Doubts about Lake Calumet carp theory

CHICAGO, Aug. 15 (UPI) -- Some fisheries experts are questioning the theory that an Asian carp caught just 6 miles from Lake Michigan got there with human help.

The capture of the carp in Lake Calumet, Ill., earlier this month raised fears that an electrical fish barrier downstream from the lake was not stopping the invasive fish's migration toward the Great Lakes.

The agency in charge of countering the carp problem said a study of the captured fish indicated it could have spent most of its life in Lake Calumet, possibly brought there with intentional or unintentional help from people.

But some scientists say the analysis of the carp's ear bones, known as otoliths, was not concrete proof of its origins. "No otolith analysis can ever provide information about how a fish got from one environment to another," University of Notre Dame biologist David Lodge told the Journal Sentinel.

The debate has added to the controversy over the carp and the demands from Great Lakes states that the Chicago canal system locks be closed to head off the carp migration. Illinois has refused to do so because of its potential impact on shipping.