One of the electric fish barriers in Chicago. Source: U.S. Coast Guard.
Editor’s Note: It’s an Echo tradition to revisit one of our favorite holiday stories: Tim Campbell’s The Twelve Days of Aquatic Invasive Species Christmas.
Campbell rewrote the lyrics of the holiday tune for the Wisconsin Sea Grant in 2011. We’re publishing a new verse on each of the actual twelve days of Christmas.
On the first day of Christmas, a freighter sent to me..
A carp barrier in the city! — There is not only one electric barrier in Chicago, but three! One barrier is always on (usually the middle), while the other two are on standby to provide emergency backup or to be functional during periods of maintenance. The original barrier is closest to Lake Michigan and only generates a high-voltage field. The two newer barriers are a short distance downstream, and both generate a low-voltage and high-voltage field. The lower intensity field does a better job of making fish uncomfortable, while the higher intensity field is more likely to stun the fish. The dual fields have made it so no radio tagged fish involved in an U.S. Army Corps of Engineers study have traversed the barriers in an upstream direction. The barriers should prove to be effective at preventing the silver and bighead carp from entering the Great Lakes until a permanent solution can be found..