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grass carp

USGS

TRAVERSE CITY, Mich. (AP) - Scientists say grass carp have invaded three of the Great Lakes and pose a significant environmental risk. But they say there's still time to prevent them from becoming established.

Grass carp are among four Asian carp species threatening to reach the lakes, where they could upend ecological systems and compete with native fish for food.

A U.S.-Canadian assessment released Friday says grass carp have been found in Lakes Erie, Michigan and Ontario. At least some are reproducing, although most are believed to be sterile.