The Obama administration is expanding its campaign to keep Asian carp out of the Great Lakes.
The federal government is already cooperating with states to build a network of barriers to keep the voracious jumping carp from Great Lakes waters.
Now, new research is underway on controlling carp with poisons, pheromones, or even removing the food they eat.
"And we're going to be looking at whether steel-hulled barges passing across electric barriers might be providing some protection for fish while they're in the area of the electric barrier, and could possibly be a way they're crossing the barrier," said John Goss, Asian Carp Director at the Council on Environmental Quality.
Goss said new tactics include getting more aggressive about inspecting bait shops.
"We're concerned that carp minnows could be in bait shops or could be transported as bait at fish processors, fish markets, and retail establishments," Goss said.
Early this month, an Illinois judge rejected a request from five states suing over carp, that Chicago area locks be closed immediately. The judge said the groups had not shown convincing evidence of harm.
This year the carp-control effort is costing nearly $50 million.