From the Milwaukee Journal Sentinel:
Asian carp are on the move north and are likely within about 10 miles of an electric barrier designed to keep the giant filter feeders from invading the Great Lakes.
A new type of DNA testing indicated last week that silver carp had cleared one of the last physical obstacles standing between the fish and Lake Michigan, the Journal Sentinel has learned.
For several years, the northern migration of the silver carp, which can grow to 50 pounds, had stalled in a pool just above the Dresden Island Lock and Dam on the Des Plaines River southwest of Joliet, Ill. – about 20 miles downstream from the barrier.
Now it looks like they have cleared the upstream Brandon Road Lock and Dam, leaving only about 10 river miles and one navigational lock between the fish and the barrier – the last line of defense for the Great Lakes. Read more.