A newly released scientific paper raises fresh concerns about the potential for grass carp to invade the Great Lakes and do significant damage. The fight to prevent Asian carp from reaching the lakes has focused mostly on bighead and silver carp, which could unravel food chains because they gobble huge amounts of plankton. Grass carp also come from Asia. They're used in many states to control aquatic weeds. But scientists say they wouldn't be good for the Great Lakes because they would eat plants needed for fish habitat. The paper by researchers at the University of Notre Dame and other institutions says evidence shows grass carp could survive in all five Great Lakes. They say it appears some of the prolific fish are evading efforts to keep them from reproducing.