PEORIA - There has been a major fish die-off in the Illinois River, but state conservation officials are far from worried about it. If anything, they wish it had been even worse - because the dying fish are invasive Asian carp.

Since Tuesday evening, thousands of dead carp have been seen floating down the river. Their bodies have been spotted from the Starved Rock area to as far downstream as Havana.

"From a biological standpoint this is a good thing," Joe Ferencak, Illinois Department of Natural Resources impoundment program manager, told the (LaSalle) News-Tribune.

Biologists say the die-off seems to have been widespread.

"We were trying to collect live fish for federal folks doing a study on (Asian carp) reproduction and we started seeing quite a few carcasses," biologist Wayne Herndon told the (Peoria) Journal Star.

Two species of Asian carp, the bighead and the silver, have become a major ecological problem in the Illinois River Valley, where they have been competing successfully for food and habitat with native species. They have also been the object of intensive efforts to keep them from spreading into the Great lakes.

The carp were imported by catfish farmers in the 1970s to remove algae and suspended matter out of catfish ponds in the South. Many of those farm ponds overflowed their banks during flooding in the early 1990s, releasing the Asian carp into the Mississippi River basin.

So far, the fish kill appears to have affected only Asian carp and a few carpsuckers.