Great Lakes barrier may be too weak to stop carp

By Andrew Stern; editing by Vicki Allen
Fri Mar 25, 2011 CHICAGO (Reuters) – Voltage coursing through electrical barriers designed to keep invasive Asian carp out of the Great Lakes may need to be raised to keep out juvenile fish, U.S. officials said on Friday. The Army Corps of Engineers has mounted a multimillion-dollar effort to keep voracious Bighead and Silver Carp that now infest the Mississippi River Basin out of the Great Lakes, where scientists predict they could decimate the lakes’ $7 billion fishery. “The current barrier operating parameters are effective for fish as small as 5.4 inches in length,” the U.S. Army Corps of Engineers said in a news release. “The research published in this report suggests that slightly higher operating parameters than those currently in use may be necessary to immobilize all very small Asian carp, as small as 1.7 to 3.2 inches in length.” Juvenile carp can swim 37 miles by the time they reach 6 inches in length. Environmentalists and several state governments have fought to create a permanent ecological separation between the Mississippi River basin and the Great Lakes. …