MILWAUKEE, Nov. 27 (UPI) -- Invasive Asian carp pose a dire threat to the Great Lakes' ecosystem but may not be able to breed in open lake waters, a U.S. expert on the fish said.
"If a few fish get into the Great Lakes, it's not game over," said Duane Chapman, a U.S. Geological Survey researcher who studies the food-hogging fish on the heavily infested Missouri River.
Researchers believe the big fish have breached an electric barrier on the Chicago Sanitary and Ship Canal, a link between Lake Michigan and the Mississippi River basin.
To breed, enough fish have to enter the lake to find each other and then find a place to spawn. Open waters present a problem because fertilized Asian carp eggs require long free-flowing rivers.
Without a current to keep the eggs afloat, the eggs sink to the bottom and die, Chapman told the Milwaukee Journal Sentinel in a story published Friday.