HAVANA – As scientists aboard a research boat activate an electric current, the calm Illinois River transforms into a roiling, silvery mass. Asian carp by the dozen hurtle from the water as if shot from a gun, soaring in graceful arcs before plunging beneath the surface with splashes resembling tiny geysers.

Water quality specialist Thad Cook grunts as a whopper belts him in the gut. His colleagues duck and dodge to avoid the missile-like fish that plop onto the deck, writhing madly until someone can grasp the slimy, slithering critters and heave them over the side.

It's like a scene from a Hitchcock movie – and indeed the flying carp have played villainous roles in many a YouTube video. Biologists, however, fear a different kind of horror story may be taking shape underwater: a war for survival between the aggressive Asian carp newcomers and native species important to people who catch fish for a living or fun.