsin.

"There's no reason not to expect them to come up the Rock River."

Another invasive species, the giant snakehead, a voracious, predatory fish that can wriggle short distances on land, was discovered in the Rock River south of Janesville in 2003.

State wildlife officials have been concerned about people releasing the snakehead inWisconsin.

A fisherman caught an Asian carp on Sunday below Rockford's Fordam Dam that weighed between seven and eight pounds and was 22 inches long, Sallee said.

The fish could have come upstream from the Mississippi or have been dumped from an angler's bait bucket when it was young, Sallee said. It could also have been released into the river as an adult, he said.

The Mississippi and Illinois rivers have established big head populations, which entered those waterways after escaping fish farms during flooding.