Asian Carp Seen As 'Ultimate Invader'

September 25, 2007

Release from: Steve Tarter
Peoria Journal Star (Illinois)

PEORIA - Among the topics to be discussed at next week's conference on the Illinois River at the Holiday Inn City Centre is a forum on "the ultimate invader."

The invader, of course, is the much-publicized Asian carp, prominently featured in newspaper and television stories as a big fish that will fling itself out of the river, bouncing off boaters and water skiers.

But Asian carp are much more than a media darling: They threatens the aquatic life of the river.

The problem is their numbers. Fish reproduce rapidly, with females carrying up to 2 million eggs, said Bob Frazee, University of Illinois educator and conference co-chairman.

"We've probably got millions of fish out here, and they spawn a couple of times a year," said Greg Sass, director of the Illinois River Biological Station and Illinois Natural History Survey in Havana.

Introduced to the southern United States in the early 1970s to control algae growth in catfish farms, floods washed Asian carp into the Mississippi River in the 1980s. They migrated up the Illinois River in the 1990s, he said.

The problem is fish that can reach 80 pounds or more feed at the bottom of the food chain, on plankton, the same food source required by other fish.

"Bass, crappie and other native fish also rely on zoo plankton. As a result of the competition (for food), we may already be seeing a decrease in the size of buffalo, another native fish," said Sass.

Because fish feed virtually all the time, Asian carp remove a lot of plankton from the river, said fishery biologist Greg Conover with the National Fish & Wildlife Conservation Office in Carterville. "That could cause changes in the food web," he said.

Asian carp grow so quickly - 12 inches in a year - that they quickly outgrow possible predators, he said.

The river conference seminar will look into ways to reduce the number of the fish in the river, said Conover. While discussion has been raised over possible commercial uses for the carp - as pet food, fertilizer or possible export, Conover warned the river has proved to be a difficult environment for such efforts.

"Commercial fishing efforts would need to harvest a set number of metric tons on a regular basis. But the fish are spread out seasonally, and the river can be a difficult area to collect fish in," he said.

"Any business that uses these fish must also develop an exit strategy, allowing for an alternative (to harvesting carp)," said Conover.

A multi-pronged plan of attack similar to that fashioned to fend off threat of the sea lamprey in the Great Lakes is needed, he said.

Asian carp pose a real threat to the Great Lakes, said Conver. "They're within 50 miles on the Illinois River. They could have a huge effect on the economy of the Great Lakes," he said.

The river conference runs Oct. 2-4.