CHICAGO (AP) – A three-day sweep of Chicago’s Lake Calumet turned up no sign of Asian carp, though DNA from the invasive fish has been found repeatedly in the waterway not far from Lake Michigan.

Authorities are trying to prevent the plankton-gobbling carp from reaching the Great Lakes.

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Three consecutive rounds of sampling of Lake Calumet turned up genetic material from bighead or silver carp.

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Crews used nets to drag six miles of the lake last Wednesday through Friday, with no sign of any Asian carp.

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