Asian carp have moved no closer to the Great Lakes during the past few years. They remain about 50 miles away. But they are spawning closer, and that's bad news.
"The bottom line is that the juvenile front is advancing, and made a big jump last year," said Joel Brammeier of the non-profit Alliance for the Great Lakes. "And we still don't have a permanent solution in place that's going to solve the problem."
That "big jump" was 90 miles.
Two electrical barriers and three locks and dams on the canal/river system serve as the final protection for Lake Michigan. Thus far, they have effectively blocked adult silver and bighead carp. But the smaller ones are much more likely to slip through in the wake of commercial barge traffic, which also can disrupt the effectiveness of the barriers.
"It seems like the wolves are at the door, and the door is still opening and closing," said Daniel O'Keefe of Michigan Sea Grant.
Meanwhile, a third electrical barrier is being constructed upstream of the other two, which are about 35 miles south of Lake Michigan. Intent is to make it more effective against juvenile fish, according to Charles Wooley, deputy director of the U.S. Fish and Wildlife Service's Great Lakes Region.
"There are no fish that are probing these electrical barriers on a daily basis," he added. "The closest these fish are is about 15 to 20 miles downstream, and that leading edge hasn't really changed much in the past five or six years."